Geiger Counter Power Supply - Tested to 600V

264

02:44:30

This is a regulated high voltage boost converter, it can output up to 600V with loads not exceeding 1Meg ohm as is typical in driving Geiger-Muller tubes, it can run at down to 6V supply voltage without any problems, typical quiescent current is 120mA with 60% to 70% conversion efficiency.
This circuit doesn't work very well in everycircuit due to the narrow current duty cycle required however it works perfectly well in real life, for the switching transistor I used FDP7N60NZ, for the diode FR107 and a LM319 dual comparator, the transistor right on the output isn't needed that's just so it works as a comparator rather than an op-amp in everycircuit.
Switch input duty must exceed 70%  to minimize power dissipation, optimal duty is around 95% at 10kHz.

published 9 years ago

WTFCircuit

9 years ago

I suggest to use a step up transformer instead the inductor, so it would be much safer and probably a bit more efficient

Chryseus

9 years ago

Safety isn't too much of a concern as long as you put it in an enclosure, in my particular design the high voltage return has to be the case so even a transformer will not help there. Certainly it would improve efficiency but I designed this for ease of construction, your average person isn't going to want to wind a high frequency transformer.

rich11292000

9 years ago

"The high voltage return has to be the case" can you elaborate with what tour talking about here? Also 8 amps into the transistor's base or from the output of a opamp will smoke instantly.

Chryseus

9 years ago

The construction I'm using connects to the GM tube via a coaxial bias tee so the high voltage ground is connected to the shield which is in turn connected to the case, 400V plus the return signal is on the center conductor. The transistor on the output of the op-Amp forces it to be behave as a comparator in everycircuit, in the real circuit you'd use a comparator like LM393 since comparators have a far higher slew rate than op-amps.

WTFCircuit

9 years ago

I prefere to use transformers not only because it is safer for me, but also for the rest of the circuitry. If something goes wrong you can destroy probably everything. I'm just saying that could happened and not that this will happened

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