Disk rotation controlling device

Abstract

A disk rotation control device is charactered in that it comprises: a signal generator for generating a signal in synchronism with a reproduced signal from a disk; a control controlling the rotation of the disk in terms of a constant linear velocity using the signal generated by the signal generator; a detector detecting whether or not a velocity error signal is not larger than a prescribed value in the control; and an accelerator supplying an accelerating signal for accelerating the disk when the velocity error signal is not larger than the prescribed value, and canceling the accelerating signal when the error signal is not smaller than the prescribed value.

Description

technical field [0001] The present invention relates to a disk rotation control device, and more particularly to a spindle motor drive control circuit for optical disks and the like. Background technique [0002] In a disk that records digital signals in a constant linear velocity (CLV) method, when performing tracking by an optical pickup, as the optical pickup moves from the inner peripheral portion of the disk to the outer peripheral portion, the disk is driven to a rotational speed of decline. The rotational speed is controlled so that the frequency of a synchronous clock (a clock generated from the reproduced signal in a phase-locked loop circuit) synchronized with a reproduced signal reproduced from the disc becomes a predetermined frequency, and the rotational speed of the spindle motor is controlled. [0003] Hereinafter, a DVD device is taken as an example for description. [0004] First, FIG. 10 is a block diagram of a circuit for controlling a spindle motor in a...

AI Technical Summary

Problems solved by technology

However, this method is different from the constant rotation speed CAV method. In the case of track crossing from the inner circumference to the outer circumference or in the opposite direction other than normal regeneration, since the rotation speed of the disc 1 varies greatly, the receiving disc 1 Inertial effect, etc., it takes time to enter the state of constant linear velocity again and establish a state where the signal can be read

In order to improve the readability, if the signal is read in the CAV mode, although this problem can be solved, if the DVD signal recorded in the CLV mode is to be read in the CAV mode, the frequency of the reproduced signal increases as the closer to the outer periphery. Corresponding high-speed processing

[0010] However, since there is a limit on the access speed of the memory used in the storage circuit in the subsequent digital signal processing circuit 6, etc., and the PLL circuit 7 is also required to be a wide-band circuit, and only low-speed processing can be performed on the inner periphery, therefore There is a limitation in increasing the rotation speed of the disk 1

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