A protection circuit and a gate driving circuitry. The protection circuit is for protecting a p-type back-to-back MOS switch. The circuit receives an input driving signal and provides a driving output signal to common gates of the p-type back-to-back MOS switch. The circuit comprises a driving signal insulation switch for disconnecting the common gate of the p-type back-to-back MOS switch from the received input driving signal when the voltage of the common gates is larger than the supply voltage of the circuit. The circuit further comprises a gate source coupling switch for coupling a voltage received at the common source of the p-type back-to-back MOS switch to the common gate if a received voltage at the common sources is larger than a reference voltage Vref.