A piezo-powered floating-gate sensor array for long-term fatigue monitoring in biomechanical implants

Nizar Lajnef, Niell G. Elvin, Shantanu Chakrabartty

Research output: Contribution to journalArticlepeer-review

49 Scopus citations

Abstract

Measurement of the cumulative loading statistics experienced by an implant is essential for prediction of long-term fatigue failure. However, the total power that can be harvested using typical in-vivo strain levels is less than 1 μW. In this paper, we present a novel method for long-term, battery-less fatigue monitoring by integrating piezoelectric transduction with hot-electron injection on a floating-gate transistor array. Measured results from a fabricated prototype in a 0.5-μ CMOS process demonstrate that the array can sense, compute, and store loading statistics for over 70000 stress-strain cycles which can be extended to beyond 107 cycles. The measured response also shows excellent agreement with a theoretical model and the nominal power dissipation of the array has been measured to be less than 800 nW.

Original languageEnglish
Pages (from-to)164-172
Number of pages9
JournalIEEE Transactions on Biomedical Circuits and Systems
Volume2
Issue number3
DOIs
StatePublished - 2008

Keywords

  • Biomechanics
  • Fatigue
  • Piezoelectric transducers
  • Self-powered sensing
  • Strain sensors

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