Fan control system and method for controlling fan speed

Abstract

A fan control system for processor is provided. The system has: a fan, configured to cool the processor; a power measurement module, coupled between the processor and a power supply of the processor, configured to measure the power of the processor; and a control module, coupled between the fan and the power measurement module, configured to control a speed of the fan according to the power of the processor, wherein when the power is higher than a predetermined power upper limit, the control module control the fan to increase the rotation speed.

What is claimed is: 
     
         1 . A fan control system for processor, comprising:
 a fan, configured to cool the processor;   a power measurement module, coupled between the processor and a power supply of the processor, configured to measure the power of the processor; and   a control module, coupled between the fan and the power measurement module, configured to control a speed of the fan according to the power of the processor, wherein when the power is higher than a predetermined power upper limit, the control module control the fan to increase the rotation speed.   
     
     
         2 . The fan control system as claimed in  claim 1 , wherein when the power is lower than a predetermined power lower limit, the control module controls the fan to decrease the rotation speed. 
     
     
         3 . The fan control system as claimed in  claim 1 , wherein the control module further comprises a current sensing unit, configured to measure a current that the power supply provides to the processor. 
     
     
         4 . The fan control system as claimed in  claim 3 , wherein the control module calculates the power of the processor according to the current that sensed by the current sensing unit, and a voltage that corresponds to the current and is read from a correspondence table . 
     
     
         5 . The fan control system as claimed in  claim 3 , wherein the control module further comprises a voltage sensing unit configured to measure a voltage that the power supply provides to the processor. 
     
     
         6 . The fan control system as claimed in  claim 5 , wherein the control module calculates the power of the processor according to the current that sensed by the current sensing unit, and the voltage that sensed by the voltage sensing unit. 
     
     
         7 . The fan control system as claimed in  claim 1 , further comprising:
 a temperature sensing unit, for sensing temperature of the processor.   
     
     
         8 . The fan control system as claimed in  claim 7 , wherein the control module controls the rotation speed of the fan according to the temperature of the processor, wherein the control module controls the fan to increase the rotation speed when the temperature is higher than a predetermined temperature upper limit. 
     
     
         9 . The fan control system as claimed in  claim 7 , wherein the control module controls the fan to decrease the rotation speed when the temperature is lower than a predetermined temperature lower limit. 
     
     
         10 . The fan control system as claimed in  claim 7 , wherein when the temperature is not higher than the predetermined temperature upper limit, the control module controls the rotation speed of the fan according to the power of the processor. 
     
     
         11 . The fan control system as claimed in  claim 1 , wherein the control module is disposed in an embedded controller. 
     
     
         12 . A fan rotation speed controlling method, comprising:
 measuring the power of the processor;   controlling a rotation speed of a fan according to the power of the processor, further comprising:   controlling the fan to increase the rotation speed when the power is higher than a predetermined power upper limit; and   controlling the fan to decrease the rotation speed when the power is lower than a predetermined power lower limit.   
     
     
         13 . The fan rotation speed controlling method as claimed in  claim 12 , further comprising:
 measuring a current that is provided from the power supply to the processor.   
     
     
         14 . The fan rotation speed controlling method as claimed in  claim 13 , further comprising:
 calculating the power of the processor according to the measured current, and a voltage that corresponds to the measured current and is read from a correspondence table between the voltage and the current.   
     
     
         15 . The fan rotation speed controlling method as claimed in  claim 13 , further comprising:
 measuring a voltage that the power supply provides to the processor.   
     
     
         16 . The fan rotation speed controlling method as claimed in  claim 15 , further comprising:
 calculating the power of the processor according to the measured current and the voltage.   
     
     
         17 . The fan rotation speed controlling method as claimed in  claim 12 , further comprising:
 measuring the temperature of the processor.   
     
     
         18 . The fan rotation speed controlling method as claimed in  claim 17 , further comprising:
 controlling the rotation speed of the fan according to the temperature of the processor, further comprising:   controlling the fan to increase the rotation speed when the temperature is higher than a predetermined temperature upper limit; and   controlling the fan to decrease the rotation speed when the temperature is lower than a predetermined temperature lower limit.   
     
     
         19 . The fan rotation speed controlling method as claimed in  claim 17 , further comprising:
 controlling the rotation speed of the fan according to the temperature of the processor, further comprising:   controlling the fan to increase the rotation speed when the temperature is higher than a predetermined temperature upper limit; and   controlling the rotation speed of the fan according to the power of the processor when the temperature is not higher than the predetermined temperature upper limit.