Patent ID: 8841594

Claim:
A ramp signal generator for converting an image signal of a pixel into a digital signal, comprising: a comparator operative to output a ramp signal by comparing a reset voltage input to an inversion input terminal and a bias voltage input to a non-inversion input terminal; a ramp signal adjustment unit connected in parallel between a first input terminal of the comparator and an output terminal of the comparator; and a controller operatively coupled to the ramp signal adjustment unit, operative to adjust the ramp signal output from the comparator such that the ramp signal includes a nonlinear interval, wherein a first slope of a first signal portion of the ramp signal corresponding to a first pixel portion of a darker pixel is adjusted to be gentle, while a second slope of a second signal portion of the ramp signal corresponding to a second pixel portion of a brighter pixel is adjusted to be steep, and wherein the reset voltage has same value as the value of a reset signal of the pixel.