Samsung Electronics Co., Ltd.

Sung-du Kwon

Yong-jun Cho

Pyong-yong Seong

Jun-Hyuk Lee

Jong-koog Lee

Kun-soo Kim

Hyun-cheal Bang

Chul-ho Jeon

Seung-man Han

Dong-Ryul Lee

Chang-hoon Baek

Chui-ho Jeon

Jung-koog Lee

An apparatus for controlling a monitor photo diode (PD) of an optical pickup system monitors an optical power signal output for writing data on or reading data from a disk. The apparatus includes a comparator which compares a voltage signal corresponding to the optical power signal output from the LD with a predetermined reference voltage signal, and a gain selector which selectively issues a gain output from the comparator depending on the type of the optical power signal output from the LD.

Apparatus for controlling monitor photo diode in optical pickup system

An apparatus and method for detecting beam power generated by a plurality of light sources, using a single device. The apparatus includes a light-receiving unit that receives the beam power generated by one of a plurality of light sources, and an amplifying unit that selects a gain, amplifies the beam power received by the light-receiving unit according to the selected gain, and outputs the beam power amplified as a detected beam power. According to the apparatus and method, received beam power (or amplification gain) is amplified by a gain determined according to the characteristics of the respective light sources. Thus, it is possible to provide the detected beam power in consideration of a sufficient dynamic range for the each light source, thereby realizing effective APC.

Apparatus and method for detecting beam power in optical drive

In order to improve the frequency characteristic of a laser power monitor device and the precision of laser power control when low-speed recording is performed, there is provided a laser power monitor device for an optical recording and/or reproducing apparatus, the laser power monitor device including a photo diode unit to receive part of a light emitted from a laser diode and output a current proportional to optical power, and a monitor circuit to receive the current output from the photo diode unit, convert the received current into a voltage, and outputs the voltage to an automatic laser power control circuit, and the photo diode unit includes a plurality of photo diodes connected to the monitor circuit to supply current to the monitor circuit. The laser power monitor device further includes a switch unit, wherein the switch unit is located between the photo diode unit and the monitor circuit to receive a signal on a current recording speed and switch so that the number of photo diodes supplying current to the monitor circuit is reduced as the recording speed is increased.

Laser power monitor device, optical pickup including the same, and optical recording and/or reproducing apparatus including the same

An optical signal converter and a method or controlling an amplification gain according to a rotating speed of an optical disc. An optical signal detector detects an optical signal reflected from an optical disc in a reproduction mode and converts the detected optical signal into an electrical signal. A gain control signal generator generates a gain control signal when a voltage level of a driving signal used to drive the optical disc exceeds a maximum output voltage of the optical signal converter. A gain switcher selects an amplification gain of the optical signal converter in response to the gain control signal and an external control signal. A signal amplifier amplifies a signal output from the optical signal detector in response to an output signal of the gain switcher.

Optical signal converter and method of controlling amplification gain according to rotating speed of optical disc

A laser power control device for use in an optical recording and/or reproducing apparatus that records data on and/or reproduces data from an optical recording medium by driving a laser diode with a laser diode driver. The device includes: a peak power monitor which monitors a peak power by a sample-and-hold operation, the peak power being output by the laser diode when pits are formed in the optical recording medium; an elimination power monitor which monitors an elimination power by the sample-and-hold operation, the elimination power being output by the laser diode when a space between pits of the optical recording medium is formed; a peak power setter which sets a peak power in the laser diode driver based on a monitoring result of the peak power monitor; an elimination power setter which sets an elimination power in the laser diode driver based on a monitoring result of the elimination power monitor; and a bias power setter which sets a bias power in the laser diode driver based on the monitoring results of the peak power monitor and the elimination power monitor.

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Seoul, South Korea

Sung-du Kwon