Patent ID: 8077239

Claim:
A solid-state image pickup device comprising: a plurality of pixels which are arranged two-dimensionally and output pixel signals derived by photoelectric conversion; a plurality of output lines each coupled to a respective line of said pixels, and each of which transmits the pixel signals output from said pixels arranged in one line; a plurality of variable gain amplifiers each coupled to a respective one of said output lines, each comprising (a) a differential amplifier, (b) a first coupling capacitor connecting said output line and one input terminal of said differential amplifier, which removes noise of the pixel signal or signals received thereby, and (c) a second coupling capacitor connecting said one input terminal and an output terminal of said differential amplifier, wherein the gain of each of said plurality of variable gain amplifiers is determined by the ratio of capacitor values of said first coupling capacitor and said second coupling capacitor, wherein said solid-state image pickup device operates in a first mode of reading the output signal from every pixel, and a second mode of reading and adding the output signals from the plurality of pixels, wherein the gain of each of said variable gain amplifiers is higher in the second mode than in the first mode, wherein said plurality of pixels are provided with color filters, such that, in the second mode, the output signals read out from said pixels having the color filter of the same color are added, and wherein said solid-state image pickup device further comprises an adder circuit comprising a plurality of capacitive elements each holding an output from a respective one of said differential amplifiers, and being arranged such that different ones of said capacitive elements share the same input and output terminal selectively connected in the second mode.