3V voltage regulation

Thread Starter

issc29

Joined Oct 9, 2011
3
Hi,

I would like to use a CR2032 3V battery for a project that I am doing. It will be powering an atmega 328p microcontroller (which accepts 1.8-5.5v). I am thinking of using a Low Dropout Regulator (LDO) to ensure that it doesn't go above 3V to protect the IC, but what do I do when battery voltage of the battery goes below 3v casuing the LDO to outputting current? (or below the droput voltage for that matter?). I pretty much want a 3V (or 2.7?) regulated power supply to the IC.

Any suggestions would be appreciated!

Thanks!
 

MrChips

Joined Oct 2, 2009
19,384
There is no need to use a regulator since the battery voltage of 3V will never exceed the max supply rating of 5.5V.
 

Thread Starter

issc29

Joined Oct 9, 2011
3
Ok great. Should i worry about when the voltage gets too low? Will there be unexpected results from the atmega328p?
 

thatoneguy

Joined Feb 19, 2009
6,359
If you wanted to sacrifice 10% of the battery life, you could add a buck/boost converter so the output would always 3V, but the benefit would be a Low battery warning, blinking LED or something, providing the uC has an ADC port to spare.

CR2032 are only rated for about 200mAH, about 75% of what a 9V battery has for capacity (odd, isn't it?) So if you use sleep mode all you can, don't have long delays in the firmware, and take advantage of interrupts, one battery could last over a year if it wasn't driving a load other than maybe an LCD for 15 seconds/day without a backlight.
 
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