HV design problem

J

Jim Thompson 20 years ago

As a start... what limits G-S voltage?

...Jim Thompson

Vote

J

Jim Thompson 20 years ago

All the 1N4148's are doing is limiting reverse G-S voltage, NOT forward.

If you are exceeding 20V G-S who knows what may be happening.

Put zeners in there NOW!

...Jim Thompson

Vote

P

Peter Andersen 20 years ago

Hi

I have done some experimenting with a HV power supply design. I have posted my regulation design here:

formatting link

The problem is this when I reach about 270V output it starts to oscillate and I have some very nice sinus curves at the output. Under and over 270 there is no problem.

I tried to follow the example in AoE page 372 and placed some caps (100nF) on the divider resistors but that blew the first to of my fets.

Any help?

Peter

Vote

P

Peter Andersen 20 years ago

I know the right way to do it is with zeners. In this one I just use

1N4148 - but surely that couldn't have anything to do with this problem? in the final design I will off cause have some zeners!

Peter

Vote

R

Robert Baer 20 years ago

1) Why don't you drive the 100K divider and first FET gate from the "pulldown", dispensing the 470K chain? 2) Why don't you use one FET?

Vote

HV design problem

Join the Discussion

Didn't find your answer?