Apparatus and method for detecting beam power in optical drive
View Patent ↗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.
1. An optical drive system, comprising:
a light-receiving unit to receive a beam, of a plurality of potential light beams;
a first stage amplifying unit to amplify an output of the light-receiving unit into a voltage signal; and
an amplifying unit to amplify the voltage signal according to a selectable gain based on a type of an optical medium in the optical drive, the type of the optical medium being at least one of a first and second optical medium types, and to output the amplified voltage signal as a beam power, for a respective one of the first and second optical medium types, to be used for automatic power control (APC) of the optical drive,
wherein the amplifying unit selects the gain to be one of a first gain based on a variable resistance and a feedback gain resistance and a second gain based on the variable resistance and another feedback gain resistance.
2. The system of claim 1 , wherein a value of the variable resistance is determined such that light beams corresponding to the plurality of light beams have linear characteristics and/or by considering scatter.
3. An optical drive system, comprising:
a light-receiving unit to receive a beam, of a plurality of potential light beams;
a first stage amplifying unit to amplify an output of the light-receiving unit into a voltage signal; and
an amplifying unit to amplify the voltage signal according to a selectable gain based on a type of an optical medium in the optical drive, the type of the optical medium being at least one of a first and second optical medium types, and to output the amplified voltage signal as a beam power, for a respective one of the first and second optical medium types, to be used for automatic power control (APC) of the optical drive,
wherein the amplifying unit selects the gain to be one of a first gain based on a first variable resistance, a first invariable resistance, and a feedback gain resistance, and a second gain based on a second variable resistance, a second invariable resistance and the feedback gain resistance.
4. The system of claim 3 , wherein values of the first and second variable resistances are determined such that a light beam corresponding to one of the plurality of light sources has linear characteristics and/or by considering scatter, and the first and second invariable resistances are determined in consideration of a ratio of a maximum beam power generated by different light sources.