Digitally controlled bench PSU project update


An update on Bertho’s digitally controlled bench PSU project, we wrote about it previously:

Finally some spare time to get the PCBs finished and on order. Lets see how many brainfarts are there to be discovered ;-)
Expected delivery in a couple of weeks, so there is some time before I can dive into the lab to do some testing.

A rendering of the PCBs…
Power board

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  1. You know what would be nice? a good DIY switching PSU that delivers 48V at 500-600 watts.
    I’ve read many tutorials that involve hacking existing PSUs to drive voltage up to 48V, and others that deal with connecting several PSUs in series to achieve 24v. But why not a DIY as-simple-as-one-can-get switching PSU capable of delivering 500-600watts of power?

    What’s the use of one you might ask? powering up blades outside their enclosure, for instance!

    1. For day to day usage, get a proper product. A DIY power supply project is almost never going to capture the many years of knowledge of the product engineers, what more a high-power one — they would have noted many failure modes and reliability issues. We can’t instantly replicate that knowledge with hobby power projects. Note that most DIY power supplies are designed and built as bench supplies, for prototyping use. I think nobody is going to leave any DIY bench supply running at near full load and go to the pub.

      So be aware of the risks, don’t let your enthusiasm completely shut down your risk-analysis thinking. If you are a software person, please recognize that in hardware sometimes things are more complicated than hitting the rebuild button. Respect electricity, if you don’t you may get hurt.

  2. @KH: that’s a pro argument. There’s also a con: no schematics, closed design.

    I have bought two commercial products that worked OK, but wich rendered useless within two years. I’d like something where I have access to service manual and schematics. At least something that will enable me to repair/modify it and know what I’m doing. Because I have access to the design info.

    1. I see the PSU as a black box. The designers have complied with a great many regulations in order to bring you that thingy. It’s a commodity part, and for some things, a commodity part is fine with me. A Kickstarter for a open-source PSU may be possible, but realistically, no EE will encourage end-users to open up the chassis, tinker and have end-users exposed to mains voltage circuitry. EEs have done plenty to make these things safe for consumers, an open-source PSU will be a hard sell from a safety perspective. Stick with the commodity brick, change brands or OEM suppliers.

      Yeah I understand sometimes products are flakey. Working products also do not last forever. I had a good PSU on a PC and still needed to replace a low-ESD capacitor after ~5 years. Bulging a bit and might have caused a few extra reboots. Of course I would not have fixed anything more complex than an obviously bulging cap. Possibly a slightly worse air flow issue and the cap seemed to have reached its useful lifetime a bit faster than another identical one in the same chassis. I think not much could have been done to increase the lifetime of that cap, because a PC PSU is cramped and has large heat sinks. If you want to fix PSUs, best to just stick to obviously failing caps.

      If your intended end-use is okay with DIY PSUs, then I’ll wash my hands off this notion immediately :-). Good luck, maybe someone will really run a Kickstarter, then we’d know the market’s response. Insurers surely will not pay if forensics find a DIY PSU on your server rack for instance. Also note the recent X99 mobo failures for two reviewers running the latest Intel CPU — switching circuitry can be tricky. Better to junk a PSU with a serious malfunction than attempt a fix.

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