Compressive Self-Powering of Piezo-Floating-Gate Mechanical Impact Detectors

This paper describes a novel compressive self-powering technique that significantly extends the powering and sensing range of our previously reported piezo-floating-gate (PFG) sensors for applications in mechanical impact monitoring. At the core of the proposed technique is a nonlinear impedance circuit that dynamically loads the output of a piezoelectric transducer in a manner such that the sensor can be self-powered at low-levels of mechanical strain and yet is able to sense and detect large variations in strain-levels. The compressive approach requires precise programming of event detection thresholds and requires precise nonvolatile event counting, both of which are achieved using variants of a linear floating-gate injector circuit. Measured results obtained from prototypes fabricated in a 0.5- μm standard CMOS process validate the proposed compressive powering and the proposed programming technique.