Patent ID: 8421657

Claim:
An AD conversion circuit that converts an input analog signal into digital data and corrects an error of the digital data, the AD conversion circuit comprising: an AD converting section adapted to receive the analog signal, a power source voltage, and a reference voltage, and to AD-convert the analog signal and the reference voltage using the power source voltage; and a correction processing section adapted to correct a conversion value which is output by the AD converting section, wherein the correction processing section is adapted to: calculate a voltage variation of the actual power source voltage based on a first conversion value obtained by AD-converting the reference voltage by the AD converting section in a state that an ideal power source voltage is supplied to the AD converting section and a second conversion value obtained by AD-converting the reference voltage by the AD converting section in a state that an actual power source voltage is supplied to the AD converting section; and correct, using the calculated voltage variation, a third conversion value produced by AD-converting the analog signal by the AD converting section in a state that the actual power source voltage is supplied to the AD converting section.