I am new to EE but I see that FETs such as the FQP30N06L have an input capacitance of 800pF. Can that be used to store a charge for some time?
The goal is to push a momentary button to power on a Raspberry Pi and after about 60 seconds detect on a Pi GPIO input that the power button was pushed. And because it is solar-powered, a requirement is to minimize the current in use when the Pi is not powered. Power on events could be hours apart.
The circuit powers on a power control latch via a FET gate. This latch starts the Pi booting. The circuit also feeds voltage into the gate of another FET which would start current flowing. After the Pi is booted, I want it to read the state on the second FET to determine if the power button was pressed. (The Pi could be started via other means so I need to be able to determine what started it.)
Is this doable? Is there a better FET for the job? Is there a better way to meet the goal?
It doesn't work on Falstad, but I'm not sure if that's because of a limitation there; they don't have a parameter on FETs for input capacitance.