Abstract: The present invention relates to an active brake circuit for a fan with backup power, which comprises a protection circuit, a motor driving unit, a motor, a fan controller, and at least one bypass unit. The protection circuit receives an input power source. The motor driving unit connected between the protection circuit and the motor outputs a driving signal to the motor. The fan controller connected to the motor driving unit and the protection circuit outputs a control signal to the motor driving unit. The bypass unit is between the input power source and the motor driving unit such that the bypass unit passes the input power source to the motor driving unit. When the protection circuit disconnects the input power source to the motor, the motor driving unit outputs the driving signal to the motor such that a short circuit is formed to brake the motor.

Abstract: The present invention relates to an active brake circuit for a fan with backup power, which comprises a protection circuit, a motor driving unit, a motor, a fan controller, and at least one bypass unit. The protection circuit receives an input power source. The motor driving unit connected between the protection circuit and the motor outputs a driving signal to the motor. The fan controller connected to the motor driving unit and the protection circuit outputs a control signal to the motor driving unit. The bypass unit is between the input power source and the motor driving unit such that the bypass unit passes the input power source to the motor driving unit. When the protection circuit disconnects the input power source to the motor, the motor driving unit outputs the driving signal to the motor such that a short circuit is formed to brake the motor.

Abstract: A fan operating control system includes a magnetic sensor unit, a control unit, a rectifier unit and a coil unit. The control unit is electrically connected to the magnetic sensor unit and the rectifier unit; the rectifier unit is further electrically connected to a ground; and the coil unit is electrically connected to the control unit and the ground. The control unit detects any fan electric current flowing through the coil unit and generates a rotating speed signal accordingly. When no fan electric current is detected at the coil unit, the control unit stops generating the rotating speed signal. Therefore, it is able to avoid a whole fan system from making an error decision and outputting rotating speed signal continuously when there is not fan electric current flowing through the coil unit, and any abnormal condition that would adversely affect the fan service life can be avoided, too.

Abstract: The present invention provides a control circuit for speed and rotational direction of a fan, including a signal conversion unit, a processing unit, and a drive unit. The signal conversion unit converts the received input signal into a DC level signal. The processing unit determines to generate a plurality of control signals for the fan based on the received DC level signal and at least one preset voltage therein to drive the drive unit, further controlling the rotational speed or clockwise/counter-clockwise rotation of the fan, whereby to reduce the cost and increase the layout space.

Abstract: A fan operating control system includes a magnetic sensor unit, a control unit, a rectifier unit and a coil unit. The control unit is electrically connected to the magnetic sensor unit and the rectifier unit; the rectifier unit is further electrically connected to a ground; and the coil unit is electrically connected to the control unit and the ground. The control unit detects any fan electric current flowing through the coil unit and generates a rotating speed signal accordingly. When no fan electric current is detected at the coil unit, the control unit stops generating the rotating speed signal. Therefore, it is able to avoid a whole fan system from making an error decision and outputting rotating speed signal continuously when there is not fan electric current flowing through the coil unit, and any abnormal condition that would adversely affect the fan service life can be avoided, too.

Abstract: The present invention provides a control circuit for speed and rotational direction of a fan, including a signal conversion unit, a processing unit, and a drive unit. The signal conversion unit converts the received input signal into a DC level signal. The processing unit determines to generate a plurality of control signals for the fan based on the received DC level signal and at least one preset voltage therein to drive the drive unit, further controlling the rotational speed or clockwise/counter-clockwise rotation of the fan, whereby to reduce the cost and increase the layout space.