RE: More SSTC Questions

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Pete Komen by way of Terry Fritz <twftesla-at-qwest-dot-net>" <pkomen-at-zianet-dot-com>

Matt,

I'm not sure.  Do you have a diode going across the primary?  (opposite
direction across the inductive load)

International Rectifier has lots of somewhat scattered information about
snubbers, MOSFET/IGBT drivers, and etc.
http://www.irf-dot-com/
Look under "technical information".

Pete Komen


-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Wednesday, December 26, 2001 9:12 PM
To: tesla-at-pupman-dot-com
Subject: More SSTC Questions

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<Fucian-at-aol-dot-com>

Hi all, I am wondering if a getdrive xfmr is all that neccesary?Can i use a
half bridge w/o the stupid transformer?Or is it really that hard to make?

I am still killing mosfets and now 555s!I have tried putting an MOV across
the source and drain and still no help.I have tried all the diodes and still
no help!?Whats wrong?

I know a half-bridge is better but I REALLY want to make the 555 and 1
MOSFET
ciruit work.Success would be full variac voltage(120v) without the parts
frying.Now WHY is the MOSFET dying with the diodes in place also?Wont a
ultrafast diode stop CEMF?I also have tried the schotty in series with the
MOSEFT source and then another ultrafast diode going drain to
ground.(Correct?)

I have measured the gate voltage at about 15volts.

What could kill the MOSFET now?CEMF should not be an issue.The internal
diode
heating should not either.Ugggggggg!!!!!!!

Thanks,
Matt