Patent ID: 11936396
Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
Field: Measurement (Instruments)
Classification: CPC H  G | IPC H

Claim 2:
3. The AD converter with self-calibration function according to claim 1, wherein the calibration control section comprises:
an offset measurement processing portion that measures a summation count of the unit voltage that is required until an output of the comparator is inverted after the capacitance is precharged with a unit voltage equivalent to the reference voltage;
a positive-negative unit voltage correlation measurement processing portion that measures a positive-negative correlation summation count if the input voltage is greater than the reference voltage, the positive-negative correlation summation count being a number of summations that is required until the output of the comparator is inverted as a result of adding a positive unit voltage by an over-summation count equal to the summation count plus a predetermined number of times to generate a summed voltage and thereafter subtracting a negative unit voltage from the summed voltage until the summed voltage becomes smaller than the reference voltage; and
a unit voltage measurement processing portion that measures a unit voltage summation count after the unit voltage is reset, the unit voltage summation count being a number of summations of the unit voltage that is required until the output of the comparator is inverted as a result of summation of the positive unit voltage.