Automatic power control apparatus of disc drive
AssigneeSamsung Electronics Co., Ltd.
InventorsJong-hoon Lee, Sung-ro Go, Kyoung-bok Jin, Ki-bong Yun
Life of this patent
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Abstract
An automatic power control (APC) apparatus reducing time necessary for stabilizing an APC circuit at the initial stage of automatic power control of a disc drive is provided. The APC circuit is designed such that a voltage of a predetermined percent of an expected output voltage is previously added to an APC output voltage of the APC circuit of a laser diode, thereby greatly reducing a stabilizing time necessary for stabilizing an APC output voltage at an initial stage in a write or read mode. Therefore, the loss of data in a high speed write or read mode can be reduced. Particularly, the loss of data in a high speed write mode can be greatly reduced.
Claims21
An automatic power control apparatus of a disc drive having a pickup with a laser diode powered by a laser diode driving circuit, for writing information on a disc and/or reading the information from the disc, the automatic power control apparatus comprising:
- a controller generating an automatic power control reference voltage signal and a stabilizing compensation voltage signal which are suitable for a selected mode;
- a sampling and holding circuit sampling a section of a monitor signal estimating a level of an output power of the laser diode to generate a voltage signal;
- an amplifier determining a voltage difference between the automatic power control reference voltage signal and the voltage signal, and amplifying the voltage difference with a predetermined gain;
- and
- an adder summing the amplified voltage difference, to output the summed result to the laser diode driving circuit.
An automatic power control (APC) apparatus of a disc drive having an optical pickup with a laser diode, the APC apparatus comprising:
- an APC voltage generator generating an APC output voltage signal according to an output of the laser diode;
- a controller generating a predetermined voltage signal at an initial stage of a selected mode;
- and
- an adder adding the APC output voltage signal and the predetermined voltage signal at the initial stage of the selected mode.
A method of controlling the power of a disc drive, comprising:
- generating an automatic power control reference voltage signal and a stabilizing compensation voltage signal suitable for a selected mode;
- amplifying the voltage difference between said automatic power control reference voltage signal and a signal obtained by sampling a selected mode section of a monitor signal estimating the level of the output power of a laser diode with a predetermined gain;
- obtaining an automatic power control output voltage signal by summing said amplified voltage difference and said stabilizing compensation voltage signal;
- and
- providing said automatic power control output voltage signal to a laser diode driving circuit which drives the laser diode.
Dependencies are inferred from the claim text.