Re: SSTC idea - DRSSTC ?

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

Original poster: "Jan Wagner by way of Terry Fritz <teslalist-at-qwest-dot-net>" <jwagner-at-cc.hut.fi>

Hi!

On Fri, 28 Mar 2003, Tesla list wrote:
 > Original poster: "jimmy hynes by way of Terry Fritz 
<teslalist-at-qwest-dot-net>" <chunkyboy86-at-yahoo-dot-com>
 >
 > If you haven't seen yet, I have done some work on the website. The log book
 > is now in htm format, and I have an explanation up too. It asked for a
 > password right? If you just hit cancel you can open a read only version,
 > but I think I got everything working now.
 >
 > http://hot-streamer-dot-com/chunkyboy86/

just a quick note on your findings in the log:

You write that the gate drive xfmrs saturate with DC bias. Actually you
can get rid of this problem by adding a good quality capacitor in series
with each xfmr primary. It should be large capacitance (1uF or more) so
you don't get any unwanted high frequency resonance of this capacitor and
the gate drive xfmr inductances. And, you should add a small value
resistor in series on the secondaries, 10 Ohms or so (experiment on this),
to remove spikes and damp out resonances.

The capacitor will make
http://www.hot-streamer-dot-com/chunkyboy86/jimmyLogBook_files/image001.jpg
unnecessary, I'd think. Unless there's some other purpose that you use the
extra "on" pulse glitch for...

Btw you could get some good gate drive xfmr samples from www.coilcraft-dot-com
(they think these tiny xfmrs belong into the "power magnetics" product
section, very odd... ;-) That'd be at least one worry less. And remember
to add the output protection/clamping schottkys to your driver chips,
especially if you're using Microchip's TC44xx parts. And a series resistor
on the logic input of these, so your microcontroller is less likely to fry
if the driver blows up....

cheers,
   - jfw

--
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  Jan OH2GHR