I'm looking to sense the voltage of a battery pack that is powering a device by the device. Depending the the level of the pack (2 cell LiPo 1200mAh) the device will change it's behavior. As the pack voltage decreases the device will shut down peripherals until it safes completely. Also when the device is being charged that it will only partially function.
The sense circuit will be attached all the time and i'm trying to minimize the drain on the battery from it. My though is to use a voltage divider with very high value resistors then buffer the signal with a low quiescent current OpAmp. I'm looking at the TI LPV511 OpAmp and a 1M and 3M ohm resistors. The OpAmp is rated at 1.5uA max and the voltage divider should be 2.5uA worst case. The uC is a 3.3v device.
Is this circuit sufficient or are there alternatives I haven't thought of?