Al - Thanks for your answer. I took a few days off to let things simmer, and everything is a bit little clearer now. I have taken your suggestions and completely re-designed my circuit.
Quote:
Originally Posted by Al Skierkiewicz
I am not sure I understand your application fully. Are you using a standard PWM signal as an input?
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No - my application is increasing current handling capabilities of a cheap RC car receiver. In this case, the direction selected with P-FETs, and the PWM is applied with N-FETs at around 345hz with a duty cycle of ~ 0% - 95%.
Basically, this is what comes in (and also out):
Here is what I have worked out, version 3...
The thing that was giving me problems is that the negative signal is either grounded or floating (essentially tri-state). This was an interesting problem, but I think that pull-up resistors on the inputs can take care of it the way it is set up above.
What do you think?