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Old 9th Jul 2020, 6:25 am   #38
Diabolical Artificer
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Join Date: Jul 2009
Location: Sleaford, Lincs. UK.
Posts: 5,452
Default Re: High voltage regulator circuit.

Thanks Dave. Is Q3/4 a current mirror? i'll try and find time to do some work on this but have a tfmr to rewind by hand today. I've noted all the IP, have a TL341 etc. Re pots across HV, the schematic I posted back in post #1 (re- posted here)uses a pot across 350v, a 470/500k. I've used two of these PSU's in a homebrew tester with no issues. i put two 10M from wiper to each end if I remember right.

Got you David, the Sussex PSU is essentially the same as the attached schematic, but uses a CCS, zener (avalanche) string to get a HV V ref then uses a potential divider instead of the pot. I only briefly tried it, saw how the zeners drifted, moved on. David said of the circuit " IT isn't actually a regulator. It's a pot with a current booster and a current limiter. Any variation of the input voltage comes through proportionately onto the output." I thought it possible to do a bit better by adding foldback. i'll admit to not being 100% on this stuff but have some idea, thanks for your concern though.

Elektor published such a circuit that has a opamp and Farnell used a similar approach in their E350 ( though that use valves as the series pass element) and uses discreet FB circuit. If I can get Dave's schematic working it would be nice.

Attached Thumbnails
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Name:	Mosfet reg same as sussex.jpg
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Name:	Sussex HV PSU.jpg
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Name:	Farnell E350.jpg
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Curiosity hasn't killed this far.

Last edited by Diabolical Artificer; 9th Jul 2020 at 6:44 am.
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