Patent ID: 7154825
Filing Date: 2006-12-26
Classification: G11B

Abstract:
1. An optical recording/reproducing apparatus including a semiconductor laser for recording a sequence of data blocks onto an optical recording medium by using a laser driving current waveform to control emission of a laser beam by a semiconductor laser, and reproducing the data blocks from the medium, the waveform including a sequence of mark and space data portions each having a data length that corresponds to a multiple of a period of a channel clock based on a recording data modulation method, the optical recording/reproducing apparatus comprising: a semiconductor laser driver supplying a selected one of a plurality of drive currents, including at least a bias-level drive current and a peak-level drive current, to the semiconductor laser to control the emission of a laser beam by the laser; a bias-level current driver for selectively outputting one of a plurality of bias-level drive currents to the laser driver in response to control signals, the plurality of bias-level drive currents including a first drive current supplied to the laser driver during an automatic power control APC process and a second drive current supplied to the laser driver during an automatic current control ACC process; a switching unit; and a control unit selectively executing one of the APC process and the ACC process on the current driver by supplying the control signals to the current driver, the control unit outputting a sampling signal to the current driver in response to a power-monitor signal of the laser beam emitted by the laser when recording data onto the recording medium, wherein, when the control unit outputs the sampling signal within a predetermined time, the control unit continuously executes the APC process on the current driver so that the current driver supplies the first drive current to the laser driver, and when the control unit does not output the sampling signal over a period exceeding the predetermined time, the control unit terminates the execution of the APC process and starts the execution of the ACC process by using the switching unit that operates in response to the control signals supplied to the current driver, so that the current driver supplies the second drive current to the laser driver.