Patent ID: 8004445

Claim:
An A/D converter comprising; a first A/D conversion unit; a second A/D conversion unit; a digital calibration section which calibrates an output of the first A/D conversion unit; and a controller which operates based on an information of input-signal identification, wherein the second A/D conversion unit performs A/D conversion with higher accuracy at slower sampling rate than the first A/D conversion unit, wherein when the information of input-signal identification indicates that an input signal to the A/D converter is a first signal, the controller controls in such a way that A/D conversion is performed by the first A/D conversion unit, the second A/D conversion unit and the digital calibration section, and A/D conversion result of the first signal is obtained from an output of the digital calibration section, and when the information of input-signal identification indicates that the input signal to the A/D converter is a second signal which has narrower bandwidth than the first signal, the controller controls in such a way that A/D conversion is performed by the second A/D conversion unit, and A/D conversion result of the second signal is obtained from an output of the second A/D conversion unit.