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Re: Dan's ultrafast gate drive, schematic?



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