The sense resistor is more accurate, but you'll need to synchronise the sampling with the switching frequency anyway. Ideally you want to know the current at the time the MOSFET is about to be shut off. If you get Switchercad from National, it is very easy to simulate various topologies and investigate current sensing methods.
To convert the PWM controller output into the signals to drive the hbridge, I need to take the PWM controller signal and split it into two signals that are each of half the frequency, each output signal on for alternating input signals. These two signals can drive the hbridge in push pull mode. I haven't done digital logic design for a long time, I think it takes two flip flops but that is about as far as I've gotten :) Anyone know the circuit for this clock divider/splitter?
cheers, Jamie
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