Patent ID: 7991030
Filing Date: 2011-08-02
Classification: G11B

Abstract:
1. A method for deriving precise control over laser power of an optical pickup unit (OPU), the method comprising: providing an analog-to-digital converter (ADC) within an automatic power calibration (APC) circuit to derive a path gain and/or a path offset from the APC circuit, wherein the APC circuit comprises an analog gain amplifier for generating a second voltage level according to a first voltage level; selectively performing compensation according to the path gain and/or the path offset, in order to control the laser power by a target command; multiplexing the first voltage level or the second voltage level; converting the first voltage level into a first value and converting the second voltage level into a second value by utilizing the ADC; and calculating a ratio of the second value to the first value in order to derive the path gain.