Patent ID: 8040263

Claim:
An analog-to-digital converter comprising: a reference voltage generator that outputs a reference voltage; a first comparator and a second comparator that compare the reference voltage and a voltage of an input signal and output a digital signal having a first logical value or a second logical value; and a calibrator that compares an output of the first comparator and an output of the second comparator and outputs a first offset control signal and a second offset control signal, wherein the first comparator sets an offset value having a positive or negative polarity to an output inversion threshold level based on the first offset control signal, the second comparator sets an offset value having a polarity opposite to the polarity set by the first comparator to an output inversion threshold level based on the second offset control signal, the first comparator comprises a first counter that increases or decreases a value of a first adjustment factor to output based on a polarity of the first offset control signal and sets the offset value based on the value of the first adjustment factor, and the second comparator comprises a second counter that increases or decreases a value of a second adjustment factor to output based on a polarity of the second offset control signal and sets the offset value based on the value of the second adjustment factor.