A Low-Power Capacitance-to-Voltage Converter For MEMS Capacitive Sensors

Abstract

A new low-power capacitance-to-voltage converter (CVC) for MEMS capacitive sensors is presented. The CVC is implemented using a charge transfer technique, based on a current signal. Its mainly composed of a current mirror and a negative feedback system. The proposed CVC noise performance is less sensitive to parasitic capacitance unlike conventional capacitance-to-voltage converters. The theory of operation of the proposed CVC is presented together with a noise-analysis. The proposed CVC architecture is used to implement an interface circuit in 180nm CMOS technology. Also simulation results are presented to verify the operation of the proposed CVC. The simulation results show that the interface achieves 37μW for capacitance range 5.5pF and 1.8V supply CMOS technology.