Re: 300 mA from a microcontroller pin

In article <24H3j.23523$j7.444019@xxxxxxxxxxxxxx>, toe@xxxxxxxxxxx
says...

Thanks for all you driver chip suggestions. Unfortunately I'm a virgin
when it comes to reading datasheets so I'll just make a list of the ones
you select and go over them with my lecturers.

If there's any more suggestions, keep them coming.

Thanks everyone for your help :D


After looking over your JPG schematic, it seems that you may have a
problem using two pins per channel. One way to handle this---at the
cost of a lot of research on transistor characteristics might be:

+5V +5V
| |
10K |---P-Chan
| | |
P1.1-----------------| |------------- Output
| | |
10K |---N-Chan
| |
GND GND

If you can select the P-Chan and N-Chan transistors such that
they are off with 2.5V gate voltage and On with 5V gate
voltage then you could get your Hi/Low/OFF behavior
at the output. Note that this is an inverting driver,
so adjust your P1.1 level as appropriate.

Of course, if you get the wrong transistors, or
mismatched thresholds, you'll let the magic smoke out
of the transistors. ;-) For this reason, you might
want to add two current-limiting resistors between
the P-channel N-Channel transistors and the output.

Mark Borgerson

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