Fan control system

Abstract

The present invention relates to a fan control system. The fan control system includes a first micro controller, a second micro controller and a first logic circuit. The first micro controller provides at least one first control signal. The second micro controller is connected to the first micro controller. The second micro controller detects operational status of the first micro controller, and provides at least one second control signal. The first logic circuit receives the first control signal and the second control signal to process logic operation and to generate at least one driving signal to fan. The fan control system of the invention utilizes two micro controllers, when one of the two micro controllers malfunctions, the first logic circuit allows the other micro controller to continue proper operation of the fan, thereby preventing the problem of insufficient heat dissipation that results from malfunction of the single micro controller of a conventional fan control system.

1 . A fan control system, comprising:
 a first micro controller, for providing at least one first control signal;   a second micro controller, for connecting the first micro controller and for detecting operational status of the first micro controller, the second micro controller for providing at least one second control signal; and   a first logic circuit, for receiving the first control signal and the second control signal to process logic operation and to generate at least one driving signal to at least one fan.   
     
     
         2 . The fan control system according to  claim 1 , wherein the first logic circuit is a logic OR circuit. 
     
     
         3 . The fan control system according to  claim 2 , wherein the first control signal is a first pulse width modulation signal, when the second micro controller detects the first micro controller under normal operating conditions, the second control signal serves as a low logic level signal so that the driving signal serves as the first pulse width modulation signal; when the second micro controller detects the first micro controller under abnormal operating conditions, the second control signal serves as a high logic level signal so that the driving signal serves as the high logic level signal. 
     
     
         4 . The fan control system according to  claim 2 , wherein the first control signal is a first pulse width modulation signal, when the second micro controller detects the first micro controller under normal operating conditions, the second control signal serves as a low logic level signal so that the driving signal serves as the first pulse width modulation signal; when the second micro controller detects the first micro controller under abnormal operating conditions, the second control signal serves as a second pulse width modulation signal so that the driving signal serves as the second pulse width modulation signal. 
     
     
         5 . The fan control system according to  claim 1 , further comprising a rotating speed detector for detecting the rotating speed of the fan and for generating at least one rotating speed signal to the second micro controller, the second micro controller transmits the rotating speed signal to the first micro controller. 
     
     
         6 . The fan control system according to  claim 1 , further comprising a second logic circuit and an alarm, wherein the first micro controller is used for further providing at least one first alarm signal to the second logic circuit, the second micro controller is used for further providing at least one second alarm signal to the second logic circuit, the second logic circuit receives the first alarm signal and the second alarm signal to process logic operation and to generate at least one actuating signal to the alarm. 
     
     
         7 . The fan control system according to  claim 6 , wherein the second logic circuit is a logic OR circuit, when one of the first micro controller or the second micro controller is under abnormal operating conditions, the second logic circuit processes logical OR operation on the first alarm signal and the second alarm signal to generate the actuating signal to actuate the alarm. 
     
     
         8 . The fan control system according to  claim 7 , wherein the first micro controller further comprises a first communicating interface, and the second micro controller further comprises a second communicating interface, the first communicating interface and the second communicating interface connects to detect the operational status of the first micro controller and the second micro controller.