> When using PWM to control the speed of a motor that is controlled by an
> H-bridge, what gets turned no-and-off?  I mean, do you send the PWM to the
> transistors that control the direction, or do you send the PWM to a
> transistor that is in series with the power supply?  Am I making any
sense?

For any one motor direction, you need one top and one bottom transistor on.
Either one can be pulsed because they are in series.  However, the bottom
transistors are usually a little easier to drive and may be faster.
Typically, the top transistor is left on as long as the direction is not
changed and the bottom transistor is pulsed by PWM.


********************************************************************
Olin Lathrop, embedded systems consultant in Littleton Massachusetts
(978) 742-9014, olin@embedinc.com, http://www.embedinc.com

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