To assure the start of a motor with no need for modifying a circuit operation for generating a PWM signal, even if a duty ratio of the PWM signal is small in starting the motor.

A PWM control unit 102 prohibits PWM control based on the PWM input signal by a motor drive unit 104 when and after a predetermined number of PWM input signals are detected after the circuit operation is started, and outputs the PWM signal causing a motor 105 to start driving at the duty of 100%. Meanwhile it outputs the signal corresponding to the PWM input signal when and after a hall signal is detected a predetermined number of times after the motor 105 starts driving, and further allows the motor drive unit 104 to perform PWM control of the motor 105.

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