Title :
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
fDate :
3/1/1997 12:00:00 AM
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;
Journal_Title :
Solid-State Circuits, IEEE Journal of
