Wim Claes

A 40 /spl mu/A/channel compensated 18-channel strain gauge measurement system for stress monitoring in dental implants

This paper presents an ASIC of an autonomous monitoring system that is capable of measuring 18 strain gauges simultaneously. The sensor interface chip is implemented in a 0.7 /spl mu/m CMOS technology and includes a PTAT-current reference, an 8-bit DAC, together with a digital interface for multi-gauge nulling, an SC instrumentation amplifier, an SC S/H and a 9-bit successive approximation ADC. The accuracy is better than 20 /spl mu/strain, while consuming only 40 /spl mu/A/channel.

A 136-/spl mu/W/channel autonomous strain-gauge datalogger

A single-chip 18-channel strain gauge datalogger IC is integrated in a 0.7/spl mu/m CMOS technology. The chip combines a 10 microstrain accuracy sensor interface with digital offset-compensation, a wireless 132kHz/66kHz transceiver and a 23.4kgate digital unit with adjustable data-processing. The dataloggers maximum power consumption, including an external 2Mb RAM, is 136/spl mu/W/channel at 3.1V.

Towards the limits in detecting low-level strain with multiple piezo-resistive sensors

Strain gauges are widely accepted to quantify load figures in many applications. Their noise immunity is a major factor for their success. In the present work, the limits are explored up to where these strain gauges can be operated in minimal power conditions, and yet allowing strain levels as low as 10 μstrain. A system is proposed which is capable of monitoring 18 gauges simultaneously and continuously with an overall mean current consumption of about 670 μA (at 3.1 V). The final goal is to monitor stress in dental implants, using a miniaturised battery (40 mA h), built into the prosthesis itself. This paper is a first report on work in progress.

Design and integration of a remotely programmable dental monitoring device

In attempts to improve the quality of life (QOL), continuously methods are sought that make use of the symbiosis between medicine and technology. The knowledge of biomedical processes opens the way to a technically controlled rehabilitation. One such approach uses the knowledge on bone remodeling and bone growth in a dental environment. By applying immediate load on a newly placed implant, the bone growth is positively stimulated. However, excessive loading should be avoided at all times. Therefore a complete device was designed that is able to monitor the implant loading and gives patient feedback when overloading occurs. To the authors knowledge, it is the first time such a system is proposed. In this paper, the design of the smart dental prosthesis is elaborated

An autonomous smart dental prosthesis for fast rehabilitation

The continuous miniaturization of electronics and increasing knowledge of biological processes enable us to develop intelligent implantable systems to enhance the quality of life. One of such systems controls the passive stimulation of bone formation in a dental environment. By giving patient feedback in case of overload, one should be able to minimize rehabilitation period drastically. We developed an electronic dental prosthesis, incorporating an ASIC (application specific IC), power supply system and necessary sensors. The electronic components are incorporated into a custom designed dental framework. The system can communicate wirelessly with an external transceiver which enables a patient tailored approach. In situ calibration and threshold programming is performed before the dental prosthesis works as a completely autonomous device

136μW/channel autonomous strain gauge datalogger

A single-chip 18-channel strain-gauge datalogger IC is integrated in a 0.7m CMOS technology. It combines a 10m strain-accuracy sensor interface with digital offset compensation, a wireless 132-kHz/66-kHz transceiver and a 23.4-kgates digital unit with adjustable data processing. The datalogger’s maximum power consumption, including an external 2-Mb RAM, is 136 W/channel at 3.1 V.

A Miniaturized, Autonomous, Programmable Stress Monitoring Device, part of a Dental Prosthesis

This paper presents a low power miniaturized, autonomous data logger, capable of measuring, compensating and processing 18 different strain gauges simultaneously. The total system, which is part of dental prosthesis, consists of a multi-channel strain gauge interface, a bi-directional RF link, a 2 MB RAM and a digital data processing/controlling unit. The sensor interface has been implemented in a 0.7 (µm CMOS technology and includes a Proportional To Absolute Temperature current reference, an 8-bit Digital-to-Analog Converter for compensation, a Switched-Capacitor instrumentation amplifier, a Switched-Capacitor Sample-and-Hold and a 9-bit successive approximation Analog-to-Digital Converter. This interface chip consumes a mere 40 µA/channel, allowing functionality of the data logger for a 2-day period in the highest sampling mode, i.e. continuous sampling of 6 abutments with 3 strain gauges at a 111 Hz sampling rate/channel with a 20 µstrain accuracy.