I want to know the working principle of the given mosfet driver circuit.drive signal is from pin no 12 of microcontroller. kindly explain the working principle of the circuit if any one knows.i am confused that the source of mosfet is not grounded then what will be the gate to source voltage to turn on the mosfets.
The "battery negative wire" (the line following the bottom of the schematic) is the circuit ground. The MOSFETS are a switch to ground the negative side of the solar panel so presumably the PV positive side is permanently connected. Without seeing the rest of the circuit it's difficult to be sure.