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Reply-To: "fred bartoli"
From: "fred bartoli"
References: <3DAA0563.9040507@BOGUS.earthlink.net> <firstname.lastname@example.org> <3DAB8ABA.4030602@BOGUS.earthlink.net> <email@example.com> <3DAC188B.7D82A78E@rica.net> <3DAC2D91.firstname.lastname@example.org> <3DAC688E.9C870D83@rica.net> <email@example.com> <3DACADDC.4D60329A@rica.net> <firstname.lastname@example.org>
Subject: Re: My flyback experiment is on the web
Date: Wed, 16 Oct 2002 19:08:41 +0200
X-Newsreader: Microsoft Outlook Express 5.00.2314.1300
Organization: Guest of ProXad - France
NNTP-Posting-Date: 16 Oct 2002 19:07:30 MEST
John Larkin a écrit dans le
message : email@example.com...
> >Schottky diodes for a 200V output will be "hard" to find. But 2 diodes,
> >in series with the maos drain, the other in parallel with the "new" level
> >shifted drain will do the trick.
> I just got samples (30!) of the new Infineon 600 volt silicon carbide
> schottkies. I've been waiting years for these to be real, so now I can
> build my... (laughs diabolically...) But Vf is a tad high for shunting
> the fet substrate. IR has 200 volt silicon parts.
Yes, I was aware of those new silicon carbide diodes and was looking for
some samples almost 1 year ago for my PFC I've surge pb now (don't laugh to
diabolically...). At that time, the french distributors couldn't even manage
to know what they could be, so for samples.... Nevertheless I found a really
good fast IR diode (8ETH03) that had even lower forward drop than the
supposed top competition schottky. I'm very pleased I found them.
> >Oh, spice can provide you some of those nice multiKV ultra low forward
> Yeah, life and love would be better if they behaved like the
> >BTW, SRDs becoming almost impossible to find, does somebody have a
> >for good "bad diode", exhibiting (really)good step recovery behaviour at
> >resonnable power levels ? I have some at SMPS power levels but that to
> >power waste just for the purpose of a generator.
> If you mean little dinky SRDs, there's Metelics, M-pulse, and M/Acom.
> All SRD makers must begin with 'M'. M/Acom has the only
> distributor-stocked parts I know of (MA44769 and such; cheap.) If you
> mean power SRDs, I don't know of anybody who makes them any more. The
> alternative is Grehkov-type DSRDs (drift step-recovery diodes) which,
> as far as I know, people seem to make only by accident.
I'm not seeking for power SRD but low power ones.
I knew those manufacturers but looking for just sample quantity (home
projects) I'm afraid I'll never have hands on a real one. This is why I'm
seeking for some substitute like varicaps you mention hereafter.
> I've been told that some varicaps make nice SRDs, but haven't had time
> to explore that.
> Where did you get your power-level SRDs?
These were not "real" SRDs but normal diodes that exhibit a not so soft
The above 8ETH03, IIRC from my PFC investigation show a good willingness. I
don't remember the figures but I believe 5ns for 15/20A and 200V+ swing is
something reasonable. Also the banal BYV27C when properly driven show
recovery di/dt largely in excess of what the datasheet gives.
Unfortunately all my attempts with low power devices have failed today.
Didn't try varicaps though.
> Fun stuff!
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