/members-area/personalblogs/b/blog/posts/instrument-control-board---prototyping-the-power-sectionIntroductionThis post is continuing the series on creating a control board for an electronic load. Having created a prototype board to test various configurations of features, described in this post , I have spent some time evaluating the Power ...en-USTelligent Community 12https://community.element14.com/members-area/personalblogs/b/blog/posts/instrument-control-board---prototyping-the-power-sectionSat, 14 Nov 2020 10:32:59 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:51264ccd-41a8-4aeb-a446-9ddf8631668cjc20481<p>Your &#39;final changes&#39; schematic has some electrolytics the wrong way round.</p><p>&nbsp;</p><p>C19, C37, C38, C39.</p><img src="https://community.element14.com/aggbug?PostID=10224&AppID=293&AppType=Weblog&ContentType=0" width="1" height="1">https://community.element14.com/members-area/personalblogs/b/blog/posts/instrument-control-board---prototyping-the-power-sectionMon, 09 Nov 2020 15:18:55 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:51264ccd-41a8-4aeb-a446-9ddf8631668cmichaelkellett2<p>If you add LC filters with large inductors you can very easily get issues with large voltage overshoots at switch on. You can mitigate this by carefully placed additional resistance to reduce the Q of the LC filter but this will often reduce its filtering effect as well. An alternative is to use zener diodes to clamp the rail but beware that there will be a large difference between the zener clamping voltage and its &quot;zero&quot; current voltage.</p><p><span>[View:/resized-image/__size/620x271/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-51264ccd-41a8-4aeb-a446-9ddf8631668c/3666.contentimage_5F00_192951.jpg:620:271]</span></p><p>&nbsp;</p><p>This is the power supply from one of my designs - L2 and L3 are Bourns SRR0735A-681M and C90 and C91 are 100uF 10V polymer electrolytics with ESR about 0.016 ohms. (Kemet A758EK107M1AAAE016).</p><p>The zeners are 5.1V BZX84.</p><p>&nbsp;</p><p>MK</p><img src="https://community.element14.com/aggbug?PostID=10224&AppID=293&AppType=Weblog&ContentType=0" width="1" height="1">https://community.element14.com/members-area/personalblogs/b/blog/posts/instrument-control-board---prototyping-the-power-sectionMon, 09 Nov 2020 09:30:30 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:51264ccd-41a8-4aeb-a446-9ddf8631668cJan Cumps1<p>An inductor on position R20 may be better for filtering than a resistor. It will be better for the DC path too.</p><img src="https://community.element14.com/aggbug?PostID=10224&AppID=293&AppType=Weblog&ContentType=0" width="1" height="1">https://community.element14.com/members-area/personalblogs/b/blog/posts/instrument-control-board---prototyping-the-power-sectionSun, 08 Nov 2020 21:21:29 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:51264ccd-41a8-4aeb-a446-9ddf8631668cthree-phase1<p>Interesting set of tests and results. I presume at some point you will meet the law of diminishing returns and the gains in noise reduction you make, will not be worth either the cost of either the parts or the time taken to conduct the experiments.</p><p>&nbsp;</p><p>Does the 4duino have a specification for maximum ripple on its power supply lines? That would be the starting point for me.</p><p>&nbsp;</p><p>Kind regards.</p><img src="https://community.element14.com/aggbug?PostID=10224&AppID=293&AppType=Weblog&ContentType=0" width="1" height="1">https://community.element14.com/members-area/personalblogs/b/blog/posts/instrument-control-board---prototyping-the-power-sectionSun, 08 Nov 2020 19:47:08 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:51264ccd-41a8-4aeb-a446-9ddf8631668cfmilburn1<p>Hi Andrew,</p><p>&nbsp;</p><p>Nicely done.&nbsp; I am always impressed with the thought you put into your designs and the documentation.</p><p>&nbsp;</p><p>Frank</p><img src="https://community.element14.com/aggbug?PostID=10224&AppID=293&AppType=Weblog&ContentType=0" width="1" height="1">