- Tue Sep 13, 2011 2:01 am
#133258
Hi Sparkfunions!
Does anyone have a nifty circuit suggestion for the following problem? You MUST have had this requirement this before
I have a 2 x AA cell powered circuit that I want to stay off (draw < 10 uA) until the user keeps a button pressed for, say 1s or more. The button must then enable the BOOST power supply that outputs +3V3 to the micro controller. The micro controller must then keep itself powered. Thereafter the button becomes a user interface, so it must be wired to an micro input. After a while, the micro controller must be able to power down by releasing the enable line.
Attached is a SCH of my best solution so far (but not perfect!). Feel free to shoot it down and point down all the pitfalls of doing it that way. I do not want any parasitic current to flow from the 2 x AA cells to the +3V3 circuit and drain the batteries, therefor I indicated the ESD diodes inside the micro controller.
I am looking for the simplest / cheapest / most robust solution. Maybe the best solution should be captured for posterity...
thanks in advance,
Pieter
P.S. It is not an option for me to keep the micro controller in a deep sleep mode and wake up on interrupt. The BOOST supply MUST be switched off.
Does anyone have a nifty circuit suggestion for the following problem? You MUST have had this requirement this before
I have a 2 x AA cell powered circuit that I want to stay off (draw < 10 uA) until the user keeps a button pressed for, say 1s or more. The button must then enable the BOOST power supply that outputs +3V3 to the micro controller. The micro controller must then keep itself powered. Thereafter the button becomes a user interface, so it must be wired to an micro input. After a while, the micro controller must be able to power down by releasing the enable line.
Attached is a SCH of my best solution so far (but not perfect!). Feel free to shoot it down and point down all the pitfalls of doing it that way. I do not want any parasitic current to flow from the 2 x AA cells to the +3V3 circuit and drain the batteries, therefor I indicated the ESD diodes inside the micro controller.
I am looking for the simplest / cheapest / most robust solution. Maybe the best solution should be captured for posterity...
thanks in advance,
Pieter
P.S. It is not an option for me to keep the micro controller in a deep sleep mode and wake up on interrupt. The BOOST supply MUST be switched off.
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