US Patent 10547319 Background calibration of reference, DAC, and quantization non-linearity in ADCS

Multi-step ADCs performs multi-step conversion by generating a residue for a subsequent stage to digitize. To generate a residue, a stage in the multi-step ADC would reconstruct the input signal to the stage using a feedforward digital to analog converter (DAC). Non-linearities in the DAC can directly affect the overall performance of the multi-step ADC. To reduce power consumption and complexity of analog circuit design, digital background calibration schemes are implemented to address the non-linearities. The non-linearities that the calibration schemes address can include reference, DAC, and quantization non-linearities.