Patent ID: 8969771
Filing Date: 2015-03-03
Classification: H03M,H04N

Abstract:
1. An imaging system including a plurality of pixels arranged in a matrix each of which outputs a pixel signal corresponding to incident light, and a plurality of A/D converting circuits provided in correspondence with columns of the plurality of pixels, the A/D converting circuit comprising: a holding unit which holds the pixel signal as a voltage level; a comparator which compares the voltage level held by the holding unit with a reference level; and a circuit capable of changing the voltage level held by the holding unit so as to approach the reference level at one of a first rate and a second rate lower than the first rate, wherein the voltage level of the pixel signal held by the holding unit is changed by the circuit at the first rate, higher bits are determined in accordance with inversion of a relationship between the reference level and the voltage level held by the holding unit, after that, the voltage level held by the holding unit is changed at the second rate, and lower bits are determined in accordance with inversion of the relationship between the reference level and the voltage level held by the holding, and the imaging system further comprising an adjusting unit which adjusts the voltage level held by the holding unit during a period until the voltage level held by the holding unit is changed at the second rate after determination of the higher bits so that the lower bits and the voltage level held by the holding unit hold a linear relationship throughout a possible range of the voltage level held by the holding unit after determination of the higher bits, wherein the adjusting unit adjusts, during the period, the voltage level held by the holding unit, by causing the circuit to change the voltage level held by the holding unit at the first rate.