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Topic: Power-on delay circuit (Read 1 time) previous topic - next topic


If it were about 30ma or less I would have suggested running the regulator directly off an i/O pin on the MCU.

To contradict that statement, I would never consider using an I/O pin as a power source for a "circuit", an LED or other single low current component "maybe", but to be used for generic "power source", I call that pin abuse.

My philosophy:  Output pins are TTL High/Low "signals", not power sources, that "tell" other components to do some work.

Considering removing the "magic smoke" from an $0.11 transistor versus a $5.00 MCU... the math is easy.


I did say 30ma or less.  Or did you miss  that?  30ma or less is not pin abuse and it matters not the tiniest squat what that 30ma is used for.  Your post, however, might just be a little nasty.
Facts just don't care if you ignore them.


Use a mcu's pin to float the regulator's GND pin to shut it down. Ground that pin to turn on the regulator.

Andy Brown

Good suggestions guys, thank you very much.
Home of the Nokia QVGA TFT LCD hacks: http://andybrown.me.uk

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