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Re: Dan's ultrafast gate drive, schematic?
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- Subject: Re: Dan's ultrafast gate drive, schematic?
- From: "Tesla list" <tesla@xxxxxxxxxx>
- Date: Thu, 08 Sep 2005 14:02:17 -0600
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Original poster: Jan Wagner <jwagner@xxxxxxxxx>
Tesla list wrote:
Original poster: Jimmy Hynes <jphynes@xxxxxxxxx>Yeah, that was the concept. Thanks! :) Dan had also sent me the
original schematic. It has a NPN pass transistor from filter cap to
actual gate, and a gate shorting p-channel mosfet with a 10ohm series resistor.
I don't have an exact schematic, but I remember the concept. He was
basically rectifying the output, and using it as a DC/DC converter,
and getting the signal from the diode bridge, so the transformer
supplied both power and signal.
It should be possible to get it to cope with variations in duty
cycle, with a proper DC blocking capacitor, but it might be tricky
to get it to work right.
Hmm. Maybe it will get tricky. I'll experiment a bit and see. I
actually don't need to transformer-couple the gate charge, just a
3.3Vpp PWM signal from a TAS5012 which then is input to a
TC4421/UCC37322/driverchip that has a bootstrapped +12V supply. As
power comes from elsewhere, large duty cycle variations might be a
lot less tricky. Fingers crossed that this works! :-)
And, to keep remotely Tesla related, the same mosfet drive circuit
for this audio amp I might later also start using in:
http://users.tkk.fi/~jwagner/electr/dsp-sstc/ (no DSP SSTC code yet,
might also opt to use Freescale MC56F8300DSK devel board kit of $79
with SSTC addons 8-)