Re: [CAD_CAM_EDM_DRO] Re: Current and the L298 & IRF530/IRF540

If you have room and don't mind spending the bucks, use Hexfred diodes
with your Mosfets to really clamp those pulses. IR says your fets will
run cooler etc. I have used them and they do work.

On my 10A design with the L297, I have the Hexfreds on the Pc board
but didn't populate them. I'm testing them with just the diode in the IRF540
taking the reverse pulses. So far so good. I'm only running it at 5A for
the motors I have on it however. I've only cooked two fets on the prototype
and that was due to a wiring error to my IR2103 drivers. Fixed that and
no problems so far.

I'm also only running at 40 volts for now. I was lazy with my voltage
regulator
so that's as high as it can run. Next rev will take 60 volts input.

later,
Larry E.

> One thing for people new to MOSFETS, use a high enough voltage rated
> part. Inductive pulses were killing those 100v fets protected by a
> 68v znr. The problem was the peak clamping volatage of the znr was
> over 100v by a little. Live and learn. IRF540's were rock solid.
>
> Dave