To enable the control of the movement of an optical pickup of an optical drive and enable the detection of the innermost circumferential position of the optical pickup of the optical drive, without requiring a Hall device or an inner switch.
A motor current of a motor 1, used for driving an optical pickup, is detected by a current detecting means 5 and a ripple component, generated in the phase switching, is extracted from the detected current by a ripple component detecting means 7. Pulses are generated by a pulse-generating means 8 from the ripple component and the rotation value and the revolution of a motor are calculated by a calculation unit 4 according to the pulses. The rotation value and revolution of the motor 1 can be controlled by using the obtained information. With such an arrangement, the rotation state of the motor can be grasped, even if a Hall device and an inner switch are not used, and it is accurately recognized that the optical pickup is at an innermost circumferential position. Further, the motor can be controlled easily according to the obtained information and the position of the optical pickup and be move easily.
KATO NORIYUKI
WATANABE HIROOMI
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