I am working on a switch for my quadcopter. I designed a basic circuit with MOSFET as the switching device. I am using an LDO to supply the gate voltage to the Mosfet. The circuit diagram is attached below.
The switch SW3 is connected to the ground so that gate voltage is zero when SW3 is in OFF position, when SW3 is in ON state the quadcopter turns on. I did multiple flight tests and everything was working fine.
To validate the leakage current, I left the circuit connected with SW3 in OFF position for a few hours and found out that Mosfet has been damaged with drain and source shorted internally. Can someone help me out in finding the reason why this could happen?