A Noise-Free DIY Switching Power Supply - How Hard Can It Be?

Comments · 178

• TO

  @tookitogo · 1 year ago

  Pro tip for switcher design: TI’s “WEBENCH Power Designer” online tool. You tell it the specs you need (input voltage range, output voltage, output current, and some design preferences (e.g. prioritize size, efficiency, or cost), and it spits out a list of designs using their parts, each complete with schematic, PCB layout, and suggested components (like actual parts, not just values). And it’s all fully simulated and editable, so you can change components and see how that affects performance. And when you’ve got a design you like, you can export it to your EDA software.<br><br>I’ve used it to design several DC-DC converters and it’s worked great. (I’m not affiliated with TI, just a happy customer.)

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• EF

  @efox29 · 4 years ago

  This is an unbelievably great video. The early mistakes and making incremental changes to show what each change does.. Nice. For new EEs this is invaluable. Great video!

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• TN

  @tnekkc · 1 year ago

  I designed power supplies from 1980 to 2008 for aircraft, missiles, &nbsp;and medical......because that is where the money was.

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• BR

  @brandtharen · 4 years ago

  I quite like those PCBs with clear solder mask. They&apos;re helpful for seeing traces, but they also look great.

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• RO

  @rossjohnson7916 · 4 years ago

  It would be really interesting to see what difference a 4 layer PCB would make, with the ground plane shifted up to layer 1 (just below the top layer). Rick Hartley often makes the point that the bottom layer of a 1.6mm PCB is just too far away to be truly effective, and that there&apos;s almost never a good time to use 2 layer PCBs for EMC management. The prepreg separating the top two layers would typically be less than 0.2mm thick.

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• CH

  @ChristopherBrandsdal · 2 years ago

  Now this is a VERY good video for explaining how this works. So many new makers makes these mistakes on power supplies. I have done it myself. Several times.

  3

• JS

  @jstro-hobbytech · 3 years ago

  Great video. Switch mode design is a specialty all it&apos;s own. Infact i know someone who has spent his whole career designing switch mode and he is at the top of his profession and still struggles with emi problems. He&apos;s almost had to dedicate most of his ongoing learning to that. Hes told me about testing the design in different attitudes, temps, humidity; controlled and relative. It&apos;s definitely an artform.

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• JE

  @jeremylister89 · 1 year ago (edited)

  Minimise switching loop distances on input and output. Separate high dv/dt nodes (tracks) from other stable dc nodes by several millimeters. Add RC damping positions to reduce hf ringing if they occur.

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• AB

  @absurdengineering · 3 years ago

  Pours are the means to an end. The end is low impedances between nodes in the power path where switching currents flow <b>and</b> small loop areas. The best-performing layout can still be improved. Ultimately, with a 2-sided board, it’s possible to close the current loops with loop area projecting sideways through the board, and it’s possible to get the on and off state current loops at right angles to each other. For some hints as to how that may work, look into multiphase converter app notes where they really emphasize small loop areas on the layout. Components on two sides of the board can make a big difference. The resulting volume is still the same or better.

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• MA

  @MAYERMAKES · 4 years ago

  James is in the zone today.

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• HL

  @HL65536 · 4 years ago

  I once built a flyback converter on a breadboard. It worked. Until the output capacitor became loose. Then the USB unplug sound sounded a bunch of times as USB connections half a meter away were killed due to interference.<br>But other than that, if you try to minimize parasitic inductance, resistance and capacitance in the critical sections, it should be fine to test a SMPS design on a breadboard before making a permanent PCB. Just make sure the connections are solid.<br>It would be interesting to actually see a breadboard version of the circuit from this video.

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• TH

  @tHaH4x0r · 1 year ago

  Great video, love the different pcbs showing how improvements help.<br>Perhaps consider a follow up video, &apos;A noise-free EMI compliant DIY switching PSU - How hard can it be?&apos; where you revisit the design and measure conducted and near field EMI, and try to get a board compliant in that (it is much harder).

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