Patent ID: 8023001

Claim:
An analog front-end circuit comprising: an analog processing circuit that receives an analog input image signal from an image sensor, performs a given process on the input image signal, and outputs an analog image signal; an A/D converter that A/D-converts the analog image signal input from the analog processing circuit; a correction amount register, a correction amount for a correction process being set in the correction amount register; and a calculation circuit that monitors an A/D-converted value output from the A/D converter and performs calculations, the analog processing circuit including an offset adjustment circuit that includes an offset adjustment register and performs an offset adjustment on an image signal based on an offset adjustment value set in the offset adjustment register; and the calculation circuit monitoring the A/D-converted value output from the A/D converter, detecting a change amount of the A/D-converted value when changing the offset adjustment value set in the offset adjustment register by 1 LSB as the correction amount, and setting the detected correction amount in the correction amount register, the calculation circuit calculating a different value between the A/D-converted value when changing the offset adjustment value set in the offset adjustment register by 1 LSB and the A/D-converted value before changing the offset adjustment value set in the offset adjustment register, detecting the calculated differential value as the correction amount, and setting the detected correction amount in the correction amount register.