Patent ID: 8068047

Claim:
An AD conversion apparatus comprising: a differential amplifier that generates a differential input voltage according to an analog input signal; a differential DA converter of a charge redistribution type, which outputs a differential output voltage resulting from subtracting the differential input voltage from a differential comparison voltage that is in accordance with comparison data; a comparator that compares a positive output voltage and a negative output voltage in the differential output voltage; a control section that identifies the comparison data at which the differential output voltage becomes substantially 0 based on a comparison result of the comparator, and outputs the identified comparison data as output data; and a setting section that sets at least one of a common potential of the differential amplifier and a common potential of the differential DA converter, according to a targeted value of a common potential of the comparator, such that (a) the common potential of the differential amplifier is set independently of the common potential of the differential DA converter, (b) the common potential of the differential DA converter is set independently of the common potential of the differential amplifier, or (c) the common potential of the differential amplifier and the common potential of the differential DA converter are set independently of each other.