Mr. Tilley take note Rich Rudman is not hiding anything ,even gives the part numbers . I have been fooling with this type of circuit when ever I get the time .Last try made so much noise on the AM radio I have to put it aside (again) .I have been using the lm3524 chip and feel like I kind of know it but power side keeps leaking smoke so I'll be reading your stuff with great interest. ----- Original Message ----- Sent: Sunday, August 25, 2002 9:05 AM
From: "Rich Rudman" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]>Subject: Re: switchmode (not all that) bad boy charger? > Seth wrote: > > > > Lee- > > > > Thanks for the comments, they are always appreciated. > > > > First, I am not sure of the topology myself, I was going on memory from > > the last time I read anything about switching power supplies. The > > transformer is a high frequency type formerly used as a step up stage > > after rectification of the 60Hz AC line and it was placed after the > > rectified AC was switched. I believe it was switched between 10 and > > 20kHz. Not audible at least. (If I remember correctly). It actually came > > out of a early 90's vintage 1kW switcher but it no longer works. > > > > I will try my hand at a bit of ascii > > > > Is this what I should have for a flyback? I didn't put in gate drive, > > Isense, Vsense (if required) or pwm generation circuits. > > > > ___________ cap diode > > AC----| |-------|------------)||(--|>----|--------| > > | bridge | --- )||( --- 48V > > | rectifier| --- )||( --- Battery > > GND---| | | / )||( | (52-60V) > > | |----------/ -------)||(-----------------| > > ------------ xfmer cap > > 10kHz 17:11 > > IGBT > > > > > > > > > > borrowed from: http://www.web-ee.com/primers/files/AN120.pdf > > > > I can probably afford a different transformer but would like to use the > > IGBTs unless there is a good reason not to. I am not sure about margin > > on voltage for the 200 or 250V IGBTs. I suspect it will be fine, but I > > doubt I will be good at protecting the IGBT from spikes, at least for > > the first (few) builds. But the price is right for those parts, like you said. > > > > Seth > > Seth, Lee is correct in the Ig selection. Use 600 volters!!! Since you > are giving Smalley a toasted motor drive, I can get you a hand full of > 1200 volt 150 amp IGbt modules. Some I can actually garentte work. > The old 250volts were Most likley Powerex trench gates "5Fs"that I > blew up severly in the mid 90s. > They have the lowest Vsat, and the smallest package for the amps of any > Igbt that I have found. They were so easy to break the they were gone > before I knew it. What lived, ran cool, really nice. Also forget 20 Khz, > use 10Khz. The switching losses are kinda obsene in these old Igs. > I am using Powerex "12Fs" in the PFC50s. 600 volt, and they are being > driven in "2 trasnistor Boost-buck" mode. Main PWM control chip is the > TI UCC 3854. I have one client that wants 500+ volts of output... that > will require 1200v parts. > > > -- > Rich Rudman > Manzanita Micro > www.manzanitamicro.com > 1-360-297-7383,Cell 1-360-620-6266 > >
