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Topic: Counter EMF Protection (Read 954 times) previous topic - next topic

spcomputing

Okay, I understand now.  This Toshiba chip is oddly robust for how ridiculously small it is.  Just as Doc has suggested, your mileage may vary.

Since this chip has no thermal protection other than the package and 175C overtemp circuit, the "paste" or "tape" is irrelevant.  All you want to do is protect the MCU from the "EMF" or current backlash (AC) from the motor(s).  Doc may have some suggestions better than my 1N4001 diode on your PWM output, but I do believe you are on your own on such a small device (298s or 293s have much more built into the device).  Maybe somebody can suggest where to put the diode to get your reverse back ;)

Docedison

a small Tranzorb of the appropriate voltage might work well for 'back emf' but I have another real 'old school idea that I will develop and share in the next few days might just work better... I don't have a good spice model for a motor, have to go with my experience first. Real tired now and not thinking as clearly as I might like. For the follower idea use the PIR device as a distance controller and the beacon for required movement...
I'm going to bed shortly. I do however need my hour with the 2 books I am reading. A Book on C and the C++ Primer. Electronics is easy and fun, C is difficult...

Doc
--> WA7EMS <--
"The solution of every problem is another problem." -Johann Wolfgang von Goethe
I do answer technical questions PM'd to me with whatever is in my clipboard

TeslaIaint

cool. I would like to hear it. Like I said this small robot is just a prototype for my bigger robot that I will build. For that one I don't think I need an h-bridge, but they will be much bigger motors. about 200w.

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