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发明公开
CN103573666A 风扇控制电路 无效 - 撤回

风扇控制电路
摘要：
一种风扇控制电路，包括风扇控制器、开关控制器及频率检测器。当风扇控制器的脉宽调制信号输出引脚输出脉宽调制信号时，频率检测器的使能端输出高电平信号，以使得开关控制器的输入端与输出端导通，进而将脉宽调制信号输出至风扇；当风扇控制器的脉宽调制信号输出引脚不输出脉宽调制信号时，频率检测器的使能端输出低电平信号，以使得开关控制器的输出端的输出为高阻态，进而使得通过上拉电阻与电源相连的风扇仍然会收到高电平的信号。上述风扇控制电路可使得风扇在风扇控制器无法工作时仍能正常工作。
摘要（英）：

The invention discloses a fan control circuit, which comprise a fan controller, a switch controller and a frequency detector, wherein when a pulse width modulating signal is output by a pulse width modulating signal output pin of the fan controller, the enabling end of the frequency detector is used for outputting a high level signal to communicate the input end of the switch controller with the output end to further output the pulse width modulating signal to the fan; when a pulse width modulating signal is not output by the pulse width modulating signal output pin of the fan controller, the enabling end of the frequency detector is used for outputting a low level signal to keep the output of the output end of the switch controller in a high resistance state to further allow the fan connected with a power supply through a pull-up resistor to still receive the high level signal. According to the fan control circuit, the fan can work normally when the fan controller cannot work.

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