Two stage analoge-to-digital converter having unique fine encoding circuitry

摘要

An analog to digital converter for the conversion of an analog input signal to a digital output code of n bits has a plurality of voltage references created in a voltage reference generator that divides the total range of voltage of the conversion input into increments of voltage equal to the smallest increment of resolution. The n bits of digital output are divided into most significant bits and least significant bits. The most significant bits are encoded from a set of digital signals that are formed in a set of coarse comparators, that compare the analog input signal with a subset of the voltage references representing the coarse range. The digital code that is the output of the coarse comparators is used to determine the selection of the subset of the plurality of the voltage references that are the fine voltage references. The least significant bits are encoded from a set of digital signals that are formed in a set of fine comparators that compare the analog input signal to the fine voltage references. The digital codes that form the most significant bits and the least significant bits are corrected encoded in an output encoder to form the digital output word.