Offset and Charge Injection Compensation in an Incremental Analog to Digital Converter

This paper describes a high-resolution incremental A/D converter integrated in a CMOS technology. The accuracy of the converter is independent of the precision of capacitance ratios or comparator. An autozero system cancels error sources such as the operational amplifier offset voltage and the charge injection due to the MOS transistor switches. Unlike for other MOS A/D converters, bipolar operation requires only a single voltage reference.