Charge-sharing digital to analog converter and successive approximation analog to digital converter

Abstract

In one embodiment, an analog to digital converter includes a comparator having a first input, a second input and an output, the first input being coupled to an analog signal, a successive approximation register having a serial input coupled to the output of the comparator, and being configured to generate a plurality of control signals and an N-bit digital value corresponding to the analog signal, and a digital to analog converter having an input coupled to the plurality of control signals, the digital to analog converter further comprising a first, a second, and a third capacitor and a plurality of switches controlled by the plurality of control signals and being configured to couple the first capacitor to the second capacitor and the third capacitor to the second capacitor mutually exclusively to share charge on the first capacitor and charge on the third capacitor with charge on the second capacitor and to generate an analog signal on the second capacitor, the second capacitor being coupled to the second input of the comparator.