Electronic – 3V to 500V DC converter

dc/dc converterhigh voltage

I am making 3V to 500V DC converter for a GM (Geiger-Müller) tube kind of application. Basically the tube needs to see 500V across it.
I read this relevant thread here :
5V to 160V DC converter
and I have a couple of queries:

  1. Would the LT1073 circuit be suitable for this application.What
    would be the maximum voltage felt by the LT1073 at the SW1 pin ? SW1
    pin MAX is mentioned as 50V. Is this independent of the supply
  2. Suppose I use the common low cost MC34063 , would 3V be the
    absolute minimum I could go down to? Suppose I use a flyback
    topology instead of a boost converter,would I be able to get by
    using the internal switch of the MC34063 instead of an additional
    external switch? I suppose the external switch is needed more for
    the HV rather than the current drawn.

Best Answer

Making a 500V supply capable of a few uA is actually pretty trivial:

enter image description here
From TechLib.com

The transformer can be any generic 1:1 isolation transformer, the phone isolation transformers you can buy at radioshack work quite well.

However, this power supply is not capable of supplying any real power. It works great for a geiger-counter, but if you have a load smaller then ~\$50M\Omega\$, you will begin to overload it.