I have a microPC (the Jetson Nano, 10 W) that cannot handle a sudden power loss. However, the casing I need to design it for only has a latching switch for powering on and off. I need to design a circuit that will facilitate the powering of Jetson Nano (along with some power converters) and will keep powering it for about 30 seconds when the user switches off the system with the switch. This way the Nano will be able to read the switch and shut down in time.
To read the battery status I will be using a ATmega328PB and a small 1inch OLED. This MCU will come out of low power mode by a momentary "check battery" button. The system will be using a 99 Wh battery so a few milliamps of power are no problem. Is the schematic below a viable solution? Can I use analog components to completely power down the system?
(battery display and button are not shown for clarity)