New PWM scheme for SSTC Audio Implementation

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Original poster: "Mccauley, Daniel H by way of Terry Fritz <twftesla-at-qwest-dot-net>" <daniel.h.mccauley-at-lmco-dot-com>



Per Jan, Malcom, and Dan's responses, I've decided to go with a new scheme
for my PWM modulation for my SSTC.  Heres what I currently am going to do.
Please let me know what you think.


1.  Using an XR2209 (i have bunches of them) VCO to generate a 250kHz
triangle wave (secondary resonant frequency) with amplitude of 6Vp-p.  This
will be fed into an op-amp to dc bias the signal centered at 6VDC. (only
using 12V single supply)

2.  My audio input is 5.68Vp-p (2Vrms) and will be fed into an op-amp to dc
bias this signal centered at 6VDC.

3.  These two signals will then be fed into a comparator to PWM the audio
signal.  Since both signals are biased around the same centerpoint, when the
audio signal is 0V, this results in a bias condition of 50% Duty output.

4.  The output of the comparator is tied via pull-up resistor to 12V so the
output PWM signal will be a 12V PWM square wave and be fed directly into the
TC4421 and TC4422 MOSFET drivers for my SSTC full bridge circuit.


Anything I'm missing????

Thanks
Dan