Accuracy improvements for cyclic charge-balancing A/D converter using digital correction algorithm

The conversion accuracy of a cyclic charge-balancing A/D converter is limited by capacitor mismatch, parasitic capacitors, charge injection, and finite operational amplifier gain. In order to improve the conversion accuracy, a digital correction algorithm is proposed. The correction algorithm is simple and makes good use of the high accuracy of charge-balancing A/D conversion. The results with a prototype indicate that the missing codes caused by error sources are eliminated using the correction algorithm, and that 9-bit conversion accuracy is achieved