Patent ID: 8520353

Claim:
An electronic device, comprising: a power input pin selectively connected to and disconnected from an external power supply; a load; and a surge suppression circuit connected between the power input pin and the load, the surge suppression circuit comprising: a sensing electrode pin selectively connected to and disconnected from the external power supply; a voltage divider circuit having a common node; a first capacitor charged by the external power supply via the common node of the voltage divider circuit; a first transistor connected between the power input pin and the load, and the first transistor being switched on and switched off according to the change of an electric potential of the first capacitor; a second transistor connected between the first transistor and ground, and the second transistor being switched on and switched off according to a voltage provided by the sensing electrode pin; wherein the second transistor varies from off to on upon the condition that a time when the sensing electrode pin is disconnected from the external power supply is previous to a time when the power input pin is disconnected from the external power supply.