I am putting together a battery powered audio amplifier using the PAM8403 class D chip.
It has an active low STANDBY pin which turns off the circuits bias and brings idle current to <1uA. The PAM8403 will be powered by a 3.7V lipo battery and a DC/DC boost circuit to bring it up to 5V so I'd like to conserve all the microamps I can. I'm thinking of a circuit that checks for voltage or current at the amp inputs and sends the low signal to the STANDBY pin if nothing is detected after x amount of time. Ideally the circuit would have to be low current itself as it would be on so long as the battery is connected.
What are my options here? I tried google and couldn't find anything but I am thinking a small microcontroller might be the best bet?