Patent ID: 8810165

Claim:
A fan control system, comprising: a fan; and a fan control circuit comprising: a connector comprising a control pin to output a rotation speed control signal, and a power pin to output a voltage signal; a control unit connected to the control pin of the connector to receive the rotation speed control signal, and connected to the fan; a switch unit connected to the power pin of the connector to receive the voltage signal, and connected to the control unit; and a delay unit connected to the control pin of the connector to receive the rotation speed control signal, and connected to the switch unit; wherein the delay unit outputs a first control signal to turn off the switch unit in response to the delay unit not receiving the rotation speed control signal, the voltage cannot be transmitted to the control unit through the switch unit, the fan does not operate; and wherein the delay unit outputs a second control signal to turn on the switch unit after a delay time in response to the delay unit receiving the rotation speed control signal, the voltage is transmitted to the control unit through the switch unit, the fan operates, the control unit controls rotation speed of the fan according to the rotation speed control signal.