Patent ID: 7683686

Claim:
A power-on circuit for a computer comprising: a heat sink installed on an electronic device mounted on a motherboard by a clip; a super input/output (SIO) chip comprising a power supply on pin; a connector configured for coupling to an advanced technology extended power supply, the connector comprising a power supply on pin; a first electric switch comprising a first terminal connected to the heat sink and a power supply via a first resistor, a second terminal connected to the power supply via a second resistor, and a grounded third terminal; a second electric switch comprising a first terminal connected to the power supply on pin of the SIO chip, a second terminal connected to the second terminal of the first electric switch, and a grounded third terminal; and a third electric switch comprising a first terminal connected to the second terminal of the first electric switch, a second terminal connected to the power supply on pin of the connector, and connected to the power supply via a third resistor, and a grounded third terminal; wherein upon a condition that the heat sink is installed on the motherboard of the computer properly, the heat sink is grounded, the first electric switch is turned off; after a power-on button is pressed down, the power supply on pin of the SIO chip sends a low level signal to turn off the second electric switch, the third electric switch is turned on, the power supply on pin of the connector is at a low level, the computer is powered on; and upon a condition that the heat sink is installed on the motherboard of the computer improperly, so that the heat sink is not grounded, the first electric switch is turned on, the third electric switch is turned off, the power supply on pin of the connector is at a high level, the computer cannot be powered on.