Accurate dynamic-feedback CMOS cross-quad suitable for low-voltage operation

Abstract

This paper presents the implementation of a crossquad circuit suitable for low-voltage operation. The proposed cell exploits a dynamic positive feedback gm boosting technique to achieve linear voltage-to-current conversion, while it manages to work with low-voltage with no extra bias current and minimal additional hardware. Results for a 0.5 m CMOS implementation supplied at 3 V show a 0.972 % voltage-tocurrent accuracy, improving the 0.867 % accuracy of a previously reported cross-quad topology also suitable for lowvoltage operation which is based on folded transistors.