Patent ID: 7839127

Claim:
A power supply circuit for motherboard, comprising: a first resistor; an input/output (I/O) controller comprising an I/O controller voltage pin and an I/O controller case open detection (COPEN) pin; and a power circuit capable of providing a stable working voltage for the I/O controller, comprising: an input connected to a standby power supply; a first output connected to the I/O controller voltage pin; a second output connected to the I/O controller COPEN pin via the first resistor; and a GND pin grounded; a battery, capable of providing direct current voltages, comprising a battery anode and a battery cathode; and a Schottky diode comprising a Schottky first anode, a Schottky second anode, and a Schottky cathode; wherein the Schottky first anode serves as the input of the power circuit and is connected to the standby power supply; the Schottky second anode serves as the first output of the power circuit and is connected to the battery anode and the I/O controller voltage pin; the battery cathode is grounded; and the Schottky cathode serves as the second output of the power circuit and is connected to the I/O controller COPEN via the first resister.