Analog-to-digital conversion with linearity calibration

Abstract

The embodiments described herein provide analog-to-digital converters (ADCs) and systems and methods for calibrating ADCs, including ADCs with poorly characterized nonlinearities that cannot be effectively calibrated with traditional calibration techniques. In general, the embodiments described herein calibrate by measuring output values from an ADC with a known calibration input values being applied. The measured output values are used to determine localized polynomial interpolants. Each of the determined localized polynomial interpolants is then evaluated at an uncorrected output value, and the evaluated localized polynomial interpolants are then used to generate correction values. These correction values can then be used to calibrate the ADC during later operation. Such a calibration technique can provide effective calibration for a variety of ADCs, including ADCs that use inverter-based voltage-to-current (VI) converters and current-controlled ring oscillators.