Patent ID: 8803054

Claim:
An apparatus comprising: a plurality of unit pixels each configured to output a signal generated by photoelectric conversion; an output line provided for the plurality of unit pixels and configured to transmit signals output from the unit pixels; a plurality of circuit blocks each provided for one of the unit pixels and connected between the one of the unit pixels and the output line; and a first constant current source configured to supply a current to the output line, wherein each of the circuit blocks includes a differential amplifier circuit and a first switch, the differential amplifier circuit includes a transistor configured to form a source follower with the first constant current source, the differential amplifier circuit has a non-inverting input terminal to which the signal output from a corresponding unit pixel is applied, a first terminal of the first switch is connected to a source of the transistor, and a second terminal of the first switch is directly connected to the output line, and connected to an inverting input terminal of the differential amplifier circuit.