Analog circuit for processing output signal of image sensor and imaging apparatus using the same

Abstract

An analog circuit includes a pulse control circuit for outputting pulse signals for operating component circuits based on reference pulse signals for driving an image sensor, a noise reduction circuit that is operated in accordance with a pulse signal of a horizontal drive frequency output from the pulse control circuit to reduce noise present in image signals output from the image sensor, a gain variable amplifier for adjusting an amplitude of signals output by the noise reduction circuit, an AD converter for converting the output signals of the gain variable amplifier into digital signals and output these digital signals, a clamp circuit that is operated in accordance with a pulse signal at a horizontal drive frequency output from the pulse control circuit to perform feedback control of the digital signals output by the AD converter, and a frequency-dependent bias circuit that supplies a current amount corresponding to the frequency of at least one kind of pulse signal from among the reference pulse signals and the pulse signals that are output from the pulse control circuit. The analog circuit is operated at a sufficient current amount required for the processing of signals from various image sensors having different horizontal drive frequency specifications.