Analog-to-digital converters for successive approximation incorporating delta sigma analog-to-digital converters and hybrid digital-to-analog with charge-sharing and charge redistribution

Abstract

An A/D converter including a sample and hold circuit, first and second A/D converters and a combination circuit. The sample and hold circuit samples an analog input signal to generate bits. The first A/D converter generate a first digital signal based on the analog input signal and includes charge-sharing and charge-redistribution D/A converters that convert respectively a most-significant-bit and a first least significant bit. The first digital signal is generated based on outputs of the charge-sharing and charge redistribution D/A converters. The second A/D converter generates a second digital signal based on an output of the first A/D converter and includes a delta sigma D/A converter, which converts a second least significant bit. The second digital signal is generated based on an output of the delta sigma D/A converter. The second A/D converter is a fine conversion A/D converter relative to the first A/D converter.