Re: Dan's ultrafast gate drive, schematic?

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Jan Wagner <jwagner@xxxxxxxxx>

Tesla list wrote:

> Original poster: Jimmy Hynes <jphynes@xxxxxxxxx>
> 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.
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.

> 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-)

thanks,
- Jan