MOTOR DRIVING CIRCUIT FOR OPTICAL DISK REPRODUCING DEVICE

PURPOSE:To shorten the locking time of a constant accelerating velocity (CAV) disk by deciding the classification of the disk and reaccelerating a motor when the disk is the CAV disk in an optical disk reproducing device to lock the driving motor near the middle layer of the disk. CONSTITUTION:A horizontal synchronizing signal extracted out of a reproducing signal and the phase of a reference signal from an oscillator 3 are compared at a phase detecting circuit 2, a disk driving motor 11 is driven through a phase compensating circuit 8 and a driving circuit 10 and feedback-controlled by a revolution detecting circuit 18 and an accelerating circuit 22, and the revolution of the motor 11 becomes a prescribed value. Thereafter, the motor 11 is locked near the middle layer of the disk, and a locking signal is outputted from a motor locking detecting circuit 28. When this locking signal is not generated within a prescribed time, a system controller circuit 29 decides that the disk is the CAV disk and reaccelerates the motor 11 by an adder circuit 32 and the circuit 22. Thus, the locking time of the CAV disk can be shortened.