Patent ID: 8704694
Filing Date: 2014-04-22
Classification: H03M,H04N

Abstract:
1. An A/D converter for converting a signal from an image sensor into a digital value of N+M bits (where N≧2, M≧2), the A/D converter being arranged in a column of the image sensor and comprising: a first cyclic A/D converter circuit for receiving an analog value and generating a first digital value having upper N bits indicating the analog value and a residue value; and an A/D converter circuit for receiving the residue value and generating a second digital value having lower M bits indicating the residue value; wherein the first cyclic A/D converter circuit includes a sub A/D converter circuit, a logic circuit, a D/A converter circuit, and an arithmetic unit; wherein the sub A/D converter circuit generates a digital value having N1 bits (where N1<N) for each cycle; wherein the logic circuit receives the digital value from the sub A/D converter circuit; wherein the D/A converter circuit generates a D/A-converted value corresponding to the signal from the logic circuit; wherein the arithmetic unit has an input, an output for providing the residue value, and a feedback path connecting the output and input to each other for a cyclic A/D conversion; and wherein the arithmetic unit amplifies the input value received at the input and generates a difference between the amplified input value and the D/A-converted value.