Patent ID: 7142138

Claim:
An on-line calibration method of a multi-step analog/digital converter (ADC), wherein said multi-step ADC is comprised of a first ADC, a second ADC, a digital/analog converter (DAC) and a residue amplifier, the on-line calibration method comprising the steps of: performing a gain error calibration for the residue amplifier, the step of performing the gain error calibration for the residue amplifier comprises the steps of: sampling an analog signal to generate a plurality of first digital codes and a plurality of second digital codes, wherein the second digital codes are based on a comparison of the analog signal with a residue signal of the first digital codes; calculating a gain error based on a plurality of relative maximums and a plurality of relative minimums of the second digital codes; and performing a calibration procedure based on the gain error; and performing a non-linearity calibration for the DAC.