Converters dedicated to long-term monitoring of strain gauge transducers

Author

Begueret, Jean-Baptiste ; Benbrahim, Mohammed Reda ; Li, Zhiqun ; Rodes, Francis ; Dom, Jean-Paul

Author_Institution

IXL Microelectron. Lab., Bordeaux I Univ., Talence, France

Volume

32

Issue

3

fYear

1997

fDate

3/1/1997 12:00:00 AM

Firstpage

349

Lastpage

356

Abstract

This paper presents two new strain gauge bridge-to-pulse position modulation (PPM) converters. They have been developed in 2-μm BiCMOS technology. The first one uses a chopper amplifier and a voltage-to-time converter associated in a feedback loop. This topology mainly exhibits an automatic offset cancellation capability, a ratiometric transfer function, and 10-b accuracy. The second one is a voltage-to-frequency converter using the switched-capacitor (SC) technique. It is an optimized version in terms of size minimization and noise rejection. Furthermore, a special RF transmitter has been designed in order to send the data from an intracorporal sensing and conditioning circuitry to an external computer dedicated to data analysis. Moreover, these converters are insensitive to offset drifts and are well suited for long term monitoring of orthopedic implants used for the treatment of bone fractures

Keywords

BiCMOS analogue integrated circuits; biomedical electronics; biomedical telemetry; choppers (circuits); circuit optimisation; prosthetics; pulse position modulation; radio transmitters; strain gauges; strain sensors; switched capacitor networks; transfer functions; voltage-frequency convertors; 180 MHz; 2 mum; BiCMOS technology; RF transmitter; automatic offset cancellation capability; biomedical telemetry; bone fracture treatment; bridge-to-pulse position modulation converters; chopper amplifier; data analysis; feedback loop; intracorporal sensing/conditioning circuitry; long-term monitoring; noise rejection; offset drift insensitivity; optimized version; orthopedic implants; ratiometric transfer function; size minimization; strain gauge transducers; switched-capacitor technique; voltage-to-frequency converter; voltage-to-time converter; BiCMOS integrated circuits; Capacitive sensors; Choppers; Feedback loop; Minimization; Monitoring; Switching converters; Topology; Transfer functions; Voltage;

fLanguage

English

Journal_Title

Solid-State Circuits, IEEE Journal of

Publisher

ieee

ISSN

0018-9200

Type

jour

DOI

10.1109/4.557633

Filename

557633