Conventionally, there is an image pickup device such as a CMOS (Complementary Metal Oxide Semiconductor) image sensor in which a plurality of A/D converters (ADCs (Analog Digital Converters)) are connected to each output line to which pixels are connected for each column and high-speed data reading is achieved by using the plurality of ADCs (for example, see Patent Document 1).
Further, there is an image pickup device in which a plurality of comparators and counters are mounted on each output line, a voltage of a D/A converter (DAC (Digital Analog Converter)) is shifted by an arbitrary value, and a signal of high bit accuracy is read at high speed (for example, see Patent Document 2).
Further, there is an image pickup device in which noise is reduced and dynamic range is improved by performing A/D conversion twice on a read-out signal (for example, see Patent Document 3 and Patent Document 4).