Tri-step analog-to-digital converter

摘要

An analog to digital converter for the conversion of an analog input signal to a digital output code is disclosed. The analog to digital converter has a voltage reference generator to create a plurality of voltage references that divides the total conversion range of the input into increments equal to the smallest resolution increment. The digital output code is divided into most significant bits, intermediate significant bits and least significant bits. The most significant bits are encoded from a set of coarse digital signals that are formed in a set of coarse comparators. The coarse digital code is used to determine the selection of the sub-coarse voltage references. The intermediate significant bits are encoded from a set of subcoarse digital signals. The subcoarse digital code that and the coarse digital code are used to determine the selection of the fine voltage references. The least significant bits and a correction factor for the intermediate significant bits are encoded from a set of fine digital signals. The digital codes that form the most significant bits, the intermediate bits, the fine bits, and the correction factor are encoded in an output encoder to form the digital output word.