Re: 300 mA from a microcontroller pin

On Nov 29, 1:07 pm, Tomás Ó hÉilidhe <t...@xxxxxxxxxxx> wrote:
Arlet Ottens:

What are you driving that you need 3-state 300 mA outputs ? Depending on
the application, there may be alternative solutions.

A bi-colour LED that has only two pins (they're in parallel facing in
different directions). If the microcontroller pin is high, then it'll be
red. If low, it'll be green. If high impedance, it'll be off.

The maximum current rating for the LED package is 30 mA... except I'm
flashing a display and will only have them lit one sixteenth of the time,
so I'm gonna put a burst of 300 mA through them. (I've seen experiments
where people flashed an LED putting an entire amp through it, so I don't
think 300 mA will be a problem for a duty cycle of one sixteenth).

So this would be overkill :)

http://www.intersil.com/cda/deviceinfo/0,1477,EL7158,00.html#data

500 mA Continuous, 12A peak.

Although it strikes me a discrete solution would be cheaper and not
much more complex , an h bridge with a quartet of sot-23 fets, add a
couple of comparators and a bias circuit on the output if you insist
on using a single pin. I think that could work.

Robert
.

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