At 08:42 AM 2/8/02 -0800, you wrote:

>  Remember that your losses
>are quite often governed by the back diode voltage, so the on resistance
>is not that important. At 50% duty cycle the diode is the biggest sucker
>of power.

You shouldn't have any diode drops involved. Remember MOSFETs conduct in
either direction when ON. In the simple case (one MOSFET/PWM) you just add
another MOSFET in parallel with the motor and drive it out of phase.

This stuff at 100A+ requires *significant* care as to inductance and such
like. Stubby little traces start to act like nasty voltage sources that
can cause drive latchup etc.

Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com
9/11 United we Stand

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