I am working on a project where I am building a device working on a battery. It’s coming along nicely, and I am looking into ways to reduce my part count.
As an on/off switch, I am currently using the following circuit to make a tactile button latch the circuit on and off:
This work quite well, but it uses quite some parts. To make the part count lower, I thought I would use the power down mode on the Arduino chip. The chip I am using is an ATmega4809.
As I understand it, the power down mode simply turns most parts of the chip off, leaving only what is needed to turn the chip back on, while consuming very little power. Using this functionality, I want to make a new circuit like this (ATmega4809 not shown)
In which a “permanent” (from the battery) power source supplies power to a switch controller (which is also currently used by the circuit shown earlier), and to the ATmega4809. Then a button is connected to one of the digital pins (interrupt capable), which notices when the on/off button is pressed. This triggers the chip to disable the switch controller, and put the chip itself in power down mode.
Now if the button is pressed again, the chip should wake up again, and enable the switch controller, thereby powering up the device again.
Can the power down mode be used like this? Or am I miss-understanding something about its functionality? Is there anything else I should look out for if I implement this?