In this project, I power cycle a RaspberryPi Zero over a 5V USB powerbank, please have a look at my previous question: Blocking current from Backup battery (3x1.5V=4.5V) when powerbank (5V) is turned on my timer switch
I use the TPl5110 as a timer switch and 2xAA as backup battery. My circuit looks as follows:
- The power bank is 10.000mAh, 5V, noname. EDIT: I've checked with the Varta consumer service and according to the datasheets of most powerbanks, they require a minimum current of 50mA -> this question is more universal than it initially looked.
- The P mosfet is a NDP6020 with a low Vth of max 2V
- The Diode is standard silicon 1N4001
According to the manufacturer, the powerbank needs a minimum of 50mA to be turned on/stay on.
I've set the potentiometer of the timer switch to 5min and I've verified it is working.
The problem is: after the first cycle, the RPI0 won't power up anymore since (for the 2nd and subsequent cycles) 0mA current (measured with multimeter) is drawn from the powerbank when the switch kicks in again. Clarification note, as requested: In the first power cycle, 130mA current are drawn (if I turn on the powerbank manually by pressing the on switch).
Can you see a flaw in this simple circuit that prevents current to be drawn from the powerbank on the power cycling events?