A switched-capacitor interface for differential capacitance transducers

High-speed interface circuit for differential capacitance transducers

A high-speed capacitance difference-to-sum ratio measurement circuit is presented for differential capacitance transducers. It consists of a switched-capacitor input stage, two sample-and-hold (S/H) circuits followed by voltage-to-current (V/I) converters, and a current-ratio-controlled relaxation oscillator. This circuit offers a square-wave output whose oscillation period is directly proporti...

Switched capacitor triple slope capacitance to digital converter

A high accuracy switched capacitor, triple slope digital converter suitable for differential capacitive sensors is presented. The proposed technique accepts differential capacitive sensors possessing either linear or inverse characteristics and provides a linear capacitance to digital conversion. The output is dependent only on a pair of d.c. reference voltages and the clock frequency. Detailed...

Very low-voltage fully differential amplifier for switched-capacitor applications

A fully differential opamp suitable for very-low voltage switched-capacitor circuits in standard CMOS technologies is introduced. The proposed two stage opamp needs a simple low voltage CMFB switched-capacitor circuit only for the second stage. Due to the reduced supply voltage, the CMFB circuit is implemented using bootstrapped switches. Minor modifications allow to use chopper stabilization f...

A Fully Differential Switched Capacitor Amplifier Modelling and Parameter Evaluation

This paper develops an analytical model for a standard topology, fully differential, switched capacitor amplifier; including the base amplifier offset voltage and common mode range, and capacitor mismatch effects. The amplifier is designed in a 0.6 μm process and the analytical model accuracy is compared with the simulation results.

Low-Voltage Fully Differential CMOS Switched-Capacitor Amplifiers