Abstract: A rotation speed control circuit for controlling a rotation speed of a fan includes: a rotation speed detector, for generating a rotation speed voltage according to a rotation speed signal corresponding to the rotation speed; a sample and hold element, coupled to the rotation speed detector, for sampling and storing the rotation speed voltage; an error amplifier, coupled to the sample and hold element, for controlling a voltage of a filter capacitor according to the rotation speed voltage and a reference voltage, to adjust an error voltage; and a pulse width modulation signal generator, coupled to the filter capacitor, for generating a pulse width modulation signal according to the error voltage and a triangle wave.

Abstract: A method for driving a two-phase brushless motor is disclosed. The motor includes a rotator with permanent magnetism and a stator including a first coil and a second coil. The method includes activating the two-phase brushless motor, detecting an output voltage of a disabled coil of the first coil and the second coil to generate a detection result, comparing the detection result and a reference voltage to determine a commutation time point between the first coil and the second coil, generating a commutation signal according to the commutation time point, and driving the two-phase brushless motor according to the commutation time point.

Abstract: A rotation speed control circuit for controlling a rotation speed of a fan includes: a rotation speed detector, for generating a rotation speed voltage according to a rotation speed signal corresponding to the rotation speed; a sample and hold element, coupled to the rotation speed detector, for sampling and storing the rotation speed voltage; an error amplifier, coupled to the sample and hold element, for controlling a voltage of a filter capacitor according to the rotation speed voltage and a reference voltage, to adjust an error voltage; and a pulse width modulation signal generator, coupled to the filter capacitor, for generating a pulse width modulation signal according to the error voltage and a triangle wave.

Abstract: A driving method for a motor includes sensing variation of magnetic pole of a rotator of the motor, to generate a magnetic pole sensing signal, determining dead zone of the motor according to the magnetic pole sensing signal, to generate a determination result, and adjusting voltage outputted to a coil of the rotator according to the determination result.

Abstract: A method for driving a two-phase brushless motor is disclosed. The motor includes a rotator with permanent magnetism and a stator including a first coil and a second coil. The method includes activating the two-phase brushless motor, detecting an output voltage of a disabled coil of the first coil and the second coil to generate a detection result, comparing the detection result and a reference voltage to determine a commutation time point between the first coil and the second coil, generating a commutation signal according to the commutation time point, and driving the two-phase brushless motor according to the commutation time point.

Abstract: A driving method for a motor includes sensing variation of magnetic pole of a rotator of the motor, to generate a magnetic pole sensing signal, determining dead zone of the motor according to the magnetic pole sensing signal, to generate a determination result, and adjusting voltage outputted to a coil of the rotator according to the determination result.