Pll control circuit of optical disc apparatus, and program for controlling the optical disc apparatus

Abstract

A PLL control circuit of an optical disc apparatus comprising: a voltage frequency conversion circuit that adjusts an oscillating frequency based on a control voltage to generate a first frequency signal; a phase comparison circuit that compares the phase of the first frequency signal with the phase of a second frequency signal generated based on an RF (Radio Frequency) signal at the time of photoelectric conversion of reflected light of the laser beam applied to an optical disc, to generate a phase difference signal indicating a phase difference between the first frequency signal and the second frequency signal; a charge pump circuit that generates the control voltage for synchronizing the phases of the first frequency signal and the second frequency signal according to the phase difference signal; a first detection circuit that detects whether the RF signal exceeds a predetermined level; a second detection circuit that detects whether the phases of the first frequency signal and the second frequency signal are synchronized; and a control circuit that controls the charge pump circuit to generate the control voltage regardless of the phase difference signal, if the first detection circuit detects that the RF signal exceeds the predetermined level, and to generate the control voltage according to the phase difference signal, if the second detection circuit detects that the phases of the first frequency signal and the second frequency signal are synchronized.

Description

technical field [0001] The present invention relates to a PLL control circuit of an optical disc device and a program for controlling the optical disc device. Background technique [0002] Currently, there are optical disc devices that reproduce information by rotating an optical disc (eg, CD (Compact Disc), DVD (Digital Versatile Disc), etc.) and irradiating laser light. Some of these optical disc devices have a PLL (Phase Locked Loop) circuit for generating a clock (hereinafter referred to as a playback clock) used for playback processing, rotation control of the optical disc, and the like. Next, it will be described with reference to FIG. 7. First, the reflected light of the laser beam irradiated on the recording surface of the optical disc is photoelectrically converted to generate an RF (Radio Frequency) signal. This RF signal is binarized at a slice level fixed by the feedback control of the SLC (Slice Level Control) circuit 101 to become a binarized signal, and outpu...

AI Technical Summary

Problems solved by technology

Therefore, since the period during which the charge pump circuit 104 pressurizes becomes longer, power consumption may increase.

In addition, since the voltage is increased during the period when the clipping level of the SLC101 is unstable, the VCO control voltage becomes more unstable, and as a result, the phase synchronization may be delayed.

Alternatively, when the period T12 is shorter than the period T11, the boosting period of the charge pump circuit 104 in the period T12 may be shortened.

Therefore, even though a reproducible binarized signal is input to the PLL control circuit 100, the phase synchronization of the binarized signal and the frequency signal is delayed, so that the optical disc device may not be able to perform rapid information reproduction processing.

As a result, the performance related to the reproduction process of the information in the optical disc device may be reduced.

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