Patent ID: 7671777

Claim:
An AD converter comprising: an analog data storing unit for storing an input analog data; a first DA converter for converting an input digital data into a first analog reference voltage which varies within a first voltage range in a range of every possible signal voltage of the input analog data; a second DA converter for converting the input digital data into a second analog reference voltage which varies within a second voltage range in the range of every possible signal voltage of the input analog data; a first comparator for comparing the input analog data from the analog data storing unit with the first reference voltage; a second comparator for comparing the input analog data from the analog data storing unit with the second reference voltage; and a digital data storing unit for storing a digital data corresponding to a point of time when a change of state occurs in the comparison results of each of the first and second comparators, wherein: the first voltage range and the second voltage range have an overlapping range between them, and the AD converter further comprises a correction circuit for correcting the value of the digital data stored in the digital data storing unit when the input analog data exists in the overlapping range.