Optical disc player with sleep mode

Abstract

An optical disc player enters a sleep (low power consumption) mode when inactive for a predetermined time. The optical disc player includes a buffer RAM for storing index information read from a disc. A refresh circuit is connected to the buffer RAM to refresh the RAM. The refresh circuit includes a reference clock generator which generates a reference clock signal having a predetermined frequency from a reference clock using an oscillator. When the disc player enters the sleep mode, it issues a stop signal to the reference clock generator, which then stops generating the reference clock signal and produces a sleep mode clock signal having a frequency necessary to refresh the buffer RAM. A refresh signal generator circuit connected to the reference clock generator produces a refresh signal for the buffer RAM using the sleep mode clock signal. A control circuit connected to the refresh circuit produces the stop signal when it receives a sleep command and deactivates the stop signal when it receives a recovery command. Since the oscillator is stopped during the sleep mode, the disc player dissipates very little power in the sleep mode.