A micropower front-end interface for differential-capacitive sensor systems

Author

Constandinou, Timothy G. ; Georgiou, Julius ; Toumazou, Chris

Author_Institution

ECE Dept., Univ. of Cyprus, Nicosia

fYear

2008

fDate

18-21 May 2008

Firstpage

2474

Lastpage

2477

Abstract

This papers presents a front-end circuit for interfacing to differential capacitive sensors, including certain micro- electromechanical systems (MEMS). The system combines a self- resetting, biphasic integrator with a difference timer, producing a word parallel output representing the differential capacitance. The measurable capacitance range is tunable by means of an input current bias and system clock frequency. For an input bias of lOnA and system clock of 128 KHz, the measurable capacitance range is +/-5 pF (to 8 bit resolution) consuming below 26 muW total system power.

Keywords

capacitance; capacitive sensors; clocks; microsensors; biphasic integrator; difference timer; differential capacitance; differential-capacitive sensor systems; input current bias; microelectromechanical systems; micropower front-end interface; system clock frequency; Capacitance measurement; Capacitive sensors; Clocks; Current measurement; Electromechanical systems; Frequency measurement; Integrated circuit measurements; Micromechanical devices; Sensor systems; Tunable circuits and devices; capacitive sensor interface; differential capacitance; dual slope converter; integrate and fire; low power;

fLanguage

English

Publisher

ieee

Conference_Titel

Circuits and Systems, 2008. ISCAS 2008. IEEE International Symposium on

Conference_Location

Seattle, WA

Print_ISBN

978-1-4244-1683-7

Electronic_ISBN

978-1-4244-1684-4

Type

conf

DOI

10.1109/ISCAS.2008.4541957

Filename

4541957