Flyback Converter

From: 	RODERICK MAXWELL[SMTP:tank-at-mail.magnolia-dot-net]
Reply To: 	tank-at-mail.magnolia-dot-net
Sent: 	Tuesday, December 23, 1997 8:00 PM
To: 	tesla-at-pupman-dot-com
Subject: 	Flyback Converter

I have tested The flyback converter that I,ve been working on for the
last couple of weeks. With the new spilt supply I am able to attach the
o,scope probe directly to the drains of the transistors. True to it's
name the flyback voltage is much greater than the applied voltage. At
40vdc I am seeing abot 150 volts on the o,scope. The waveform looks
somewhat trapazoidal in shape. This is due in part to the capacitor
snubber I have across the two parrallel transistors. Current draw at
40volts is about two amps. The transformer is the same one used for the
push-pull supply except that the center tap has been removed, and I,m
using the entire primary. No sign of saturaration so far. I cannot test
it at a higher supply voltage yet because the heat sink I have the
transistors mounted on is not large enough. I have ordered a whole bar
of heat sink material to solve this problem. It come in four foot long
sections! I plan to use about a foot of the material to mount 5 or 6
transistors in parrallel. I'm back to using fets because the bipolar
blew as soon as I applied power!? I also have this large fan to keep the
whole thing cool.
  Also I finally finished winding the secondary. I think I'll call it
stumpy because it's wide and squat. The resonant freq. should be around
200khz. All I have to do to it is coat it with epoxy.

                                 Frankensteins Helper