tag:blogger.com,1999:blog-5351772248369156172024-03-10T20:23:28.008-07:00TDK-Lambda Americas BlogKnowledge is Power. Power is TDK-Lambda.Power Guyhttp://www.blogger.com/profile/15282245011253622251noreply@blogger.comBlogger113125tag:blogger.com,1999:blog-535177224836915617.post-84827295044591906822021-12-31T13:39:00.014-08:002022-09-15T12:35:45.123-07:00What are Bi-polar power supplies?<p> <span face="Arial, sans-serif">Most power
supplies are “unipolar”, capable of suppling a positive voltage and current
only (Figure 1).</span></p>
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<p align="center" class="MsoNormal" style="text-align: center;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEgaGqpSFl5SvlQDns6QRRusSqTMDf5AgFLwxa535tjfKf7inRgAf8Z9hGYjKvaLrw7DpwjacWZ7pGRw3yMbmLUy24yegAdDfsPlnypvaRIBaUzlbJCM8F0i-6fT9ET-Dq6_k_Ehv49R8Xn4oD9pI5wCb55TIgVzNVGLIv5zBXtkY9FZDdhIQKjKOJFqoA=s2013" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1607" data-original-width="2013" height="255" src="https://blogger.googleusercontent.com/img/a/AVvXsEgaGqpSFl5SvlQDns6QRRusSqTMDf5AgFLwxa535tjfKf7inRgAf8Z9hGYjKvaLrw7DpwjacWZ7pGRw3yMbmLUy24yegAdDfsPlnypvaRIBaUzlbJCM8F0i-6fT9ET-Dq6_k_Ehv49R8Xn4oD9pI5wCb55TIgVzNVGLIv5zBXtkY9FZDdhIQKjKOJFqoA=s320" width="320" /></a></div><p></p><p align="center" class="MsoNormal" style="text-align: center;"><span face=""Arial",sans-serif">Figure 1: Single quadrant unipolar power
supply<o:p></o:p></span></p>
<p class="MsoNormal"><span face=""Arial",sans-serif">In some applications
the load may need the power source to provide a positive or a negative output
voltage. One application for this would be a DC motor, applying a positive
voltage would make it rotate clockwise and a negative voltage counterclockwise.<o:p></o:p></span></p>
<p class="MsoNormal"><span face=""Arial",sans-serif">One could use a
bipolar power supply (Figure 2), transitioning seamlessly between providing
a positive or negative voltage from a single pair of output terminals.<o:p></o:p></span></p>
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<p align="center" class="MsoNormal" style="text-align: center;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEgOsxd4xcYNi7yMcgV-ruzB5qUUu79nQVhu6IjX5IZ-cFcEDkzDNYXOgjbeSx0ug11OUpFq0Pl_UMWAfbKjcjsoJY6dUV4DzcfKKVfbByIq9G0bzvdRAvhQ11kVxgvh626YabzDGPCxHOrgEocBXeWN4wlzj9o18VmiXfA5GoSNZRTMyUU0Lg-QyE0x-g=s2013" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1607" data-original-width="2013" height="255" src="https://blogger.googleusercontent.com/img/a/AVvXsEgOsxd4xcYNi7yMcgV-ruzB5qUUu79nQVhu6IjX5IZ-cFcEDkzDNYXOgjbeSx0ug11OUpFq0Pl_UMWAfbKjcjsoJY6dUV4DzcfKKVfbByIq9G0bzvdRAvhQ11kVxgvh626YabzDGPCxHOrgEocBXeWN4wlzj9o18VmiXfA5GoSNZRTMyUU0Lg-QyE0x-g=s320" width="320" /></a></div><p></p><p align="center" class="MsoNormal" style="text-align: center;"><span face=""Arial",sans-serif">Figure 2: Dual quadrant bipolar power
supply</span></p><p class="MsoNormal"><span face=""Arial",sans-serif">As these ty<span style="font-family: inherit;">pes
of power supplies are complex and do not have the economy of scale of a
unipolar, they are usually more expensive and ni</span>che. </span><span face="Arial, sans-serif" style="font-size: 11pt;">The term “bipolar” can also refer to four-quadrant power supplies which
can source and sink power (Figure 3).</span></p><p align="center" class="MsoNormal" style="text-align: center;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEhvvGxhD5cbBzvL0klPninXAKEjXyG_dNRquefwzDG_ixBfW551SuShj02m3gctf6HIkpJ0zyrQR9OmOnmY1173LAWkJXqm5GC4QxnziyoTpcCxUCE7AgfmnTENWiOd-rMwEmhKmtAcN9PSEkFHWmJS0foveMpckrBp9Q6XKvfXAYn0zs11rsv3EgkPuA=s2013" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1607" data-original-width="2013" height="255" src="https://blogger.googleusercontent.com/img/a/AVvXsEhvvGxhD5cbBzvL0klPninXAKEjXyG_dNRquefwzDG_ixBfW551SuShj02m3gctf6HIkpJ0zyrQR9OmOnmY1173LAWkJXqm5GC4QxnziyoTpcCxUCE7AgfmnTENWiOd-rMwEmhKmtAcN9PSEkFHWmJS0foveMpckrBp9Q6XKvfXAYn0zs11rsv3EgkPuA=s320" width="320" /></a></div><br /><span style="font-family: inherit;"><br /></span><p></p><p align="center" class="MsoNormal" style="text-align: center;"><span style="font-family: inherit;">Figure 3: Four-quadrant bipolar power
supply</span><span face="Arial, sans-serif"><o:p></o:p></span></p><p class="MsoNormal">The simplest
way is to buy a power supply with a polarity reversal switch. In the case of
the <a href="https://www.us.lambda.tdk.com/products/high-voltage-power/high-voltage-programmable-dc/phv.html" target="_blank">TDK-Lambda PHV</a> series of programmable high voltage power supplies, this is
an optional feature. It can be changed electronically for voltages up to 35kV
and manually at up to 65kV. One drawback is that the power supply may have to
be turned off during the change which will extend test times.</p><p class="MsoNormal" style="text-align: center;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEggy5be6nS2-esuA-0BsDXQqiGrMVYqQf5TOqIFSPL8Y9ZL42ZShIE9pGf0Wv2iZmr-zAku1Tv2QfVHGu6RiAFD8GATj0ICJ1S2owTaQgbUyRKnpciN_ux2zfGq49MTd3JaqW3u-bOiZyF8PX9-oA6YyFQBYA2YcOg0ByaSJV5-J-1W5XAZQaZfqxTeUQ=s838" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="515" data-original-width="838" height="197" src="https://blogger.googleusercontent.com/img/a/AVvXsEggy5be6nS2-esuA-0BsDXQqiGrMVYqQf5TOqIFSPL8Y9ZL42ZShIE9pGf0Wv2iZmr-zAku1Tv2QfVHGu6RiAFD8GATj0ICJ1S2owTaQgbUyRKnpciN_ux2zfGq49MTd3JaqW3u-bOiZyF8PX9-oA6YyFQBYA2YcOg0ByaSJV5-J-1W5XAZQaZfqxTeUQ=s320" width="320" /></a></div><br /><span face=""Arial",sans-serif"><br /></span><p></p><p class="MsoNormal" style="text-align: center;"><span face=""Arial",sans-serif">TDK-Lambda PHV power supply</span></p>
<p class="MsoNormal"><span style="font-family: inherit;"><span face=""Arial",sans-serif">An alternate way is to use polarity changing relays. TDK-Lambda’s <a href="https://www.us.lambda.tdk.com/products/programmable-power/genesys-plus.html" target="_blank">Genesys+</a> and <a href="https://product.tdk.com/en/power/zplus" target="_blank">Z+ series</a>
of programmable power supplies have two programmable terminals. These can be
electronically programmed to active relays as shown in Figure 4. </span>With the relays off, a positive voltage will be provided to the load and
when the relays are turned on, a negative voltage will be applied. Note that if
remote sense is being used (+s and -s), those connections will have to be
changed too. The output will have to be disabled during the change-over, again extending test times.</span></p>
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<p align="center" class="MsoNormal" style="text-align: center;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEgJ4q1RiBIpOhA5KXmANpgnRG14y92i22v-L7TG8driTZlsBlosN3N7GElOT_3pKS7ZtJLnPLUfSA87Yy7je_xzLizUDusPlkuZkr29rgP0HteCtSiyVssF0urXSmru2PC30-EQ4hvmxy6p0_DOdBghnXd6T0s6-zkgLwPuZ8kKVaSBYLilSeD9JmbuTg=s672" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="287" data-original-width="672" height="213" src="https://blogger.googleusercontent.com/img/a/AVvXsEgJ4q1RiBIpOhA5KXmANpgnRG14y92i22v-L7TG8driTZlsBlosN3N7GElOT_3pKS7ZtJLnPLUfSA87Yy7je_xzLizUDusPlkuZkr29rgP0HteCtSiyVssF0urXSmru2PC30-EQ4hvmxy6p0_DOdBghnXd6T0s6-zkgLwPuZ8kKVaSBYLilSeD9JmbuTg=w497-h213" width="497" /></a></div><span face="Arial, sans-serif"><p align="center" class="MsoNormal" style="text-align: center;">Figure 4: Using relays to change the polarity
of the power supply voltage</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEi6ewWI7sw4BHcXup1SqD7rIYoiH32Mz982Cam-shtAEO7wFs2-vfEss-bwtsCV_umQX18kVPqyTz1L_z_EX8O-w3yTKCyZSbwjb-qteoBuwCP1ZTkIo98wXnMWfEEGBWy2rt4g00m3zwJgs6LeLS-KhYrFJTwhhW-DQsYr4aTOJC2blTnMdq9URPKKgg=s1134" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="116" data-original-width="1134" height="48" src="https://blogger.googleusercontent.com/img/a/AVvXsEi6ewWI7sw4BHcXup1SqD7rIYoiH32Mz982Cam-shtAEO7wFs2-vfEss-bwtsCV_umQX18kVPqyTz1L_z_EX8O-w3yTKCyZSbwjb-qteoBuwCP1ZTkIo98wXnMWfEEGBWy2rt4g00m3zwJgs6LeLS-KhYrFJTwhhW-DQsYr4aTOJC2blTnMdq9URPKKgg=w467-h48" width="467" /></a></div><br /><div class="separator" style="clear: both; text-align: center;">TDK-Lambda Genesys+ power supply</div></span><p></p>
<p class="MsoNormal" style="text-align: center;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEjTG7i_uLmzQwUKelj249MgtVj8LxtIIibouV7WJeQOjRf4RAqXiRosrVOxpZ1wbuDQj6EltfWeyzih0rAIPtbE7P-OIK3OQssei9QwR_oFxlV9Reupdt7l3FGz-xJwEy_eTVuXrM8VvodI-FE8zOrOsl0ZwSYAemkPa2c1zMI4Ejpc0x0-SWWjjniIDA=s1438" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1438" data-original-width="1200" height="309" src="https://blogger.googleusercontent.com/img/a/AVvXsEjTG7i_uLmzQwUKelj249MgtVj8LxtIIibouV7WJeQOjRf4RAqXiRosrVOxpZ1wbuDQj6EltfWeyzih0rAIPtbE7P-OIK3OQssei9QwR_oFxlV9Reupdt7l3FGz-xJwEy_eTVuXrM8VvodI-FE8zOrOsl0ZwSYAemkPa2c1zMI4Ejpc0x0-SWWjjniIDA=w267-h309" width="267" /></a></div><p></p><p align="center" class="MsoNormal" style="text-align: center;">TDK-Lambda Z+ power supply</p><p class="MsoNormal"><br /></p>
<p class="MsoNormal"><span face=""Arial",sans-serif">Power Guy<o:p></o:p></span></p>
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Power Guyhttp://www.blogger.com/profile/15282245011253622251noreply@blogger.com0tag:blogger.com,1999:blog-535177224836915617.post-55493963949963719442021-09-30T08:09:00.005-07:002022-09-15T12:26:24.277-07:00Voltage adjustment methods for power supplies and converters<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><u><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Introduction<o:p></o:p></span></u></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">AC-DC power supplies and DC-DC converters often feature an output
voltage adjustment, the range of which is stated in the datasheet. An AC-DC
power supply may have a potentiometer accessible to set the output voltage from
the original factory set point. (See Figure 1). Adjusting the output voltage
may be needed to compensate for voltage drops in the load cables, or to
optimize the load’s performance or efficiency.</span></p><p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"></span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiCwlzDhUvjDGY9Ci4GFD2qt9gIvNK6WEYQ_lJRK2DDMoBc1TqrFSAnfV4rFohN0zo9Htn7zAsjF_ZK1YDP2L73Rc9rf7V0_gj2IUGaj69U6ifqKK5lwch5xsFlKrHka-2NgzqTvqCsfnCY/s419/1.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="260" data-original-width="419" height="199" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiCwlzDhUvjDGY9Ci4GFD2qt9gIvNK6WEYQ_lJRK2DDMoBc1TqrFSAnfV4rFohN0zo9Htn7zAsjF_ZK1YDP2L73Rc9rf7V0_gj2IUGaj69U6ifqKK5lwch5xsFlKrHka-2NgzqTvqCsfnCY/s320/1.jpg" width="320" /></a></div><br /><p></p>
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<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Figure 1: RWS50B output adjustment
potentiometer (left side)<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Board mount DC-DC converters may also have an output voltage adjustment
range, usually achieved via the “trim” terminal. The trim connection is either
pulled high or low via a resistor depending on the product.<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><u><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Isolated DC-DC converters<o:p></o:p></span></u></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">An isolated model typically has a narrow adjustment range. For example
TDK-Lambda’s 30W rated single output CCG30 models (Figure 2) can be set within
+ or -10% of the nominal output voltage.</span></p><p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"></span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKuipL32IgXEZXKrHXiIZOWrEKZV9cTbparJH7eNT49nSZ_mtLjruUeM_Zp2l5GWKQ2d2b36jG2TjrXZ-QHK-ga_jmIk_2MWDDGtILjfU5TvFJRk4a3awgQk7MxQzEec_N2AsT6n5YDDTH/s769/2.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="549" data-original-width="769" height="228" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKuipL32IgXEZXKrHXiIZOWrEKZV9cTbparJH7eNT49nSZ_mtLjruUeM_Zp2l5GWKQ2d2b36jG2TjrXZ-QHK-ga_jmIk_2MWDDGtILjfU5TvFJRk4a3awgQk7MxQzEec_N2AsT6n5YDDTH/s320/2.jpg" width="320" /></a></div><p></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-ansi-language: EN-US; mso-fareast-font-family: "Times New Roman"; mso-no-proof: yes;"><v:shape id="Picture_x0020_3" o:spid="_x0000_i1029" style="height: 132.85pt; mso-wrap-style: square; visibility: visible; width: 158.15pt;" type="#_x0000_t75">
<v:imagedata cropbottom="8633f" cropleft="12369f" cropright="11698f" croptop="8145f" o:title="" src="file:///C:\Users\STEVE~1.ZMI\AppData\Local\Temp\msohtmlclip1\01\clip_image002.jpg">
</v:imagedata></v:shape></span><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p></o:p></span></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Figure 2: CCG30 DC-DC converter<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">A resistor is fitted between the trim pin and either the -Vout or the +Vout
terminal depending if the voltage needs to be increased or reduced (Figure 3).<span style="mso-spacerun: yes;"> </span>If no resistor is fitted, the output will be
the nominal value stated on the datasheet.<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-ansi-language: EN-US; mso-fareast-font-family: "Times New Roman"; mso-no-proof: yes;"><v:shape id="Picture_x0020_2" o:spid="_x0000_i1028" style="height: 133.7pt; mso-wrap-style: square; visibility: visible; width: 451.3pt;" type="#_x0000_t75">
<v:imagedata o:title="" src="file:///C:\Users\STEVE~1.ZMI\AppData\Local\Temp\msohtmlclip1\01\clip_image003.jpg">
</v:imagedata></v:shape></span><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p></o:p></span></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p></o:p></span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgV8iuyKDg8-mj2Rie1pKtB8QGlCK98EqIEY7IQkkT-e9cC5jeFANjxZnH0PgtbOAYcBz_jigw_CnECYorzKY7S2hTb2dFZNiLwLnqeJXOuEtbSZukru6x5fIgVH2O5_5qAq230c2xxxwB8/s1284/3.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="381" data-original-width="1284" height="190" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgV8iuyKDg8-mj2Rie1pKtB8QGlCK98EqIEY7IQkkT-e9cC5jeFANjxZnH0PgtbOAYcBz_jigw_CnECYorzKY7S2hTb2dFZNiLwLnqeJXOuEtbSZukru6x5fIgVH2O5_5qAq230c2xxxwB8/w640-h190/3.jpg" width="640" /></a></div><br /> <p></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Figure 3: Adjusting the output of a CCG
converter<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><u><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Non-isolated DC-DC converters<o:p></o:p></span></u></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Non-isolated DC-DC models can have very wide adjustment ranges because
of the topology used in the design. TDK-Lambda’s i7C4W008A120V converter
(Figure 4), for example, has an output voltage range of up to 9.6 to 48V. This
enables one part number to be used for several different system voltages and
help inventory management.<o:p></o:p></span></p><p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhxqcSwRSBr8wHc8_l1UjNslZ5IUtdQCLoYEDinsrX1OkKldLyA0Pkg4akZLLsw0UiXIKlrR2s93FXE2jxOOIgd-24WrVGBS1XePPcLtjvZutQKnJjQY1HLSAkJ2JTLU80G2hTCEYhd4E32/s2048/4.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1463" data-original-width="2048" height="229" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhxqcSwRSBr8wHc8_l1UjNslZ5IUtdQCLoYEDinsrX1OkKldLyA0Pkg4akZLLsw0UiXIKlrR2s93FXE2jxOOIgd-24WrVGBS1XePPcLtjvZutQKnJjQY1HLSAkJ2JTLU80G2hTCEYhd4E32/s320/4.jpg" width="320" /></a></div><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><br /></span><p></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><v:shape id="_x0000_i1025" style="height: 210pt; width: 294pt;" type="#_x0000_t75">
<v:imagedata o:title="i7C_openframe" src="file:///C:\Users\STEVE~1.ZMI\AppData\Local\Temp\msohtmlclip1\01\clip_image004.jpg">
</v:imagedata></v:shape><o:p></o:p></span></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Figure 4: TDK-Lambda’s i7C 300W
buck-boost DC-DC converter<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">The trim connection for the i7C, and other non-isolated models like the
i3A, i6A and i7A, is slightly different.<span style="mso-spacerun: yes;">
</span>If no trim resistor is fitted the output voltage will default to the low
limit. From Figure 5 the trim resistor is always fitted between trim and –Vout.
The full product specification provides the values and formula.<span style="mso-spacerun: yes;"> </span>As the resistance is lowered, the output
voltage increases.</span><span style="font-family: Arial, sans-serif; font-size: 10.5pt;"> </span></p><p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"></span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjbbGzQlHtAA2RxDUFk8Isy_RRTOZq-V8gcoYy_gsn0R4g1rR9DYH43vn7vjVsFhPGafGp1MqQr8Rgc3bFJxORjgGRb8_IrkC44u3c1PVavl10vgaI8CnSfFtPkNnPsi4UghjiW5RIvUQmD/s614/5.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="553" data-original-width="614" height="360" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjbbGzQlHtAA2RxDUFk8Isy_RRTOZq-V8gcoYy_gsn0R4g1rR9DYH43vn7vjVsFhPGafGp1MqQr8Rgc3bFJxORjgGRb8_IrkC44u3c1PVavl10vgaI8CnSfFtPkNnPsi4UghjiW5RIvUQmD/w400-h360/5.jpg" width="400" /></a></div><br /><p></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-ansi-language: EN-US; mso-fareast-font-family: "Times New Roman"; mso-no-proof: yes;"><v:shape id="Picture_x0020_4" o:spid="_x0000_i1027" style="height: 195pt; mso-wrap-style: square; visibility: visible; width: 216.45pt;" type="#_x0000_t75">
<v:imagedata o:title="" src="file:///C:\Users\STEVE~1.ZMI\AppData\Local\Temp\msohtmlclip1\01\clip_image005.jpg">
</v:imagedata></v:shape></span><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p></o:p></span></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Figure 5: i7C trim circuit<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><u><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Adjusting a converter using a digital-to-analog converter<o:p></o:p></span></u></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">With the growing number of autonomous applications for battery powered
robots and drones, there are demands for the output voltage to be
electronically adjusted using a programmable digital voltage. <span style="mso-spacerun: yes;"> </span>A lower voltage might be used to extend
battery life, enabling the robot to return to its charging station for example.<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">One method is to use a D/A converter (DAC) connected to the trim
terminal of the DC-DC converter (Figure 6). TDK-Lambda recently posted an
application note on how to use a DAC to adjust their buck and buck-boost
non-isolated series. A link can be found </span><span lang="EN-GB"><a href="https://product.tdk.com/system/files/dam/doc/product/power/switching-power/dc-dc-converter/app_note/dac_output_trim_appnote.pdf"><span style="font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">here</span></a></span><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">.<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgyCdLZ52R1-iH21QOGNR_f6Sq6xXL_9-fLOl9Ueh17cgx6U8LH4imnHptNK8d50w2H9GAhp3wg6h-18dCDFwlGjbJFPOwMxncpcJ6U6c2C6uwPizlXwoBRnvPWSW1PQ31PiSNuxgomHqu4/s680/6.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="307" data-original-width="680" height="288" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgyCdLZ52R1-iH21QOGNR_f6Sq6xXL_9-fLOl9Ueh17cgx6U8LH4imnHptNK8d50w2H9GAhp3wg6h-18dCDFwlGjbJFPOwMxncpcJ6U6c2C6uwPizlXwoBRnvPWSW1PQ31PiSNuxgomHqu4/w640-h288/6.jpg" width="640" /></a></div><br /><p></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;"><span style="mso-ansi-language: EN-US; mso-no-proof: yes;"><v:shape id="Picture_x0020_5" o:spid="_x0000_i1026" style="height: 159.45pt; mso-wrap-style: square; visibility: visible; width: 353.55pt;" type="#_x0000_t75">
<v:imagedata o:title="" src="file:///C:\Users\STEVE~1.ZMI\AppData\Local\Temp\msohtmlclip1\01\clip_image006.png">
</v:imagedata></v:shape></span><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p></o:p></span></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Figure 6: Typical application circuit
for digital output voltage adjustment<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">The application note details the type of DAC needed and shows the test results
of an i7C converter being digitally controlled.<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">The DAC must be connected with short, direct traces to trim and ground
terminal of the DC-DC power module. To avoid regulation errors from voltage
drops, the ground paths need to be kept separate from the power traces carrying
load currents. Any noise or voltage drop at the DAC output will cause
unexpected output voltage variation.<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">It should also be noted that when adjusting the output up in voltage,
the maximum power rating of the power supply or converter is not exceeded.
Likewise the maximum current must not be exceeded when the voltage is below the
nominal set point.<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span lang="EN-GB" style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Power Guy</span><span lang="EN-GB" style="font-family: "Arial","sans-serif";"><o:p></o:p></span></p>
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Power Guyhttp://www.blogger.com/profile/15282245011253622251noreply@blogger.com0tag:blogger.com,1999:blog-535177224836915617.post-90868045102751751612021-06-29T13:38:00.004-07:002022-12-22T09:16:22.581-08:00Charging capacitors using constant current power supplies<p></p><p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">We have all seen defibrillators in movies and on TV. The device is
switched on, the paddles are applied to the patient’s chest, the operator shouts
“clear” and a jolt of electricity, around (3,000V) is applied to the patient. If
a second application is required, a short period of time is needed to recharge the
defibrillator. Similarly, professional photographers often use studio strobe
lighting, which requires a delay or “recycle time” to recharge after a
photograph is taken.</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Many pulsed load applications use capacitors to store energy. This
enables high levels of current to be available to a load for a very short
duration. The capacitor should be situated next to the load to provide a low
impedance source. A power supply (or battery for portable equipment) is used to
charge the capacitor to a set voltage.<span style="mso-spacerun: yes;"> </span>There
are two ways of charging a capacitor, using a fixed voltage power supply or
using a supply that is capable of providing a constant current.</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Lasers are now commonly used in cosmetic surgery equipment, material
cutting and additive manufacturing (including 3D printing). Many lasers do not
operate in a continuous-wave mode, but are pulsed on and off at extremely high frequencies
to control the amount of heat energy they apply to the material.</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Using an off-the-shelf constant voltage power supply to charge a capacitor
can cause problems. When the power supply is initially connected to the
capacitor, it will try to deliver its maximum allowable current and probably go
into an overload condition. An uncharged capacitor is effectively a short
circuit to a constant voltage power supply and if its protection circuit is the
hiccup type, it may remain locked in that state. It is also not wise to
repeatedly operate a power supply in an over-current condition for reliability
purposes.</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">One method of avoiding an overload condition is to put a resistor in
series with the capacitor to limit the current (Figure 1).</span></p><p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhq_h0AfkUCCyRdn597Yb_NRB5s7wPubSLuiGCBJguFVQtrn-S18Zd2b6UWKnifrHZN9mfBBLUNBNe8tLBgLZ-aL7dURSdn4VaiSW8hDyyNcyDjkItVYmV5I_YHQn1qYuYbFuc5NB2WEaO-/s801/RGA+Outline.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="282" data-original-width="801" height="141" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhq_h0AfkUCCyRdn597Yb_NRB5s7wPubSLuiGCBJguFVQtrn-S18Zd2b6UWKnifrHZN9mfBBLUNBNe8tLBgLZ-aL7dURSdn4VaiSW8hDyyNcyDjkItVYmV5I_YHQn1qYuYbFuc5NB2WEaO-/w400-h141/RGA+Outline.jpg" width="400" /></a></div><br /><p></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-no-proof: yes;"><v:shapetype coordsize="21600,21600" filled="f" id="_x0000_t75" o:preferrelative="t" o:spt="75" path="m@4@5l@4@11@9@11@9@5xe" stroked="f">
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<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Figure 1: Resistor limiting the capacitor charging
current</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">The main drawbacks to this approach are potentially significant power
losses in the resistor and the charging voltage has an exponential response time.
This is defined by:</span></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 16.0pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Vcap = Vin x (1-e<sup>(-t/RC)</sup>)</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">The term RC “time constant” is used. This is the time required to charge
the capacitor, through the resistor, from a discharged state to approximately
63.2% of the value of the applied DC voltage.</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Figure 2 shows an example of a 10,000µF capacitor (C) charging up to
2,000V via a 100Ω resistor (R). <span style="mso-spacerun: yes;"> </span>After 5
time constants the capacitor is approximately 99% charged. In our case the time
to charge would be 5RC: 5 x 100 x 0.01 = 5 seconds.</span></p><p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgBjNE1TSzmFcZgU9PXaFgl0RvMyyC979iOT4J7VuofzUyO2OIUSbe7fIVmj5fUCl_jXa7nGD6VtI4M-mNKS1w4Y2cErB0wVJNLEmBg8Whgs5TpbB8cVNZ9f_3yrt9M12wbZa4HtT7FllZv/s1075/time.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="852" data-original-width="1075" height="318" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgBjNE1TSzmFcZgU9PXaFgl0RvMyyC979iOT4J7VuofzUyO2OIUSbe7fIVmj5fUCl_jXa7nGD6VtI4M-mNKS1w4Y2cErB0wVJNLEmBg8Whgs5TpbB8cVNZ9f_3yrt9M12wbZa4HtT7FllZv/w400-h318/time.jpg" width="400" /></a></div><br /><p></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Figure 2: Capacitor charging curve for a 2,000V
10,000µF capacitor via a 100Ω resistor</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Another method is to use a constant current power supply. Note, we do
not need a series resistor as the power supply will internally limit the amount
of current supplied (Figure 3). This current level is usually user adjustable.<span style="mso-spacerun: yes;"> </span>Charge efficiency is dramatically improved
with no losses in the resistor.</span></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-no-proof: yes;"><v:shape id="Picture_x0020_4" o:spid="_x0000_i1028" style="height: 100.7pt; mso-wrap-style: square; visibility: visible; width: 285.85pt;" type="#_x0000_t75">
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<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiIEKLXiFSTD3PpAVD1SIzzrh4MFjW_Lm8tPcHSPY8iL36bVw9IZDAJmELDLwwUNtTJjsVltjDgC_msCfxQRc-NHlK63IeBrISrI8X3ePKeZk1M5_to3ANHqyJ-VVr0XIyjMQhICGEvY7EU/s801/3.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="282" data-original-width="801" height="141" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiIEKLXiFSTD3PpAVD1SIzzrh4MFjW_Lm8tPcHSPY8iL36bVw9IZDAJmELDLwwUNtTJjsVltjDgC_msCfxQRc-NHlK63IeBrISrI8X3ePKeZk1M5_to3ANHqyJ-VVr0XIyjMQhICGEvY7EU/w400-h141/3.jpg" width="400" /></a></div><br /><p></p><p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Figure 3: Constant current power supply connection</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">In this case (Figure 4) we do not have an exponential rise, but a
controlled linear increase in voltage until the capacitor is fully charged. The
amount of time to charge the capacitor is determined by the power supply. One supply
with twice the output current will halve the charging time.<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p><p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"></span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMWbvCOcnwj9Z37wtv-V0L58tgkGpa0_tHh5h-DKCMByWrABN1nbXqxhOhDtjyyWQJfRucBvKisUVhU9AQpx2hK0rkn8pKKNZvplHB3XS55oeJXSSiX1_FYMo2ZGv44mTvnCBK1da8tgvu/s1075/4.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="852" data-original-width="1075" height="318" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMWbvCOcnwj9Z37wtv-V0L58tgkGpa0_tHh5h-DKCMByWrABN1nbXqxhOhDtjyyWQJfRucBvKisUVhU9AQpx2hK0rkn8pKKNZvplHB3XS55oeJXSSiX1_FYMo2ZGv44mTvnCBK1da8tgvu/w400-h318/4.jpg" width="400" /></a></div><div class="separator" style="clear: both; text-align: center;"><span style="font-family: Arial, sans-serif; font-size: 10.5pt;"> </span></div><p></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Figure 4: Charging a capacitor with a constant
current power supply</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Once the desired capacitor voltage is reached, the power supply will
stop delivering current.</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">For someone who is very familiar with constant voltage power supplies,
constant current power supplies are a little like driving on the “wrong” side
of the road in another country. TDK-Lambda’s High Voltage Product Line Manager
had sent me an application story which took me a couple of reads before I
understood the problem!</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">A customer had a 1,000V rated ALE 802 high voltage supply with a charge
rating of 18A. To test it, an 80nF capacitor with a 20MΩ resistor in series was
connected across the output and the power supply shutdown. As the power supply
can deliver an 18A constant current it would try to generate 18 (A) x
20,000,000 (Ohms) = 360,000,000V (V = I x R). Of course the power supply
protected itself and shutdown! Even if the resistor was shorted out, 18A
charging up the very small 80nF capacitor would take just 4µs (charge time = C
x V/I). That was faster than the power supply’s control circuit.</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">His words of wisdom to the customer were “First, keep the voltage drop
in any series resistance/impedance to around 1% or less of the rated voltage to
avoid false overvoltage issues. Second, use a capacitor that charges in
500microseconds or more to give the control electronics sufficient time to
respond. There’s always exceptions to the rules, but these numbers are a good
starting point.”</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">TDK-Lambda has a large range of programmable power supplies that can
operate in constant current mode. The 4000W </span><a href="https://product.tdk.com/system/files/dam/doc/product/power/switching-power/ac-dc-converter/catalog/tps4k_e.pdf"><span style="font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">TPS4000</span></a><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"> 3-phase has nominal
output voltages of 24V and 48V. At the other end of the spectrum is the </span><a href="https://www.us.lambda.tdk.com/products/high-voltage-power/capacitor-charging/ale-oem.html"><span style="font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">ALE series</span></a><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">, capable of providing
outputs from 0 to 50,000V with power levels up to 1MW. The fully programmable GENESYS+™
series of constant voltage/current power supplies have 0 to 10V up to 0 to
1500V outputs with power levels from 1,000W to many tens of kWs.</span></p><p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"></span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjlQJKFXKFZflNACK0hYCSyKBtL_-I0iLAaUpqy7dxqn2tMubsWr7NSoeKxMmRjVrtn-uvclJyothcfpApnXmCDnRbVFa59nymqq-Rr27JvVkzbIDRBY1DK7APnNYpT8pGMnqrwUvHjXee8/s263/5.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="241" data-original-width="263" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjlQJKFXKFZflNACK0hYCSyKBtL_-I0iLAaUpqy7dxqn2tMubsWr7NSoeKxMmRjVrtn-uvclJyothcfpApnXmCDnRbVFa59nymqq-Rr27JvVkzbIDRBY1DK7APnNYpT8pGMnqrwUvHjXee8/s0/5.jpg" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEizYKAsOioZhyphenhyphenNyyH4d3U1nlkpgN7IrIhb9KSuV5f-_SiU5e9H0etlzAgo5_4UpL_9Uans_b0YX6D9JEGV4G3CuXju-KFn-bo-i6Lg-rHnHJ9R___cWYUmQ38mSCav-R9O27rcO5dYmAvd8/s232/6.jpg" imageanchor="1" style="font-family: Arial, sans-serif; font-size: 10.5pt; margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="196" data-original-width="232" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEizYKAsOioZhyphenhyphenNyyH4d3U1nlkpgN7IrIhb9KSuV5f-_SiU5e9H0etlzAgo5_4UpL_9Uans_b0YX6D9JEGV4G3CuXju-KFn-bo-i6Lg-rHnHJ9R___cWYUmQ38mSCav-R9O27rcO5dYmAvd8/s0/6.jpg" /></a><br /></div><p></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;"><span style="mso-no-proof: yes;"><v:shape id="Picture_x0020_7" o:spid="_x0000_i1026" style="height: 180.85pt; mso-wrap-style: square; visibility: visible; width: 197.15pt;" type="#_x0000_t75">
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<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Figure 5: TPS4000 and ALE power supplies</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">There is a great selection of information on high voltage capacitor
charging on TDK-Lambda’s website, including a pdf with useful equations.<span style="mso-spacerun: yes;"> </span></span><a href="https://product.tdk.com/info/en/products/power/tec_data/ps_ale.html">https://product.tdk.com/info/en/products/power/tec_data/ps_ale.html</a></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in;"><span style="color: black; font-family: "Arial","sans-serif"; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Power Guy<o:p></o:p></span></p><br /><p></p>
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Power Guyhttp://www.blogger.com/profile/15282245011253622251noreply@blogger.com0tag:blogger.com,1999:blog-535177224836915617.post-86365760946493363442021-04-30T01:59:00.009-07:002022-12-22T09:15:53.327-08:00What do buffer modules do and how do I use them?<p><span><u><span face="Arial, sans-serif" lang="EN-US">Introduction</span></u></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="Arial, sans-serif" lang="EN-US" style="color: black;"><span>When the AC input to the power supply is interrupted for a period longer
than the power supply’s hold-up time, the addition of a buffer module will
continue to provide power to the load until its stored energy is depleted.<span style="mso-spacerun: yes;"> </span>Without a buffer module, short interruptions
of greater than 10 to 20ms may cause a system to reboot, or leave a machine
(like a robotic arm) in an undesirable state or position; hence the term “buffer
module”, as it “buffers” the load from interruptions of the AC power.<o:p></o:p></span></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span><span face="Arial, sans-serif" lang="EN-US">An uninterruptable power supply (UPS) could be used; however it would
consume more energy, cost more to operate, and add considerable cost to the
system. As batteries are normally used to store the back-up energy, periodic
preventative maintenance and battery replacement is required. Could a bank of capacitors be attached across
the output of the power supply? Yes, maybe,
but I suggest you read a previous </span><span class="MsoHyperlink"><span face="Arial, sans-serif" lang="EN-US"><a href="https://power-topics.blogspot.com/2020/04/how-can-i-increase-power-supplys-hold.html">blog
article</a></span></span><span face="Arial, sans-serif" lang="EN-US"> outlining the pros and cons of doing so.</span></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><u><span face="Arial, sans-serif" lang="EN-US"><span>How do I connect them?</span></span></u></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="Arial, sans-serif" lang="EN-US" style="color: black;"><span>The buffer module is connected in the same way as additional capacitors
would be, across the power supply / load.<span style="mso-spacerun: yes;">
</span>See Figure 1.<o:p></o:p></span></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt; text-align: center;"><span face="Arial, sans-serif" lang="EN-US" style="color: black;"><o:p><span> </span></o:p></span></p><div class="separator" style="clear: both; text-align: center;"><span><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgRVx1kAFwX5uhH1fCDKnhwYoPsK_nBEA28WSX4WuamcjCXHKBO_-HsR9wo7Njjjr_2kVJTeACPmRRboEBfsHyfYMzlSnm-1ldovsDdB44rtof5b8DPlyJcoBUhAnTpLPS8es3Bxeu5bDc-/s1004/Block+diagram+1.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="481" data-original-width="1004" height="267" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgRVx1kAFwX5uhH1fCDKnhwYoPsK_nBEA28WSX4WuamcjCXHKBO_-HsR9wo7Njjjr_2kVJTeACPmRRboEBfsHyfYMzlSnm-1ldovsDdB44rtof5b8DPlyJcoBUhAnTpLPS8es3Bxeu5bDc-/w559-h267/Block+diagram+1.jpg" width="559" /></a></span></div><p></p><p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face="Arial, sans-serif" lang="EN-US" style="color: black;"><span>Figure 1: Connection of a buffer module<o:p></o:p></span></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><u><span face="Arial, sans-serif" lang="EN-US"><span>What will they do?</span></span></u></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="Arial, sans-serif" lang="EN-US" style="color: black;"><span>Current will only flow into the buffer module when it needs charging. It
will only flow out (discharge) to the load when the AC input is interrupted and
the output voltage of the AC-DC power supply to starts to decrease.</span></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="Arial, sans-serif" lang="EN-US" style="color: black;"><span>Figure 2 shows that without a buffer module, the voltage to the load
will drop once the power supply’s hold-up time “T” is exceeded, typically
within 10 to 20ms.</span></span></p><p class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt; text-align: center;"><span face="Arial, sans-serif" lang="EN-US" style="color: black;"><o:p><span></span></o:p></span></p><div class="separator" style="clear: both; text-align: center;"><span><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi6qzTbkIudw9AuA6-cfFSUHObNzfuU6HK1s_udP9EQ0NAMXX2Sl-7y8osk53dJJx5OeJlNZgJuxxH2QxR_NLCe9lwiRT7JfBiOzYE7O_5AdAAB_wT77IPZBbSjB65ibtyYmzTcN1t5Jnpr/s1080/No+buffer.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="446" data-original-width="1080" height="225" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi6qzTbkIudw9AuA6-cfFSUHObNzfuU6HK1s_udP9EQ0NAMXX2Sl-7y8osk53dJJx5OeJlNZgJuxxH2QxR_NLCe9lwiRT7JfBiOzYE7O_5AdAAB_wT77IPZBbSjB65ibtyYmzTcN1t5Jnpr/w546-h225/No+buffer.jpg" width="546" /></a></span></div><p></p><p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face="Arial, sans-serif" lang="EN-US" style="color: black;"><o:p><span> </span></o:p></span><span face="Arial, sans-serif">Figure 2: No buffer module in circuit</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="Arial, sans-serif" lang="EN-US" style="color: black;"><span>With a buffer module in circuit (Figure 3), the voltage to the load is
present during a brief loss of the AC. Time “T” is the power supply’s hold-up
and time “Tb” is the additional hold-up provided by the buffer module. The
maximum value of Tb will depend on the energy shortage capability of the buffer
module and the amount of load being drawn.<o:p></o:p></span></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt; text-align: center;"><span face="Arial, sans-serif" lang="EN-US" style="color: black;"><o:p><span></span></o:p></span></p><div class="separator" style="clear: both; text-align: center;"><span><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjwg683D-RhMtgTvNQL1Pf_vUoHdZap7NnipXk5xhl65J6b5bP_KfygSsMafv0j1wib1-bzXxxl5qu78kBJkwu9010lNMVa8Kxf3d9XLVTohEbgLJjfUk9_8VDOvJ0XqNuHVtybt6EYyLk4/s1081/Buffer+used.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="446" data-original-width="1081" height="226" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjwg683D-RhMtgTvNQL1Pf_vUoHdZap7NnipXk5xhl65J6b5bP_KfygSsMafv0j1wib1-bzXxxl5qu78kBJkwu9010lNMVa8Kxf3d9XLVTohEbgLJjfUk9_8VDOvJ0XqNuHVtybt6EYyLk4/w550-h226/Buffer+used.jpg" width="550" /></a> </span></div><p></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span><span face="Arial, sans-serif" style="color: black;"><v:shape id="Picture_x0020_8" o:spid="_x0000_i1028" style="height: 151.5pt; mso-wrap-style: square; visibility: visible; width: 367.5pt;" type="#_x0000_t75">
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<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face="Arial, sans-serif" lang="EN-US" style="color: black;"><span>Figure 3: Buffer module in circuit</span></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="Arial, sans-serif" lang="EN-US" style="color: black;"><span>The extended hold-up from the buffer module can also be used to provide
power to the load for a longer period of time. This may allow a piece of
machinery to safely shutdown or store information on the progress of a
particular process.<span style="mso-spacerun: yes;"> </span>Figure 4 shows this.
<o:p></o:p></span></span></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span><span face="Arial, sans-serif" style="color: black;"><v:shape id="Picture_x0020_2" o:spid="_x0000_i1027" style="height: 2in; mso-wrap-style: square; visibility: visible; width: 483.75pt;" type="#_x0000_t75">
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<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face="Arial, sans-serif" lang="EN-US" style="color: black;"></span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgQK6budTmis1p3iDw8bPZmobhHI08WgJskFoMTARfxxscTx9lBD2fJWVgqXIGspyGZEch2EbmFurSFoSz1FYI8-z68Yiztnsu1QbIq58orSSivX7Y_yOzcqUsA5g6cQPerJnu8_k8ayQY1/s1498/Extended+Buffer.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="446" data-original-width="1498" height="192" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgQK6budTmis1p3iDw8bPZmobhHI08WgJskFoMTARfxxscTx9lBD2fJWVgqXIGspyGZEch2EbmFurSFoSz1FYI8-z68Yiztnsu1QbIq58orSSivX7Y_yOzcqUsA5g6cQPerJnu8_k8ayQY1/w648-h192/Extended+Buffer.jpg" width="648" /></a></div><p></p><p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face="Arial, sans-serif" lang="EN-US" style="color: black;"><span>Figure 4: Keeping the load powered
longer<o:p></o:p></span></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span><span face="Arial, sans-serif">The time Tb is stated on the manufacturer’s datasheet at a specified
power level.</span><span face="Arial, sans-serif"> </span><span face="Arial, sans-serif">The 20A rated TDK-Lambda
DBM20 for example provides an additional 250ms at a power level of 448W.</span><span face="Arial, sans-serif"> </span><span face="Arial, sans-serif">When operated at lower power / current
levels, the hold-up increases, see Figure 5.</span><span face="Arial, sans-serif" style="text-align: center;"> </span></span></p><p class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt; text-align: center;"><span face="Arial, sans-serif" lang="EN-US" style="color: black;"><o:p><span></span></o:p></span></p><div class="separator" style="clear: both; text-align: center;"><span><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiIWjZ31m0D3Rq7d-Ytv6xge_DgkdW_6Dc8OBNuMtUCSuGbYQI7IgAaKzPY33AxV_mzVgKMK5mVFsWnE0PJxzB6Q9gkWbGriGyOZl8i2PrUgHfdlC1N8QwWZSj0lFo0QZclEn-Do4o3Ktnn/s1478/Buffer+time+vs+load.JPG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="672" data-original-width="1478" height="266" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiIWjZ31m0D3Rq7d-Ytv6xge_DgkdW_6Dc8OBNuMtUCSuGbYQI7IgAaKzPY33AxV_mzVgKMK5mVFsWnE0PJxzB6Q9gkWbGriGyOZl8i2PrUgHfdlC1N8QwWZSj0lFo0QZclEn-Do4o3Ktnn/w587-h266/Buffer+time+vs+load.JPG" width="587" /></a></span></div><p></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span><span face="Arial, sans-serif" style="color: black;"><v:shape id="Picture_x0020_4" o:spid="_x0000_i1026" style="height: 205.5pt; mso-wrap-style: square; visibility: visible; width: 451.5pt;" type="#_x0000_t75">
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<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face="Arial, sans-serif" lang="EN-US" style="color: black;"><span>Figure 5: DBM20 buffer time vs load
current<o:p></o:p></span></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span><span face="Arial, sans-serif" lang="EN-US">If the load is 5A, the buffer time (Tb) will be just under 1 second. Buffer
modules like TDK-Lambda’s </span><span class="MsoHyperlink"><span face="Arial, sans-serif" lang="EN-US"><a href="https://product.tdk.com/en/power/dbm">DBM20</a></span></span><span face="Arial, sans-serif" lang="EN-US"> and </span><span class="MsoHyperlink"><span face="Arial, sans-serif" lang="EN-US"><a href="https://product.tdk.com/system/files/dam/doc/product/power/switching-power/pwr-acc/catalog/zbm20_e.pdf">ZBM20</a></span></span><span face="Arial, sans-serif" lang="EN-US"> utilize high quality
electrolytic capacitors to store the energy.
This eliminates the use of rechargeable batteries and any necessary
servicing or periodic maintenance. The curves labelled as “typical” include the
tolerance in the electrolytic capacitors.
Buffer modules can usually be connected in parallel to further extend
the time Tb.</span></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><u><span face="Arial, sans-serif" lang="EN-US" style="color: black;"><span>Fixed Mode and Variable/Dynamic Mode<o:p></o:p></span></span></u></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="Arial, sans-serif" lang="EN-US" style="color: black;"><span>These terms can be seen on some datasheets and a switch found on the
buffer module (Figure 6).</span></span></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span><span face="Arial, sans-serif" style="color: black;"><v:shape id="Picture_x0020_5" o:spid="_x0000_i1025" style="height: 189pt; mso-wrap-style: square; visibility: visible; width: 357.75pt;" type="#_x0000_t75">
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<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face="Arial, sans-serif" lang="EN-US" style="color: black;"></span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiGNcp1MWcKJnGeutK0ILffVQFYz9aefPdBxwrdewLMKGKloFbCjbA-NTIQrXhexTBJXyoOpHYy4CafEE3gSyBy0FJOPzW4oFVoStSsrPig4YmiqGJI5BvuS6vKq5F48xrI46KaIhmKuTxk/s745/Fixed+and+variable.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="393" data-original-width="745" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiGNcp1MWcKJnGeutK0ILffVQFYz9aefPdBxwrdewLMKGKloFbCjbA-NTIQrXhexTBJXyoOpHYy4CafEE3gSyBy0FJOPzW4oFVoStSsrPig4YmiqGJI5BvuS6vKq5F48xrI46KaIhmKuTxk/s320/Fixed+and+variable.jpg" width="320" /></a></div><p></p><p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face="Arial, sans-serif" lang="EN-US" style="color: black;"><span>Figure 6: DBM20 showing the fixed mode
and variable / dynamic mode switch</span></span><span face="Arial, sans-serif"> </span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="Arial, sans-serif" lang="EN-US" style="color: black;"><span>When the switch is in “Fixed Mode” the output voltage will be set at the
factory setting. For our DBM20 that is 22.4V for use with a 24V AC-DC power
supply. When the AC is interrupted, the buffer module will start supplying
power to the load at 22.4V.<span style="mso-spacerun: yes;"> </span>This
provides hysteresis to stop the buffer module from discharging unnecessarily.
Note in Figure 3 and 4, the output has dropped slightly (24V vs. 22.4V).</span></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="Arial, sans-serif" lang="EN-US" style="color: black;"><span>If the switch is in the “VIN-1” position, the buffer module will operate
in “Variable” or “Dynamic” mode.<span style="mso-spacerun: yes;"> </span>VIN-1
refers to the input voltage (VIN) minus 1V.<span style="mso-spacerun: yes;">
</span>If the output voltage of the AC-DC power supply is set to 28V, then the
buffer module will start supplying power to the load at 27V. The manufacturer’s
datasheet will state the input voltage range when used in this mode.</span></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="Arial, sans-serif" lang="EN-US" style="color: black;"><span>The TDK-Lambda ZBM20 module mentioned in this article is a similar
product suitable for non-DIN-rail mount applications.</span></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="Arial, sans-serif" lang="EN-US" style="color: black;"><span>Power Guy</span><span style="font-size: 10.5pt;"><o:p></o:p></span></span></p>
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Power Guyhttp://www.blogger.com/profile/15282245011253622251noreply@blogger.com0tag:blogger.com,1999:blog-535177224836915617.post-26566949283037926002021-02-26T12:19:00.007-08:002022-12-22T09:15:24.031-08:00What is UKCA? Updated Sept 2nd 2021<p><span face="Arial, sans-serif" style="font-size: 10.5pt;">Before I start this article, I will clarify some geographic terms.</span><span face="Arial, sans-serif" style="font-size: 10.5pt;"> </span><span face="Arial, sans-serif" style="font-size: 10.5pt;">The United Kingdom (UK) consists of four
countries, England, Scotland, Wales and North Ireland.</span><span face="Arial, sans-serif" style="font-size: 10.5pt;"> </span><span face="Arial, sans-serif" style="font-size: 10.5pt;">Great Britain (GB) consists of England,
Scotland and Wales.</span><span face="Arial, sans-serif" style="font-size: 10.5pt;"> </span><span face="Arial, sans-serif" style="font-size: 10.5pt;">This is why you may have
heard the phrase “Great Britain and Northern Ireland” or the “United Kingdom of
Great Britain and Northern Ireland”.</span><span face="Arial, sans-serif" style="font-size: 10.5pt;">
</span><span face="Arial, sans-serif" style="font-size: 10.5pt;">Under the Brexit (withdrawal of the UK from the European Union) agreement
though, Northern Ireland is currently following EU (European Union) regulations
to ease border checks with the Republic of Ireland.</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><br /></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face=""Arial","sans-serif"" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">According to the UK government website, “the UKCA (<u>UK</u> <u>C</u>onformity
<u>A</u>ssessed) marking is a new UK product marking that is used for goods
being placed on the market in Great Britain (England, Wales and Scotland). It
covers most goods which previously required the CE marking.”<span style="mso-spacerun: yes;"> </span>Figure 1 shows the marking.</span></p><p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face=""Arial","sans-serif"" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><br /></span></p><p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face=""Arial","sans-serif"" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p></o:p></span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhCHUit67xnoR0zObSlyQM6V_6buKPFKJDZ4gSWHCSoFlgRTkK1VJKIf_G_6_133LTEethalsoMhJF-V7nT_VHF7CN_XrWcP-BbGZPlaFmvPzqdgzkyKYDGMNYLKQ80UzjZjhPx6BkvGlK8/s162/UKCA.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="158" data-original-width="162" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhCHUit67xnoR0zObSlyQM6V_6buKPFKJDZ4gSWHCSoFlgRTkK1VJKIf_G_6_133LTEethalsoMhJF-V7nT_VHF7CN_XrWcP-BbGZPlaFmvPzqdgzkyKYDGMNYLKQ80UzjZjhPx6BkvGlK8/s0/UKCA.jpg" /></a></div><br /><p></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face=""Arial","sans-serif"" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Figure 1: UKCA mark<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face=""Arial","sans-serif"" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face=""Arial","sans-serif"" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Before Brexit, the UK used the CE Mark to show conformity with the
relevant EU legislation. After Brexit, UK and EU legislation may start to
differ, and the UK needed an independent mark to indicate conformity with UK
law. In the future, products will need to carry both marks if imported into
both areas.<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face=""Arial","sans-serif"" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face=""Arial","sans-serif"" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Some important points:<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in; margin-left: .5in; margin-right: 0in; margin-top: 0in; margin: 0in 0in 0in 0.5in;"><span face=""Arial","sans-serif"" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoListParagraphCxSpFirst" style="line-height: normal; margin-bottom: 0in; mso-add-space: auto;"><span face=""Arial","sans-serif"" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Note that this is a label change
process not a safety certification process<o:p></o:p></span></p>
<p class="MsoListParagraphCxSpMiddle" style="line-height: normal; margin-bottom: 0in; mso-add-space: auto;"><span face=""Arial","sans-serif"" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoListParagraphCxSpMiddle" style="line-height: normal; margin-bottom: 0in; mso-add-space: auto;"><span face=""Arial","sans-serif"" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">The UK currently references the same EN
standards as the EU - for a power supply these include EN 62368-1, EN 60335-1
and EN 60601-1. This means there is no additional safety certification work
required.<o:p></o:p></span></p>
<p class="MsoListParagraphCxSpMiddle" style="line-height: normal; margin-bottom: 0in; mso-add-space: auto;"><span face=""Arial","sans-serif"" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoListParagraphCxSpMiddle" style="line-height: normal; margin-bottom: 0in; mso-add-space: auto;"><span face=""Arial","sans-serif"" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">The UKCA marking came into effect on
January 1<sup>st</sup> 2021 but to give businesses time to adjust (in most
cases) the CE marking can continue to be used until January 1<sup>st</sup> 2023 (was 2022).<span style="mso-spacerun: yes;"> </span>From that date onwards, CE marking will no
longer be recognized in Great Britain.<o:p></o:p></span></p>
<p class="MsoListParagraphCxSpMiddle" style="line-height: normal; margin-bottom: 0in; mso-add-space: auto;"><span face=""Arial","sans-serif"" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoListParagraphCxSpMiddle" style="line-height: normal; margin-bottom: 0in; mso-add-space: auto;"><span face=""Arial","sans-serif"" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Until January 1<sup>st</sup> 2023 there
is an option to apply the UKCA mark to the product, product packaging or an
accompanying document. This can also be a packing slip and/or an invoice.<o:p></o:p></span></p>
<p class="MsoListParagraphCxSpMiddle" style="line-height: normal; margin-bottom: 0in; mso-add-space: auto;"><span face=""Arial","sans-serif"" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoListParagraphCxSpMiddle" style="line-height: normal; margin-bottom: 0in; mso-add-space: auto;"><span face=""Arial","sans-serif"" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">From January 1<sup>st</sup> 2023
onwards, it is compulsory to have the mark on the product and if this is not
possible, the mark should be on the product packaging or accompanying product documentation as
appropriate.<o:p></o:p></span></p>
<p class="MsoListParagraphCxSpMiddle" style="line-height: normal; margin-bottom: 0in; mso-add-space: auto;"><span face=""Arial","sans-serif"" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoListParagraphCxSpMiddle" style="line-height: normal; margin-bottom: 0in; mso-add-space: auto;"><span face=""Arial","sans-serif"" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">The product, product packaging or an
accompanying document must also have the contact address of the authorized UK
representative. In TDK-Lambda’s case this will be TDK-Lambda UK.<o:p></o:p></span></p>
<p class="MsoListParagraphCxSpMiddle" style="line-height: normal; margin-bottom: 0in; mso-add-space: auto;"><span face=""Arial","sans-serif"" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoListParagraphCxSpLast" style="line-height: normal; margin-bottom: .0001pt; margin: 0in; mso-add-space: auto;"><span face=""Arial","sans-serif"" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">The UKCA marking is not a replacement
for the CE marking. Both marks will be required if a product is to be sold in
both regions. Both will require a Declaration of Conformity.<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face=""Arial","sans-serif"" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face=""Arial","sans-serif"" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">For further advice and application support on this, or any other power
supply related topic, please contact your local TDK-Lambda office.<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face=""Arial","sans-serif"" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face=""Arial","sans-serif"" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face=""Arial","sans-serif"" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Power Guy<o:p></o:p></span></p>
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Power Guyhttp://www.blogger.com/profile/15282245011253622251noreply@blogger.com0tag:blogger.com,1999:blog-535177224836915617.post-9471810866285956552020-12-28T07:27:00.006-08:002022-12-22T09:14:51.822-08:00Peak power ratings with convection and conduction cooled power supplies<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="Arial, sans-serif" lang="EN-US">Many open frame power supplies now offer two power ratings, one with
convection or conduction cooling and one where external forced air is applied. As some applications require low acoustic
noise levels, for example in healthcare where patient comfort is important,
fan-less cooling is preferred. This can
be achieved through operating a power supply at its convection rating, and if it is also capable of conduction cooling, a combination of both.<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="Arial, sans-serif">If the output load significantly varies with time it may be possible to
utilize a power supply with a peak power rating.</span><span face="Arial, sans-serif"> </span><span face="Arial, sans-serif">This allows a lower power product to be
selected, saving cost and reducing its size, as the convection cooled peak
power rating is often the same as the forced air continuous rating.</span><span face="Arial, sans-serif"> </span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="Arial, sans-serif" lang="EN-US">For example, modern hospital beds are fitted with electric motors that
can adjust the angle of the bed to allow the patient to sit upright, or raise the
lower portion to elevate the legs. These motors may only operate for short
periods of time. The same will apply for dental chairs, thermal warmers for
babies and incubators.</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="Arial, sans-serif" lang="EN-US">Power supply manufacturers will state the maximum peak power level and the length of time it can be drawn. The
datasheet or application notes indicate if the peak power rating is calculated using RMS or average power. Alternatively, examples may be given in
the application notes or instruction manual with a list of components to be monitored and their maximum temperatures.</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="Arial, sans-serif" lang="EN-US">TDK-Lambda’s <a href="https://product.tdk.com/en/power/cus-m">CUS600M
power supply</a> (Figure 1) has a convection cooled and RMS peak rating of 400W.
It can deliver 600W peak for a maximum continuous duration of 10 seconds.<o:p></o:p></span></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face="Arial, sans-serif"><v:shapetype coordsize="21600,21600" filled="f" id="_x0000_t75" o:preferrelative="t" o:spt="75" path="m@4@5l@4@11@9@11@9@5xe" stroked="f">
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<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face="Arial, sans-serif" lang="EN-US"></span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhpsCBkFBRdx719fSLHOdyz_nWXcph7KbGSiHCt7Ux5ZISlcvT6KpLIHmomfdcTkYjEv1kQ6KnJpg18SiONp49P_jejt-6llRZPGqPE5unFc4WPMUvu0oi6FwaXPYkxiFYrzUTgvS-93_1Z/s1111/CUS600M-24+to+-48.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="738" data-original-width="1111" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhpsCBkFBRdx719fSLHOdyz_nWXcph7KbGSiHCt7Ux5ZISlcvT6KpLIHmomfdcTkYjEv1kQ6KnJpg18SiONp49P_jejt-6llRZPGqPE5unFc4WPMUvu0oi6FwaXPYkxiFYrzUTgvS-93_1Z/s320/CUS600M-24+to+-48.jpg" width="320" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><br /></div><p></p><p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face="Arial, sans-serif" lang="EN-US">Figure 1: TDK-Lambda’s CUS600M power
supply</span><span face="Arial, sans-serif"> </span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="Arial, sans-serif" lang="EN-US">To determine the RMS power of a repetitive peak load, we shall use the
example shown in Figure 2. OPa = minimum output power drawn, OPb = maximum output
power, t = peak load time in seconds and T = quiescent load time in seconds.</span></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face="Arial, sans-serif"><v:shape id="Picture_x0020_2" o:spid="_x0000_i1027" style="height: 172.5pt; mso-wrap-style: square; visibility: visible; width: 306pt;" type="#_x0000_t75">
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<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face="Arial, sans-serif" lang="EN-US"> </span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEim5qJ3yBqG9hXgVZ76a_GIxAGSHNs3V4BHhSGzUchiw-U3b9DmpxMKxaiHz6ypMXl9RB4qOtSmWGgFW55Pukp8YyZ6tK7J4NRuO7r9LQBKIV88LHP46B0vN41QyOtAZ9oakZEWovbYysYv/s1047/Figure+1.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="589" data-original-width="1047" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEim5qJ3yBqG9hXgVZ76a_GIxAGSHNs3V4BHhSGzUchiw-U3b9DmpxMKxaiHz6ypMXl9RB4qOtSmWGgFW55Pukp8YyZ6tK7J4NRuO7r9LQBKIV88LHP46B0vN41QyOtAZ9oakZEWovbYysYv/s320/Figure+1.png" width="320" /></a></div><br /><p></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face="Arial, sans-serif" lang="EN-US">Figure 2: Repetitive peak power load
example</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="Arial, sans-serif" lang="EN-US">To calculate the RMS power we use equation 1.</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><u><span face="Arial, sans-serif" lang="EN-US">Equation 1:</span></u><span face="Arial, sans-serif" lang="EN-US">
RMS Power = √((OPb<sup>2</sup> x t + OPa<sup>2</sup>xT)/(t + T))</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="Arial, sans-serif" lang="EN-US">It OPb=600W, OPa=100W, t=10s and T=20s, the maximum RMS power would be 356W.<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="Arial, sans-serif"><br /></span></p><p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="Arial, sans-serif">Alternatively, if the power supply had an average power rating stated we
would use equation 2.</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><u><span face="Arial, sans-serif" lang="EN-US">Equation 2:</span></u><span face="Arial, sans-serif" lang="EN-US">
Maximum Average Power <u>></u> ((OPb-OPa) x t/T) + OPa</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="Arial, sans-serif" lang="EN-US">For the previously used values that would calculate as 350W.</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="Arial, sans-serif" lang="EN-US">TDK-Lambda’s <a href="https://product.tdk.com/en/power/cus-m">CUS400M power
supply</a> (Figure 3) can deliver 400W with forced air or, with a combination
of convection and conduction cooling, provide up to 250W continuous output
power and a peak power of 400W.<o:p></o:p></span></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face="Arial, sans-serif"><v:shape id="Picture_x0020_5" o:spid="_x0000_i1026" style="height: 195.75pt; mso-wrap-style: square; visibility: visible; width: 274.5pt;" type="#_x0000_t75">
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<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjuI_jWDoODsYqwfWA7JBpDBcM50kAt2vl1lwrSqhZQmB4C78frsefV2rdTpX9jW4tLlLBiE4CEs_Rw7YN0sCk6ZSacIQo3eI4h3rb0nxdxeJON-Z-sSDESl1Pk1-bHhTMziivAw9N7xTuU/s2048/CUS400M-UX.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1463" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjuI_jWDoODsYqwfWA7JBpDBcM50kAt2vl1lwrSqhZQmB4C78frsefV2rdTpX9jW4tLlLBiE4CEs_Rw7YN0sCk6ZSacIQo3eI4h3rb0nxdxeJON-Z-sSDESl1Pk1-bHhTMziivAw9N7xTuU/s320/CUS400M-UX.jpg" width="320" /></a></div><p></p><p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face="Arial, sans-serif" lang="EN-US">Figure 3: TDK-Lambda’s CUS400M power
supply</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="Arial, sans-serif" lang="EN-US">Derating curves (Figure 4) are provided in the application notes as a
guide rather than firm limits with the CUS600M, as it is expected that
component temperatures will be measured and confirmed in the end system.</span></p><p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face="Arial, sans-serif" lang="EN-US"></span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh7zIs7k9dEFsVdox0pBIhWyC_gG7b_BmCR41FDAcV0-XY1gGIypV_A6po3wakTms1HUyMVl6aibdqPVFY1CpIPbizJgVBqhu6qm8mg4cX1VF8BF9D7_lAB1p8X-Bbq0N-CMNO8XckGb_SO/s1181/CUS400M+derating+curves.JPG" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="705" data-original-width="1181" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh7zIs7k9dEFsVdox0pBIhWyC_gG7b_BmCR41FDAcV0-XY1gGIypV_A6po3wakTms1HUyMVl6aibdqPVFY1CpIPbizJgVBqhu6qm8mg4cX1VF8BF9D7_lAB1p8X-Bbq0N-CMNO8XckGb_SO/s320/CUS400M+derating+curves.JPG" width="320" /></a></div><br /><p></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face="Arial, sans-serif" lang="EN-US">Figure 4: CUS400M peak power performance
curves</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="Arial, sans-serif" lang="EN-US">Whereas many power supplies have peak power durations measured in seconds,
the mechanical construction of this series provides additional cooling through
the use of a metal baseplate. With a 230Vac input, the 400W peak rating applies
up to 30 minutes with a 40<sup>o</sup>C ambient, or 5 minutes with 115Vac at 30<sup>o</sup>C.
This makes this type of product very suitable for powering applications with
occasional peak demands.</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="Arial, sans-serif" lang="EN-US">To ensure long term reliability, convection cooled power supplies should
always have their critical component temperatures measured to ensure conformity
with the manufacturer’s recommendations. This should be done in the end
equipment at the worst-case conditions of ambient, input voltage and
orientation, allowing the temperatures to fully stabilize.</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="Arial, sans-serif" lang="EN-US">For further advice and application support on this, or any other power
supply related topic, please contact your local TDK-Lambda office.</span></p>
<p><span face="Arial, sans-serif">Power Guy</span> </p>
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Power Guyhttp://www.blogger.com/profile/15282245011253622251noreply@blogger.com0tag:blogger.com,1999:blog-535177224836915617.post-17895575599273518562020-10-26T09:51:00.019-07:002022-09-15T12:17:00.803-07:00Using a Class I power supply in a Class II construction<p><span style="font-size: 10.5pt;">I have to admit that I was a little skeptical when I was first told it
was possible to use a Class I power supply (with an earth ground connection) in
a Class II (no earth ground connection) construction.</span><span style="font-size: 10.5pt; mso-spacerun: yes;"> </span><span style="font-size: 10.5pt;">After some discussion with a colleague, he
pointed out that if certain actions are taken, it is perfectly safe - even in a
medical application.</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span style="font-size: 10.5pt;">A general statement of safety is that a product must have two levels of
protection between live (primary) parts and the end user.</span><span style="font-size: 10.5pt; mso-spacerun: yes;"> </span><span style="font-size: 10.5pt;">If one level of protection fails, the end
user is still safe.</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span style="font-size: 10.5pt;">A Class I example would be a clothes dryer. Usually they have an earth
ground connection which is securely connected to the drier’s metal
enclosure.</span><span style="font-size: 10.5pt; mso-spacerun: yes;"> </span><span style="font-size: 10.5pt;">This is to protect the user
if the insulation on the AC input cable frays or the heater element
malfunctions and makes contact with the enclosure.</span><span style="font-size: 10.5pt; mso-spacerun: yes;"> </span><span style="font-size: 10.5pt;">The fault current would flow through the
earth wire, tripping the home’s earth leakage breaker and the AC power would be
disconnected.</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span style="font-size: 10.5pt;">For our clothes dryer example, one protection level is the insulation on
the internal wiring, the second level is the protective earth connection.</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span style="font-size: 10.5pt;">As mentioned in previous blog articles, the home healthcare standard
(IEC 60601-1-11) stipulates the need for Class II equipment, as the integrity
of the safety earth connection cannot be guaranteed in the home environment.</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span style="font-size: 10.5pt;">TDK-Lambda’s medically certified open frame <a href="https://product.tdk.com/en/power/cus-m" target="_blank">CUS600M</a> series (see Figure
1) can be used in either Class I or Class II applications.</span><span style="font-size: 10.5pt; mso-spacerun: yes;"> </span><span style="font-size: 10.5pt;">It has two levels of protection, achieved
through the use of double or reinforced insulation.</span></p><p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face=""Arial","sans-serif"" lang="EN-GB" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><br /></span></p><p class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt; text-align: center;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiadsau_hrifhPZfflEjwaNHai9r1fejxn2MEsLFeD6_BPaRtTnt8vvHckfMGnXTrfhlWQ-9rqBGFXcV0GtTdxuasPithjhhqeHVN_2KVuYODZvS2xH6wmgN6Vp_ItB-bQ0jHil2Bag6xM2/s731/1.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="469" data-original-width="731" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiadsau_hrifhPZfflEjwaNHai9r1fejxn2MEsLFeD6_BPaRtTnt8vvHckfMGnXTrfhlWQ-9rqBGFXcV0GtTdxuasPithjhhqeHVN_2KVuYODZvS2xH6wmgN6Vp_ItB-bQ0jHil2Bag6xM2/s320/1.jpg" width="320" /></a></div><span face=""Arial","sans-serif"" lang="EN-GB" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><br /></span><p></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face=""Arial","sans-serif"" style="color: black; font-size: 10.5pt; mso-ansi-language: EN-US; mso-fareast-font-family: "Times New Roman"; mso-no-proof: yes;"><v:shapetype coordsize="21600,21600" filled="f" id="_x0000_t75" o:preferrelative="t" o:spt="75" path="m@4@5l@4@11@9@11@9@5xe" stroked="f">
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</v:imagedata></v:shape></span><span face=""Arial","sans-serif"" lang="EN-GB" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p></o:p></span></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><b><span face=""Arial","sans-serif"" lang="EN-GB" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Figure 1: CUS600M </span><span face="Arial, sans-serif" style="font-size: 10.5pt;">power supply</span></b></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face=""Arial","sans-serif"" lang="EN-GB" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face=""Arial","sans-serif"" lang="EN-GB" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">The CUS600M/EF versions though have a metal enclosure and fan fitted. See
Figure 2.<span style="mso-spacerun: yes;"> </span>This changes the situation for
a Class II application as during a single fault condition, the metal cover may <span style="mso-spacerun: yes;"> </span>become live. If the cover was accessible to
the user, we would no longer have two levels of protection. Fortunately, there
is a solution!</span></p><p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh3G596lgf9Yl1jdIY0BRwazjsrCtcuWSo5jwiM11OFKe6f1WxTWVSpxdzwzTHzIxcCR6vXXamlYKhVhpUd-G7GIrCv6-RIaLhvQEthqTX6z8F_kDzSU4QdXNlAwNlCashLRApN0LbaRZfk/s780/2.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="557" data-original-width="780" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh3G596lgf9Yl1jdIY0BRwazjsrCtcuWSo5jwiM11OFKe6f1WxTWVSpxdzwzTHzIxcCR6vXXamlYKhVhpUd-G7GIrCv6-RIaLhvQEthqTX6z8F_kDzSU4QdXNlAwNlCashLRApN0LbaRZfk/s320/2.jpg" width="320" /></a></div><p></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face=""Arial","sans-serif"" style="color: black; font-size: 10.5pt; mso-ansi-language: EN-US; mso-fareast-font-family: "Times New Roman"; mso-no-proof: yes;"><v:shape id="Picture_x0020_2" o:spid="_x0000_i1028" style="height: 181.7pt; mso-wrap-style: square; visibility: visible; width: 254.15pt;" type="#_x0000_t75">
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</v:imagedata></v:shape></span><span face=""Arial","sans-serif"" lang="EN-GB" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p></o:p></span></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face=""Arial","sans-serif"" lang="EN-GB" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><b>Figure 2: CUS600M/EF power supply</b><o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face=""Arial","sans-serif"" lang="EN-GB" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face=""Arial","sans-serif"" lang="EN-GB" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">First, the power supply <u>must</u> have 1 x MOPP (Means of Patient
Protection) from the input to ground (chassis) <i style="mso-bidi-font-style: normal;">and</i> 1 x MOPP from the output to ground.<span style="mso-spacerun: yes;"> </span><o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in; margin-left: .5in; margin-right: 0in; margin-top: 0in; margin: 0in 0in 0in 0.5in;"><span face=""Arial","sans-serif"" lang="EN-GB" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><br /></span></p><p class="MsoNormal" style="line-height: normal; margin-bottom: 0in; margin-left: .5in; margin-right: 0in; margin-top: 0in; margin: 0in 0in 0in 0.5in;"><span face=""Arial","sans-serif"" lang="EN-GB" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Our CUS600M/EF has
that - see Figure 3.<o:p></o:p></span></p><p class="MsoNormal" style="line-height: normal; margin: 0in 0in 0.0001pt 0.5in; text-align: center;"></p><div class="separator" style="clear: both; text-align: center;"><br /></div><p></p><p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face=""Arial","sans-serif"" lang="EN-GB" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhXeqWjxjQ5S0ieNeAfFD81OwIrRlw7b1nAH4XH2tNJb3dGum1wvrwJ1UGNT0U39yJtkruNKmylFHEN55AS6UleM_Zg293BQHFhWX7tiQhJ0P_2WJg5pRKYBX1ENXflDl56ia9vt-_mVJAw/s789/3.jpg" style="font-family: "Times New Roman"; font-size: medium; margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="440" data-original-width="789" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhXeqWjxjQ5S0ieNeAfFD81OwIrRlw7b1nAH4XH2tNJb3dGum1wvrwJ1UGNT0U39yJtkruNKmylFHEN55AS6UleM_Zg293BQHFhWX7tiQhJ0P_2WJg5pRKYBX1ENXflDl56ia9vt-_mVJAw/s320/3.jpg" width="320" /></a></span></p><p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face="Arial, sans-serif" style="font-size: 14px;"><b>Figure 3: CUS600M/EF MOPP isolation barriers</b></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span style="font-size: 10.5pt;">Second, ensure the output touch current does not violate the safety
requirements of the end equipment.</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in; margin-left: .5in; margin-right: 0in; margin-top: 0in; margin: 0in 0in 0in 0.5in;"><span face=""Arial","sans-serif"" lang="EN-GB" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><br /></span></p><p class="MsoNormal" style="line-height: normal; margin-bottom: 0in; margin-left: .5in; margin-right: 0in; margin-top: 0in; margin: 0in 0in 0in 0.5in;"><span face=""Arial","sans-serif"" lang="EN-GB" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">In our case the
CUS600M touch current (enclosure leakage) is very low, <100µA, which should
be acceptable in most applications.<o:p></o:p></span></p>
<p class="MsoListParagraph" style="line-height: normal; margin-bottom: 0in; mso-add-space: auto;"><span style="font-size: 10.5pt;">Third, the power supply chassis should have 1 x MOPP isolation from the
final equipment enclosure.</span></p>
<p class="MsoListParagraphCxSpFirst" style="line-height: normal; margin-bottom: 0in; mso-add-space: auto;"><span style="font-size: 10.5pt;">From Figure 4 it can
be seen that we now have achieved our two levels of protection, even without
the use of an earth ground connection.</span></p><p class="MsoListParagraphCxSpMiddle" style="line-height: normal; margin-bottom: 0in; mso-add-space: auto;"><span face=""Arial","sans-serif"" lang="EN-GB" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><br /></span></p><p class="MsoListParagraphCxSpMiddle" style="line-height: normal; margin-bottom: 0.0001pt; text-align: center;"><span face=""Arial","sans-serif"" lang="EN-GB" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"></span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEijE1TdWCllmaIHsqNI6dfWw198y8cdwYm0VXm2b92aOxx1-Qy7_ATkoD32ghoQ5FvX2DuWmzOMxOdJqU71nqVP1ya9g6wQW8iaUIHTJT3ZIHDeSICFVDT7sAnWQEc_bxhmMSEajdt0O6t-/s850/4.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="631" data-original-width="850" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEijE1TdWCllmaIHsqNI6dfWw198y8cdwYm0VXm2b92aOxx1-Qy7_ATkoD32ghoQ5FvX2DuWmzOMxOdJqU71nqVP1ya9g6wQW8iaUIHTJT3ZIHDeSICFVDT7sAnWQEc_bxhmMSEajdt0O6t-/s320/4.jpg" width="320" /></a></div><br /><p></p>
<p align="center" class="MsoListParagraphCxSpMiddle" style="line-height: normal; margin-bottom: 0in; mso-add-space: auto; text-align: center;"><span face=""Arial","sans-serif"" style="color: black; font-size: 10.5pt; mso-ansi-language: EN-US; mso-fareast-font-family: "Times New Roman"; mso-no-proof: yes;"><v:shape id="Picture_x0020_4" o:spid="_x0000_i1026" style="height: 273pt; mso-wrap-style: square; visibility: visible; width: 367.7pt;" type="#_x0000_t75">
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</v:imagedata></v:shape></span><span face=""Arial","sans-serif"" lang="EN-GB" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p></o:p></span></p>
<p align="center" class="MsoListParagraphCxSpMiddle" style="line-height: normal; margin-bottom: 0in; mso-add-space: auto; text-align: center;"><span face=""Arial","sans-serif"" lang="EN-GB" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><b>Figure 4: CUS600M/EF
isolation from the final enclosure</b></span></p>
<p class="MsoListParagraphCxSpMiddle" style="line-height: normal; margin-bottom: 0in; mso-add-space: auto;"><span face=""Arial","sans-serif"" lang="EN-GB" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">The 1 x MOPP
isolation between the power supply and the system enclosure can be achieved by
mounting the power supply on a plastic / non-conductive insulating plate or by
mounting the unit on plastic / non-conductive stand-offs. See Figure 5.</span></p><p class="MsoListParagraphCxSpMiddle" style="line-height: normal; margin-bottom: 0in; mso-add-space: auto;"><span face=""Arial","sans-serif"" lang="EN-GB" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><br /></span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjdOZy4gUmxx2ZxIE5YRE4qilrfqoBpvv3sjt5ki8o4qb1v8zJbzXFljLrbnbXWGuCL5wEd4wYTEkXkAM6gid9fvPhLzR9MiDMzwZ0Uaj6LYjGux9zIWikA8VFuiIJ0RtrU091Ktb5Qb4hm/s392/5.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="262" data-original-width="392" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjdOZy4gUmxx2ZxIE5YRE4qilrfqoBpvv3sjt5ki8o4qb1v8zJbzXFljLrbnbXWGuCL5wEd4wYTEkXkAM6gid9fvPhLzR9MiDMzwZ0Uaj6LYjGux9zIWikA8VFuiIJ0RtrU091Ktb5Qb4hm/s320/5.jpg" width="320" /></a></div>
<p align="center" class="MsoListParagraphCxSpMiddle" style="line-height: normal; margin-bottom: 0in; mso-add-space: auto; text-align: center;"><span face=""Arial","sans-serif"" style="color: black; font-size: 10.5pt; mso-ansi-language: EN-US; mso-fareast-font-family: "Times New Roman"; mso-no-proof: yes;"><v:shape id="Picture_x0020_5" o:spid="_x0000_i1025" style="height: 135pt; mso-wrap-style: square; visibility: visible; width: 201.85pt;" type="#_x0000_t75">
<v:imagedata o:title="" src="file:///C:\Users\STEVE~1.ZMI\AppData\Local\Temp\msohtmlclip1\01\clip_image005.jpg">
</v:imagedata></v:shape></span><span face=""Arial","sans-serif"" lang="EN-GB" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p></o:p></span></p>
<p align="center" class="MsoListParagraphCxSpMiddle" style="line-height: normal; margin-bottom: .0001pt; margin: 0in; mso-add-space: auto; text-align: center;"><span face=""Arial","sans-serif"" lang="EN-GB" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><b>Figure 5: Power
supply with a metal chassis mounted on plastic / non-conductive stand-offs</b></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span style="font-size: 10.5pt;">Last, the EMC performance must not be adversely affected</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in; margin-left: .25in; margin-right: 0in; margin-top: 0in; margin: 0in 0in 0in 0.25in;"><span face=""Arial","sans-serif"" lang="EN-GB" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><br /></span></p><p class="MsoNormal" style="line-height: normal; margin-bottom: 0in; margin-left: .25in; margin-right: 0in; margin-top: 0in; margin: 0in 0in 0in 0.25in;"><span face=""Arial","sans-serif"" lang="EN-GB" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">The EMI performance
of the CUS600M open frame power supply in a Class II application already meets EN55032-B
for both conducted and radiated emissions.<span style="mso-spacerun: yes;">
</span>The same applies to its immunity performance.<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in; margin-left: .25in; margin-right: 0in; margin-top: 0in; margin: 0in 0in 0in 0.25in;"><span face=""Arial","sans-serif"" lang="EN-GB" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face=""Arial","sans-serif"" lang="EN-GB" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Even a Class I modular power supply like <a href="https://product.tdk.com/en/power/qm" target="_blank">QM series</a> can be used in this manner too, as the output to chassis
isolation is 1 x MOPP. It should be noted that many other modular power supplies just have basic (non MOPP) isolation</span><span face="Arial, sans-serif" style="font-size: 10.5pt;">.</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face=""Arial","sans-serif"" lang="EN-GB" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">For further advice and application support on this, or any other power
supply related topic, please contact your local TDK-Lambda office.<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><br /></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face=""Arial","sans-serif"" lang="EN-GB" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Power Guy<o:p></o:p></span></p>
<script>
window.location = "https://www.us.lambda.tdk.com/resources/blogs/202010.html";
</script>Power Guyhttp://www.blogger.com/profile/15282245011253622251noreply@blogger.com0tag:blogger.com,1999:blog-535177224836915617.post-11148339185772464812020-08-28T08:54:00.019-07:002022-12-22T09:13:52.197-08:00Buck & Buck-Boost Converter Operating Ranges<p style="text-align: left;"><span face="" lang="" style="font-size: 10.5pt;">This is a follow-on to a </span><span lang=""><a href="http://power-topics.blogspot.com/2020/07/what-are-buck-boost-and-buck-boost-dc.html"><span face="" style="font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">recent post</span></a></span><span face="" lang="" style="font-size: 10.5pt;"> where I discussed
the difference between a buck, boost and buck-boost converter. Now we will review the operating ranges of a buck
and a buck-boost converter.</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: left;"><span face="" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">As a quick recap - buck and buck-boost DC-DC converters are widely used
in power supply designs, and have been for many years.<span style="mso-spacerun: yes;"> </span>They are popular because of their simplicity,
low cost and high efficiency.<span style="mso-spacerun: yes;"> </span>There is
no transformer used in the design, and as such, there is no isolation between
the input voltage and the output voltage.<span style="mso-spacerun: yes;">
</span>Manufacturers like TDK-Lambda offer both buck and buck-boost
converters.<span style="mso-spacerun: yes;"> </span>With less components and
complexity, a buck converter will offer a lower cost, higher efficiency and
either a smaller package or more output power than an isolated converter.</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: left;"><span face="" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">As with any power supply and DC-DC converter, there are limits to their
operation.<span style="mso-spacerun: yes;"> </span>A programmable power supply
like TDK-Lambda’s </span><span lang=""><a href="https://product.tdk.com/en/search/power/switching-power/prg-power/info?part_no=GH10-150"><span face="" style="font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">GH10-150</span></a></span><span face="" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"> is rated to operate
from 0 to 10V with a maximum current of 150A with a maximum output power of
1500W.<span style="mso-spacerun: yes;"> </span>It is rather unreasonable to
expect it to deliver 5V at 300A.</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: left;"><span face="" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">The main restriction of a non-isolated (step down) buck DC-DC converter
is that the input voltage has to be higher than the output voltage. One example
is the </span><span lang=""><a href="https://product.tdk.com/en/search/power/switching-power/dc-dc-converter/info?part_no=i6A4W010A033V-001-R"><span face="" style="font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">i6A4W010A033V-001-R</span></a></span><span face="" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"> which has an input
range of 9 to 53Vdc, an output adjustment range of 3.3 to 40V and a maximum
output current of 10A.<span style="mso-spacerun: yes;"> </span>Figure 1 shows
the relationship between the input voltage and the allowable output
voltage.<span style="mso-spacerun: yes;"> </span>Only the maximum output power restricts
the amount of output current that can be produced.</span></p><p class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXTyL8b9gYTrIDgbbR6LSz0pJaPRRLg0mAyJb57jDUA-8PkviUejDD5CfWe8pKnI3RlZ_NIxQqPHnEiLHMLGDswwXiVDXAH4ADdHJgnEnkxS7fSUWsvrII6crv8uxx1owZ1jcKJciFAw3Z/s572/Blog+1+Image.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="341" data-original-width="572" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiXTyL8b9gYTrIDgbbR6LSz0pJaPRRLg0mAyJb57jDUA-8PkviUejDD5CfWe8pKnI3RlZ_NIxQqPHnEiLHMLGDswwXiVDXAH4ADdHJgnEnkxS7fSUWsvrII6crv8uxx1owZ1jcKJciFAw3Z/s0/Blog+1+Image.png" /></a></div><p></p><p class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face="" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><b>Figure 1: i6A4W 10A buck converter
output versus input voltage</b></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: left;"><span face="" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">A non-isolated buck boost (step-up / step-down) DC-DC converter has different
constraints to its operation, besides the rated output power, current and voltage.<span style="mso-spacerun: yes;"> </span>The TDK-Lambda </span><span lang=""><a href="https://product.tdk.com/info/en/catalog/datasheets/i7c_e.pdf"><span face="" style="font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">i7C series</span></a></span><span face="" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"> has quite clear
operating parameters on its datasheet, so we will use that as an example.</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: left;"><span face="" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">The part number i7C4W008A120V-001-R has an input voltage range of 9 to
53V, an output adjustment range of 9.6 to 48V and a maximum output current of
8A. In the datasheet the operating range is defined by two plots. These show the
valid input and output voltage operating range and the maximum output current
against input and output voltage.</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: left;"><span face="" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Figure 2 is a pictorial representation of the valid input and output voltage
operating range stated in the datasheet.<span style="mso-spacerun: yes;">
</span>Note this differs significantly from the buck converter discussed
previously, as the buck-boost topology allows it to generate voltages lower and
higher than the input voltage.<o:p></o:p></span></p><p class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face="" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><br /></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face="" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgHd3h_D1u_eUwIEp_rkAvV8-rSeQjAo6XXeIfj1i23ZL2CDeyM2Artk-eTkqOc934-rOKG73TK2ClA9t9zBhl2OpJzOdWmIvmgCHFOdszcl7U1b3e_P3DTRV-n11GnBAxDhzQclnWiZIX4/s589/Blog+2+Image.png" style="margin-left: 1em; margin-right: 1em; text-align: center;"><img border="0" data-original-height="350" data-original-width="589" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgHd3h_D1u_eUwIEp_rkAvV8-rSeQjAo6XXeIfj1i23ZL2CDeyM2Artk-eTkqOc934-rOKG73TK2ClA9t9zBhl2OpJzOdWmIvmgCHFOdszcl7U1b3e_P3DTRV-n11GnBAxDhzQclnWiZIX4/s0/Blog+2+Image.png" /></a></p><p class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><b style="font-size: 10.5pt;">Figure 2: i7C 8A valid input and output
voltage operating range</b></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: left;"><span face="" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">From Figure 3, we can see the x axis matches the 9.6 to 53V input range
stated on the datasheet and Figure 2.<span style="mso-spacerun: yes;"> </span>The
y axis has a maximum limit of 8A for the output current. There are four plots
for different output voltages.</span></p><p class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face="" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><br /></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhbLhqbeibSWaocARBETTuFK9Z8POXedDEJB4Z4iv28mUBZCoysSs7tUCbMxISJmHtO-0TSxKRbHRmQEjO03He3zbvwIPH8KqNk2PbUwvW9DSp1OQZn_QXdgds12uR4Z_DjzeJEkxxeesMb/s738/Blog+3+Image.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="461" data-original-width="738" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhbLhqbeibSWaocARBETTuFK9Z8POXedDEJB4Z4iv28mUBZCoysSs7tUCbMxISJmHtO-0TSxKRbHRmQEjO03He3zbvwIPH8KqNk2PbUwvW9DSp1OQZn_QXdgds12uR4Z_DjzeJEkxxeesMb/s640/Blog+3+Image.png" width="640" /></a></p><p class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><b style="font-size: 10.5pt;">Figure 3: i7C 8A Maximum output current
vs the input and output voltage</b></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: left;"><span face="" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">As an example, a machine has 24Vdc available from an existing AC-DC DIN
rail power supply. A new feature, which requires 48Vdc at 3A is required.<span style="mso-spacerun: yes;"> </span>One way of generating this additional output
voltage is to use a non-isolated DC-DC converter, like the i7C4W008A120V-001-R.
We would use the purple plot (48Vo) and see that the maximum current we can
safely draw from the converter is around 5A.<span style="mso-spacerun: yes;">
</span>If the DIN rail power supply had a 24V battery back-up feature and the
AC power failed, the i7C would continue to deliver 48V at 3A until the battery
discharged down to 15V.</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: left;"><span face="" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">When a buck-boost DC-DC converter has a low input voltage, the input
current switched by the FET is much larger than when it is operating at a high
input voltage. This is the main restriction to the amount of output power it
can deliver.</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: left;"><span face="" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Like any power supply or DC-DC converter, having determined that the
electrical parameters have been met, proper thermal management then has to be
followed to ensure long term, reliable operation.</span></p><p class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: left;"><span face="" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><br /></span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEidZT-ZjTKI9VH4oQOpL3a2VznGZ_C4j8VJm8dQ6hF_uNKqscyD_OCeYJ0jdtLMiPI8sSL7tt7TGA1r5CNxPEWsnmz0ohj0kfGfxgU0b5OSdA3qLpsOm4_eTTmQ7BeBAemXwZVaHZ_3vyp9/s2048/blog+4+image.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1463" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEidZT-ZjTKI9VH4oQOpL3a2VznGZ_C4j8VJm8dQ6hF_uNKqscyD_OCeYJ0jdtLMiPI8sSL7tt7TGA1r5CNxPEWsnmz0ohj0kfGfxgU0b5OSdA3qLpsOm4_eTTmQ7BeBAemXwZVaHZ_3vyp9/s640/blog+4+image.jpg" width="640" /></a></div><p class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><b style="font-size: 10.5pt;">Figure 4: TDK-Lambda’s i7C 300W buck-boost DC-DC converter</b></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: left;"><span face="" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: left;"><span face="" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Power Guy</span></p><p></p>
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Power Guyhttp://www.blogger.com/profile/15282245011253622251noreply@blogger.com0tag:blogger.com,1999:blog-535177224836915617.post-69716340713846720292020-07-31T11:22:00.006-07:002022-09-15T12:03:18.687-07:00What are buck, boost and buck-boost DC-DC converters?<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="arial, sans-serif" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Buck, boost and buck-boost DC-DC converters are widely used in power
supply designs, and have been for many years.<span style="mso-spacerun: yes;">
</span>They are popular because of their simplicity, low cost and high
efficiency.<span style="mso-spacerun: yes;"> </span>There is no transformer used
in the design, and as such, there is no isolation between the input voltage and
the output voltage.<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="arial, sans-serif" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="arial, sans-serif" style="font-size: 10.5pt; line-height: 115%;">In this post I will explain the differences between these three converters and a high level review on how they function..(As a note the simplified schematics do show diodes and switches, in reality FETs are used as synchronous rectifiers to reduce losses and improve efficiency.)</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="arial, sans-serif" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="arial, sans-serif" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">A <u>buck converter</u> reduces voltage and the output voltage is lower
than the input voltage. See Figure 1.</span></p><p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="arial, sans-serif" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><br /></span></p><p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="arial, sans-serif" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"></span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi63rUOKXEBRTKqiw0rF0Qb5MBndl2QqMFw_n5qU_3HG5O7KK9_HYZ5VUnNdLSkbavq9MYlrQdhzddFnjiFrS5P5a0U3fYvMpQTic52mZZvPPEINBNwWblfGR1mtovavAOBLiMfpj2xHuwu/s861/Buck+1.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="271" data-original-width="861" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi63rUOKXEBRTKqiw0rF0Qb5MBndl2QqMFw_n5qU_3HG5O7KK9_HYZ5VUnNdLSkbavq9MYlrQdhzddFnjiFrS5P5a0U3fYvMpQTic52mZZvPPEINBNwWblfGR1mtovavAOBLiMfpj2xHuwu/s640/Buck+1.jpg" width="640" /></a></div><p></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face="arial, sans-serif" style="color: black; font-size: 10.5pt; mso-ansi-language: EN-US; mso-fareast-font-family: "Times New Roman"; mso-no-proof: yes;"><v:shapetype coordsize="21600,21600" filled="f" id="_x0000_t75" o:preferrelative="t" o:spt="75" path="m@4@5l@4@11@9@11@9@5xe" stroked="f">
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</v:imagedata></v:shape></span><span face="arial, sans-serif" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p></o:p></span></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face="arial, sans-serif" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Figure 1: Buck converter<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="arial, sans-serif" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="arial, sans-serif" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">When transistor S is turned on, energy is stored in inductor L as the current
flows to the load and capacitor C is charged. When S is off, the energy stored
in L is released and current flows into the load and circulates via diode D.
Capacitor C also provides energy to the load.<span style="mso-spacerun: yes;">
</span>This is repeated at a high frequencies, greater than 100,000 times a second.<span style="mso-spacerun: yes;"> </span>The length of the time S is turned on defines
the output voltage.<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="arial, sans-serif" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="arial, sans-serif" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">A <u>boost converter</u> increases voltage and the output voltage is
higher than the input voltage. See Figure 2.<o:p></o:p></span></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face="arial, sans-serif" style="color: black; font-size: 10.5pt; mso-ansi-language: EN-US; mso-fareast-font-family: "Times New Roman"; mso-no-proof: yes;"><v:shape id="Picture_x0020_3" o:spid="_x0000_i1027" style="height: 87.85pt; mso-wrap-style: square; visibility: visible; width: 273pt;" type="#_x0000_t75">
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<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><br /></p><p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjgP9qTkcMcUXlEJI_fOf0B28umD7IWVqfaXRM77fikRSf_CzJrMrXgK7AjZIUs7mRGGd1rurW4Tku0RQNyg-psCDPo0hhq7sB1PaylDOJRIjaabnTATsDSvR4oJECVcEzjOv7cTkyA9hXV/s860/Buck+2.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="277" data-original-width="860" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjgP9qTkcMcUXlEJI_fOf0B28umD7IWVqfaXRM77fikRSf_CzJrMrXgK7AjZIUs7mRGGd1rurW4Tku0RQNyg-psCDPo0hhq7sB1PaylDOJRIjaabnTATsDSvR4oJECVcEzjOv7cTkyA9hXV/s640/Buck+2.jpg" width="640" /></a></div><span face="arial, sans-serif" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><br /></span><p></p><p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face="arial, sans-serif" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Figure 2: Boost co</span><span face="arial, sans-serif" style="font-size: 10.5pt;">nverter</span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="arial, sans-serif" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="arial, sans-serif" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">When transistor S is turned on, current flows through inductor L,
through transistor S back to the input. During this period energy is stored in the
inductor.<span style="mso-spacerun: yes;"> </span>When transistor S is off, the inductor
acts a voltage source in series with the input voltage.<span style="mso-spacerun: yes;"> </span>The inductor’s stored energy is circulated
through diode D to the load. This charges capacitor C to a higher level than
the input voltage. Again, the length of the time S is turned on defines the
output voltage.<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="arial, sans-serif" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="arial, sans-serif" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">This boost converter topology is also used in most Power Factor Control (PFC)
sections of AC-DC power supplies. The control IC is different of course, as its
purpose is to ensure the AC input current drawn is sinusoidal in shape.<span style="mso-spacerun: yes;"> </span>At high line voltages greater than 240Vac the
DC input may be higher than the voltage on capacitor C.<span style="mso-spacerun: yes;"> </span>This will reduce the PFC boost converter’s
performance and the power factor will be degraded slightly.<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="arial, sans-serif" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="arial, sans-serif" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">A <u>buck-boost</u> converter is a combination of a buck and boost
converter. The output voltage can be higher or lower than the input voltage.
See Figure 3.</span></p><p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="arial, sans-serif" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><br /></span></p><p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="arial, sans-serif" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"></span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgcXOug-ETOQddtNJLERlbLXlBRIztvgU66-OsbX9wgNivzm7BNzB6TMfST2VcEqp6bZVHaw0nbhpRhRwoDxw7YANi07ohGvoBG1g5r8fME786yOk9-7Lq3q8XjIkAeJHDWDbwppg_YnWar/s860/Buck+3.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="282" data-original-width="860" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgcXOug-ETOQddtNJLERlbLXlBRIztvgU66-OsbX9wgNivzm7BNzB6TMfST2VcEqp6bZVHaw0nbhpRhRwoDxw7YANi07ohGvoBG1g5r8fME786yOk9-7Lq3q8XjIkAeJHDWDbwppg_YnWar/s640/Buck+3.jpg" width="640" /></a></div><p></p><p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><br /></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face="arial, sans-serif" style="color: black; font-size: 10.5pt; mso-ansi-language: EN-US; mso-fareast-font-family: "Times New Roman"; mso-no-proof: yes;"><v:shape id="Picture_x0020_6" o:spid="_x0000_i1026" style="height: 87pt; mso-wrap-style: square; visibility: visible; width: 264.85pt;" type="#_x0000_t75">
<v:imagedata o:title="" src="file:///C:\Users\STEVE~1.ZMI\AppData\Local\Temp\msohtmlclip1\01\clip_image003.jpg">
</v:imagedata></v:shape></span><span face="arial, sans-serif" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p></o:p></span></p>
<p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face="arial, sans-serif" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Figure 3: Buck-boost converter<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="arial, sans-serif" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span lang="" style="font-size: 14px; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><font face="arial, sans-serif">As you can see the circuit is more complicated and has more components. S2, L, and D2 is the boost converter (S1 being on) and S1, L and D1 the buck section (S2 being off)</font></span><span face="arial, sans-serif" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">.<o:p></o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="arial, sans-serif" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="arial, sans-serif" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Many manufacturers like TDK-Lambda offer both buck and buck-boost
converters.<span style="mso-spacerun: yes;"> </span>With less components and
complexity, a buck converter will offer a lower cost, higher efficiency and
either a smaller package or more output power.</span></p><p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="arial, sans-serif" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"></span></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgR7ZujWtmibQsSKH39pscJqFZ4DfhZ66FXmZC8gk3ktwNpwSWcCu5scWuabrca6cwgRSyf0H9EodtQb4Qs_7kQLqmchyphenhypheny2mZqU_lIr0hipF5oF4JytDAIJsicvkzHhwwnSJO2YnZY8FyI_/s2048/Buck+4.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="1463" data-original-width="2048" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgR7ZujWtmibQsSKH39pscJqFZ4DfhZ66FXmZC8gk3ktwNpwSWcCu5scWuabrca6cwgRSyf0H9EodtQb4Qs_7kQLqmchyphenhypheny2mZqU_lIr0hipF5oF4JytDAIJsicvkzHhwwnSJO2YnZY8FyI_/s640/Buck+4.jpg" width="640" /></a></div><p></p><p align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0in; text-align: center;"><span face="arial, sans-serif" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;">Figure 4: <a href="(https://product.tdk.com/info/en/catalog/datasheets/i7c_e.pdf)" target="_blank">TDK-Lambda’s i7C 300W buck-boos tDC-DC converter</a></span></p>
<p class="MsoNormal" style="line-height: normal; margin-bottom: 0in;"><span face="arial, sans-serif" lang="" style="color: black; font-size: 10.5pt; mso-fareast-font-family: "Times New Roman"; mso-fareast-language: EN-GB;"><o:p> </o:p></span><span face="arial, sans-serif" style="font-size: 10.5pt;">Power Guy</span></p><br />
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Power Guyhttp://www.blogger.com/profile/15282245011253622251noreply@blogger.com0tag:blogger.com,1999:blog-535177224836915617.post-31175675568609916792020-06-23T11:23:00.000-07:002020-06-26T00:37:04.758-07:00Selecting a High Voltage Programmable Power Supply<div class="MsoNormal">
<span lang="EN-GB">High-voltage power supplies are used in many
scientific and industrial applications including research, development, process
control, power conditioning, test and measurement. Sometimes a fixed output power supply may be
used, rather than one with a variable or programmable output, which lowers the
initial acquisition cost.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB">As technology rapidly advances, new markets
are identified or production levels ramp up, voltage, current and power requirements
can change significantly. This can
result in a need for a new high voltage supply or one with more features or
functions. Specifying a programmable power
supply is a sound alternative, ensuring flexibility both in the near and long
term. <o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB">The decision as to which attributes should
be considered and how may they benefit the user is an important one. When specifying and evaluating programmable
power supplies, users should look for as many of the following features and
functions as possible. <o:p></o:p></span></div>
<div class="MsoNormal">
<u><span lang="EN-GB"><br /></span></u></div>
<div class="MsoNormal">
<u><span lang="EN-GB">High voltage outputs</span></u><span lang="EN-GB"> <o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB">Scientific instruments can require tens of
kilovolts to perform their specialized tasks. The power supply needs to be able to provide
stable, regulated voltages with a range of outputs that could be as high as 50
kV and power levels of 1kW. Even if the
current application requires less, having a higher rated adjustable power
supply provides future flexibility.<o:p></o:p></span></div>
<div class="MsoNormal">
<u><span lang="EN-GB"><br /></span></u></div>
<div class="MsoNormal">
<u><span lang="EN-GB">Compact size</span></u><span lang="EN-GB"><o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB">Space within a 19” rack is often at a
premium and the power supply competes with other instruments for this space. Selecting a supply that is 2U rather than 3U
in height will reduce the overall rack height or allow additional system functionality
to be added. A shorter depth may mean
that a shallower rack can be used, consuming less space in a laboratory or on a
factory floor, and saving costs.<o:p></o:p></span></div>
<div class="MsoNormal">
<u><span lang="EN-GB"><br /></span></u></div>
<div class="MsoNormal">
<u><span lang="EN-GB">Input voltage, active PFC and efficiency</span></u><span lang="EN-GB"><o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB">A power supply that operates just from a
230Vac input restricts operation in many countries that also use 115Vac. In the Americas or Japan, 208Vac may not be
readily available in the desired location, requiring an additional electrical circuit
to be wired in by an electrician.
Ideally chose a power supply that has the ability to operate from a wide
range 110 to 230Vac input.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB">The power supply should have active power
factor correction (PFC). This ensures that a sinusoidal input current is drawn
from the AC supply, reducing the RMS line current and increases the available
output power that can be drawn from an AC outlet or breaker panel. Active PFC also reduces the harmonic
distortion of the AC current which avoids an adverse impact on any sensitive
instruments on the same AC feed.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB">A high efficiency power supply consumes
less electricity and generates less internal heat. A supply that is 90% efficient wastes half
the power of an 80% efficient model, and allows other system instruments to
operate cooler.<o:p></o:p></span></div>
<div class="MsoNormal">
<u><span lang="EN-GB"><br /></span></u></div>
<div class="MsoNormal">
<u><span lang="EN-GB">Easy operation<o:p></o:p></span></u></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB">Engineers should not have to spend their valuable
time reading instruction manuals to be able to program a complex power supply. Choose one that has an intuitive, easy-to-use
graphical display. Ensure that the
supply has both coarse and fine adjustment for accurate output voltage and
current setting. Ideally a product
should utilize encoders, rather than potentiometers, for longer field life and
the ability to program the magnitude of the steps.<o:p></o:p></span></div>
<div class="MsoNormal">
<br /></div>
<div class="separator" style="clear: both; text-align: center;">
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<div class="MsoNormal">
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<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB">Figure
1: TDK-Lambda’s FLX-HV series front panel display<o:p></o:p></span></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<u><span lang="EN-GB">Quiet operation<o:p></o:p></span></u></div>
<div class="MsoNormal">
<u><span lang="EN-GB"><br /></span></u></div>
<div class="MsoNormal">
<span lang="EN-GB">Loud or annoying audible fan noise can
cause operators and nearby personnel to become fatigued. Scientific equipment
will often not be operating continuously and the high voltage power supply will
not require as much airflow for cooling at light loads. Selecting a power supply that has a variable
speed fan will reduce audible noise and prolong the life of the fan.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<u><span lang="EN-GB">Digital interfaces<o:p></o:p></span></u></div>
<div class="MsoNormal">
<u><span lang="EN-GB"><br /></span></u></div>
<div class="MsoNormal">
<span lang="EN-GB">For remote or automated operation a
standard digital interface is essential.
Chose a standard interface like USB or LAN. The manufacturer may include
additional features in additional to status and programming capability, like
being able to see the total operating hours and fault history. Check to see if the manufacturer offers a GUI
(Graphical User Interface) which will save time and effort to get the equipment
running.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<u><span lang="EN-GB">Safeguards and safety agency certification</span></u><span lang="EN-GB"><o:p></o:p></span></div>
<div class="MsoNormal">
<u><span lang="EN-GB"><br /></span></u></div>
<div class="MsoNormal">
<span lang="EN-GB">When working with high voltages, protective
functions are critical. Rackmount power
supplies need to manage the internal heat generation, and must be capable of protecting
the (often expensive) external load from damage due to an output overvoltage or
overcurrent condition. IEC 61010-1 is an
industry wide safety standard, allowing the product to be CE marked for easy
importation into the European Union.
Compliance to EN61000-6-2 for immunity and EN61000-6-3 for emissions
will reduce susceptibility to external electrical noise and avoid the power
supply from interfering with other equipment or instrumentation.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<u><span lang="EN-GB">Load arcs<o:p></o:p></span></u></div>
<div class="MsoNormal">
<u><span lang="EN-GB"><br /></span></u></div>
<div class="MsoNormal">
<span lang="EN-GB">Load arc events are common in high-voltage
applications, and require a power supply that responds in a controlled and
predictable manner. <a href="https://www.us.lambda.tdk.com/products/high-voltage-power/high-voltage-programmable-dc/flx-hv.html">TDK-Lambda’s
FLX-HV series</a> for example will count load arc events, and if three or more arcs
are detected in a five-second period, the unit will shut down for a 10-second
interval. Arc activity is shown on the front panel display and reported on the remote
interface. An integrated arc counter
records load arcs and can be read back via the remote interface, and reset to
zero if required. The FLX-HV supply also
includes a second non-resettable arc counter remote interface query.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<u><span lang="EN-GB">The manufacturer and product series<o:p></o:p></span></u></div>
<div class="MsoNormal">
<u><span lang="EN-GB"><br /></span></u></div>
<div class="MsoNormal">
<span lang="EN-GB">Selecting a global manufacturer like
TDK-Lambda is also recommended. If your product may be exported, technical
support is likely to be more accessible than a supplier that is focused on just
one region.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB">The correct choice of a programmable high
voltage power supply will provide you with flexibility, reliability and ease of
use. If your budget allows, select a
higher wattage model for expansion and use in another project. Remember, with a programmable product, the
output voltage and current limits can always be set lower.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB">Some manufacturers offer a range of
products, like the FLX-HV series mentioned earlier which has nine models
ranging from 10kV to 50kV and 200W to 1,000W. <span class="MsoHyperlink"><o:p></o:p></span></span></div>
<div class="MsoNormal">
<br /></div>
<div class="separator" style="clear: both; text-align: center;">
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<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB">Figure
2: FLX-HV high voltage power supply<o:p></o:p></span></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB">For more information visit <a href="https://www.us.lambda.tdk.com/products/high-voltage-power/high-voltage-programmable-dc/flx-hv.html">FLX-HV series</a><span class="MsoHyperlink"><o:p></o:p></span></span></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<br /></div>
<span lang="EN-GB" style="font-family: "calibri" , "sans-serif"; font-size: 11.0pt; line-height: 107%;">Power Guy</span>Power Guyhttp://www.blogger.com/profile/15282245011253622251noreply@blogger.com0tag:blogger.com,1999:blog-535177224836915617.post-57953752718498428802020-05-28T09:24:00.005-07:002022-12-22T09:12:56.923-08:00Avoiding noise issues when operating power supplies in parallel<br />
<div style="margin: 0in 0in 10pt;">
<span lang="EN-GB" style="font-size: 12pt; line-height: 115%;"><span style="font-family: "calibri";">Operating
power supplies in parallel is commonly used to increase the available output
power or to provide system redundancy in the event of a power supply
failure.<span style="mso-spacerun: yes;"> </span>Not all power supplies can be
connected in this manner, so please consult the manufacturer’s documentation
first.</span></span></div>
<br />
<div style="margin: 0in 0in 10pt;">
<span lang="EN-GB" style="font-size: 12pt; line-height: 115%;"><span style="font-family: "calibri";">One
method is “active” current sharing and is available as standard, or as an
option, on most power supplies rated 1,000W or higher.<span style="mso-spacerun: yes;"> </span>An internal high impedance circuit monitors
the output current and compares its voltage level to the other units via a parallel
connection (PC) wire. <span style="mso-spacerun: yes;"> </span>A common
connection (COM) serves as the return wire. <span style="mso-spacerun: yes;"> </span>The power supply output voltage is
automatically adjusted up or down to balance the output currents between the
paralleled power supplies.<span style="mso-spacerun: yes;"> </span>See Figure 1.</span></span></div>
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<div align="center" style="margin: 0in 0in 10pt; text-align: center;">
<span lang="EN-GB" style="font-size: 12pt; line-height: 115%;"><span style="font-family: "calibri";"><strong>Figure 1: Two power supplies
connected in parallel</strong></span></span></div>
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<div style="margin: 0in 0in 10pt;">
<span lang="EN-GB" style="font-size: 12pt; line-height: 115%;"><span style="font-family: "calibri";">At
first glance, this looks perfectly acceptable. When the system is operating
however, it may be observed that the power supplies are oscillating very
slightly.<span style="mso-spacerun: yes;"> </span>This is not a function of the
power supplies malfunctioning when in parallel, but actually may be due to
noise pick-up or noise currents circulating in the wiring.</span></span></div>
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<div style="margin: 0in 0in 10pt;">
<span lang="EN-GB" style="font-size: 12pt; line-height: 115%;"><span style="font-family: "calibri";">The
first thing to check is that the wiring between the PC and COM connections is
twisted, short as possible and routed away from any potentially noisy cables.</span></span></div>
<br />
<div style="margin: 0in 0in 10pt;">
<span lang="EN-GB" style="font-size: 12pt; line-height: 115%;"><span style="font-family: "calibri";">If
that does not solve the problem it may be due to how the negative remote sense
is wired.<span style="mso-spacerun: yes;"> </span>Looking at Figure 2, we can
see that the COM connection is internally connected to the negative sense
connection and as a result creating a potential noise loop.<span style="mso-spacerun: yes;"> </span>The oscillation may be the result of the currents
flowing in the negative load cables affecting the sensitive parallel and
sensing circuitry.</span></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 115%;"><span style="font-family: "calibri";"><strong>Figure 2: Noise loop within the parallel,
sensing and load system wiring</strong></span></span></div>
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<div style="margin: 0in 0in 10pt;">
<span lang="EN-GB" style="font-size: 12pt; line-height: 115%;"><span style="font-family: "calibri";">The
solution for this is to disconnect the wire between the two COM pins and connect
the negative remote sense wiring at the load. It will also compensate for voltage
drops in the negative load cables.<span style="mso-spacerun: yes;"> </span>See
Figure 3.</span></span><br />
<span lang="EN-GB" style="font-size: 12pt; line-height: 115%;"><span style="font-family: "calibri";"><br /></span></span></div>
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<br /></div>
<div align="center" style="margin: 0in 0in 10pt; text-align: center;">
<span lang="EN-GB" style="font-size: 12pt; line-height: 115%;"><span style="font-family: "calibri";"><strong>Figure 3: Negative remote sense
cables connected to the load and COM link removed</strong></span></span></div>
<br />
<div style="margin: 0in 0in 10pt;">
<span lang="EN-GB" style="font-size: 12pt; line-height: 115%;"><span style="font-family: "calibri";">With
this configuration, the internal signal common is isolated from noise on the
power cables and any voltage differentials. If desired, the positive remote
sense terminals can be connected to the positive of the load to compensate for
voltage drops in those cables too.</span></span></div>
<br />
<div style="margin: 0in 0in 10pt;">
<span lang="EN-GB" style="font-size: 12pt; line-height: 115%;"><span style="font-family: "calibri";">Power
Guy</span></span><br />
<br />
<br />
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Power Guyhttp://www.blogger.com/profile/15282245011253622251noreply@blogger.com0tag:blogger.com,1999:blog-535177224836915617.post-33093324840063865732020-04-15T09:44:00.002-07:002022-09-15T12:23:00.625-07:00How can I increase a power supply’s hold-up time?<div class="MsoNormal">
<b><u><span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;"><br /></span></u></b>
<b><u><span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">What is hold-up time?<o:p></o:p></span></u></b></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">When an AC-DC power supply’s input voltage is interrupted, during a brown out condition or a very brief power failure, the DC output will only remain within regulation for a short period of time. This is specified on the power supply datasheet as the hold-up time. During this hold-up time the power supply relies on energy stored in its capacitors to maintain operation.<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;"><br /></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">Figure 1 shows a simple block diagram of a power supply.<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">Figure 1: Power supply block diagram<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;"><br /></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">The AC input voltage is filtered, rectified and boosted to provide a DC bus voltage of around 390V. The DC-DC converter section of the power supply provides primary-secondary isolation and reduces the 390V bus down to the desired DC output voltage. The function of the high voltage bus electrolytic capacitor C1 is to reduce the ripple voltage on the 390V bus and store energy to keep the DC-DC converter operational during brief interruptions to the AC input.</span></div>
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<br /></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">Depending on the application, the length of the hold-up time varies from a half or full cycle of the incoming AC 50/60Hz voltage. This is typically 8 to 20ms at 100% load, but is normally sufficient to avoid electronic equipment from having to restart or reboot.<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;"><br /></span></div>
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<b><u><span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">When is extended hold-up time required?<o:p></o:p></span></u></b></div>
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<b><u><span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;"><br /></span></u></b></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">The medical industry’s concern regarding hold-up time has increased since the release of the EN 60601-1-2; 2015 (Ed4) immunity standard. Primarily created to address the growing number of products used in home healthcare, this standard specifies multiple AC voltage dips ranging from 20ms to 5 seconds. The longer outages are addressed by batteries or ensuring that no harm will occur to the patient or operator if the power supply output voltage drops out of the regulation band.<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;"><br /></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">Airborne equipment is covered by the DO-160 standard. Section 16 refers to power input, simulating conditions of aircraft power from before engine start (using auxiliary ground based power) to after landing, including emergencies. The requirement is for a hold-up time of at least 200ms.<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;"><br /></span></div>
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<b><u><span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">What techniques are available to increase hold-up time?<o:p></o:p></span></u></b></div>
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<b><u><span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;"><br /></span></u></b></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">There are various methods to extend power supply hold-up time, each with advantages and disadvantages. As the amount of energy stored in a capacitor C is calculated as: ½ x C x V<sup>2</sup>, to increase that energy storage and hence the hold-up time, either the amount of capacitance or the voltage on the capacitor has to increase. Since V is squared, an increase in the value of V will have a greater impact.<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">The following examples are based on a hypothetical system requiring a load of 150W at 12V, with a minimum output voltage requirement of 11.5V as the output decays to zero; 200ms is the desired hold-up time.<o:p></o:p></span></div>
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<div class="MsoListParagraphCxSpFirst" style="margin-left: 0.25in; text-indent: -0.25in;">
<b><span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">1.<span style="font-size: 7pt; font-stretch: normal; font-variant-east-asian: normal; font-variant-numeric: normal; font-weight: normal; line-height: normal;"> </span></span></b><b><span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">Using a higher rated power supply and operating it at a reduced load<o:p></o:p></span></b></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">If we were to use the 150W 12V output TDK-Lambda RWS150B-12 power supply and operate it at 100% load, we would have a hold-up of just over 30ms based on the evaluation test data. See Figure 2.</span></div>
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<span style="font-size: 12pt; line-height: 18.4px;"><v:shapetype coordsize="21600,21600" filled="f" id="_x0000_t75" o:preferrelative="t" o:spt="75" path="m@4@5l@4@11@9@11@9@5xe" stroked="f"><v:stroke joinstyle="miter"><v:formulas><v:f eqn="if lineDrawn pixelLineWidth 0"><v:f eqn="sum @0 1 0"><v:f eqn="sum 0 0 @1"><v:f eqn="prod @2 1 2"><v:f eqn="prod @3 21600 pixelWidth"><v:f eqn="prod @3 21600 pixelHeight"><v:f eqn="sum @0 0 1"><v:f eqn="prod @6 1 2"><v:f eqn="prod @7 21600 pixelWidth"><v:f eqn="sum @8 21600 0"><v:f eqn="prod @7 21600 pixelHeight"><v:f eqn="sum @10 21600 0"></v:f></v:f></v:f></v:f></v:f></v:f></v:f></v:f></v:f></v:f></v:f></v:f></v:formulas><v:path gradientshapeok="t" o:connecttype="rect" o:extrusionok="f"><o:lock aspectratio="t" v:ext="edit"></o:lock></v:path></v:stroke></v:shapetype><v:shape id="Picture_x0020_7" o:spid="_x0000_i1030" style="height: 228.85pt; visibility: visible; width: 267.85pt;" type="#_x0000_t75"><v:imagedata o:title="" src="file:///C:\Users\STEVE~1.ZMI\AppData\Local\Temp\msohtmlclip1\01\clip_image001.jpg"></v:imagedata></v:shape></span><span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;"><o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">Figure 2: Hold-up time versus output load for the RWS150B-12 power supply<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">As expected, the hold-up time is dependent on the output load drawn. The greater the load, the quicker C1’s stored energy is depleted. To obtain 200ms hold-up, we could use the TDK-Lambda’s 1500W rated CUS1500M-12 power supply. See Figure 3.</span></div>
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<span style="font-size: 12pt; line-height: 18.4px;"><v:shape id="Picture_x0020_16" o:spid="_x0000_i1029" style="height: 233.15pt; visibility: visible; width: 282.85pt;" type="#_x0000_t75"><v:imagedata o:title="" src="file:///C:\Users\STEVE~1.ZMI\AppData\Local\Temp\msohtmlclip1\01\clip_image002.jpg"></v:imagedata></v:shape></span><span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;"><o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">Figure 3: Hold-up time versus output load for the CUS1500M-12 power supply<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;"><br /></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">The larger value of “C1” in the CUS1500M-12 would provide enough energy to hold-up a 150W load for over 200ms.<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;"><br /></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">This would be a simple off the shelf solution, but a much larger, more expensive power supply would be required.<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;"><br /></span></div>
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<b><span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">2.<span style="font-size: 7pt; font-stretch: normal; font-variant-east-asian: normal; font-variant-numeric: normal; font-weight: normal; line-height: normal;"> </span></span></b><b><span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">Adding capacitance across the power supply output terminals or load<o:p></o:p></span></b></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">Figure 3: Adding load capacitance<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">At first glance adding additional capacitance (C3) across the output seems like an easy solution. Based on the equation 2 in the appendix, however, C3 would have to be a massive <b><u>4,595,745uF</u></b>.<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 16pt; line-height: 24.5333px;">C = 2 x Pout x t / (V<sup>2</sup> – Vend<sup>2</sup>)</span><span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;"><o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">C = 2 x 150 x 0.18 / (12<sup>2</sup> - 11.5<sup>2</sup>)<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">Note as the power supply already has 20ms of hold-up capability, t is reduced to 180ms (0.18s).<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">Even with a supercap this would consume a large amount of space. One other major concern is the over-current characteristics of the power supply during initial turn on. An uncharged C3 would appear to the power supply control circuit as a dead short across the output. The power supply would most likely fail to establish a 12V output when initially turned on.<o:p></o:p></span></div>
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<b><span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">3.<span style="font-size: 7pt; font-stretch: normal; font-variant-east-asian: normal; font-variant-numeric: normal; font-weight: normal; line-height: normal;"> </span></span></b><b><span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">A customized power supply with a larger high voltage bus capacitor (C1)<o:p></o:p></span></b></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">As previously mentioned, the energy stored in a capacitor is equal to ½ x C x V<sup>2</sup>, so adding capacitor C1a across the high 390Vdc bus has a greater effect than adding capacitance across the 12V output. See Figure 4.</span><span style="font-size: 12pt; line-height: 18.4px;"><v:shape id="Picture_x0020_18" o:spid="_x0000_i1027" style="height: 122.15pt; visibility: visible; width: 451.3pt;" type="#_x0000_t75"><v:imagedata o:title="" src="file:///C:\Users\STEVE~1.ZMI\AppData\Local\Temp\msohtmlclip1\01\clip_image004.jpg"></v:imagedata></v:shape></span><span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;"><o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">Figure 4: Adding high voltage bus capacitance<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">As the DC bus is not accessible on most power supplies, adding capacitors would involve creating a custom or modified standard design. This would involve engineering charges and safety re-certification fees, plus time to make the modification.<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">If the power supply to be modified had a hold-up time of 20ms, increasing it to 200ms would require adding the equivalent of nine more C1 capacitors. As C1 typically occupies 5 to 6% of the internal space of a power supply, it would increase the size of the power supply by around 50% for the same product height.<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">A power module based solution could also be created using a non-isolated AC-DC 360Vdc output converter (TDK-Lambda’s PF series) and a high voltage input isolated DC-DC 12V output converter (TDK-Lambda PH-A series). This again would require a custom board design with engineering and safety certification charges.<o:p></o:p></span></div>
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<b><span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">4.<span style="font-size: 7pt; font-stretch: normal; font-variant-east-asian: normal; font-variant-numeric: normal; font-weight: normal; line-height: normal;"> </span></span></b><b><span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">A 48V or 60V output AC-DC power supply and a wide range input DC-DC Converter<o:p></o:p></span></b></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">For an off-the-shelf standard product solution, a 48V output AC-DC power supply could be used with an isolated wide-range input 18 to 75V DC-DC converter with a 12V output. See Figure 5. The DC-DC converter may require a heatsink or cold plate for cooling.<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">Figure 5: 48V or 60V power supply and an isolated wide range input DC-DC converter<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">In addition to the hold-up inside the 48V output AC-DC power supply, capacitor C1 can be used for additional energy storage. We have taken advantage of the energy storage formula ½ x C x V<sup>2</sup> as V is now 48V rather than 12V in scenario 1. The efficiency of the DC-DC converter is considered as 90%. The hold-up of the AC-DC power supply is 20ms, requiring an additional 180ms (t).<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 16pt; line-height: 24.5333px;">C = 2 x P x t / (Eff x (V<sup>2</sup> – Vend<sup>2</sup>))<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">For our example, the required value of C1 would be 2 x 150 x 0.18 / (0.9 x (48<sup>2</sup> – 18<sup>2</sup>)) which calculates as <b><u>30,300uF</u></b>. <o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">If the 48V AC-DC power supply was replaced by one that had a 60V output, the additional capacitance could be reduced to <b><u>18,315uF</u></b>. A 72V output power supply would reduce that further to <b><u>12,345uF</u></b>.<o:p></o:p></span></div>
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<b><span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">5.<span style="font-size: 7pt; font-stretch: normal; font-variant-east-asian: normal; font-variant-numeric: normal; font-weight: normal; line-height: normal;"> </span></span></b><b><span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">A 48V output AC-DC power supply and a wide range input non-isolated DC-DC Converter<o:p></o:p></span></b></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">In this case, the chosen DC-DC converter is non-isolated (for higher efficiency, smaller size and lower cost) having a wide input range of 9 to 53V. See Figure 6. A non-isolated DC-DC converter would not require heatsinking.<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">Figure 6: 48V power supply and a non-isolated DC-DC converter<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">The efficiency of the non-isolated DC-DC (TDK-Lambda i6A series) converter is considered as 96%. The hold-up of the AC-DC power supply as 20ms, requiring an additional 180ms (t).<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 16pt; line-height: 24.5333px;">C = 2 x P x t / (Eff x (V<sup>2</sup> – Vend<sup>2</sup>))<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">For our example, the required value of C1 would be 2 x 150 x 0.18 / (0.96 x (48<sup>2</sup> – 9<sup>2</sup>)) which calculates as <b>25,304<u>uF</u></b>.<o:p></o:p></span></div>
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<b><span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">Summary<o:p></o:p></span></b></div>
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<b><span lang="EN-GB" style="font-size: 12pt;">Method<o:p></o:p></span></b></div>
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<b><span lang="EN-GB" style="font-size: 12pt;">Additional capacitance<o:p></o:p></span></b></div>
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<b><span lang="EN-GB" style="font-size: 12pt;">Pros<o:p></o:p></span></b></div>
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<b><span lang="EN-GB" style="font-size: 12pt;">Cons<o:p></o:p></span></b></div>
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<span lang="EN-GB" style="font-size: 12pt;">Larger power supply<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt;">None<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt;">Standard part<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt;">Cost and size of bigger supply<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt;">Larger output cap<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt;">4,595,745uF<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt;">Standard part<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt;">Size and potential start-up issues<o:p></o:p></span></div>
</td></tr>
<tr><td style="border-bottom: 1pt solid windowtext; border-image: initial; border-left: 1pt solid windowtext; border-right: 1pt solid windowtext; border-top: none; padding: 0in 5.4pt; width: 161.75pt;" width="377"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
<span lang="EN-GB" style="font-size: 12pt;">Larger HV bus cap<o:p></o:p></span></div>
</td><td style="border-bottom: 1pt solid windowtext; border-left: none; border-right: 1pt solid windowtext; border-top: none; padding: 0in 5.4pt; width: 81pt;" width="189"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt; text-align: center;">
<span lang="EN-GB" style="font-size: 12pt;">9 x C1 (~9,000uF)<o:p></o:p></span></div>
</td><td style="border-bottom: 1pt solid windowtext; border-left: none; border-right: 1pt solid windowtext; border-top: none; padding: 0in 5.4pt; width: 1.75in;" width="294"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt; text-align: center;">
<span lang="EN-GB" style="font-size: 12pt;">Custom solution<o:p></o:p></span></div>
</td><td style="border-bottom: 1pt solid windowtext; border-left: none; border-right: 1pt solid windowtext; border-top: none; padding: 0in 5.4pt; width: 1.5in;" width="252"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt; text-align: center;">
<span lang="EN-GB" style="font-size: 12pt;">Eng. cost and development time<o:p></o:p></span></div>
</td></tr>
<tr><td style="border-bottom: 1pt solid windowtext; border-image: initial; border-left: 1pt solid windowtext; border-right: 1pt solid windowtext; border-top: none; padding: 0in 5.4pt; width: 161.75pt;" width="377"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
<span lang="EN-GB" style="font-size: 12pt;">48V AC-DC + isolated DC-DC<o:p></o:p></span></div>
</td><td style="border-bottom: 1pt solid windowtext; border-left: none; border-right: 1pt solid windowtext; border-top: none; padding: 0in 5.4pt; width: 81pt;" width="189"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt; text-align: center;">
<span lang="EN-GB" style="font-size: 12pt;">30,300uF<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt;">Standard parts<o:p></o:p></span></div>
</td><td style="border-bottom: 1pt solid windowtext; border-left: none; border-right: 1pt solid windowtext; border-top: none; padding: 0in 5.4pt; width: 1.5in;" width="252"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt; text-align: center;">
<span lang="EN-GB" style="font-size: 12pt;">Space for DC-DC and heatsinking<o:p></o:p></span></div>
</td></tr>
<tr><td style="border-bottom: 1pt solid windowtext; border-image: initial; border-left: 1pt solid windowtext; border-right: 1pt solid windowtext; border-top: none; padding: 0in 5.4pt; width: 161.75pt;" width="377"><div class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt;">
<span lang="EN-GB" style="font-size: 12pt;">60V AC-DC + isolated DC-DC<o:p></o:p></span></div>
</td><td style="border-bottom: 1pt solid windowtext; border-left: none; border-right: 1pt solid windowtext; border-top: none; padding: 0in 5.4pt; width: 81pt;" width="189"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt; text-align: center;">
<span lang="EN-GB" style="font-size: 12pt;">18,315uF<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt;">Uncommon 60V AC-DC<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt;">Standard DC-DC<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt;">Space for DC-DC and heatsinking<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt;">72V AC-DC + isolated DC-DC<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt;">12,345uF<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt;">Uncommon 72V AC-DC<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt;">Standard DC-DC<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt;">Space for DC-DC and heatsinking<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt;">48V AC-DC + non-isolated DC-DC<o:p></o:p></span></div>
</td><td style="border-bottom: 1pt solid windowtext; border-left: none; border-right: 1pt solid windowtext; border-top: none; padding: 0in 5.4pt; width: 81pt;" width="189"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: 0.0001pt; text-align: center;">
<span lang="EN-GB" style="font-size: 12pt;">25,345uF<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt;">Standard parts<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt;">Space for DC-DC<o:p></o:p></span></div>
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<b><u><span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">Appendix - Calculating the required capacitance<o:p></o:p></span></u></b></div>
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<b><u><span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;"><br /></span></u></b></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">Below are the equations for calculating the required hold-up capacitance. The units of measure are Energy – Joules, Power – Watts, time – seconds, Voltage – Volts, Capacitance – Farads, Efficiency – Percentage.<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">Energy E is the product of the output power Pout and time t<o:p></o:p></span></div>
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<u><span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">Equation 1:</span></u></div>
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<span lang="EN-GB" style="font-size: 16pt; line-height: 24.5333px;">E = Pout x t<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 16pt; line-height: 24.5333px;"><br /></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">Stored energy (E) is half the product of the Capacitance (C) and the voltage (V) squared<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;"><br /></span></div>
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<span lang="EN-GB" style="font-size: 16pt; line-height: 24.5333px;">E = 0.5 x C x V<sup>2<o:p></o:p></sup></span></div>
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<span lang="EN-GB" style="font-size: 16pt; line-height: 24.5333px;"><sup><br /></sup></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">Rearranging for C we get</span></div>
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<span lang="EN-GB" style="font-size: 16pt; line-height: 24.5333px;"> C = 2 x E/V<sup>2</sup><o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 16pt; line-height: 24.5333px;"><sup><br /></sup></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">Note: The voltage on capacitor C will drop as it discharges into the load. At some point the voltage will be too low for the load to function leaving unused energy in the capacitor. That voltage point will be referred to as “Vend”. In the scenarios 2, 4, 5, 6 a voltage of 11.5V is used.<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;"><br /></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">Our “useful” energy for hold-up will be the initial minus the remaining energy.<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 16pt; line-height: 24.5333px;">E = (0.5 x C x V<sup>2</sup>) – (0.5 x C x Vend<sup>2</sup>)<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 16pt; line-height: 24.5333px;"><br /></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">Factoring the equation we get:</span></div>
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<span lang="EN-GB" style="font-size: 16pt; line-height: 24.5333px;">E = 0.5 x C x (V<sup>2</sup> – Vend<sup>2</sup>) </span><span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">or</span><span lang="EN-GB" style="font-size: 16pt; line-height: 24.5333px;"> C = 2 x E / (V<sup>2</sup> – Vend<sup>2</sup>)<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 16pt; line-height: 24.5333px;"><br /></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">Substituting for E from equation 1 we have<o:p></o:p></span></div>
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<u><span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">Equation 2:<o:p></o:p></span></u></div>
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<span lang="EN-GB" style="font-size: 16pt; line-height: 24.5333px;">C = 2 x Pout x t / (V<sup>2</sup> – Vend<sup>2</sup>)<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 16pt; line-height: 24.5333px;"><br /></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">In cases where a separate DC-DC converter is used, that converter will not be 100% efficient (Eff) and we need to adjust the value of our AC-DC output power Pout to compensate:<o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;"><br /></span></div>
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<span lang="EN-GB" style="font-size: 16pt; line-height: 24.5333px;">P = Pout / Eff</span><span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;"><o:p></o:p></span></div>
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<span lang="EN-GB" style="font-size: 16pt; line-height: 24.5333px;"><br /></span></div>
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<u><span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;">Equation 3:<o:p></o:p></span></u></div>
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<span lang="EN-GB" style="font-size: 12pt; line-height: 18.4px;"></span></div>
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<span lang="EN-GB" style="font-size: 16pt; line-height: 24.5333px;">C = 2 x P x t / (Eff x (V<sup>2</sup> – Vend<sup>2</sup>))<o:p></o:p></span></div>
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Power Guyhttp://www.blogger.com/profile/15282245011253622251noreply@blogger.com0tag:blogger.com,1999:blog-535177224836915617.post-3507569548898288152020-02-20T11:50:00.004-08:002022-12-22T09:08:43.849-08:00How do I evaluate a convection cooled power supply’s performance?<div class="MsoNormal">
<span lang="EN-GB">I discussed convection cooling in a previous article, giving guidance on how to position (mount) a power supply in a system. It did not cover how to evaluate a product’s performance though, a subject worthy of mention as testing methods across the industry differ significantly.<o:p></o:p></span></div>
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<span lang="EN-GB">First, a quick recap on convection cooling as it is widely assumed a convection cooled power supply does not need any airflow to operate. One definition of convection is “The transfer of heat by the circulation or movement of the heated parts of a liquid or gas”. In our case – the <u>circulation or movement of hot air</u>.<o:p></o:p></span></div>
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<span lang="EN-GB">An open frame power supply is typically mounted on a flat surface upon standoffs. Figure 1 shows how the air behaves. As the hot air rises, cooler air is drawn in from the sides. Although the airspeed is quite low, just 0.3m/s, it is sufficient to reduce internal temperatures.<o:p></o:p></span></div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjPIYpERXrUC9recSUhoGgVg4hyphenhyphenaBEo3GHVgepEYOCA4niOATuZQ2Ns5PEy4JO4IX-rzghLHPA2j9rlVERUj9J274Ba34z59-3aSEN7ZkeNxX8Pn5kpBIUC2rneVpJeQE8p8PoIo_wepUWC/s1600/Power+Supply+Diagram.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="564" data-original-width="1021" height="220" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjPIYpERXrUC9recSUhoGgVg4hyphenhyphenaBEo3GHVgepEYOCA4niOATuZQ2Ns5PEy4JO4IX-rzghLHPA2j9rlVERUj9J274Ba34z59-3aSEN7ZkeNxX8Pn5kpBIUC2rneVpJeQE8p8PoIo_wepUWC/s400/Power+Supply+Diagram.jpg" width="400" /></a></div>
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<span lang="EN-GB"><b>Figure 1: Natural airflow around a convection cooled power supply</b><o:p></o:p></span></div>
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<span lang="EN-GB">Before making the choice of vendor and power supply it is advisable to download not only the datasheet, but also the manufacturer’s evaluation report, reliability data, application information and safety files for the “Conditions of Acceptability”. If it is not available from the website request it. This “homework” is paramount to ensuring you are not going to have program delays due to non-performing power supplies or worse, excessive field failures.<o:p></o:p></span></div>
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<span lang="EN-GB">The report listing the thermal measurements is a key section and may raise some suspicions.<o:p></o:p></span></div>
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<span lang="EN-GB">Most power supplies are capable of operating over a wide range input. From a thermal aspect 115Vac is tougher than 230Vac, due to the higher currents (I<sup>2 </sup>x R=losses) in the input filtering and rectification circuitry. If the report only states results measured at 230V, this may be an issue.<o:p></o:p></span></div>
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<span lang="EN-GB">Convection cooled power supplies often have a higher forced air cooling rating stated on the datasheet. In this case the report should confirm if the test results were recorded with convection cooling. If that statement has not been made it should be noted for your own follow up testing. Check that the output loading is at 100%.<o:p></o:p></span></div>
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<span lang="EN-GB">The mounting orientation affects the thermal performance of the power supply. This too should be identified in the report.<o:p></o:p></span></div>
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<span lang="EN-GB">Where was the ambient temperature measured? Some reports show the temperature recorded above the power supply. This falsely overstates the true ambient temperature. Ambient should be recorded on both sides of the power supply, or underneath for a vertically mounted or DIN rail mounted supply.<o:p></o:p></span></div>
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<span lang="EN-GB">At what ambient temperature were the measurements recorded at and how long was the power supply running before the tests took place?<o:p></o:p></span></div>
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<span lang="EN-GB">A convection cooled power supply will take between two and three hours for the temperatures to stabilize. The larger, hotter components like the isolation transformer and power semiconductor heatsinks have a greater thermal mass than a small capacitor. If the report states that the power supply was run for one hour at 25<sup>o</sup>C and for one hour at 50<sup>o</sup>C then there should be at approximately a 20<sup> o</sup>C delta between the two sets of results. Power semiconductors do operate more efficiently at higher case temperatures, and the natural convection airflow will be higher, so there will be some discrepancies. This is why extrapolating results can give errors due to non-linearity.<o:p></o:p></span></div>
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<span lang="EN-GB">Having received your sample power supplies, you can start testing. If a thermal chamber is not readily available, it is advisable to bench test with the unit covered with a large enclosure. This avoids external airflow from air-conditioning systems affecting the results. Even in a thermal chamber, there may be an internal fan to circulate air. TDK-Lambda recommends placing the power supply in a sealed enclosure to shield that air from interfering with the results. Remember to test at all the input voltages your system will be operating from.<o:p></o:p></span></div>
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<span lang="EN-GB"><br /></span></div>
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<span lang="EN-GB">Ideally the temperature of each electrolytic capacitor should be measured using thermocouples attached to the exposed metal case at the top of the component. This data can be used to determine each capacitor’s life. TDK-Lambda can assist, supplying a sample with thermocouples already attached*.<o:p></o:p></span></div>
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<span lang="EN-GB">In the end system it is very important to ensure that there is adequate space for the air to be drawn in from the sides and allowed to exit above the power supply. A distance of 50mm is considered safe, less than this will cause interference with the natural convection airflow. Power supply thermal testing has to be repeated again in the end system to verify the naturally circulating airflow has not been restricted.<o:p></o:p></span></div>
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<span lang="EN-GB">The cooler a power supply operates, the longer it will last. Care taken during the early stages of product development can avoid last minute launch delays.<o:p></o:p></span></div>
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<span lang="EN-GB"><br /></span></div>
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<span lang="EN-GB">*A follow-up article will be available shortly on assessing capacitor life.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB">Power Guy<o:p></o:p></span></div>
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Power Guyhttp://www.blogger.com/profile/15282245011253622251noreply@blogger.com0tag:blogger.com,1999:blog-535177224836915617.post-54033803608111981222019-12-06T16:00:00.006-08:002022-12-22T08:59:27.592-08:00Can I operate my three phase power supply from WYE and Delta AC inputs?<div class="MsoNormal">
<div class="MsoNormal">
<span lang="EN-GB">Before addressing how we connect, or even
if we can connect, a three phase power supply to an AC voltage source, I think we
should review some background information.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB">AC-DC power supplies that are rated higher
than 2.5kW frequently have a three phase AC input. In the US the voltage can be 208/220Vac or
480Vac. In Europe it is a “harmonized
400Vac” which in actuality is 415Vac in the UK and 380Vac for Europe. A higher input voltage allows more power to
be drawn from the incoming AC at a lower current. These three phase AC voltages can be one of
two configurations – Delta or Wye (pronounced “why”).<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB">The following should also clarify what
three phase input voltage would be best suited for a large power system. Just as important, how to read a
manufacturer’s datasheet to make sure that power supply can be used in the US,
Europe and globally.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<br />
<div class="MsoNormal">
<span lang="EN-GB">Typically very high voltage power is
transmitted from the power generation plants to local substation transformers
(where it is reduced in voltage) and then to facilities in a Delta
configuration (Figure 1). Note that a Delta
configuration only uses three wires and has no neutral or ground wire. This saves the cost of a fourth wire, which
is not needed during transmission.</span></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiRD_ngarmgK15iJ-SnQjGiALhl5EiQihxUhOkrEEkJkHmRyVQUw0mdwwh1XRdcRRxxh8cCadgdIgcHNKt1RVKvSJhVsPXasxLCbNCWa4kzlzvtoRsQmcCS8Expktp98tNThYK9H-YhDv_d/s1600/Blog+1.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="471" data-original-width="554" height="272" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiRD_ngarmgK15iJ-SnQjGiALhl5EiQihxUhOkrEEkJkHmRyVQUw0mdwwh1XRdcRRxxh8cCadgdIgcHNKt1RVKvSJhVsPXasxLCbNCWa4kzlzvtoRsQmcCS8Expktp98tNThYK9H-YhDv_d/s320/Blog+1.png" width="320" /></a></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB">Figure
1: Delta wiring configuration (US voltage shown)<o:p></o:p></span></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB">
</span></div>
<div class="MsoNormal">
<span lang="EN-GB">I will start with the US first. Figure 2 shows a basic overview of what a manufacturing
facility receives from the Grid, at what point it is lowered in voltage and how
it is distributed to the loads.</span></div>
<div class="separator" style="clear: both; text-align: center;">
<br /></div>
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEghbmJRfPz2LvTM5kBO86KH_fDNah4FYitJG03LRxEtelqKJF-5Opnj3nWBE4ccX9I2QDrdAZcDoJ7mFuY5Hy4I2MSGU82PVQmVtcFbWBFdaj5R7fA5vPDLVah-3grNueE42IGQB8vfhzLs/s1600/blog+2.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="601" data-original-width="1380" height="276" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEghbmJRfPz2LvTM5kBO86KH_fDNah4FYitJG03LRxEtelqKJF-5Opnj3nWBE4ccX9I2QDrdAZcDoJ7mFuY5Hy4I2MSGU82PVQmVtcFbWBFdaj5R7fA5vPDLVah-3grNueE42IGQB8vfhzLs/s640/blog+2.jpg" width="640" /></a></div>
<div class="MsoNormal">
<br /></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB">Figure
2: Typical US facility power distribution<o:p></o:p></span></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB">Starting at the left, a 480Vac Delta three-wire
feed enters the facility from the substation.
From the incoming distribution panel, 480Vac Delta is supplied to electrical
equipment needing a large amount of power.
Large ovens, test equipment for semiconductors, burn in chambers and
machines fabricating metal (including laser cutting and additive manufacturing)
would typically use 480Vac Delta. It is
important to note that equipment connected to this voltage feed can reduce the
size of the Delta-Wye step down transformer, saving cost, energy losses and
floor space.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB">
</span></div>
<div class="MsoNormal">
<span lang="EN-GB">To supply the rest of the facility, the
three phase is reduced from a 480Vac Delta configuration to a 4 wire 208Vac
phase to phase Wye configuration (Figure 3) via a step-down Delta-Wye
transformer. <o:p></o:p></span></div>
<div class="MsoNormal">
<br /></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi38NDwA0ctL1WdNwwsaZlIfM3C_VoehGaG8fqzBp-954qiXWo-KjlbGlIytU2ndBZ7Bs_7O1Sp5MwcQyMaXCLWdlhx8RpEjjeSOWJySGJAjxN7hbZpTtA5uTVOcmeWgAoE2B36BI9MlcVL/s1600/blog+3.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="586" data-original-width="731" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi38NDwA0ctL1WdNwwsaZlIfM3C_VoehGaG8fqzBp-954qiXWo-KjlbGlIytU2ndBZ7Bs_7O1Sp5MwcQyMaXCLWdlhx8RpEjjeSOWJySGJAjxN7hbZpTtA5uTVOcmeWgAoE2B36BI9MlcVL/s400/blog+3.jpg" width="400" /></a></div>
<div class="MsoNormal">
<br /></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB">Figure
3: 208Vac phase to phase Wye configuration<o:p></o:p></span></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB">From the distribution panel, in addition to
being able to supply 208Vac phase to phase, 120Vac is available by connecting
to either one of the Lines (L1, L2 or L3) and neutral N.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB">As very rough order of magnitude, 208Vac
three phase would be used for mid-sized loads, greater than 5kW and less than
25kW and single phase 208Vac for smaller loads greater than 1.5kW. We are all aware of the 120Vac wall outlet
which can support around 1kW. The amount
of power depends on the wiring size and fusing, consult your local qualified
electrician!<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB">There may also be a second Delta-Wye
transformer in some facilities. As
discussed in another blog, this provides 277Vac feeds to lighting and HVAC
(Heating, Ventilation and Air Conditioning) equipment.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB">
</span></div>
<div class="MsoNormal">
<span lang="EN-GB">In Europe the arrangement and voltages are different
than the US, see Figure 4.<o:p></o:p></span></div>
<div class="MsoNormal">
<br /></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgoIlJYrPV2bMHaV096QD2M_dTcBpZWSIih9RVrhZlbUtX1emL8usnKQpNWOEInykb2z49FZAie126Z-gDneFminEBc-yEPqiWLvYdzkljYH75Yq4mXuaVecMGNXFp-yST2n-xeXZis-86Q/s1600/blog+4.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="562" data-original-width="1379" height="260" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgoIlJYrPV2bMHaV096QD2M_dTcBpZWSIih9RVrhZlbUtX1emL8usnKQpNWOEInykb2z49FZAie126Z-gDneFminEBc-yEPqiWLvYdzkljYH75Yq4mXuaVecMGNXFp-yST2n-xeXZis-86Q/s640/blog+4.jpg" width="640" /></a></div>
<div class="MsoNormal">
<br /></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB">Figure
4: Typical European facility<o:p></o:p></span></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<br /></div>
<div class="MsoNormal">
<span lang="EN-GB">
</span></div>
<div class="MsoNormal">
<span lang="EN-GB">Again starting on the left, high voltage
(11kVac in a Delta configuration in the UK) is provided by from the Grid and a
step down transformer delivers three phase in a four wire Wye configuration to
the facility’s distribution panel. See
Figure 5. As explained earlier
380V/220Vac is mainly used in mainland Europe, 415/240Vac in the UK.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh22ZdDPVO81BfgOpL_zz6ppMOrbnbWOHJdZNSgEAP8Dp04iXQ1HG8NpS2Ss6HdnLxk4GotJsEWAQMSRKVifGe9nK3PRrNaxEscqV-YpdIHEvpUw3rxcrQeUwcGYK9kocJ8JwypL2m9bvv4/s1600/blog+5.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="585" data-original-width="739" height="316" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh22ZdDPVO81BfgOpL_zz6ppMOrbnbWOHJdZNSgEAP8Dp04iXQ1HG8NpS2Ss6HdnLxk4GotJsEWAQMSRKVifGe9nK3PRrNaxEscqV-YpdIHEvpUw3rxcrQeUwcGYK9kocJ8JwypL2m9bvv4/s400/blog+5.jpg" width="400" /></a></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<br /></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB">Figure
5: 380/415Vac phase to phase Wye configuration<o:p></o:p></span></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB">From the distribution panel, in addition to
being able to supply 380/415Vac phase to phase, 220/240Vac is available by
connecting to either one of the Lines (L1, L2 or L3) and neutral N. <o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB">Returning to the subject of three phase
AC-DC power supplies, we shall review some examples from TDK-Lambda’s product
offering.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal" style="margin-left: .5in;">
<span lang="EN-GB">The HWS1800T-24 is
a 1.8kW rated power supply accepting a 170-265Vac 3 phase input. This would be suitable for operation on a
standard US type of 208Vac three phase Wye input. It could also be operated in Europe, but
would require a 400Vac to 220Vac three phase Wye-Wye step down transformer.<o:p></o:p></span></div>
<div class="MsoNormal" style="margin-left: .5in;">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal" style="margin-left: .5in;">
<span lang="EN-GB">The TPS4000-24 is
a 4kW rated power supply accepting a 350-528Vac 3 phase input, either Delta or
Wye. This would be suitable for operation
in the US and in Europe without the need to change connections to the power
supply, or additional transformers.<o:p></o:p></span></div>
<div class="MsoNormal" style="margin-left: .5in;">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal" style="margin-left: .5in;">
<span lang="EN-GB">The Genesys+</span><span style="font-family: Calibri, sans-serif; font-size: 11pt;">™</span> series of programmable power supplies has a large number of models ranging from
1.5kW to 15kW. Depending on the power
level the units have different input voltages, covering most of the global
input voltages.</div>
<div class="MsoNormal" style="margin-left: .5in;">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in; margin-left: .5in; margin-right: 0in; margin-top: 0in;">
<span lang="EN-GB">GH1.5kW / G1.7kW: 1ø 85 to 265Vac<o:p></o:p></span></div>
<div class="MsoNormal" style="margin-bottom: .0001pt; margin-bottom: 0in; margin-left: .5in; margin-right: 0in; margin-top: 0in;">
<span lang="EN-GB">G2.7kW / G3.4kW: 1ø
170 to 265Vac or 3ø 208Vac or 3ø 400Vac<o:p></o:p></span></div>
<div class="MsoNormal" style="margin-left: .5in;">
<span lang="EN-GB">G5kW / GSP10kW
& 15kW: 3ø 208Vac, or 3ø 400Vac
or 3ø 480Vac<o:p></o:p></span></div>
<div class="MsoNormal" style="margin-left: .5in;">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB">Ensure that the manufacturer has internal
fuses fitted, as some low cost power supplies do not. A high voltage fuse is required for each
phase. They are bulky and are not
inexpensive.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB">After reading this blog, you might even
take a second glance at those big grey mystery boxes surrounded by chain link
fencing and high voltage warnings in the company parking lot!<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB">
<span lang="EN-GB" style="font-family: "calibri" , "sans-serif"; font-size: 11.0pt; line-height: 115%;">Power Guy</span></span></div>
</div>
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<o:p></o:p></div>
<div class="MsoNormal">
<o:p></o:p></div>
<div class="MsoNormal">
<o:p></o:p></div>
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Power Guyhttp://www.blogger.com/profile/15282245011253622251noreply@blogger.com0tag:blogger.com,1999:blog-535177224836915617.post-28523320451617480092019-09-30T14:54:00.001-07:002022-12-22T08:58:40.881-08:00Fan cooling power supplies, which airflow direction is better?<div class="MsoNormal">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;">Even though the
efficiency levels of new power supply designs are now routinely in the 94 to
95% range, the push for higher power densities continues. Fan cooling is one
option to reduce the product’s overall size for mid to high power requirements.
Should the fan blow air into the power supply or extract air out? This depends on several factors.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;"><br /></span></div>
<span style="font-family: inherit;"><span lang="EN-GB" style="font-size: 12.0pt; line-height: 115%;">In rack mounted products
like the Genesys+</span><span lang="EN-GB" style="font-size: 12.0pt; line-height: 115%;">™</span><span lang="EN-GB" style="font-size: 12.0pt; line-height: 115%;"> programmable power supplies </span><span style="font-size: 12pt;">the airflow is drawn through the front and out
the rear. This is to offer the best possible cooling for these products, to
optimize the overall system’s performance and avoid the operator being
subjected to hot exhaust air.</span></span><br />
<span style="font-family: inherit;"><span style="font-size: 12pt;"><br /></span>
</span><br />
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;">For enclosed power
supplies, air flow direction can depend upon which direction the system air is
being directed.<span style="mso-spacerun: yes;"> </span>Having the power supply’s
air flowing in the opposite direction to larger system’s fans can cause the
airflow to reduce dramatically due to the system’s pressure, and cause
overheating.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;"><br /></span></div>
<div class="MsoNormal">
<span style="font-family: inherit;"><span lang="EN-GB" style="font-size: 12.0pt; line-height: 115%; mso-ascii-font-family: Calibri; mso-hansi-font-family: Calibri;">Where the fan is
positioned in a power supply is another consideration.<span style="mso-spacerun: yes;"> </span>The lifetime of an e</span><span style="font-size: 12pt;">lectrolytic capacitor is
extremely sensitive to heat.</span><span style="font-size: 12pt;"> </span><span style="font-size: 12pt;">Each 10</span><sup>o</sup><span style="font-size: 12pt;">C
rise in the capacitor’s temperature will halve its operating life, thus cool
air has to be directed accordingly.</span></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;">Figure 1 shows the
top view of a typical product (the cover removed) and the location of the
capacitors and fan.<span style="mso-spacerun: yes;"> </span>In the case of this
power supply, as the input and output connectors are both located on the left
side (front) for system wiring access, the fan is situated on the right hand
side (rear).<o:p></o:p></span></div>
<div class="MsoNormal">
<span style="font-family: inherit;"><br /></span></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiar52ppu8WZ4-gcBJx7KWe91h_yLu2rc7CvR7IuUKXdDPcXzVBVw-npaePKbWGu8i4z2hdGxsipbLb7ifrheQisVddcxEpYN5lSV-K5rU7_A6L7h4A0wn38c456bWMeaJlTW_5pTYgfbBn/s1600/Blog+Diagram+1.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-family: inherit;"><img border="0" data-original-height="535" data-original-width="1380" height="248" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiar52ppu8WZ4-gcBJx7KWe91h_yLu2rc7CvR7IuUKXdDPcXzVBVw-npaePKbWGu8i4z2hdGxsipbLb7ifrheQisVddcxEpYN5lSV-K5rU7_A6L7h4A0wn38c456bWMeaJlTW_5pTYgfbBn/s640/Blog+Diagram+1.jpg" width="640" /></span></a></div>
<div class="MsoNormal">
<span style="font-family: inherit;"><br /></span></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;">Figure 1: Electrolytic capacitors and fan
location</span></div>
<span style="font-family: inherit;"><br /></span>
<br />
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;">Should the fan
blow air out, or in? As with any design, there are advantages and
disadvantages.<o:p></o:p></span></div>
<div class="MsoNormal">
<span style="font-family: inherit;"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;">
</span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;">Figure 2 shows the
fan blowing air out (exhaust). <o:p></o:p></span></div>
<span style="font-family: inherit;"><br /></span>
<br />
<div class="MsoNormal">
<span style="font-family: inherit;"><br /></span></div>
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<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;">Figure 2: Fan exhausts the hot air</span></div>
<span style="font-family: inherit; font-size: 12pt;">Advantages</span><br />
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;"><br /></span></div>
<div class="MsoNormal" style="margin-left: .5in;">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;">The cool air is drawn in over the output capacitors, this keeps these
components cool and their lifetime is improved.<o:p></o:p></span></div>
<div class="MsoNormal" style="margin-left: .5in;">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;"><br /></span></div>
<div class="MsoNormal" style="margin-left: .5in;">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;">As indicated by the size of the arrows, the speed of the air entering
the power supply is lower than the exit speed.
This is due to the cross sectional area of the input being twice that of
the output Lower speed air is less
likely to draw in outside contaminants (dust and dirt) which could impact
product lifetime. <o:p></o:p></span></div>
<div class="MsoNormal" style="margin-left: .5in;">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;">Disadvantages<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;"><br /></span></div>
<div class="MsoNormal" style="margin-left: .5in;">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;">The input capacitors receive warmer air, but with an air directing
baffle and perforations in the cover this could be mitigated. In general though,
the input capacitors are less sensitive than the output filtering capacitors.<o:p></o:p></span></div>
<div class="MsoNormal" style="margin-left: .5in;">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;"><br /></span></div>
<div class="MsoNormal" style="margin-left: .5in;">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;">Higher speed airflow cannot easily be directed at hot items like
magnetics.<o:p></o:p></span><br />
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;"><br /></span>
<span style="font-family: inherit; font-size: 12pt;">Hot air is drawn across the
fan bearings, which could affect fan life. If the fan speed is controlled
according to ambient temperature, this too would be mitigated. Higher quality
or higher temperature fans can also be used.</span></div>
<span style="font-family: inherit;"><br /></span>
<br />
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;"><br /></span></div>
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<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;"></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;">Figure 3 shows the
fan blowing cool air in.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;"><br /></span></div>
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<span style="font-family: inherit;"><br /></span></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;">Figure 3: Fan draws in air<o:p></o:p></span></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;"><br /></span></div>
<span style="font-family: inherit;"><br /></span>
<br />
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;">Advantages<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;"><br /></span></div>
<div class="MsoNormal" style="margin-left: .5in;">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;">Cool air is drawn across the fan bearings, increasing fan life.<o:p></o:p></span></div>
<div class="MsoNormal" style="margin-left: .5in;">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;">Fast moving cool air creates backpressure and can be directed at hot
areas, like the magnetics, reducing the overall de-rating of the power supply.<o:p></o:p></span></div>
<div class="MsoNormal" style="margin-left: .5in;">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;">Disadvantages<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;"><br /></span></div>
<div class="MsoNormal" style="margin-left: .5in;">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;">The output capacitors may run hotter.
Larger capacitors can be used, which will have less internal heating and
run cooler.<o:p></o:p></span></div>
<div class="MsoNormal" style="margin-left: .5in;">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;">More contamination may be drawn into the power supply.<o:p></o:p></span></div>
<div class="MsoNormal" style="margin-left: .5in;">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;">Many fan cooled
power supplies offer “reverse fan” options on their datasheets. Often due to
reduced thermal performance within the supply and heated air moving through the
fan, additional derating may apply. <o:p></o:p></span></div>
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</span></div>
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<span lang="EN-GB" style="font-family: inherit; font-size: 12.0pt; line-height: 115%;">Power Guy<o:p></o:p></span></div>
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Power Guyhttp://www.blogger.com/profile/15282245011253622251noreply@blogger.com0tag:blogger.com,1999:blog-535177224836915617.post-64581125761872434612019-08-30T09:33:00.001-07:002022-12-22T08:57:58.796-08:00When are fuses needed in Line and Neutral for industrial applications?<span style="font-family: "arial" , "helvetica" , sans-serif;"><br /></span>
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<span style="font-family: "arial" , "helvetica" , sans-serif;"><span style="font-size: 12pt;">Last month I wrote about why using a
dual input fused medical/industrial power supply might cause an issue in some
industrial applications.</span><span style="font-size: 12pt;"> </span><span style="font-size: 12pt;">Shortly after
publication a customer requested an application note showing the fitting an
external fuse in the Neutral connection of an industrial DIN rail power supply
application. </span><span style="font-size: 12pt;"> </span><span style="font-size: 12pt;">DIN rail power supplies are
rarely certified to the medical safety standards and usually only have a single
input fuse.</span></span><br />
<span style="font-family: "arial" , "helvetica" , sans-serif;"><span style="font-size: 12pt;"><br /></span></span></div>
<div class="MsoNormal">
<span style="font-size: 12.0pt; line-height: 115%; mso-ascii-font-family: Calibri; mso-hansi-font-family: Calibri;"><span style="font-family: "arial" , "helvetica" , sans-serif;">Upon investigation, the application was
in this case operating a power supply phase to phase from a 3-phase WYE
configuration in North America, see Figure 1.<o:p></o:p></span></span></div>
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<span style="font-family: "arial" , "helvetica" , sans-serif;"><span style="mso-fareast-language: EN-GB; mso-no-proof: yes;"><v:shapetype coordsize="21600,21600" filled="f" id="_x0000_t75" o:preferrelative="t" o:spt="75" path="m@4@5l@4@11@9@11@9@5xe" stroked="f">
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<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhLQVtLwlq8Y0urM-dNPwEEZr4roB5kk3vKqtli2ASK28VPAYv-mbaWwOHdHDkvqQWwrVW7lCTMR8v3Xxn-HwszkMr4U4xiUd0rNWmYJAdAW8GoHPrvfb4wwgVdC_sPalb02kXPTstaSE1Z/s1600/WYE.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-family: "arial" , "helvetica" , sans-serif;"><img border="0" data-original-height="586" data-original-width="731" height="256" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhLQVtLwlq8Y0urM-dNPwEEZr4roB5kk3vKqtli2ASK28VPAYv-mbaWwOHdHDkvqQWwrVW7lCTMR8v3Xxn-HwszkMr4U4xiUd0rNWmYJAdAW8GoHPrvfb4wwgVdC_sPalb02kXPTstaSE1Z/s320/WYE.jpg" width="320" /></span></a></div>
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<span style="font-family: "arial" , "helvetica" , sans-serif;"><br /></span></div>
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<span style="font-size: 12.0pt; line-height: 115%; mso-ascii-font-family: Calibri; mso-hansi-font-family: Calibri;"><span style="font-family: "arial" , "helvetica" , sans-serif;">Figure 1: Phase to phase connection (208Vac)<o:p></o:p></span></span></div>
<div class="MsoNormal">
<span style="font-size: 12.0pt; line-height: 115%; mso-ascii-font-family: Calibri; mso-hansi-font-family: Calibri;"><span style="font-family: "arial" , "helvetica" , sans-serif;"><br /></span></span></div>
<div class="MsoNormal">
<span style="font-size: 12.0pt; line-height: 115%; mso-ascii-font-family: Calibri; mso-hansi-font-family: Calibri;"><span style="font-family: "arial" , "helvetica" , sans-serif;">Connecting phase to phase enables the equipment
to be supplied with 208Vac which draws less input current than using 115Vac.<span style="mso-spacerun: yes;"> </span>This allows the use of smaller wire gauges
and connectors which saves money and are easier to install.<span style="mso-spacerun: yes;"> </span>The power supply is connected as shown in
Figure 2.<o:p></o:p></span></span></div>
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<span style="font-family: "arial" , "helvetica" , sans-serif;"><span style="font-size: 12.0pt; line-height: 115%; mso-ascii-font-family: Calibri; mso-fareast-language: EN-GB; mso-hansi-font-family: Calibri; mso-no-proof: yes;"><v:shape id="Picture_x0020_1" o:spid="_x0000_i1026" style="height: 186.75pt; mso-wrap-style: square; visibility: visible; width: 348pt;" type="#_x0000_t75">
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<span style="font-size: 12.0pt; line-height: 115%; mso-ascii-font-family: Calibri; mso-hansi-font-family: Calibri;"><span style="font-family: "arial" , "helvetica" , sans-serif;"><br /></span></span></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh8uNQE709uBlzLcI4lGUGWo16Xyh7ZDeJZe2I0pSsYHSVa4K6kCFPb7Sp3QKtRMco445m35I1kF024nrISuiy0kCvRUJowrYdAczsDHB29emmt5sxZPhuZvNVYhsp80ieQGfVTJ20XI-n-/s1600/Phase+to+phase+connection.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-family: "arial" , "helvetica" , sans-serif;"><img border="0" data-original-height="610" data-original-width="1137" height="171" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh8uNQE709uBlzLcI4lGUGWo16Xyh7ZDeJZe2I0pSsYHSVa4K6kCFPb7Sp3QKtRMco445m35I1kF024nrISuiy0kCvRUJowrYdAczsDHB29emmt5sxZPhuZvNVYhsp80ieQGfVTJ20XI-n-/s320/Phase+to+phase+connection.jpg" width="320" /></span></a></div>
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<span style="font-size: 12.0pt; line-height: 115%; mso-ascii-font-family: Calibri; mso-hansi-font-family: Calibri;"><span style="font-family: "arial" , "helvetica" , sans-serif;"><br /></span></span></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span style="font-size: 12.0pt; line-height: 115%; mso-ascii-font-family: Calibri; mso-hansi-font-family: Calibri;"><span style="font-family: "arial" , "helvetica" , sans-serif;">Figure 2: Power supply connected phase to phase<o:p></o:p></span></span></div>
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<span style="font-size: 12.0pt; line-height: 115%; mso-ascii-font-family: Calibri; mso-hansi-font-family: Calibri;"><span style="font-family: "arial" , "helvetica" , sans-serif;"><br /></span></span></div>
<div class="MsoNormal">
<span style="font-size: 12.0pt; line-height: 115%; mso-ascii-font-family: Calibri; mso-hansi-font-family: Calibri;"><span style="font-family: "arial" , "helvetica" , sans-serif;">In the UL safety report Conditions of
Acceptability, or Technical Considerations section, reference is made to all
testing being performed on a protected branch circuit rated for 20A; <span style="color: black; mso-themecolor: text1;">this section also lists the items that
a user should consider before applying power to the unit. <o:p></o:p></span></span></span></div>
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<span style="font-family: arial, helvetica, sans-serif; font-size: 12pt;"><br /></span>
<span style="font-family: arial, helvetica, sans-serif; font-size: 12pt;">If a short or overload inside the power
supply occurs across the Line and Neutral or Line and Ground, the internal fuse
F1 will open.</span><span style="font-family: arial, helvetica, sans-serif; font-size: 12pt;"> </span><span style="font-family: arial, helvetica, sans-serif; font-size: 12pt;">If the short occurs from
Neutral to Ground, the fuse or breaker at the distribution panel will open.</span></div>
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<span style="font-family: arial, helvetica, sans-serif; font-size: 12pt;"><br /></span>
<span style="font-family: arial, helvetica, sans-serif; font-size: 12pt;">If, however, the equipment connection to
the building installation wiring is made via a non-industrial plug and socket,
then an external fuse or breaker (F2) has to be added in the Neutral line as
shown in Figure 3.</span><span style="font-family: arial, helvetica, sans-serif; font-size: 12pt;"> </span><span style="font-family: arial, helvetica, sans-serif; font-size: 12pt;">This applies to input
voltages of less than 240Vac +10%.</span></div>
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<span style="font-family: "arial" , "helvetica" , sans-serif;"><span style="font-size: 12.0pt; line-height: 115%; mso-ascii-font-family: Calibri; mso-fareast-language: EN-GB; mso-hansi-font-family: Calibri; mso-no-proof: yes;"><v:shape id="Picture_x0020_2" o:spid="_x0000_i1025" style="height: 198.75pt; mso-wrap-style: square; visibility: visible; width: 370.5pt;" type="#_x0000_t75">
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<span style="font-size: 12.0pt; line-height: 115%; mso-ascii-font-family: Calibri; mso-hansi-font-family: Calibri;"><span style="font-family: "arial" , "helvetica" , sans-serif;"><br /></span></span></div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjR6UB8iwy-pZTqRLE28HoeknonnC2QVsPLxdY_MKEQvEyQ6Y_-T6fP9x7IPDkIc4h1M2vOO_KTXfIhg8jRIlpGhCCocYqdHpJ0EIHKuX-XOUpiY3f9taR9T1apy15noAvQuzuU9K_vtezX/s1600/Phase+to+phase+with+ext+fuse.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-family: "arial" , "helvetica" , sans-serif;"><img border="0" data-original-height="609" data-original-width="1137" height="171" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjR6UB8iwy-pZTqRLE28HoeknonnC2QVsPLxdY_MKEQvEyQ6Y_-T6fP9x7IPDkIc4h1M2vOO_KTXfIhg8jRIlpGhCCocYqdHpJ0EIHKuX-XOUpiY3f9taR9T1apy15noAvQuzuU9K_vtezX/s320/Phase+to+phase+with+ext+fuse.jpg" width="320" /></span></a></div>
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<span style="font-size: 12.0pt; line-height: 115%; mso-ascii-font-family: Calibri; mso-hansi-font-family: Calibri;"><span style="font-family: "arial" , "helvetica" , sans-serif;"><br /></span></span></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span style="font-size: 12.0pt; line-height: 115%; mso-ascii-font-family: Calibri; mso-hansi-font-family: Calibri;"><span style="font-family: "arial" , "helvetica" , sans-serif;">Figure 3: The installation of an external fuse
or breaker in the Neutral<o:p></o:p></span></span></div>
<div class="MsoNormal">
<span style="font-size: 12.0pt; line-height: 115%; mso-ascii-font-family: Calibri; mso-hansi-font-family: Calibri;"><span style="font-family: "arial" , "helvetica" , sans-serif;"><br /></span></span></div>
<div class="MsoNormal">
<span style="font-size: 12.0pt; line-height: 115%; mso-ascii-font-family: Calibri; mso-hansi-font-family: Calibri;"><span style="font-family: "arial" , "helvetica" , sans-serif;">Always have your equipment installed by
a qualified electrician and checked by a safety engineer for compliance to the
relevant building and electrical codes!<o:p></o:p></span></span></div>
<div class="MsoNormal">
<span style="font-family: arial, helvetica, sans-serif; font-size: 12pt;"><br /></span>
<span style="font-family: arial, helvetica, sans-serif; font-size: 12pt;">Power Guy</span></div>
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Power Guyhttp://www.blogger.com/profile/15282245011253622251noreply@blogger.com0tag:blogger.com,1999:blog-535177224836915617.post-28011419450475367162019-07-31T06:18:00.001-07:002022-12-22T08:57:25.994-08:00When are dual fused power supplies not permitted?<br />
<div class="MsoNormal">
<div class="MsoNormal">
<span style="font-family: "calibri" , "sans-serif"; font-size: 12.0pt; line-height: 115%;">For
many years AC-DC power supplies for the medical market are not only safety
certified to the IEC 60601-1 medical standard, but also to the industrial IEC
60950-1 / IEC 62368-1 standards. Dual
certification reduces the number of individual model numbers that have to be
produced and stocked; this improves production efficiency and reduces the
amount of inventory held in distribution and the supply chain. One small cost adder is that two AC input
fuses are needed in many medical applications, one in the Line side and one in
the Neutral side.</span></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
<span style="font-family: "calibri" , "sans-serif"; font-size: 12.0pt; line-height: 115%;">Dual
fusing is necessary to guarantee full protection if the polarity of the Line
and Neutral wiring to the power supply should be reversed. This might be due to a wiring error at the building’s
AC socket or in the wiring feeding the power supply.</span></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
<span style="font-family: "calibri" , "sans-serif"; font-size: 12.0pt; line-height: 115%;">I
had to say I was mildly surprised when TDK-Lambda started offering a single
(Line) fuse option on their new medical/industrial power supplies. Two protective devices surely must be better
than one? Some investigation was
required, because someone else was bound to question this too!</span></div>
<div class="MsoNormal">
<br /></div>
<span style="font-family: "calibri" , "sans-serif"; font-size: 12.0pt; line-height: 115%;">If
an industrial system is consuming more current than a regular AC socket can
support, it would have to be permanently connected to a distribution panel or
building wiring. This task is normally
carried out by a professional electrician, who would be aware of the potential dangers
of a polarity reversal. Figure 1 shows a
power supply connected to the AC input, with the Neutral connected to the earth
ground at the panel.</span></div>
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<span style="line-height: 115%;"><br /></span></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg2LBPbTbWuQg2tMNCJEYUW51ArptHvfYd7u1r0wd5aGQ-351dYyIU-9-Rtnd6lR8LkhgZMtyxaAitLKkpwob-1RobSx0dWZsRa7K8-K4BcaChx5SUhhRPh534iypU4ZmK1LfWAXx_Yorl4/s1600/fuse.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="490" data-original-width="762" height="205" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg2LBPbTbWuQg2tMNCJEYUW51ArptHvfYd7u1r0wd5aGQ-351dYyIU-9-Rtnd6lR8LkhgZMtyxaAitLKkpwob-1RobSx0dWZsRa7K8-K4BcaChx5SUhhRPh534iypU4ZmK1LfWAXx_Yorl4/s320/fuse.jpg" width="320" /></a></div>
<div align="center" class="MsoNormal" style="text-align: center;">
Figure 1: AC-DC power supply permanently
installed to a distribution panel</div>
<div class="MsoNormal">
<span style="line-height: 115%;"><br /></span></div>
<div class="MsoNormal">
<span style="font-family: "calibri" , "sans-serif"; font-size: 12.0pt; line-height: 115%;">In
the event of an over-current fault condition in the power supply or fuse aging,
there is a 50% chance that either F1 or F2 would open. If F2 was to open, a service technician may
believe that there is no AC power being applied to the power supply. Inadvertent contact with the Line while
touching the earth ground would result in an electrical shock. This is even more likely if the power supply
in question is of an open frame type construction.</span></div>
<div class="MsoNormal">
<span style="line-height: 115%;"><br /></span></div>
<div class="MsoNormal">
<span style="font-family: "calibri" , "sans-serif"; font-size: 12.0pt; line-height: 115%;">To
avoid this, the NEC, CEC, IEE Wiring Regulations and IEC 364, specifically
prohibit fusing in the Neutral in this type of equipment. To overcome this a single fuse power supply
must be selected. This can be achieved
by using an industrial (single fuse) or a medical/industrial power supply that
has a single fuse option.</span></div>
<div class="MsoNormal">
<span style="font-family: "calibri" , "sans-serif"; line-height: 115%;"><br /></span></div>
<div class="MsoNormal">
<span style="font-family: "calibri" , "sans-serif"; font-size: 12.0pt; line-height: 115%;">TDK-Lambda
currently offers a single fuse option on the medical and industrial certified
QM modular series and CUS-M models.</span><br />
<span style="font-family: "calibri" , "sans-serif"; font-size: 12.0pt; line-height: 115%;"><br /></span>
<span style="font-family: "calibri" , "sans-serif"; font-size: 12.0pt; line-height: 115%;">Power Guy</span></div>
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<span style="mso-fareast-language: EN-GB; mso-no-proof: yes;"><v:shapetype coordsize="21600,21600" filled="f" id="_x0000_t75" o:preferrelative="t" o:spt="75" path="m@4@5l@4@11@9@11@9@5xe" stroked="f">
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Power Guyhttp://www.blogger.com/profile/15282245011253622251noreply@blogger.com0tag:blogger.com,1999:blog-535177224836915617.post-67744142125891767822019-05-30T14:57:00.001-07:002022-09-15T12:17:37.128-07:00Does it matter how an EMC/EMI filter is wired to a power supply?<br />
<div class="MsoNormal">
</div>
<div class="MsoNormal" style="text-align: left;">
An email was recently received by
TDK-Lambda’s Technical Support from a technician who was fault-finding a video
system. His questions about how an EMC
filter should be connected were relevant and warranted a blog article on the
subject!</div>
<div class="MsoNormal" style="text-align: left;">
<br /></div>
<div class="MsoNormal" style="text-align: left;">
<span lang="EN-GB">As indicated in Figure 1, the EMC filter is
situated between the AC input to the system and the power supply providing DC
voltage(s) to the system load.<span style="mso-spacerun: yes;"> </span>The
filter’s function is to reduce incoming noise from the AC input and/or outgoing
noise to the AC input from the power supply.<o:p></o:p></span></div>
<div class="separator" style="clear: both; text-align: center;">
<br /></div>
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhV_Kk0iNHRng2b5nE9Y3WttBtV9Iar0Jlw3qrrbyBmPozovQcVtVBgDFKBypEOez9w_bVF9mha7tpM0vns3t3axulCiU03CEaSey_3z1hyt1kgv6EuAdwcZlZcnXYNKjHsyu95hc-ve8me/s1600/fig+1.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="344" data-original-width="1447" height="152" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhV_Kk0iNHRng2b5nE9Y3WttBtV9Iar0Jlw3qrrbyBmPozovQcVtVBgDFKBypEOez9w_bVF9mha7tpM0vns3t3axulCiU03CEaSey_3z1hyt1kgv6EuAdwcZlZcnXYNKjHsyu95hc-ve8me/s640/fig+1.png" width="640" /></a></div>
<br />
<br />
<div class="separator" style="clear: both; text-align: center;">
Figure
1: System block diagram</div>
<div class="separator" style="clear: both; text-align: center;">
<br /></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<o:wrapblock><v:shape id="Picture_x0020_2" o:spid="_x0000_s1026" style="height: 244.5pt; left: 0; margin-left: 0; margin-top: 41.05pt; mso-position-horizontal-relative: margin; mso-position-horizontal: center; mso-position-vertical-relative: text; mso-position-vertical: absolute; mso-wrap-distance-bottom: 0; mso-wrap-distance-left: 9pt; mso-wrap-distance-right: 9pt; mso-wrap-distance-top: 0; mso-wrap-style: square; position: absolute; text-align: left; visibility: visible; width: 374.25pt; z-index: 251658240;" type="#_x0000_t75">
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<div style="text-align: left;">
<span lang="EN-GB">Regarding connection to the filter, let us now look at a
typical EMC filter - the 250Vac 10A rated RSEN-2010 for example (see Figure 2
and 3).<o:p></o:p></span></div>
</div>
<div align="center" class="MsoNormal" style="text-align: center;">
<br /></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj05JcNTslX8u343SegjewIDgpDJv1rbpVj9hnc4g4JwbL5vap8fmCLtxZY4wby0hnF0cWVzV3P-5CHL1wN_j1Un2_JvU_-NI8-dRij-Nwjt3ZriipXOeWRteJ8wnZt2M1b-9UXYL6VEjuH/s1600/fig+2.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="326" data-original-width="499" height="261" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj05JcNTslX8u343SegjewIDgpDJv1rbpVj9hnc4g4JwbL5vap8fmCLtxZY4wby0hnF0cWVzV3P-5CHL1wN_j1Un2_JvU_-NI8-dRij-Nwjt3ZriipXOeWRteJ8wnZt2M1b-9UXYL6VEjuH/s400/fig+2.JPG" width="400" /></a></span></div>
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<br /></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB"></span></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB">Figure
2: RSEN-2010 filter<o:p></o:p></span></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjv_hyamquiIX684D1506nZtHhA74BeE-fRIWSPt-YSsn6-nYUYvr2tIAFuBLtmKBc0i6ptRcrkguA-y0dy5XzEDbuo77ZO4uFbgVHNOmoYkRwF51AJwf_IArU4T_TqEkq8sd_tkTCo0EyD/s1600/fig+3.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="239" data-original-width="626" height="244" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjv_hyamquiIX684D1506nZtHhA74BeE-fRIWSPt-YSsn6-nYUYvr2tIAFuBLtmKBc0i6ptRcrkguA-y0dy5XzEDbuo77ZO4uFbgVHNOmoYkRwF51AJwf_IArU4T_TqEkq8sd_tkTCo0EyD/s640/fig+3.JPG" width="640" /></a></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<br /></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB">Figure
3: RSEN schematic<o:p></o:p></span></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB">Reviewing Figure 2, the nomenclature
“LINE/LOAD” on the left hand and right hand side of the label indicates that
either set of the terminals can be used for the input or load connection.<span style="mso-spacerun: yes;"> </span>It can be also noted that there is no
indication of where the Line or Neutral should be wired to, just numbers 1, 2,
3 & 4.<span style="mso-spacerun: yes;"> </span>Which connections are made to
these terminals is very important.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB">On the right hand side of the label and
schematic (Figure 3), two additional capacitors, known as “Y” capacitors can be
seen.<span style="mso-spacerun: yes;"> </span>These provide a low impedance path
to earth ground to reduce high frequency common-mode noise.<span style="mso-spacerun: yes;"> </span>When the filter is used to reduce system
noise from the power supply reaching the AC source, terminals 3 and 4 should be
connected to the <u>power supply</u>.<span style="mso-spacerun: yes;"> </span>If
the filter is being used to reduce externally generated high frequency noise
from entering the system then terminals 3 and 4 should be connected to the <u>AC
source input</u>.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB">It is essential that if the AC line is
connected to terminal “1”, then terminal “4” should be connected to the power
supply Line terminal.<span style="mso-spacerun: yes;"> </span>Likewise with
terminals “2” and “3” for the neutral wiring as shown in Figure 4. <o:p></o:p></span></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal" style="text-align: center;">
<span lang="EN-GB"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjHubbdV53h1zWmndAL3X8RjD1Vehdl7S7PBdW7Y2gQ6qZpzyTajb860qNnoTj1yl5mA7W-UO8scR1HqW6Gfa6eiQXFHbhchNRiPXp66NdIW9eSUNrPrZ-uW-V2MChPD8K8BepVx9U8brEU/s1600/fig+4.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="345" data-original-width="1480" height="148" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjHubbdV53h1zWmndAL3X8RjD1Vehdl7S7PBdW7Y2gQ6qZpzyTajb860qNnoTj1yl5mA7W-UO8scR1HqW6Gfa6eiQXFHbhchNRiPXp66NdIW9eSUNrPrZ-uW-V2MChPD8K8BepVx9U8brEU/s640/fig+4.png" width="640" /></a></span></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<br /></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span style="mso-ansi-language: EN-US; mso-no-proof: yes;"><v:shape id="Picture_x0020_6" o:spid="_x0000_i1027" style="height: 105pt; mso-wrap-style: square; visibility: visible; width: 451.3pt;" type="#_x0000_t75">
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</v:imagedata></v:shape></span><span lang="EN-GB"><o:p></o:p></span></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB">Figure
4: Connection of the filter to the AC and the power supply<o:p></o:p></span></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB">If the wiring to “3” and “4” is crossed,
there could be safety issues for a power supply with a single input fuse situated
internally in series with the AC Line terminal. <span style="mso-spacerun: yes;"> </span><o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB"><span style="mso-spacerun: yes;"><br /></span></span></div>
<div class="MsoNormal">
<span lang="EN-GB">If the AC is correctly wired (Figure 5a),
in the event the internal power supply fuse was to open due to a fault, the
internal circuitry is isolated.<span style="mso-spacerun: yes;"> </span>It is important
to note that at the breaker panel, where the AC first comes into the building,
the neutral input is grounded to earth.<o:p></o:p></span></div>
<div class="MsoNormal">
<br /></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB"><span style="mso-spacerun: yes;"><br /></span></span></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh2_Jgsj7LunnIr2afBcsVFXVATALU4-DPTLG9ik4YPFr-jwlj-ZNeloiDtERakRMU3kT-FMpqZIgKnI1H5ZnmXefCZP9n-lyaCIgqM8OShCwd3QAmH2N5_U8IHlLs91Xb4H29GIV281-xz/s1600/fig+5a.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="322" data-original-width="872" height="147" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh2_Jgsj7LunnIr2afBcsVFXVATALU4-DPTLG9ik4YPFr-jwlj-ZNeloiDtERakRMU3kT-FMpqZIgKnI1H5ZnmXefCZP9n-lyaCIgqM8OShCwd3QAmH2N5_U8IHlLs91Xb4H29GIV281-xz/s400/fig+5a.png" width="400" /></a></span></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB"><span style="mso-spacerun: yes;"><br /></span></span></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB"><span style="mso-spacerun: yes;"><br /></span></span></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB">Figure
5a: <u>Correct</u> AC connection to a single fuse power supply<o:p></o:p></span></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB">If the Line and Neutral is reversed to the
power supply due to incorrect wiring (Figure 5b), in the event of the fuse
opening the internal circuit is still live.<span style="mso-spacerun: yes;">
</span>Two issues can arise with this scenario.<span style="mso-spacerun: yes;">
</span>A service technician fault-finding the system could receive an
electrical shock, particularly with an open frame power supply without a cover.<span style="mso-spacerun: yes;"> </span>Secondly, if an internal short was to occur
in the power supply between Line and the earthed chassis, the fuse would be out
of circuit and not open.<span style="mso-spacerun: yes;"> </span>Even the simple
use of a mounting screw that is too long could cause this!<o:p></o:p></span></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal" style="text-align: center;">
<span lang="EN-GB"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjqv6MuhyBKFII1LPFqTFD2GTGh6ioT0e4eyys080cVqOouIKkB6NH7B3vu104atuU8u7NUqWgzi81nZrbeX_LNYT47rB8gk9nQXf5kl6wwtmLfrEh3ApSoEVoVSBoz4oog-xZ8XAjvhSTV/s1600/fig+5b.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="321" data-original-width="873" height="146" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjqv6MuhyBKFII1LPFqTFD2GTGh6ioT0e4eyys080cVqOouIKkB6NH7B3vu104atuU8u7NUqWgzi81nZrbeX_LNYT47rB8gk9nQXf5kl6wwtmLfrEh3ApSoEVoVSBoz4oog-xZ8XAjvhSTV/s400/fig+5b.png" width="400" /></a></span></div>
<div class="MsoNormal" style="text-align: center;">
<br /></div>
<div class="MsoNormal" style="text-align: center;">
<span lang="EN-GB"></span></div>
<div class="MsoNormal" style="text-align: justify;">
<span lang="EN-GB"></span></div>
<div class="MsoNormal">
<span lang="EN-GB"><br /></span></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB">Figure
5b: <u>Incorrect</u> AC connection to a single fuse power supply<o:p></o:p></span></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<span lang="EN-GB"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB">Always ensure that adequate inspection and
testing techniques are in place with AC wiring.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB">Power Guy<o:p></o:p></span></div>
<br />
<br />
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Power Guyhttp://www.blogger.com/profile/15282245011253622251noreply@blogger.com0tag:blogger.com,1999:blog-535177224836915617.post-50803138949501622312019-04-29T15:39:00.003-07:002022-12-22T08:46:50.018-08:00How do I balance the current between two DIN rail power supplies used in parallel?<br />
<div class="MsoNormal" style="line-height: normal; margin: 0in 0in 0pt;">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";">Before
economically priced DIN rail power supplies gained popularity, many 100W or
higher power rated units provided users with a parallel operation function in
the form of switch fitted on the front panel.<span style="mso-spacerun: yes;">
</span>This switch allowed the user to select between “droop mode” current
share between two or more supplies and single unit operation. Droop mode
allowed for balancing of the output currents between the units.</span></div>
<br />
<div class="MsoNormal" style="line-height: normal; margin: 0in 0in 0pt;">
<span lang="EN-GB" style="color: black; font-family: "arial" , "sans-serif"; font-size: 10.5pt;">If power supplies without a parallel operation function are being used
and additional current is required for the system load, a second power supply
could be connected in parallel, although many manufacturers do not recommend this.<span style="mso-spacerun: yes;"> </span>Unless the output voltages of both power
supplies are set to the same voltage, the unit with the greatest output voltage
may deliver the majority of the current and operate in an over current
condition. This will reduce the unit’s field life due to excessive internal heating.<span style="mso-spacerun: yes;"> </span>Ideally the output current of each power
supply should be routinely measured during preventative maintenance to ensure
they are balanced, which is both time consuming and cumbersome.<o:p></o:p></span></div>
<br />
<div class="MsoNormal" style="line-height: normal; margin: 0in 0in 0pt;">
<span lang="EN-GB" style="color: black; font-family: "arial" , "sans-serif"; font-size: 10.5pt;">One alternative is to use a “redundancy” module with a load balance
option, like TDK-Lambda’s DRM40.<span style="mso-spacerun: yes;"> </span>Figure
1 shows a DRM40 used to connect two 20A power supplies to deliver up to 40A and
Figure 2 the DRM40 with its current balancing LED.<o:p></o:p></span></div>
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjVbaLQh53ETcKSU6rzSJR8bIIA8aO0M5efpjqxE5GPDJ5dg_bhUW-boiWhKpME89z4wbtxug3lIhmq80kXvuauUviskfJ5ISRrAIR78gQaTtHRlYt6H_Qm6Uzw8TD8gN_VFIcHCMTxo_ST/s1600/Blog+1.png.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="478" data-original-width="1190" height="256" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjVbaLQh53ETcKSU6rzSJR8bIIA8aO0M5efpjqxE5GPDJ5dg_bhUW-boiWhKpME89z4wbtxug3lIhmq80kXvuauUviskfJ5ISRrAIR78gQaTtHRlYt6H_Qm6Uzw8TD8gN_VFIcHCMTxo_ST/s640/Blog+1.png.jpg" width="640" /></a></div>
<br />
<div align="center" class="MsoNormal" style="line-height: normal; margin: 0in 0in 0pt; text-align: center;">
<span lang="EN-GB" style="color: black; font-family: "arial" , "sans-serif"; font-size: 10.5pt;">Figure 1: Two units connected in
parallel with the DRM40<o:p></o:p></span></div>
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKvPVrTOgjAFdKPicVRULqITMyvLcIjNJuts1APQ_gGaa2W8ehMKf-hRInkwLHTDr_SCY3gwXjhcc1QTdWfGdoXZACUNii-4M6NqgJZAbNU5BkXE22FXUaWd9IozSgk4TGrJsLSPadwNaP/s1600/Blog+2.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="489" data-original-width="444" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKvPVrTOgjAFdKPicVRULqITMyvLcIjNJuts1APQ_gGaa2W8ehMKf-hRInkwLHTDr_SCY3gwXjhcc1QTdWfGdoXZACUNii-4M6NqgJZAbNU5BkXE22FXUaWd9IozSgk4TGrJsLSPadwNaP/s320/Blog+2.jpg" width="289" /></a></div>
<br />
<div align="center" class="MsoNormal" style="line-height: normal; margin: 0in 0in 0pt; text-align: center;">
<span lang="EN-GB" style="color: black; font-family: "arial" , "sans-serif"; font-size: 10.5pt;">Figure 2: DRM current balance LED<o:p></o:p></span></div>
<br />
<div class="MsoNormal" style="line-height: normal; margin: 0in 0in 0pt;">
<span lang="EN-GB" style="color: black; font-family: "arial" , "sans-serif"; font-size: 10.5pt;">If the LED is not illuminated, measure the output voltage on both power supplies.
Adjust the voltage of the power supply with the lowest voltage higher until the
LED turn on.<span style="mso-spacerun: yes;"> </span>Alternatively, one can adjust
the voltage of the power supply with the highest voltage lower.<span style="mso-spacerun: yes;"> </span>The current balance LED will be illuminated
when the difference between the voltages is less than 50mV and the output currents
are balanced.<o:p></o:p></span></div>
<br />
<div class="MsoNormal" style="line-height: normal; margin: 0in 0in 0pt;">
<span lang="EN-GB" style="color: black; font-family: "arial" , "sans-serif"; font-size: 10.5pt;">The DRM40 has internal MOSFETs, used to block reverse currents in the
event of one power supply failing short circuit.<span style="mso-spacerun: yes;"> </span>They also allow the measurement of each power
supply’s output voltage without disconnecting any load cables.<o:p></o:p></span></div>
<br />
<div class="MsoNormal" style="line-height: normal; margin: 0in 0in 0pt;">
<span lang="EN-GB" style="color: black; font-family: "arial" , "sans-serif"; font-size: 10.5pt;">The DRM40 can also be used in redundant power systems, where two power
supplies are used in a 1+1 configuration as shown in Figure 3.<span style="mso-spacerun: yes;"> </span>If one power supply fails the other will
continue to provide current to the load.<span style="mso-spacerun: yes;">
</span>The load balancing function can be used in same manner.<o:p></o:p></span></div>
<br />
<br />
<div class="separator" style="clear: both; text-align: center;">
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<br />
<br />
<div align="center" class="MsoNormal" style="line-height: normal; margin: 0in 0in 0pt; text-align: center;">
<span lang="EN-GB" style="color: black; font-family: "arial" , "sans-serif"; font-size: 10.5pt;">Figure 3: DRM40 used in a 1+1 redundant
configuration<o:p></o:p></span></div>
<br />
<div class="MsoNormal" style="line-height: normal; margin: 0in 0in 0pt;">
<span lang="EN-GB" style="color: black; font-family: "arial" , "sans-serif"; font-size: 10.5pt;">Power Guy<o:p></o:p></span></div>
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Power Guyhttp://www.blogger.com/profile/15282245011253622251noreply@blogger.com0tag:blogger.com,1999:blog-535177224836915617.post-90344734410653518112019-01-25T09:51:00.002-08:002022-12-22T08:46:18.263-08:00What is the difference between efficiency and average efficiency?<br />
<div class="MsoNormal">
<b style="mso-bidi-font-weight: normal;"><span style="font-family: "arial" , "sans-serif"; mso-ansi-language: EN-US;">Efficiency<o:p></o:p></span></b></div>
<div class="MsoNormal">
<b style="mso-bidi-font-weight: normal;"><span style="font-family: "arial" , "sans-serif"; mso-ansi-language: EN-US;"><br /></span></b></div>
<div class="MsoNormal">
<span style="font-family: "arial" , "sans-serif"; mso-ansi-language: EN-US;">Power supply datasheets include product efficiency in a percentage
format for each voltage and output power model, as a guidance to how much power
is lost in wasted heat when the product is running. <span style="mso-spacerun: yes;"> </span>As the actual operating efficiency varies
with input voltage, output load, ambient temperature and component tolerance,
usually there is a test condition noted.<span style="mso-spacerun: yes;"> </span></span></div>
<div class="MsoNormal">
<span style="font-family: "arial" , "sans-serif"; mso-ansi-language: EN-US;">Phrases like “up to 95%” or “typically 93% at 230Vac input, 100% load and
25<sup>o</sup>C ambient” are widely used.<o:p></o:p></span></div>
<div class="MsoNormal">
<br clear="ALL" style="mso-ignore: vglayout;" />
<span style="font-family: "arial" , "sans-serif"; mso-ansi-language: EN-US;">If the
selection of the power supply is being made purely on efficiency, then the
manufacturer’s evaluation data has to be studied in order to determine the
measured efficiency at the user’s load condition.<span style="mso-spacerun: yes;"> </span>Figure 1 shows the efficiency vs. output
current plot for TDK-Lambda’s 600W rated 24V output GXE600-24 for different input
voltages.<span style="mso-spacerun: yes;"> </span>At 60% load, 230Vac input one
could expect the efficiency to be 94%.<o:p></o:p></span></div>
<div class="MsoNormal">
<br /></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgwZwKzm2XjDTQPrdGOcsz1edMWaJa5aBN76hoeVPsNc344rmnj3gNIBdebkMFRIYsXrHL63Nub9SM88MX4owc4IoIXG2p4mwzu1STlllFFYns7M-3f3gCXj75w0Q79A_rrlh1bhu5o_o6m/s1600/Efficiency+Chart.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="236" data-original-width="624" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgwZwKzm2XjDTQPrdGOcsz1edMWaJa5aBN76hoeVPsNc344rmnj3gNIBdebkMFRIYsXrHL63Nub9SM88MX4owc4IoIXG2p4mwzu1STlllFFYns7M-3f3gCXj75w0Q79A_rrlh1bhu5o_o6m/s640/Efficiency+Chart.jpg" width="640" /></a></div>
<div class="MsoNormal">
<br /></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<u><span style="font-family: "arial" , "sans-serif"; mso-ansi-language: EN-US;">Figure 1:
GXE600-24 Efficiency vs Output Current</span></u></div>
<div class="MsoNormal">
<br /></div>
<div class="MsoNormal">
<b style="mso-bidi-font-weight: normal;"><span style="font-family: "arial" , "sans-serif"; mso-ansi-language: EN-US;">Average
efficiency<o:p></o:p></span></b></div>
<div class="MsoNormal">
<b style="mso-bidi-font-weight: normal;"><span style="font-family: "arial" , "sans-serif"; mso-ansi-language: EN-US;"><br /></span></b></div>
<div class="MsoNormal">
<span style="font-family: "arial" , "sans-serif"; mso-ansi-language: EN-US;">External power supplies complying with the DoE (Department of Energy)
and EU efficiency regulations will sometimes only state the standard (and its
revision) they comply with.<span style="mso-spacerun: yes;"> </span>TDK-Lambda’s
DTM110PW240C8 datasheet for example, states compliance with the latest DoE
Level VI & EU Tier 2 Efficiency standards and also includes that the
average efficiency is >89%. The average efficiency for an external power
supply rated between 49-250W has to be at least 89% to comply with the current
and proposed standards.<o:p></o:p></span></div>
<div class="MsoNormal">
<span style="font-family: "arial" , "sans-serif"; mso-ansi-language: EN-US;"><br /></span></div>
<div class="MsoNormal">
<span style="font-family: "arial" , "sans-serif"; mso-ansi-language: EN-US;">Is “Average Efficiency” the same as “Efficiency”?<span style="mso-spacerun: yes;"> </span>No.<o:p></o:p></span></div>
<div class="MsoNormal">
<span style="font-family: "arial" , "sans-serif"; mso-ansi-language: EN-US;"><br /></span></div>
<div class="MsoNormal">
<span style="font-family: "arial" , "sans-serif"; mso-ansi-language: EN-US;">Average efficiency is calculated by measuring the efficiency at 25%,
50%, 75% and 100% loads.<span style="mso-spacerun: yes;"> </span>These four values
are added together and the total is divided by four to obtain the average.
Measurements are taken at 115Vac and 230Vac inputs.<o:p></o:p></span></div>
<div class="MsoNormal">
<span style="font-family: "arial" , "sans-serif"; mso-ansi-language: EN-US;"><br /></span></div>
<div class="MsoNormal">
<span style="font-family: "arial" , "sans-serif"; mso-ansi-language: EN-US;">Using the measurements from Figure 2 for the DTM110PW240C8, the
calculated average efficiency at 115Vac is 90% and 90.5% at 230Vac.<o:p></o:p></span></div>
<div class="MsoNormal">
<span style="font-family: "arial" , "sans-serif"; mso-ansi-language: EN-US;"><br /></span></div>
<div align="center">
<table border="0" cellpadding="0" cellspacing="0" class="MsoNormalTable" style="border-collapse: collapse; mso-padding-alt: 0in 5.4pt 0in 5.4pt; mso-yfti-tbllook: 1184; width: 784px;">
<tbody>
<tr style="height: 19.35pt; mso-yfti-firstrow: yes; mso-yfti-irow: 0;">
<td style="border: solid windowtext 1.0pt; height: 19.35pt; mso-border-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 60.0pt;" width="140"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">--<o:p></o:p></span></b></div>
</td>
<td style="border-left: none; border: solid windowtext 1.0pt; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 50.0pt;" width="117"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">Input<o:p></o:p></span></b></div>
</td>
<td colspan="3" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid black 1.0pt; border-top: solid windowtext 1.0pt; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid black .5pt; mso-border-top-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 2.25in;" width="378"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">Output<o:p></o:p></span></b></div>
</td>
<td style="border-left: none; border: solid windowtext 1.0pt; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 64.0pt;" width="149"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">--<o:p></o:p></span></b></div>
</td>
</tr>
<tr style="height: 25.9pt; mso-yfti-irow: 1;">
<td style="border-top: none; border: solid windowtext 1.0pt; height: 25.9pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 60.0pt;" width="140"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">Load (%)<o:p></o:p></span></b></div>
</td>
<td style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 25.9pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 50.0pt;" valign="top" width="117"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">Power<br />
(W)<o:p></o:p></span></b></div>
</td>
<td style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 25.9pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 56.0pt;" valign="top" width="131"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">Voltage<br />
(Vdc)<o:p></o:p></span></b></div>
</td>
<td style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 25.9pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 56.0pt;" valign="top" width="131"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">Current<br />
(A)<o:p></o:p></span></b></div>
</td>
<td style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 25.9pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 50.0pt;" valign="top" width="117"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">Power<br />
(W)<o:p></o:p></span></b></div>
</td>
<td style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 25.9pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 64.0pt;" valign="top" width="149"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">Efficiency <br />
(%)<o:p></o:p></span></b></div>
</td>
</tr>
<tr style="height: 16.15pt; mso-yfti-irow: 2;">
<td colspan="6" style="border-bottom: solid windowtext 1.0pt; border-left: solid windowtext 1.0pt; border-right: solid black 1.0pt; border-top: none; height: 16.15pt; mso-border-alt: solid windowtext .5pt; mso-border-right-alt: solid black .5pt; mso-border-top-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 336.0pt;" width="784"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">Vin: 115V/50Hz<o:p></o:p></span></b></div>
</td>
</tr>
<tr style="height: 19.35pt; mso-yfti-irow: 3;">
<td nowrap="" style="border-top: none; border: solid windowtext 1.0pt; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 60.0pt;" width="140"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">100<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 50.0pt;" width="117"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">121.53<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 56.0pt;" width="131"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">24.16<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 56.0pt;" width="131"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">4.54<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 50.0pt;" width="117"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">109.69<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 64.0pt;" width="149"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">90.0<o:p></o:p></span></b></div>
</td>
</tr>
<tr style="height: 19.35pt; mso-yfti-irow: 4;">
<td nowrap="" style="border-top: none; border: solid windowtext 1.0pt; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 60.0pt;" width="140"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">75<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 50.0pt;" width="117"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">91.67<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 56.0pt;" width="131"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">24.20<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 56.0pt;" width="131"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">3.43<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 50.0pt;" width="117"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">83.11<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 64.0pt;" width="149"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">91.0<o:p></o:p></span></b></div>
</td>
</tr>
<tr style="height: 19.35pt; mso-yfti-irow: 5;">
<td nowrap="" style="border-top: none; border: solid windowtext 1.0pt; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 60.0pt;" width="140"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">50<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 50.0pt;" width="117"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">61.27<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 56.0pt;" width="131"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">24.26<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 56.0pt;" width="131"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">2.28<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 50.0pt;" width="117"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">55.40<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 64.0pt;" width="149"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">90.0<o:p></o:p></span></b></div>
</td>
</tr>
<tr style="height: 19.35pt; mso-yfti-irow: 6;">
<td nowrap="" style="border-top: none; border: solid windowtext 1.0pt; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 60.0pt;" width="140"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">25<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 50.0pt;" width="117"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">31.73<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 56.0pt;" width="131"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">24.27<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 56.0pt;" width="131"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">1.17<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 50.0pt;" width="117"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">28.35<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 64.0pt;" width="149"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">89.0<o:p></o:p></span></b></div>
</td>
</tr>
<tr style="height: 19.35pt; mso-yfti-irow: 7;">
<td nowrap="" style="border-top: none; border: solid windowtext 1.0pt; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 60.0pt;" width="140"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">10<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 50.0pt;" width="117"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">12.44<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 56.0pt;" width="131"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">24.27<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 56.0pt;" width="131"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">0.46<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 50.0pt;" width="117"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">11.07<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 64.0pt;" width="149"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">89.0<o:p></o:p></span></b></div>
</td>
</tr>
<tr style="height: 19.35pt; mso-yfti-irow: 8;">
<td nowrap="" style="border-top: none; border: solid windowtext 1.0pt; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 60.0pt;" width="140"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">0<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 50.0pt;" width="117"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">0.08<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 56.0pt;" width="131"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">24.25<o:p></o:p></span></b></div>
</td>
<td style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 56.0pt;" width="131"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">--<o:p></o:p></span></b></div>
</td>
<td style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 50.0pt;" width="117"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">--<o:p></o:p></span></b></div>
</td>
<td style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 64.0pt;" width="149"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">--<o:p></o:p></span></b></div>
</td>
</tr>
<tr style="height: 16.35pt; mso-yfti-irow: 9;">
<td colspan="6" style="border-bottom: solid windowtext 1.0pt; border-left: solid windowtext 1.0pt; border-right: solid black 1.0pt; border-top: none; height: 16.35pt; mso-border-alt: solid windowtext .5pt; mso-border-right-alt: solid black .5pt; mso-border-top-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 336.0pt;" width="784"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">Vin: 230V/50Hz<o:p></o:p></span></b></div>
</td>
</tr>
<tr style="height: 19.35pt; mso-yfti-irow: 10;">
<td nowrap="" style="border-top: none; border: solid windowtext 1.0pt; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 60.0pt;" width="140"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">100<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 50.0pt;" width="117"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">119.33<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 56.0pt;" width="131"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">24.16<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 56.0pt;" width="131"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">4.52<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 50.0pt;" width="117"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">109.07<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 64.0pt;" width="149"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">91.0<o:p></o:p></span></b></div>
</td>
</tr>
<tr style="height: 19.35pt; mso-yfti-irow: 11;">
<td nowrap="" style="border-top: none; border: solid windowtext 1.0pt; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 60.0pt;" width="140"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">75<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 50.0pt;" width="117"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">92.19<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 56.0pt;" width="131"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">24.21<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 56.0pt;" width="131"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">3.47<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 50.0pt;" width="117"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">83.87<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 64.0pt;" width="149"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">91.0<o:p></o:p></span></b></div>
</td>
</tr>
<tr style="height: 18.95pt; mso-yfti-irow: 12;">
<td nowrap="" style="border-top: none; border: solid windowtext 1.0pt; height: 18.95pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 60.0pt;" width="140"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">50<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 18.95pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 50.0pt;" width="117"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">62.11<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 18.95pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 56.0pt;" width="131"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">24.27<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 18.95pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 56.0pt;" width="131"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">2.30<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 18.95pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 50.0pt;" width="117"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">55.83<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 18.95pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 64.0pt;" width="149"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">90.0<o:p></o:p></span></b></div>
</td>
</tr>
<tr style="height: 19.35pt; mso-yfti-irow: 13;">
<td nowrap="" style="border-top: none; border: solid windowtext 1.0pt; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 60.0pt;" width="140"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">25<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 50.0pt;" width="117"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">30.74<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 56.0pt;" width="131"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">24.34<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 56.0pt;" width="131"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">1.14<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 50.0pt;" width="117"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">27.63<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 64.0pt;" width="149"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">90.0<o:p></o:p></span></b></div>
</td>
</tr>
<tr style="height: 19.35pt; mso-yfti-irow: 14;">
<td nowrap="" style="border-top: none; border: solid windowtext 1.0pt; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 60.0pt;" width="140"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">10<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 50.0pt;" width="117"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">13.26<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 56.0pt;" width="131"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">24.35<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 56.0pt;" width="131"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">0.49<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 50.0pt;" width="117"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">11.82<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.35pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 64.0pt;" width="149"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">89.0<o:p></o:p></span></b></div>
</td>
</tr>
<tr style="height: 19.5pt; mso-yfti-irow: 15; mso-yfti-lastrow: yes;">
<td nowrap="" style="border-top: none; border: solid windowtext 1.0pt; height: 19.5pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 60.0pt;" width="140"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">0<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.5pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 50.0pt;" width="117"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">0.11<o:p></o:p></span></b></div>
</td>
<td nowrap="" style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.5pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 56.0pt;" width="131"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">24.25<o:p></o:p></span></b></div>
</td>
<td style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.5pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 56.0pt;" width="131"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">--<o:p></o:p></span></b></div>
</td>
<td style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.5pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 50.0pt;" width="117"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">--<o:p></o:p></span></b></div>
</td>
<td style="border-bottom: solid windowtext 1.0pt; border-left: none; border-right: solid windowtext 1.0pt; border-top: none; height: 19.5pt; mso-border-bottom-alt: solid windowtext .5pt; mso-border-right-alt: solid windowtext .5pt; padding: 0in 5.4pt 0in 5.4pt; width: 64.0pt;" width="149"><div align="center" class="MsoNormal" style="line-height: normal; margin-bottom: .0001pt; margin-bottom: 0in; text-align: center;">
<b><span lang="EN-GB" style="font-family: "arial" , "sans-serif"; font-size: 9.5pt;">--<o:p></o:p></span></b></div>
</td>
</tr>
</tbody></table>
</div>
<div align="center" class="MsoNormal" style="text-align: center;">
<br /></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<u><span style="font-family: "arial" , "sans-serif"; mso-ansi-language: EN-US;">Figure 2:
DTM110PW240C8 Efficiency Measurements<o:p></o:p></span></u></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<u><span style="font-family: "arial" , "sans-serif"; mso-ansi-language: EN-US;"><br /></span></u></div>
<div class="MsoNormal">
<span style="font-family: "arial" , "sans-serif"; mso-ansi-language: EN-US;">Efficiency readings are also taken at 10% to check compliance to the EU
Tier 2 Efficiency standard.<span style="mso-spacerun: yes;"> </span>For a power
supply rated at 49-250W it must have a minimum efficiency of 79%.<span style="mso-spacerun: yes;"> </span>At 10% load the DTM250-D has an efficiency of
89%.<o:p></o:p></span></div>
<div class="MsoNormal">
<span style="font-family: "arial" , "sans-serif"; mso-ansi-language: EN-US;"><br /></span></div>
<div class="MsoNormal">
<span style="font-family: "arial" , "sans-serif"; mso-ansi-language: EN-US;">Power Guy<o:p></o:p></span></div>
<div class="MsoNormal">
<br /></div>
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Power Guyhttp://www.blogger.com/profile/15282245011253622251noreply@blogger.com0tag:blogger.com,1999:blog-535177224836915617.post-8754623166822285772018-11-28T10:49:00.001-08:002022-12-22T08:45:10.630-08:00Can a dual output DC-DC converter provide a single output?<span style="font-size: medium;"><br /></span>
<br />
<div class="MsoNormal" style="margin: 0in 0in 8pt;">
<span lang="EN-GB"><span style="font-family: "calibri"; font-size: medium;">Yes, many dual output DC-DC converters can
actually be used to provide a higher voltage, single output.<o:p></o:p></span></span></div>
<span style="font-size: medium;"><span style="font-family: "calibri";">Figure 1 shows a simplified block diagram
of the <a href="https://www.us.tdk-lambda.com/lp/products/ccg-series.htm" target="_blank">TDK-Lambda’s CCG</a> +/-12V dual output converter.</span><span style="font-family: "calibri";"> </span><span style="font-family: "calibri";">Two transformer secondary windings are
rectified and filtered to provide two 12Vdc voltages and are connected
together, effectively in series.</span><span style="font-family: "calibri";"> </span><span style="font-family: "calibri";">Internally
the 0V of the upper circuit is connected to the +12V of the lower circuit and
this point is supplied to the user as the 0V or common connection.</span><span style="font-family: "calibri";"> </span><span style="font-family: "calibri";">This provides a +12V and a -12V output to the
user.</span></span><br />
<span style="font-size: medium;"><br /></span>
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjalmxSj-j_2RVhcKWPAVbovcVwk59RxNjSJDKZ9pMhiyXEtt6b_IGcac76r-1oEVFu8K-VtIBuHM_OsvkFGJfHKUsPJa2JGELIFu5Scy5BvFTtZFEV1EOjayk1Gy8XK6hOhJKJrvW6EZ15/s1600/Diagram+1.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-size: medium;"><img border="0" data-original-height="729" data-original-width="1329" height="351" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjalmxSj-j_2RVhcKWPAVbovcVwk59RxNjSJDKZ9pMhiyXEtt6b_IGcac76r-1oEVFu8K-VtIBuHM_OsvkFGJfHKUsPJa2JGELIFu5Scy5BvFTtZFEV1EOjayk1Gy8XK6hOhJKJrvW6EZ15/s640/Diagram+1.png" width="640" /></span></a></div>
<div class="separator" style="clear: both; text-align: center;">
<br /></div>
<div align="center" class="MsoNormal" style="margin: 0in 0in 8pt; text-align: center;">
<span lang="EN-GB"><span style="font-family: "calibri"; font-size: medium;"><strong>Figure 1: A dual output DC-DC converter providing a +/-12V output<o:p></o:p></strong></span></span></div>
<span style="font-size: medium;"><br /></span>
<br />
<div class="MsoNormal" style="margin: 0in 0in 8pt;">
<span lang="EN-GB"><span style="font-family: "calibri"; font-size: medium;">If a single 24V output voltage is needed, a dual output converter can be used as shown in Figure 2.<o:p></o:p></span></span></div>
<div class="separator" style="clear: both; text-align: center;">
<br /></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhBRMt9kQRkJOb4vvCnX148fr5dZd2MwVrkCaxDqogXlJ1KTptImptbopIawYa7vJGjo7cSqhkfPuOkkoJChtFpM0TjH3X1Jbhfyvlo6PsTweZzVi0EUSwADka7YDfCxPvMoNvcWactUm8y/s1600/Diagram+2.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-size: medium;"><img border="0" data-original-height="731" data-original-width="1341" height="347" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhBRMt9kQRkJOb4vvCnX148fr5dZd2MwVrkCaxDqogXlJ1KTptImptbopIawYa7vJGjo7cSqhkfPuOkkoJChtFpM0TjH3X1Jbhfyvlo6PsTweZzVi0EUSwADka7YDfCxPvMoNvcWactUm8y/s640/Diagram+2.png" width="640" /></span></a></div>
<span style="font-size: medium;"><span lang="EN-GB"></span><br /></span>
<span style="font-size: medium;"><br /></span>
<br />
<div align="center" class="MsoNormal" style="margin: 0in 0in 8pt; text-align: center;">
<span lang="EN-GB"><span style="font-family: "calibri"; font-size: medium;"><strong>Figure
2: A dual output DC-DC converter providing a 24V output<o:p></o:p></strong></span></span></div>
<span style="font-size: medium;"><br /></span>
<br />
<div class="MsoNormal" style="margin: 0in 0in 8pt;">
<span lang="EN-GB"><span style="font-family: "calibri"; font-size: medium;">Internally nothing has changed, there are
still two 12Vdc voltages connected in series.<span style="mso-spacerun: yes;">
</span>If the common terminal is not connected to the user’s circuit, the
converter can now provide a 24V single output.<o:p></o:p></span></span></div>
<span style="font-size: medium;"><span style="font-family: "calibri";">Note the maximum available output current
remains the same as the maximum output current of the dual output converter.</span><span style="font-family: "calibri";"> </span><span style="font-family: "calibri";">For example the 30W CCG30-24-12D is rated at
+/-12V +/-1.25A, meaning it is capable of supplying +12V at 1.25A and -12V at
1.25A or if connected as a single output, 24V at 1.25A (30W).</span></span><br />
<span style="font-size: medium;"><br /></span>
<br />
<div class="MsoNormal" style="margin: 0in 0in 8pt;">
<span lang="EN-GB"><span style="font-family: "calibri"; font-size: medium;">Likewise a dual output +/-15V converter can
be configured to supply 30V.<o:p></o:p></span></span></div>
<span style="font-family: "calibri";"><span style="font-size: medium;">Always confirm with the manufacturer if
their datasheet does not state it can be used as a single output.</span></span><br />
<span style="font-size: medium;"><br /></span>
<br />
<div class="MsoNormal" style="margin: 0in 0in 8pt;">
<span lang="EN-GB"><span style="font-family: "calibri";"><span style="font-size: medium;">Power Guy</span><o:p></o:p></span></span></div>
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Power Guyhttp://www.blogger.com/profile/15282245011253622251noreply@blogger.com0tag:blogger.com,1999:blog-535177224836915617.post-23773354120392540892018-10-26T15:49:00.002-07:002022-12-22T08:44:32.599-08:00Z+ - Generating Arbitrary Waveforms
<br />
<div class="MsoNormal" style="margin: 0in 0in 10pt;">
<span lang="EN-GB" style="font-family: "Arial","sans-serif";">Arbitrary
waveform generators are used to test electrical and electronic equipment to
ensure that the product operates properly, or to pin point a particular
fault.<span style="mso-spacerun: yes;"> </span>These can be used either
repetitively or as a once only (single-shot).<span style="mso-spacerun: yes;">
</span>The waveforms can be triggered to run by an external event, a signal
from another piece of equipment for example, manually using the front panel
controls or by using the GUI interface.<span style="mso-spacerun: yes;">
</span>An arbitrary waveform generator differs to that of a function generator
in that specific points in the waveform can be programmed to create custom
waveforms.<o:p></o:p></span></div>
<br />
<div class="MsoNormal" style="margin: 0in 0in 10pt;">
<span lang="EN-GB" style="font-family: "Arial","sans-serif";">The
Z+ series of programmable power supplies allows the storage of up to four
arbitrary waveforms in internal non-volatile memory cells to control the output
voltage or current.<span style="mso-spacerun: yes;"> </span>Profiles can contain
up to 12 steps and be triggered to operate using the communication interfaces
or via the front panel.<span style="mso-spacerun: yes;"> </span>Additional
waveforms can be stored on a computer.<o:p></o:p></span></div>
<br />
<div class="MsoNormal" style="margin: 0in 0in 10pt;">
<span lang="EN-GB" style="font-family: "Arial","sans-serif";">These
arbitrary waveforms can be easily created by using the “Z+ Waveform Creator”
application provided on the CD-ROM.<o:p></o:p></span></div>
<br />
<div class="MsoNormal" style="margin: 0in 0in 10pt;">
<span lang="EN-GB" style="font-family: "Arial","sans-serif";">There
are two programmable modes; LIST and WAVE.<span style="mso-spacerun: yes;">
</span><o:p></o:p></span></div>
<span lang="EN-GB" style="font-family: "Arial","sans-serif"; font-size: 11pt; line-height: 115%; mso-ansi-language: EN-GB; mso-bidi-language: AR-SA; mso-fareast-font-family: Calibri; mso-fareast-language: EN-US; mso-fareast-theme-font: minor-latin;">LIST allows a step
function to be entered and run.<span style="mso-spacerun: yes;"> </span>The
example in Figure 1 sets the output from 0V to 2V after an external trigger. After
a 0.5s delay the output is increased to 4V and back down to 2V 0.5s later.<span style="mso-spacerun: yes;"> </span>After 1s the output is increased to 8V for 1s
before reducing to 5V. 1s later the output is set to 4V where it remains for
another 1s.</span><br />
<span lang="EN-GB" style="font-family: "Arial","sans-serif"; font-size: 11pt; line-height: 115%; mso-ansi-language: EN-GB; mso-bidi-language: AR-SA; mso-fareast-font-family: Calibri; mso-fareast-language: EN-US; mso-fareast-theme-font: minor-latin;"></span> <br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiF4CANpld5jAaSZtNvLB_P5o2_sDTJVBoL7EgqodHvA1BH0KaKS1Jkrs2vAT4g0PmZsEC3fwd7ch84cRuR3SxnGjtz8ics9Do7ZZo-U7XofeR1o2zGXcD1FIF-vmHgCmhTV_7MfAiwoOIH/s1600/1.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="275" data-original-width="517" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiF4CANpld5jAaSZtNvLB_P5o2_sDTJVBoL7EgqodHvA1BH0KaKS1Jkrs2vAT4g0PmZsEC3fwd7ch84cRuR3SxnGjtz8ics9Do7ZZo-U7XofeR1o2zGXcD1FIF-vmHgCmhTV_7MfAiwoOIH/s1600/1.png" /></a></div>
<div style="text-align: center;">
<span style="font-family: Times New Roman; font-size: small;"><span lang="EN-GB" style="font-family: "Arial","sans-serif"; mso-fareast-language: EN-GB; mso-no-proof: yes;"><span lang="EN-GB" style="font-family: "Arial","sans-serif"; mso-fareast-language: EN-GB; mso-no-proof: yes;">Figure 1: List example</span></span></span></div>
<div style="text-align: center;">
<span style="font-family: Times New Roman; font-size: small;"><span lang="EN-GB" style="font-family: "Arial","sans-serif"; mso-fareast-language: EN-GB; mso-no-proof: yes;"><span lang="EN-GB" style="font-family: "Arial","sans-serif"; mso-fareast-language: EN-GB; mso-no-proof: yes;"></span></span></span> </div>
<span style="font-family: Times New Roman; font-size: small;"><span lang="EN-GB" style="font-family: "Arial","sans-serif"; mso-fareast-language: EN-GB; mso-no-proof: yes;"><div class="MsoNormal" style="margin: 0in 0in 10pt;">
<span lang="EN-GB" style="font-family: "Arial","sans-serif"; mso-fareast-language: EN-GB; mso-no-proof: yes;">WAVE also allows gradual output
voltage or current changes.<span style="mso-spacerun: yes;"> </span>In Figure 2
the output is again set to 2V for 1s after an external trigger.<span style="mso-spacerun: yes;"> </span>This time it is gradually increased to 4V
over a 0.5s time period. It remains at 4V for 0.5s before being programmed to
gradually increase to 9V over 0.5s where it remains for 0.5s, before decreasing
to 3V over 1.5s period, staying at 3V for 1s.</span><span lang="EN-GB" style="font-family: "Arial","sans-serif";"><o:p></o:p></span></div>
<div class="MsoNormal" style="margin: 0in 0in 10pt; text-align: center;">
<span style="font-family: Times New Roman; font-size: small;">
<span lang="EN-GB" style="font-family: "Arial","sans-serif"; mso-fareast-language: EN-GB; mso-no-proof: yes;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhEFh3UMgcJFA0cKvCaJe33Hb22qDOy7Ph_MZkRWwPrH5heWx8yXR85NNudrIH81XRHhE8tjUR-R7vK9HW2w7_gR10ataUiMtqW3tAjCLYZVw8FWmtmR5lKIspyicZYERY-Gyc-3DVy71gS/s1600/2.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="276" data-original-width="522" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhEFh3UMgcJFA0cKvCaJe33Hb22qDOy7Ph_MZkRWwPrH5heWx8yXR85NNudrIH81XRHhE8tjUR-R7vK9HW2w7_gR10ataUiMtqW3tAjCLYZVw8FWmtmR5lKIspyicZYERY-Gyc-3DVy71gS/s1600/2.png" /></a></span></span></div>
</span></span><span lang="EN-GB" style="font-family: "Arial","sans-serif"; mso-fareast-language: EN-GB; mso-no-proof: yes;"><span lang="EN-GB" style="font-family: "Arial","sans-serif";"><div align="center" class="MsoNormal" style="margin: 0in 0in 10pt; text-align: center;">
<span lang="EN-GB" style="font-family: "Arial","sans-serif";">Figure 2: Waveform </span></div>
</span><div class="MsoNormal" style="margin: 0in 0in 10pt; text-align: left;">
<span lang="EN-GB" style="font-family: "Arial","sans-serif"; mso-fareast-language: EN-GB; mso-no-proof: yes;"><span lang="EN-GB" style="font-family: "Arial","sans-serif"; font-size: 11pt; line-height: 115%; mso-ansi-language: EN-GB; mso-bidi-language: AR-SA; mso-fareast-font-family: Calibri; mso-fareast-language: EN-US; mso-fareast-theme-font: minor-latin;">The Graphical User Interface (GUI), which can
also be downloaded from the website, contains a Waveform Profile Generator
which can be used for more complex waveforms, including sine, triangle and saw
tooth. See Figure 3.</span></span></div>
</span><div class="MsoNormal" style="margin: 0in 0in 10pt;">
<span lang="EN-GB" style="font-family: "Arial","sans-serif"; mso-fareast-language: EN-GB; mso-no-proof: yes;"><span lang="EN-GB" style="font-family: "Arial","sans-serif"; font-size: 11pt; line-height: 115%; mso-ansi-language: EN-GB; mso-bidi-language: AR-SA; mso-fareast-font-family: Calibri; mso-fareast-language: EN-US; mso-fareast-theme-font: minor-latin;"></span></span> <span lang="EN-GB" style="font-family: "Arial","sans-serif"; mso-fareast-language: EN-GB; mso-no-proof: yes;"> </span><div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjzNbdzdiaqSYpd4Lruhh9Sx_Oe_4MZIQnt8CgVblCqmWBYgBA4J3eX5XAEEWeATdvk7slWOBON2gHzVspS95NlTtcbeNhyH9f6S4YIl1IwuKkql3qxs3iLavd6SrrGQ73ZbUDoizCgCfWN/s1600/3.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="678" data-original-width="1132" height="383" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjzNbdzdiaqSYpd4Lruhh9Sx_Oe_4MZIQnt8CgVblCqmWBYgBA4J3eX5XAEEWeATdvk7slWOBON2gHzVspS95NlTtcbeNhyH9f6S4YIl1IwuKkql3qxs3iLavd6SrrGQ73ZbUDoizCgCfWN/s640/3.png" width="640" /></a></div>
<span lang="EN-GB" style="font-family: "Arial","sans-serif"; font-size: 11pt; line-height: 115%; mso-ansi-language: EN-GB; mso-bidi-language: AR-SA; mso-fareast-font-family: Calibri; mso-fareast-language: EN-US; mso-fareast-theme-font: minor-latin;"><div class="MsoNormal" style="margin: 0in 0in 10pt;">
<span style="font-family: Times New Roman; font-size: small;">
</span></div>
<div align="center" class="MsoNormal" style="margin: 0in 0in 10pt; text-align: center;">
<span lang="EN-GB" style="font-family: "Arial","sans-serif";">Figure 3: Waveform Profile Generator<o:p></o:p></span></div>
<div class="MsoNormal" style="margin: 0in 0in 10pt;">
<span style="font-family: Times New Roman; font-size: small;">
</span><span lang="EN-GB" style="font-family: "Arial","sans-serif"; font-size: 11pt; line-height: 115%; mso-ansi-language: EN-GB; mso-bidi-language: AR-SA; mso-fareast-font-family: Calibri; mso-fareast-language: EN-US; mso-fareast-theme-font: minor-latin;">The arbitrary
waveforms can be used for a variety of applications including vehicle battery
starting profiles to test automotive components and assemblies.<span style="mso-spacerun: yes;"> </span>See Figure 4.</span></div>
</span><div class="MsoNormal" style="margin: 0in 0in 10pt;">
</div>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi9kjp4Wh776CDH2aC5g5rke4HnibIa9m9EKrLeIB6yMqhWj6FwHVbG1M14RbqmoXPEhGzRnaI0K-isntc8fKaV1qEeJIj8KL3CVkIXbNdTUlC1QSfoT0RDl5EOY6FixXqorBDl3SWCNdgj/s1600/4.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="647" data-original-width="479" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi9kjp4Wh776CDH2aC5g5rke4HnibIa9m9EKrLeIB6yMqhWj6FwHVbG1M14RbqmoXPEhGzRnaI0K-isntc8fKaV1qEeJIj8KL3CVkIXbNdTUlC1QSfoT0RDl5EOY6FixXqorBDl3SWCNdgj/s1600/4.png" /></a></div>
<div class="MsoNormal" style="margin: 0in 0in 10pt;">
<span style="font-family: Times New Roman;">
</span></div>
<div align="center" class="MsoNormal" style="margin: 0in 0in 10pt; text-align: center;">
<span lang="EN-GB" style="font-family: "Arial","sans-serif";"></span><div align="center" class="MsoNormal" style="margin: 0in 0in 10pt; text-align: center;">
<span lang="EN-GB" style="font-family: "Arial","sans-serif";">Figure 4: Examples of arbitrary
waveforms<o:p></o:p></span><div class="MsoNormal" style="margin: 0in 0in 10pt; text-align: left;">
<span style="font-family: Times New Roman;">
<span lang="EN-GB" style="font-family: "Arial","sans-serif";">For
additional assistance, please contact your local TDK-Lambda sales office.<o:p></o:p></span></span><div align="center" class="MsoNormal" style="margin: 0in 0in 10pt; text-align: center;">
<span style="font-family: Times New Roman;">
</span></div>
<br />
<div align="center" class="MsoNormal" style="margin: 0in 0in 10pt; text-align: center;">
</div>
<br />
<div class="MsoNormal" style="margin: 0in 0in 10pt;">
<span style="font-family: Times New Roman;">
</span></div>
<div class="MsoNormal" style="margin: 0in 0in 10pt;">
<span lang="EN-GB"><o:p><span style="font-family: Calibri;"> </span></o:p></span></div>
<div class="MsoNormal" style="margin: 0in 0in 10pt;">
<span style="font-family: Times New Roman;">
</span></div>
<div class="MsoNormal" style="margin: 0in 0in 10pt;">
<span lang="EN-GB" style="font-family: "Arial","sans-serif";"><o:p></o:p></span> </div>
<span style="font-family: Times New Roman; font-size: small;">
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Power Guyhttp://www.blogger.com/profile/15282245011253622251noreply@blogger.com0tag:blogger.com,1999:blog-535177224836915617.post-67819853747554691572018-08-22T09:29:00.001-07:002022-12-22T08:44:00.122-08:00External Power Supply Efficiency Standards<div class="MsoNormal">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";">Note:
As the last EU implementation date has slipped, this is the current situation
as of August 24, 2018. A draft EU
amendment dated 2018 indicates that the legislation may mirror more closely the
DoE Level VI limits effective April, 2020.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";">External
power supplies (EPS) are widely used in households around the world to charge
phones or operate tablets, laptops, game consoles and a variety of consumer
electronic and electrical items.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";">Studies
on European energy use of these power supplies indicate that reducing off-load
power consumption and improving product efficiency will save nearly 10TWh of
power a year. A Terawatt hour (TWh) is 1,000,000,000,000
Watts used in an hour. Reducing energy
usage saves money, reduces the requirement to add new power generating capacity
and reduces environmental pollution.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";">Two
parameters were originally specified to regulate waste energy reduction, which
when multiplied by a billion products becomes very significant:<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";"><br /></span></div>
<div class="MsoNormal" style="margin-left: .5in;">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";">Maximum off-load power consumption<o:p></o:p></span></div>
<div class="MsoNormal" style="margin-left: .5in;">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";"><br /></span></div>
<div class="MsoNormal" style="margin-left: 1.0in;">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";">Many power supplies are left plugged in to the AC supply
and fully operational; even when the device it was charging has been
removed. Although the power supply is
not powering anything, it still consumes power.
The maximum off load power consumption varies with the output power of
the EPS and is stated in the specification.<o:p></o:p></span></div>
<div class="MsoNormal" style="margin-left: 1.0in;">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";"><br /></span></div>
<div class="MsoNormal" style="margin-left: .5in;">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";">Minimum average efficiency level<o:p></o:p></span></div>
<div class="MsoNormal" style="margin-left: .5in;">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";"><br /></span></div>
<div class="MsoNormal" style="margin-left: 1.0in;">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";">With loads less than the full rating of the EPS, the
efficiency of the power supply can decrease significantly. Low load conditions occur as a battery becomes
partially charged, or when a device goes into an inactive (sleep) mode. External power supplies rarely remain in a 75
to 100% load condition.<o:p></o:p></span></div>
<div class="MsoNormal" style="margin-left: 1.0in;">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";">First
legislation was announced in 2004, starting with the California Energy
Commission’s (CEC) intent to restrict the sale of non-efficient external power
supplies. The USA, EU, China and a host
of other countries and regions followed over the next ten years with
increasingly tighter legislation.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";">In
2014, the EU issued a voluntary Code of Conduct (CoC) version 4, running in
parallel with the mandatory Ecodesign Directive 278/2009. Also in 2014, the Department of Energy (DoE) published
their Energy Efficiency Level VI standard.
<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";">In
February 2016, the Level VI standard became law in the US. The EU issued the more stringent version 5 CoC
Tier 2 voluntary standard that was supposed to go into effect January 2018. That
has been delayed and mandatory implementation was expected early in 2018.<br clear="all" style="mso-special-character: line-break; page-break-before: always;" />
<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";"><br /></span></div>
<span lang="EN-GB" style="font-family: "arial" , "sans-serif"; line-height: 115%;">Table 1 shows some of
the differences for a single output, basic voltage power supply between these
two newest standards. Efficiency limits have been given for a power supply
rated between 49 to 250W. Please consult
the relevant US and EU websites for the full regulations.</span><br />
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<div align="center" class="MsoNormal" style="text-align: center;">
<u><span lang="EN-GB" style="font-family: "arial" , "sans-serif";">Table 1: A comparison between the
latest US and EU regulations<o:p></o:p></span></u></div>
<div align="center" class="MsoNormal" style="text-align: center;">
<u><span lang="EN-GB" style="font-family: "arial" , "sans-serif";"><br /></span></u></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";">Average
efficiency measurements are required at four load conditions; 25, 50, 75 and
100%.<span style="mso-spacerun: yes;"> </span>These are added together and
divided by four to produce an average efficiency figure.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";">Note,
the EU has added a minimum efficiency level at 10% load.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";">The
USA now includes power supplies that are rated at greater than 250W.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";">The
term external power supply is defined by the US Department of Energy as one
that is used to convert household electric current into DC current or
lower-voltage AC current to operate a consumer product.<span style="mso-spacerun: yes;"> </span>Currently the US also grants exemptions for
supplies powering FDA approved medical devices.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";">Modifying
a power supply to meet a decrease in off-load power consumption is not a simple
component change.<span style="mso-spacerun: yes;"> </span>The control IC often
has to be changed to one that draws less power and energy saving techniques
like pulse skipping implemented.<span style="mso-spacerun: yes;"> </span>Changes
to primary side circuitry requires resubmitting the products to have the safety
certifications updated.<span style="mso-spacerun: yes;"> </span>Both the
redesign and submittal process are expensive and older products are often
obsoleted as a result of this.<span style="mso-spacerun: yes;"> </span>As the
energy standards are directed at the ultra-high volume, short production life
consumer EPSs, this gives some relief to the industrial market which prefers
long production lifecycles.<o:p></o:p></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";"><br /></span></div>
<div class="MsoNormal">
<span lang="EN-GB" style="font-family: "arial" , "sans-serif";">TDK-Lambda
has a number of external power supplies in the </span><span lang="EN-GB"><a href="http://www.us.tdk-lambda.com/lp/products/dt-c-series.htm"><span style="font-family: "arial" , "sans-serif";">DT series</span></a></span><span lang="EN-GB" style="font-family: "arial" , "sans-serif";"> that meet all the latest
requirements, with ratings up to 300W.<o:p></o:p></span></div>
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Power Guyhttp://www.blogger.com/profile/15282245011253622251noreply@blogger.com0tag:blogger.com,1999:blog-535177224836915617.post-86031061927664287702018-06-27T14:31:00.002-07:002022-12-22T08:43:25.784-08:00An update to the transition from IEC 60950-1 to IEC 62368-1<br />
<div class="MsoNormal" style="margin: 0in 0in 8pt;">
<span lang="EN-GB" style="font-size: 12pt; line-height: 107%;"><span style="font-family: "calibri";">On
a blog post back in March 2015, I mentioned that a Hazard-Based Safety
Engineering (HBSE) IEC 62368-1 standard will be replacing IEC 60950-1 and IEC
60065, covering hazards and hazard prevention for ITE (Information Technology
Equipment) and audio / visual equipment.<o:p></o:p></span></span></div>
<br />
<div class="MsoNormal" style="margin: 0in 0in 8pt;">
<span lang="EN-GB" style="font-size: 12pt; line-height: 107%;"><span style="font-family: "calibri";">The
transition date to EN 62368-1:2014 has now been extended 18 months to December
20<sup>th</sup>, 2020 for new submittals (or a significant modification of the existing
60950/60065 file) in the EU.<span style="mso-spacerun: yes;"> </span>UL has also
announced that the UL 62368-1 Edition No. 2 date is now December 20th, 2020. A
number of other countries have adopted the standard, including Australia, Singapore,
Malaysia, Japan and Russia.<span style="mso-spacerun: yes;"> </span>No exact
date has been published for other countries like China, Taiwan, South Korea and
Argentina.<o:p></o:p></span></span></div>
<br />
<div class="MsoNormal" style="margin: 0in 0in 8pt;">
<span lang="EN-GB" style="font-size: 12pt; line-height: 107%;"><span style="font-family: "calibri";">The
new standard uses a Hazard Based Safety Engineering (HBSE) science discipline,
and operates in four steps:<o:p></o:p></span></span></div>
<br />
<div class="MsoListParagraphCxSpFirst" style="margin: 0in 0in 0pt 0.75in; mso-add-space: auto; mso-list: l0 level1 lfo1; text-indent: -0.25in;">
<!--[if !supportLists]--><span lang="EN-GB" style="font-size: 12pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;"><span style="font-family: "calibri";">1.</span><span style="font-size-adjust: none; font-stretch: normal; font: 7pt/normal "Times New Roman";"> </span></span></span><!--[endif]--><span lang="EN-GB" style="font-size: 12pt; line-height: 107%;"><span style="font-family: "calibri";">Identifying <u>energy
sources</u> in the product<o:p></o:p></span></span></div>
<br />
<div class="MsoListParagraphCxSpMiddle" style="margin: 0in 0in 0pt 0.75in; mso-add-space: auto; mso-list: l0 level1 lfo1; text-indent: -0.25in;">
<!--[if !supportLists]--><span lang="EN-GB" style="font-size: 12pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;"><span style="font-family: "calibri";">2.</span><span style="font-size-adjust: none; font-stretch: normal; font: 7pt/normal "Times New Roman";"> </span></span></span><!--[endif]--><span lang="EN-GB" style="font-size: 12pt; line-height: 107%;"><span style="font-family: "calibri";">Classifying the energy for
the potential of causing injury or harm<o:p></o:p></span></span></div>
<br />
<div class="MsoListParagraphCxSpMiddle" style="margin: 0in 0in 0pt 0.75in; mso-add-space: auto; mso-list: l0 level1 lfo1; text-indent: -0.25in;">
<!--[if !supportLists]--><span lang="EN-GB" style="font-size: 12pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;"><span style="font-family: "calibri";">3.</span><span style="font-size-adjust: none; font-stretch: normal; font: 7pt/normal "Times New Roman";"> </span></span></span><!--[endif]--><span lang="EN-GB" style="font-size: 12pt; line-height: 107%;"><span style="font-family: "calibri";">Identify the necessary <u>safeguards</u>
needed to protect from those <u>energy sources</u><o:p></o:p></span></span></div>
<br />
<div class="MsoListParagraphCxSpLast" style="margin: 0in 0in 8pt 0.75in; mso-add-space: auto; mso-list: l0 level1 lfo1; text-indent: -0.25in;">
<!--[if !supportLists]--><span lang="EN-GB" style="font-size: 12pt; line-height: 107%; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin;"><span style="mso-list: Ignore;"><span style="font-family: "calibri";">4.</span><span style="font-size-adjust: none; font-stretch: normal; font: 7pt/normal "Times New Roman";"> </span></span></span><!--[endif]--><span lang="EN-GB" style="font-size: 12pt; line-height: 107%;"><span style="font-family: "calibri";">Qualify the <u>safeguards</u>
as effective<o:p></o:p></span></span></div>
<br />
<div class="MsoNormal" style="margin: 0in 0in 8pt;">
<span lang="EN-GB" style="font-size: 12pt; line-height: 107%;"><span style="font-family: "calibri";">The
Energy Source ES classification handles the effect on the body for a number of
hazards.<span style="mso-spacerun: yes;"> </span>See Table 1 for example of the
two most relevant to power supplies – electrical and thermal energy.<o:p></o:p></span></span></div>
<br />
<div align="center">
<table border="1" cellpadding="0" cellspacing="0" class="MsoTableGrid" style="border-collapse: collapse; border: currentColor; mso-border-alt: solid windowtext .5pt; mso-padding-alt: 0in 5.4pt 0in 5.4pt; mso-yfti-tbllook: 1184; width: 1091px;">
<tbody>
<tr style="mso-yfti-firstrow: yes; mso-yfti-irow: 0;">
<td style="background-color: transparent; border: 1pt solid currentColor; padding: 0in 5.4pt; width: 112.7pt;" valign="top" width="263"><div align="center" class="MsoNormal" style="line-height: normal; margin: 0in 0in 0pt; text-align: center;">
<b style="mso-bidi-font-weight: normal;"><span lang="EN-GB" style="font-size: 12pt;"><span style="font-family: "calibri";">Energy Source class<o:p></o:p></span></span></b></div>
</td>
<td style="background-color: transparent; border-color: windowtext windowtext windowtext rgb(0, 0, 0); border-style: solid solid solid none; border-width: 1pt 1pt 1pt 0px; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; padding: 0in 5.4pt; width: 152.55pt;" valign="top" width="356"><div align="center" class="MsoNormal" style="line-height: normal; margin: 0in 0in 0pt; text-align: center;">
<b style="mso-bidi-font-weight: normal;"><span lang="EN-GB" style="font-size: 12pt;"><span style="font-family: "calibri";">Effect on the Body<o:p></o:p></span></span></b></div>
</td>
<td style="background-color: transparent; border-color: windowtext windowtext windowtext rgb(0, 0, 0); border-style: solid solid solid none; border-width: 1pt 1pt 1pt 0px; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; padding: 0in 5.4pt; width: 202.5pt;" valign="top" width="473"><div align="center" class="MsoNormal" style="line-height: normal; margin: 0in 0in 0pt; text-align: center;">
<b style="mso-bidi-font-weight: normal;"><span lang="EN-GB" style="font-size: 12pt;"><span style="font-family: "calibri";">Effect on combustible material<o:p></o:p></span></span></b></div>
</td>
</tr>
<tr style="mso-yfti-irow: 1;">
<td style="background-color: transparent; border-color: rgb(0, 0, 0) windowtext windowtext; border-style: none solid solid; border-width: 0px 1pt 1pt; mso-border-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt; padding: 0in 5.4pt; width: 112.7pt;" valign="top" width="263"><div align="center" class="MsoNormal" style="line-height: normal; margin: 0in 0in 0pt; text-align: center;">
<span lang="EN-GB" style="font-size: 12pt;"><span style="font-family: "calibri";">Class
1<o:p></o:p></span></span></div>
</td>
<td style="background-color: transparent; border-color: rgb(0, 0, 0); border-style: none solid solid none; border-width: 0px 1pt 1pt 0px; padding: 0in 5.4pt; width: 152.55pt;" valign="top" width="356"><div align="center" class="MsoNormal" style="line-height: normal; margin: 0in 0in 0pt; text-align: center;">
<span lang="EN-GB" style="font-size: 12pt;"><span style="font-family: "calibri";">Detectible,
but not painful<o:p></o:p></span></span></div>
</td>
<td style="background-color: transparent; border-color: rgb(0, 0, 0); border-style: none solid solid none; border-width: 0px 1pt 1pt 0px; padding: 0in 5.4pt; width: 202.5pt;" valign="top" width="473"><div align="center" class="MsoNormal" style="line-height: normal; margin: 0in 0in 0pt; text-align: center;">
<span lang="EN-GB" style="font-size: 12pt;"><span style="font-family: "calibri";">Unlikely
ignition<o:p></o:p></span></span></div>
</td>
</tr>
<tr style="mso-yfti-irow: 2;">
<td style="background-color: transparent; border-color: rgb(0, 0, 0) windowtext windowtext; border-style: none solid solid; border-width: 0px 1pt 1pt; mso-border-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt; padding: 0in 5.4pt; width: 112.7pt;" valign="top" width="263"><div align="center" class="MsoNormal" style="line-height: normal; margin: 0in 0in 0pt; text-align: center;">
<span lang="EN-GB" style="font-size: 12pt;"><span style="font-family: "calibri";">Class
2<o:p></o:p></span></span></div>
</td>
<td style="background-color: transparent; border-color: rgb(0, 0, 0); border-style: none solid solid none; border-width: 0px 1pt 1pt 0px; padding: 0in 5.4pt; width: 152.55pt;" valign="top" width="356"><div align="center" class="MsoNormal" style="line-height: normal; margin: 0in 0in 0pt; text-align: center;">
<span lang="EN-GB" style="font-size: 12pt;"><span style="font-family: "calibri";">Painful,
but not an injury<o:p></o:p></span></span></div>
</td>
<td style="background-color: transparent; border-color: rgb(0, 0, 0); border-style: none solid solid none; border-width: 0px 1pt 1pt 0px; padding: 0in 5.4pt; width: 202.5pt;" valign="top" width="473"><div align="center" class="MsoNormal" style="line-height: normal; margin: 0in 0in 0pt; text-align: center;">
<span lang="EN-GB" style="font-size: 12pt;"><span style="font-family: "calibri";">Possible
ignition, but limited<o:p></o:p></span></span></div>
</td>
</tr>
<tr style="mso-yfti-irow: 3; mso-yfti-lastrow: yes;">
<td style="background-color: transparent; border-color: rgb(0, 0, 0) windowtext windowtext; border-style: none solid solid; border-width: 0px 1pt 1pt; mso-border-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt; padding: 0in 5.4pt; width: 112.7pt;" valign="top" width="263"><div align="center" class="MsoNormal" style="line-height: normal; margin: 0in 0in 0pt; text-align: center;">
<span lang="EN-GB" style="font-size: 12pt;"><span style="font-family: "calibri";">Class
3<o:p></o:p></span></span></div>
</td>
<td style="background-color: transparent; border-color: rgb(0, 0, 0); border-style: none solid solid none; border-width: 0px 1pt 1pt 0px; padding: 0in 5.4pt; width: 152.55pt;" valign="top" width="356"><div align="center" class="MsoNormal" style="line-height: normal; margin: 0in 0in 0pt; text-align: center;">
<span lang="EN-GB" style="font-size: 12pt;"><span style="font-family: "calibri";">An
injury<o:p></o:p></span></span></div>
</td>
<td style="background-color: transparent; border-color: rgb(0, 0, 0); border-style: none solid solid none; border-width: 0px 1pt 1pt 0px; padding: 0in 5.4pt; width: 202.5pt;" valign="top" width="473"><div align="center" class="MsoNormal" style="line-height: normal; margin: 0in 0in 0pt; text-align: center;">
<span lang="EN-GB" style="font-size: 12pt;"><span style="font-family: "calibri";">Likely
ignition, growth rapid & swift<o:p></o:p></span></span></div>
</td>
</tr>
</tbody></table>
</div>
<br />
<div align="center" class="MsoNormal" style="margin: 0in 0in 8pt; text-align: center;">
<span lang="EN-GB" style="font-size: 12pt; line-height: 107%;"><span style="font-family: "calibri";">Table 1 Energy Source classification<o:p></o:p></span></span></div>
<br />
<div class="MsoNormal" style="margin: 0in 0in 8pt;">
<span lang="EN-GB" style="font-size: 12pt; line-height: 107%;"><span style="font-family: "calibri";">In
addition, a three person scenario has been adopted for 62368-1 (see Table 2).<span style="mso-tab-count: 1;"> </span><o:p></o:p></span></span></div>
<br />
<div align="center">
<table border="1" cellpadding="0" cellspacing="0" class="MsoTableGrid" style="border-collapse: collapse; border: currentColor; mso-border-alt: solid windowtext .5pt; mso-padding-alt: 0in 5.4pt 0in 5.4pt; mso-yfti-tbllook: 1184;">
<tbody>
<tr style="mso-yfti-firstrow: yes; mso-yfti-irow: 0;">
<td style="background-color: transparent; border: 1pt solid currentColor; padding: 0in 5.4pt; width: 139.25pt;" valign="top" width="325"><div align="center" class="MsoNormal" style="line-height: normal; margin: 0in 0in 0pt; text-align: center;">
<b style="mso-bidi-font-weight: normal;"><span lang="EN-GB" style="font-size: 12pt;"><span style="font-family: "calibri";">Person<o:p></o:p></span></span></b></div>
</td>
<td style="background-color: transparent; border-color: windowtext windowtext windowtext rgb(0, 0, 0); border-style: solid solid solid none; border-width: 1pt 1pt 1pt 0px; mso-border-alt: solid windowtext .5pt; mso-border-left-alt: solid windowtext .5pt; padding: 0in 5.4pt; width: 311.55pt;" valign="top" width="727"><div align="center" class="MsoNormal" style="line-height: normal; margin: 0in 0in 0pt; text-align: center;">
<b style="mso-bidi-font-weight: normal;"><span lang="EN-GB" style="font-size: 12pt;"><span style="font-family: "calibri";">Description (See standard for full
details)<o:p></o:p></span></span></b></div>
</td>
</tr>
<tr style="mso-yfti-irow: 1;">
<td style="background-color: transparent; border-color: rgb(0, 0, 0) windowtext windowtext; border-style: none solid solid; border-width: 0px 1pt 1pt; mso-border-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt; padding: 0in 5.4pt; width: 139.25pt;" valign="top" width="325"><div class="MsoNormal" style="line-height: normal; margin: 0in 0in 0pt;">
<span lang="EN-GB" style="font-size: 12pt;"><span style="font-family: "calibri";">Ordinary Person<o:p></o:p></span></span></div>
</td>
<td style="background-color: transparent; border-color: rgb(0, 0, 0); border-style: none solid solid none; border-width: 0px 1pt 1pt 0px; padding: 0in 5.4pt; width: 311.55pt;" valign="top" width="727"><div class="MsoNormal" style="line-height: normal; margin: 0in 0in 0pt;">
<span lang="EN-GB" style="font-size: 12pt;"><span style="font-family: "calibri";">A person who is a user or
is close by to the equipment<o:p></o:p></span></span></div>
</td>
</tr>
<tr style="mso-yfti-irow: 2;">
<td style="background-color: transparent; border-color: rgb(0, 0, 0) windowtext windowtext; border-style: none solid solid; border-width: 0px 1pt 1pt; mso-border-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt; padding: 0in 5.4pt; width: 139.25pt;" valign="top" width="325"><div class="MsoNormal" style="line-height: normal; margin: 0in 0in 0pt;">
<span lang="EN-GB" style="font-size: 12pt;"><span style="font-family: "calibri";">Instructed Person<o:p></o:p></span></span></div>
</td>
<td style="background-color: transparent; border-color: rgb(0, 0, 0); border-style: none solid solid none; border-width: 0px 1pt 1pt 0px; padding: 0in 5.4pt; width: 311.55pt;" valign="top" width="727"><div class="MsoNormal" style="line-height: normal; margin: 0in 0in 0pt;">
<span lang="EN-GB" style="font-size: 12pt;"><span style="font-family: "calibri";">A person that is trained to
identify sources of pain causing energy and avoid them. Must not be exposed
to injury causing energy sources, even during a single fault condition<o:p></o:p></span></span></div>
</td>
</tr>
<tr style="mso-yfti-irow: 3; mso-yfti-lastrow: yes;">
<td style="background-color: transparent; border-color: rgb(0, 0, 0) windowtext windowtext; border-style: none solid solid; border-width: 0px 1pt 1pt; mso-border-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt; padding: 0in 5.4pt; width: 139.25pt;" valign="top" width="325"><div class="MsoNormal" style="line-height: normal; margin: 0in 0in 0pt;">
<span lang="EN-GB" style="font-size: 12pt;"><span style="font-family: "calibri";">Skilled Person<o:p></o:p></span></span></div>
</td>
<td style="background-color: transparent; border-color: rgb(0, 0, 0); border-style: none solid solid none; border-width: 0px 1pt 1pt 0px; padding: 0in 5.4pt; width: 311.55pt;" valign="top" width="727"><div class="MsoNormal" style="line-height: normal; margin: 0in 0in 0pt;">
<span lang="EN-GB" style="font-size: 12pt;"><span style="font-family: "calibri";">A person who has the
training to recognize & avoid energy sources that could cause pain or
injury.<span style="mso-spacerun: yes;"> </span>Must be protected against
accidental contact with injury causing energy sources<o:p></o:p></span></span></div>
</td>
</tr>
</tbody></table>
</div>
<br />
<div align="center" class="MsoNormal" style="margin: 0in 0in 8pt; text-align: center;">
<span lang="EN-GB" style="font-size: 12pt; line-height: 107%;"><span style="font-family: "calibri";">Table 2: Description of types of person<o:p></o:p></span></span></div>
<span lang="EN-GB" style="font-family: "calibri" , "sans-serif"; font-size: 12pt; line-height: 107%;"></span><br />
<div class="MsoNormal" style="margin: 0in 0in 8pt;">
</div>
<br />
<div class="MsoNormal" style="margin: 0in 0in 8pt;">
<span lang="EN-GB" style="font-size: 12pt; line-height: 107%;"><span style="font-family: "calibri";">Depending
on the Person type and the Energy Class, Safeguards have to be in place to
protect that Person.<span style="mso-spacerun: yes;"> </span>See Figure 1.<o:p></o:p></span></span></div>
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhLveQY2db_5EvgWdqwUvCxprYiOk9fbHn-6Vn8qIB_Of4g0Yhgi42B3iLIYnNX-ZCp-z9c-7shQ8u1-vCOE9Urr60v4E_TcumwlFxO7-qS1Fww5ZJSVPZYx8UlRewJAP4e8v9kmaxYicE0/s1600/Class.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="624" data-original-width="1600" height="248" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhLveQY2db_5EvgWdqwUvCxprYiOk9fbHn-6Vn8qIB_Of4g0Yhgi42B3iLIYnNX-ZCp-z9c-7shQ8u1-vCOE9Urr60v4E_TcumwlFxO7-qS1Fww5ZJSVPZYx8UlRewJAP4e8v9kmaxYicE0/s640/Class.jpg" width="640" /></a></div>
<div align="center" class="MsoNormal" style="margin: 0in 0in 8pt; text-align: center;">
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<br />
<div align="center" class="MsoNormal" style="margin: 0in 0in 8pt; text-align: center;">
<span lang="EN-GB" style="font-size: 12pt; line-height: 107%;"><span style="font-family: "calibri";">Figure 1: Protection for an Ordinary
Person with different Energy Classes<o:p></o:p></span></span></div>
<br />
<div class="MsoNormal" style="margin: 0in 0in 8pt;">
<span lang="EN-GB" style="font-size: 12pt; line-height: 107%;"><span style="font-family: "calibri";">As
an example, one small change power supply manufacturers may have to make to
their designs to meet IEC 62369-1, concerns “capacitance discharge” of the AC
input.<span style="mso-spacerun: yes;"> </span><o:p></o:p></span></span></div>
<br />
<div class="MsoNormal" style="margin: 0in 0in 8pt;">
<span lang="EN-GB" style="font-size: 12pt; line-height: 107%;"><span style="font-family: "calibri";">Figure
2 shows the typical schematic of an EMI filter section of a power supply and
the location of a resistor that discharges the Line to Neutral X capacitors
after the AC has been removed.<span style="mso-spacerun: yes;"> </span>This
avoids a user unplugging an AC plug, touching the pins and getting an electric
shock.<o:p></o:p></span></span></div>
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiLaJlFU0sRVuNSrM6CTZa1N4cZ2h9mMz9hAlZbBXj5ryOrTqjlcCj2ZBZh0DAJh1dCaTOPW1UJFNXUoqhN8BmQ6Y6YO2fhYgFHc6ZrFk0kOcmy8lm5ZKQ_CQyGg8jiXR0jHS-imq5DbCjQ/s1600/EMI+Filter+Schematic.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="168" data-original-width="405" height="165" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiLaJlFU0sRVuNSrM6CTZa1N4cZ2h9mMz9hAlZbBXj5ryOrTqjlcCj2ZBZh0DAJh1dCaTOPW1UJFNXUoqhN8BmQ6Y6YO2fhYgFHc6ZrFk0kOcmy8lm5ZKQ_CQyGg8jiXR0jHS-imq5DbCjQ/s400/EMI+Filter+Schematic.jpg" width="400" /></a></div>
<div align="center" class="MsoNormal" style="margin: 0in 0in 8pt; text-align: center;">
<span style="font-size: 12pt; line-height: 107%; mso-ansi-language: EN-US; mso-no-proof: yes;"><!--[if gte vml 1]><v:shape id="Picture_x0020_2" o:spid="_x0000_i1025"
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</v:shape><![endif]--><!--[if !vml]--><!--[endif]--></span><span lang="EN-GB" style="font-size: 12pt; line-height: 107%;"><o:p></o:p></span><br /></div>
<br />
<div align="center" class="MsoNormal" style="margin: 0in 0in 8pt; text-align: center;">
<span lang="EN-GB" style="font-size: 12pt; line-height: 107%;"><span style="font-family: "calibri";">Fig 2: EMI Filter Schematic<o:p></o:p></span></span></div>
<br />
<div class="MsoNormal" style="margin: 0in 0in 8pt;">
<span lang="EN-GB" style="font-size: 12pt; line-height: 107%;"><span style="font-family: "calibri";">If
the line cord was removed from the AC plug at the peak of a 240V AC cycle, then
the voltage would be 339Vdc.<span style="mso-spacerun: yes;"> </span>The time
for that to decay to a safe voltage depends upon the values of the X capacitor(s),
the Line to Neutral resistor and any loading of the power supply converter
circuitry.<o:p></o:p></span></span></div>
<br />
<div class="MsoNormal" style="margin: 0in 0in 8pt;">
<span lang="EN-GB" style="font-size: 12pt; line-height: 107%;"><span style="font-family: "calibri";">IEC
60950-1 states that after one second that voltage has to be at a maximum of
42.4Vpk.<span style="mso-spacerun: yes;"> </span>IEC 62368-1 states that for an
X capacitance of 300nF or greater, after two seconds, the limit is 60Vpk in
normal condition or 120Vpk in a single fault condition.<o:p></o:p></span></span></div>
<br />
<div class="MsoNormal" style="margin: 0in 0in 8pt;">
<span lang="EN-GB" style="font-size: 12pt; line-height: 107%;"><span style="font-family: "calibri";">A
10W power phone charger will have a very small X capacitance and a high value
discharge resistor. Under 62368-1, if that resistor failed (a single fault
condition) the power supply would probably still meet the 60Vpk condition after
2 seconds.<span style="mso-spacerun: yes;"> </span>From Figure 1, this still
complies with no Basic Safeguard is needed, even for an “Ordinary Person”.<o:p></o:p></span></span></div>
<br />
<div class="MsoNormal" style="margin: 0in 0in 8pt;">
<span lang="EN-GB" style="font-size: 12pt; line-height: 107%;"><span style="font-family: "calibri";">A
higher wattage power supply on the other hand, will have a much larger X
capacitance.<span style="mso-spacerun: yes;"> </span>With a single fault
condition, the loss of the bleed resistor may result in a voltage of greater
than 120Vpk after 2 seconds.<span style="mso-spacerun: yes;"> </span>That would
then be an ES2 - Class 2 Energy Source - and from Figure 1, a Basic Safeguard
would need to be in place.<span style="mso-spacerun: yes;"> </span>Instead of
just one bleed resistor, a second one would need to be added, in parallel with
the first.<span style="mso-spacerun: yes;"> </span>The values of the resistor
would be sized accordingly to ensure that the loss of one, would still
discharge the X capacitor to a maximum of 120Vdc after 2 seconds.<o:p></o:p></span></span></div>
<br />
<div class="MsoNormal" style="margin: 0in 0in 8pt;">
<span lang="EN-GB" style="font-size: 12pt; line-height: 107%;"><span style="font-family: "calibri";">Supplementary
Safeguards would be used in other parts of the power supply circuit in the same
way as reinforced or double insulated is in 60950-1.<o:p></o:p></span></span></div>
<br />
<div class="MsoNormal" style="margin: 0in 0in 8pt;">
<span lang="EN-GB" style="font-size: 12pt; line-height: 107%;"><span style="font-family: "calibri";">One
side effect of the ES1 and ES2 limits is that IEC 62368-1 deems a 48V or even a
36V output power supply in hiccup mode over current as an AC output.<span style="mso-spacerun: yes;"> </span>The ES1 limits for DC are 60V, but for up to
1kHz that drops to 30Vrms or 42.2Vpk.<span style="mso-spacerun: yes;">
</span>IEC 60950-1 recognizes that as SELV, but under the new standard that
would be ES2 and the output should not be made accessible to an Ordinary
Person.<span style="mso-spacerun: yes;"> </span>Pins and connectors not
accessible by a blunt probe are exempt.<o:p></o:p></span></span></div>
<br />
<div class="MsoNormal" style="margin: 0in 0in 8pt;">
<span lang="EN-GB" style="font-size: 12pt; line-height: 107%;"><span style="font-family: "calibri";">Power
Guy<o:p></o:p></span></span></div>
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Power Guyhttp://www.blogger.com/profile/15282245011253622251noreply@blogger.com0tag:blogger.com,1999:blog-535177224836915617.post-11679744890213295362018-04-27T11:39:00.003-07:002022-12-22T08:42:56.942-08:00Where and why is a 277Vac input used in the USA?<span lang="EN-GB"><span style="font-family: "calibri"; font-size: large;">The AC power supplied and used by household
and commercial buildings in the USA is primarily 120Vac.<span style="mso-spacerun: yes;"> </span>This is suitable for most electrical and
electronic equipment in the home or office, but for the higher power
requirements of electric driers, air conditioning and electric ovens, 208Vac or
240Vac is available.<span style="mso-spacerun: yes;"> </span><o:p></o:p></span></span><br />
<span style="font-size: large;"><br /></span>
<br />
<div class="MsoNormal" style="margin: 0in 0in 10pt;">
<span lang="EN-GB"><span style="font-family: "calibri"; font-size: large;">The 208Vac is derived by connecting across
two phases of a “Y” or “WYE” three phase supply as shown in Figure 1. </span></span></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgcTU8sNDrXEdM4gVHVo-HSsJjpaVHbz8HZpWNWYpWrYFf3gKyNDw4Ll2TNLcz5zDQLIrTtEG9zpDC7lf1RuzHRSFSIkcw3_VJgh3feR-T8SS-J8YfFNElTPhvJ6QolRJNcZssJCl2GW5gr/s1600/Fig+1+208V+three+phase.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-size: large;"><img border="0" data-original-height="586" data-original-width="722" height="323" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgcTU8sNDrXEdM4gVHVo-HSsJjpaVHbz8HZpWNWYpWrYFf3gKyNDw4Ll2TNLcz5zDQLIrTtEG9zpDC7lf1RuzHRSFSIkcw3_VJgh3feR-T8SS-J8YfFNElTPhvJ6QolRJNcZssJCl2GW5gr/s400/Fig+1+208V+three+phase.jpg" width="400" /></span></a></div>
<div class="separator" style="clear: both; text-align: center;">
<span style="font-size: large;"><br /></span></div>
<div align="center" class="MsoNormal" style="margin: 0in 0in 10pt; text-align: center;">
<span style="font-size: large;"><span style="font-family: "calibri";"><span lang="EN-GB"><o:p></o:p></span></span> <span style="font-family: "calibri";"><span lang="EN-GB"><span lang="EN-GB"><span style="font-family: "calibri";"><strong>Figure
1<o:p></o:p></strong></span></span></span></span></span></div>
<span style="font-family: "calibri"; font-size: large;">The 240Vac is supplied from a distribution
transformer as shown in Figure 2.</span><br />
<div align="center" class="MsoNormal" style="margin: 0in 0in 10pt; text-align: center;">
<span style="font-family: "calibri";"><span lang="EN-GB" style="font-size: large;"><o:p><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiGDb0qvNubLyM5_5tQxMZZ5LHjIi53K8GC2KwHlC3L41qMIGVRv_jtyu1uGFONmvPU5NGnjiVIMdoClWOwBBcrwJ4EAvFMhm_s4K_0CtdC3QXFWWUC1UhhQkrW1Egpj0sxU1m_uTH7DFz2/s1600/Fig+2+240V.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="521" data-original-width="788" height="263" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiGDb0qvNubLyM5_5tQxMZZ5LHjIi53K8GC2KwHlC3L41qMIGVRv_jtyu1uGFONmvPU5NGnjiVIMdoClWOwBBcrwJ4EAvFMhm_s4K_0CtdC3QXFWWUC1UhhQkrW1Egpj0sxU1m_uTH7DFz2/s400/Fig+2+240V.jpg" width="400" /></a></o:p></span></span></div>
<div align="center" class="MsoNormal" style="margin: 0in 0in 10pt; text-align: center;">
<strong style="font-family: calibri; font-size: x-large;">Figure
2</strong></div>
<span style="font-family: "calibri"; font-size: large;">In larger industrial properties, in
addition to 208 and 120Vac, 480Vac three-phase is supplied to the building in a "WYE" (or Y) configuration as shown in Figure 3.</span><br />
<span style="font-family: "calibri"; font-size: large;"><br /></span>
<br />
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjLszdccIONKw7Ig_uD69k_7q820EEyS9zT3a89alycxIYx4NRxEqzxAa3-d9p7yC_jkxvbOAsVAIIfDQrs-i_EAFssvC7vgTnSz0ZvsTe8_FlrkUtT9zg34l3VJtyd-ZKVy-_UA5bCN5jS/s1600/Fig+3+277V.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><span style="font-size: large;"><img border="0" data-original-height="579" data-original-width="765" height="302" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjLszdccIONKw7Ig_uD69k_7q820EEyS9zT3a89alycxIYx4NRxEqzxAa3-d9p7yC_jkxvbOAsVAIIfDQrs-i_EAFssvC7vgTnSz0ZvsTe8_FlrkUtT9zg34l3VJtyd-ZKVy-_UA5bCN5jS/s400/Fig+3+277V.jpg" width="400" /></span></a></div>
<div align="center" class="MsoNormal" style="margin: 0in 0in 10pt; text-align: center;">
<span style="font-family: "calibri";"><span style="font-size: large; mso-ansi-language: EN-US; mso-no-proof: yes;"><span lang="EN-GB"><span style="font-family: "calibri";"><strong><br /></strong></span></span></span></span>
<span style="font-family: "calibri";"><span style="font-size: large; mso-ansi-language: EN-US; mso-no-proof: yes;"><span lang="EN-GB"><span style="font-family: "calibri";"><strong>Figure
3 480Vac three-phase</strong></span></span></span></span></div>
<span style="font-family: "calibri"; font-size: large;">The 480Vac three-phase is used to power
larger electrical equipment like fork lift battery chargers, and heavy
machinery. </span><span style="font-family: "calibri"; font-size: large;"> </span><span style="font-family: "calibri"; font-size: large;">Less current is drawn by the
load at this higher voltage, enabling the use of lighter gauge wire, and the
current is balanced equally in each phase.</span><span style="font-family: "calibri"; font-size: large;">
</span><span style="font-family: "calibri"; font-size: large;">This improves both power distribution and generation efficiency.</span><br />
<span style="font-size: large;"><br /></span>
<br />
<div class="MsoNormal" style="margin: 0in 0in 10pt;">
<span style="font-size: large;"><span lang="EN-GB"><span style="font-family: "calibri";">Measuring across each line to neutral we
see 277Vac (480Vac divided by the square root of 3</span></span></span><span style="font-family: "calibri"; font-size: large;"><span lang="EN-GB" style="mso-fareast-font-family: "Times New Roman"; mso-fareast-theme-font: minor-fareast;">)<span style="mso-spacerun: yes;"> </span>This voltage is used in the USA for powering
lighting and HVAC (Heating, Ventilation, and Air Conditioning).<span style="mso-spacerun: yes;"> </span>Using 277Vac instead of 120Vac reduces the
current drawn by lighting fixtures by over 50%, enabling smaller gauge
(lighter) and lower cost wiring.<span style="mso-spacerun: yes;">
</span>Alternately more lighting fixtures can be connected to a 277Vac feed
than with a 120Vac feed.<span style="mso-spacerun: yes;"> </span>Power losses in
the wiring is also reduced (P=I<sup><span style="font-size: xx-small;">2</span></sup> x R).</span></span></div>
<span style="font-family: "calibri"; font-size: large;">The awareness of the existence of 277Vac
feeds in commercial buildings was very limited until the introduction of LED
lighting in the late 2000s.</span><span style="font-family: "calibri"; font-size: large;"> </span><span style="font-family: "calibri"; font-size: large;">The AC-DC
power supply industry until then had focused on products that operated between
85 – 265Vac.</span><span style="font-family: "calibri"; font-size: large;"> </span><span style="font-family: "calibri"; font-size: large;">As LEDs require low voltage
DC current, LED “drivers” came on to the market, capable of operating from
input voltages of 90 to 305Vac.</span><span style="font-family: "calibri"; font-size: large;"> </span><span style="font-family: "calibri"; font-size: large;">This
voltage range covers 100V, 120V, 230V and 277Vac nominal inputs (with a
regulatory +/-10% tolerance for line variations) to enable use world-wide.</span><br />
<span style="font-family: "calibri"; font-size: large;"><br /></span>
<br />
<div class="MsoNormal" style="margin: 0in 0in 10pt;">
<span lang="EN-GB"><span style="font-family: "calibri"; font-size: large;">Some of the control infrastructure for
smart buildings is now using 277Vac for automatic window sun filtering,
intelligent thermal monitoring and security.<span style="mso-spacerun: yes;">
</span>Often the location of the controllers and monitors are in places where
120Vac is not available and 277Vac can be easily dropped down from above the
ceiling tiles.</span></span><br />
<span style="font-family: "calibri"; font-size: large;"><br /></span>
<span style="font-family: "calibri"; font-size: large;">TDK-Lambda is one manufacturer that is
providing industrial power supplies capable of operating from 90-305Vac.</span><span style="font-family: "calibri"; font-size: large;"> </span><span style="font-family: "calibri"; font-size: large;">These are an alternative to using constant
voltage LED drivers that potentially can have short product lifecycles.</span><span style="font-family: "calibri"; font-size: large;"> </span><span style="font-family: "calibri"; font-size: large;">Engineering resources then have to be diverted
to find alternative products.</span><span style="font-family: "calibri"; font-size: large;"> </span><span style="font-family: "calibri"; font-size: large;">Power
supplies developed for the industrial market tend to be produced for ten years
or more.</span><br />
<span style="font-family: "calibri"; font-size: large;"><br /></span>
<span style="font-family: "calibri"; font-size: large;">Below are two such products; the 2 to 4W
rated pcb mount </span><a href="http://www.us.tdk-lambda.com/lp/products/kas-series.htm" style="font-size: x-large;"><span style="color: blue; font-family: "calibri";">KAS series</span></a><span style="font-family: "calibri"; font-size: large;">
and the 40 to 65W rated chassis / DIN rail mount </span><a href="http://www.us.tdk-lambda.com/lp/products/csw-series.htm" style="font-size: x-large;"><span style="color: blue; font-family: "calibri";">CSW65 series</span></a></div>
<span style="font-size: large;"><br /></span>
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