Hello,

I am designing a motor controller for an underwater vehicle being
constructed as part of a school project.  The motor controller uses 4
IRF1404 power HEXFETs arranged in an H-bridge and a pair of IR2109 to drive
the low and high sides of the H-bridge.  The controller will be able to
operate from 12-24V at upto 30A.  Very standard.  I am also placing a 30A
fuse in series with the power supply to protect against short circuits.  A
PIC16F876 will be used to provide the control signals to the H-bridge.  So
far, so good.

My questions is how to I add current and thermal limiters to an H-bridge?
I've been searching the web and have found that these are standard features
on almost all motor controllers.  If someone could enlighten me on how this
is done or point me to some resources I would be most appreciative.

Thanks,
Donovan Parks

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