Sony Corporation

Akashi Ito

Shigeaki A Wachi

Fumihiko Yoshii

Takashi Nakatsuyama

A jack is disclosed capable of selectively accommodating a first or a second plug, the first plug being used for data communication based on a first data communication standard, the second plug permitting data communication as per a second data communication standard. Also disclosed are a reproducing apparatus incorporating the jack and a data communication system furnished with the jack.

Jack, reproducing apparatus and data communication system

A control circuit operating with a pulse-width modulated signal which is operative to control a driving circuit portion provided therein for driving a unit to be driven so as to operate in accordance with a pulse-width modulated control signal and in which an analog control signal is provided with a first DC voltage level at a biasing circuit portion (15), a triangular or saw-toothed waveform voltage signal which is obtained from a reference voltage producing circuit portion (17) with an amplitude varying in response to variations in a power supply voltage is superposed on both a second DC voltage level higher than the first DC voltage level and a third DC voltage level lower than the first DC voltage level, and a driving circuit portion (32) provide for driving a unit to be driven (43) is controlled with first and second pulse-width modulated control signals obtained from a level comparing circuit portion (30, 31) in which the level of the analog control signal provided with the first DC voltage level is compared respectively with the voltage level of the triangular or saw-toothed waveform voltage signal superposed on the second DC voltage level and with the voltage level of the triangular or saw-toothed waveform voltage signal superposed on the third DC voltage level. As a result of such arrangements, the control for the driving circuit portion (32) is stably carried out without requiring a specific power source stabilized particularly, and furthermore the power consumption caused by the unit to be driven (43) is effectively reduced.

Control circuits operating with pulse-width modulated signals

Start-control method and circuit for an optical disc play-back system according to this invention can allow the starting current of the system to be reduced considerably. The method includes the steps of loading the disc onto a disc drive motor, then finding the focal position of the lens, then powerfully energizing the disc drive motor for a certain period of time so as to start the disc spinning and then energizing the focus- and the tracking-servo circuits during inertial rotation of the disc drive motor. The circuit includes a disc-drive-motor servo switch capable of switching the power supply for the disc drive motor from the kick circuit to the disc-drive-motor servo circuit, a focus servo switch capable of switching the power supply for the focus servomotor from the focus search circuit to the focus servo circuit, and a tracking servo switch capable of initiating power supply to the tracking servomotor.

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Tokyo, Japan

Akashi Ito