title: An ultra-linear piezo-floating-gate strain-gauge for self-powered measurement of quasi-static-strain.
abstract: In this paper we describe a self-powered sensor that can be used for in-vivo measurement of the quasi-static-strain and also for in-vivo measurement of the L1 norm of the strain signal. At the core of the proposed design is a linear floating-gate injector that can achieve more than 13 bits of precision in sensing, signal integration and non-volatile storage. The injectors are self-powered by the piezoelectric transducers that convert mechanical energy from strain-variations into electrical energy. A differential injector topology is used to measure the quasi-static strain by integrating the difference between the L1 norm of the piezoelectric signal generated during the positive and negative strain-cycles. The linear floating-gate injectors are integrated with charge-pumps, digital calibration circuits and digital programming circuits to form a system-on-chip solution that can interface with a standard bio-telemetry platform. We demonstrate the proof-of-concept self-powered measurement of quasi-static strain and L1 norm of the strain signal using sensor prototypes fabricated in a 0.5- μm standard CMOS process and validated using a bench-top biomechanical test setup.
authors.affiliation: Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI 48824 USA.
authors.forename: Pikul
authors.initials: P
authors.lastname: Sarkar
authors.forename: Chenling
authors.initials: C
authors.lastname: Huang
authors.forename: Shantanu
authors.initials: S
authors.lastname: Chakrabartty
mesh_terms: D001696:Biomechanical Phenomena; D006801:Humans; D008991:Monitoring, Physiologic / Q000295:instrumentation*; D009991:Oscillometry; D013314:Stress, Mechanical; D013997:Time Factors; D014159:Transducers