Designing a high voltage power supply for Nixie tube projects

PCB layout for the switch-mode HV PSU

A PCB layout for the switch-mode HV PSU by Jan Rychter:

I’ve posted a page describing the design of a HV PSU (High-Voltage Power Supply) that generates up to 220V from a 12V input. In addition to that, it also provides 2*Vout (so, up to 440V, for dekatrons), and two outputs for powering digital logic: 5V and 3.3V. The primary HV boost circuit reaches 88% efficiency when going from 12V to 185V at 55mA, with a 3% output ripple.
The version I’m posting online is not perfect, but works quite well in a number of my projects. I decided I’d rather publish it as it is now rather than keep it locked forever.
It is published as Open-Source Hardware, to be used however one likes. All source design files are provided. It’s my way of paying back: I learned a lot from looking at other designs and by asking questions, so now it’s time to give back.

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  1. I would increase the clearances for the HV outputs… a good rule of thumb would be 1mm for each 100V. I haven’t opened the design file but it seems to me that this layout doesn’t respect this

  2. Hi guys — author here. As for the HV trace spacing, I already got some comments on that and I’ll be improving that in a future revision. It’s less of a problem than most people think, because of the soldermask on both sides of the board, but still, I guess it’s a valid concern.

    Fixing it, unfortunately, isn’t that obvious, as you need to route the feedback trace between the components somehow, and there are limits as to what you can do with tightly packed components.

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