Patent ID: 7446438

Claim:
A power control circuit, comprising a power unit, an electronic device, a driving circuit, an electronic switch comprising a P-channel MOSFET having a gate, a source and a drain electrically connecting with the driving circuit, the power unit and the electronic device respectively, and a mechanical switch having a first contact and a second contact electrically connecting with the driving circuit and the electronic device respectively, the mechanical switch further comprising a self-returning key which is capable of moving between the first contact and the second contact by controlling of an external force, when the self-returning key reaches the first contact, the mechanical switch producing a power-on signal when the self-returning key reaches the first contact and producing a power-off signal when the self-returning key reaches the second contact, wherein: the driving circuit comprises a first diode having a cathode and an anode, the cathode connecting with the gate of the P-channel MOSFET and the anode connecting with a control port of the electronic device; the driving circuit receives the power-on signal from the mechanical switch and signals the electronic switch to turn on and allow the power unit to supply power to the electronic device; the electronic device controls the driving circuit through the first diode connected between the gate of the P-channel MOSFET and the control port of the electronic device to maintain the electronic switch to be on and allow the power unit to continue supply the electronic device with power; and the electronic device receives the power-off signal from the mechanical switch, and the electronic device signals the driving circuit through the first diode connected between the gate of the P-channel MOSFET and the control port of the electronic device to turn off and disconnect the power unit from the electronic device.