Patent ID: 7470885

Claim:
A photodetector-amplifier circuit for outputting a voltage, depending on an intensity of incident light, comprising: a plurality of photo-detecting sections; an amplifying circuit; a plurality of first switches for connecting the corresponding respective photo-detecting sections and an input terminal of the amplifying circuit; and a plurality of second switches for connecting corresponding respective connection points between the first switches and the photo-detecting sections, and a predetermined voltage supplying point, wherein, the first switches are operated so that one of the first switches is ON while the rest of the first switches are OFF, the first and second switches connected to a same connection point are operated in a complementary manner so that one of the switches is ON while the other switch is OFF and so that the one of the switches is OFF while the other switch is ON, and when stray light enters a photo-detecting section connected to one of the rest of the first switches, the corresponding predetermined voltage supplying point supplies a photoelectric current to said photo-detecting section.