Current Excitation Method for $\Delta{R}$ Measurement in Piezo-Resistive Sensors With a 0.3-ppm Resolution

This paper presents a new highly sensitive (10 μV/ppm) bidirectional current excitation method for piezo-resistive sensor measurements, through excitation of two half bridges for ΔR measurement. The proposed circuit is insensitive to thermoelectric and stray noise effects since it measures the peak-to-peak value of the generated voltage. Measurement results using resistors show that variations as low as 0.3 ppm are measurable from 15°C to 80°C with resistors. As an experimental application, 40 parts per billion variation in gas concentration using piezo-resistive SU-8 microcantilevers is measured by the proposed circuit at room temperature.

[1]  K. Mochizuki,et al.  A linear resistance-to-frequency converter , 1995, Proceedings of 1995 IEEE Instrumentation and Measurement Technology Conference - IMTC '95.

[2]  V. Rao,et al.  Polymer microcantilever biochemical sensors with integrated polymer composites for electrical detection , 2009 .

[3]  V Seena,et al.  Polymer nanocomposite nanomechanical cantilever sensors: material characterization, device development and application in explosive vapour detection , 2011, Nanotechnology.

[4]  Dinesh K. Sharma,et al.  An ultra-sensitive ∆R/R measurement system for biochemical sensors using piezoresistive micro-cantilevers , 2009, 2009 Annual International Conference of the IEEE Engineering in Medicine and Biology Society.

[5]  William Paul King,et al.  The effect of piezoresistive microcantilever geometry on cantilever sensitivity during surface stress chemical sensing , 2008 .

[6]  T. Thundat,et al.  Use of Microcantilevers for the Monitoring of Molecular Binding to Self-Assembled Monolayers , 2003 .

[7]  Vittorio Ferrari,et al.  ASIC front-end interface with frequency and duty cycle output for resistive-bridge sensors , 2007 .

[8]  Arnaldo D'Amico,et al.  Electronic interface for the accurate read-out of resistive sensors in low voltage-low power integrated systems , 2005 .

[9]  N. Mohan,et al.  A novel signal conditioning circuit for push-pull-type resistive transducers , 2005 .

[10]  Fabrication and Characterization of a Polymeric Microcantilever With an Encapsulated Hotwire CVD Polysilicon Piezoresistor , 2009, Journal of Microelectromechanical Systems.

[11]  A. Thanachayanont,et al.  Low-voltage CMOS instrumentation amplifier for piezoresistive transducer , 2005, TENCON 2005 - 2005 IEEE Region 10 Conference.