Fan control circuit and an electronic device using the same

Abstract

A fan control circuit set in an electronic device, the fan control circuit includes a fan, a controller, a power supply, and a timer. The fan operates normally when the fan receives a control signal and a voltage. The controller outputs the control signal. The power supply supplies power. The timer is coupled between the fan, the controller, and the power supply. A first input of the timer is coupled to the controller to receive the control signal. When a second input of the timer receives a first signal from the power supply, the first input of the timer is coupled to an output of the timer. When the second input of the timer receives a second signal from the power supply, the second input of the timer is disconnected from the output of the timer after a preset time.

What is claimed is: 
     
         1 . A fan control circuit comprising:
 a fan configured to operate normally in event the fan receives a control signal and power;   a controller configured to output the control signal;   a power supply configured to supply power;   a timer coupled to the fan and the power supply, the timer comprising a first input and a second input, the first input coupled to the controller and configured to receive the control signal;   wherein when a second input of the timer receives a first signal from the power supply, the first input of the timer is coupled to an output of the timer; when the second input of the timer receives a second signal from the power supply, the first input of the timer is disconnected from the output of the timer after a preset time.   
     
     
         2 . The fan control circuit as  claim 1 , wherein the controller is a baseboard management controller. 
     
     
         3 . The fan control circuit as  claim 1 , wherein the control signal is a pulse-width modulation signal. 
     
     
         4 . The fan control circuit as  claim 1 , wherein a first output of the power supply is coupled to a power terminal of the fan, a second output of the power supply is coupled to the second input of the timer. 
     
     
         5 . The fan control circuit as  claim 4 , further comprising a voltage converter, an input of the voltage converter is coupled to the second output of the power supply, an output of the voltage converter is coupled to the power terminal of the fan, wherein when the electronic device is operating, the power supply outputs a first voltage which is at a high level to the voltage converter, the voltage converter converts the first voltage into a second voltage and outputs the second voltage to the power terminal of the fan, when the electronic device stops operating, the power supply outputs the second voltage to the fan through the first output. 
     
     
         6 . An electronic device comprising a fan control circuit, the fan control circuit comprising:
 a fan operating normally when the fan receives a control signal and a voltage;   a controller configured to output the control signal;   a power supply configured to supply power;   a timer coupled to the fan and the power supply, wherein a first input of the timer is coupled to the controller to receive the control signal, when a second input of the timer receives a first signal from the power supply, the first input of the timer is coupled to an output of the timer;   when the second input of the timer receives a second signal from the power supply, the first input of the timer is disconnected from the output of the timer after a preset time.   
     
     
         7 . The electronic device as  claim 6 , wherein the controller is a baseboard management controller. 
     
     
         8 . The electronic device as  claim 6 , wherein the control signal is a pulse-width modulation signal. 
     
     
         9 . The electronic device as  claim 6 , wherein a first output of the power supply is coupled to a power terminal of the fan, a second output of the power supply is coupled to the second input of the timer. 
     
     
         10 . The electronic device as  claim 9 , further comprising a voltage converter, an input of the voltage converter is coupled to the second output of the power supply, an output of the voltage converter is coupled to the power terminal of the fan, wherein when the electronic device is operating, the power supply outputs a first voltage which is at a high level to the voltage converter, the voltage converter converts the first voltage into a second voltage and outputs the second voltage to the power terminal of the fan, when the electronic device stops operating, the power supply outputs the second voltage to the fan through the first output.