| 摘要 |
Calibration of an analog-to-digital converter (ADC) is accomplished via a reference comparator, a first and second multiplexer (MUX), and a finite state machine (FSM). By sampling an analog input with the reference comparator and comparing the results with those of the ADC using the FSM, all the comparators in the ADC can be calibrated without interrupting the ADC's normal operation. The first MUX provides a same reference voltage to the reference comparator as a comparator selected for the calibration, and the second MUX provides the FSM with the output of the selected comparator. The FSM then performs a comparison of the reference comparator and the selected comparator, extracts the polarity of the mismatch, and updates the contents of a memory with the extracted polarity. An offset control in the selected comparator receives a signal corresponding to the extracted polarity stored in the memory and injects offset current into the comparator. |
