I have a battery powered circuit using an atmega and I've been considering the best way to conserve power when everything is idle. I could put everything to sleep and the atmega in power down mode, but current draw will still be ~5mA.
The majority of the current is consumed by the LDO. I could use a switching regulator instead of and LDO and save ~3mA, but switching regulators require quite a few more external components and I don't want to increase my BOM by that much.
What I'd like to do is put the LDO in sleep mode when the atmega powers down. I have a button tied to INT0 for a wakeup signal, the button has to be tied to ground with a pull up resistor. I was thinking about using a single inverter and an RC circuit to control switching the LDO on. The switch output would be tied to the inverter and when pressed would generate a voltage which would in turn charge the RC circuit giving the atmega enough time to boot up.
Has anyone handled this in the past? Any recommendations?