Low voltage cutoff circuit

attinylithium ionlow-powervoltage measurement

I'm powering an attiny45 from a lithium ion battery; using these batteries the voltage cannot get below 3volts or it will damage the cell. How should I go about cutting the voltage out? Software, or hardware? I'm not sure!?

Best Answer

Holding the MCU in reset is both a decent way to reduce its current consumption to almost nothing as well as indicate that the battery is low. Unfortunately most ATtinys have 2.7V as their closest BOR value so you will require an external voltage monitor if that is not high enough for your purposes.