Low power OTA-less I-V-converter with single-ended to differential conversion for capacitive sensor interfaces

This paper presents a current-mode interface circuit for capacitive sensors, with the main feature of being able to produce a differential output voltage from a single-ended capacitive sensor. The circuit has been designed combining two concepts of Folded Current Mirror and Charge Sampling. A total harmonic distortion of 34db over a 5-MHz signal bandwidth, and a DR of 48db are estimated. The circuit consumes only 60uA from a 1.5V supply. The efficiency of the proposed scheme is evaluated in a 130nm CMOS technology from Global Foundries.