title: A 5 nW Quasi-Linear CMOS Hot-Electron Injector for Self-Powered Monitoring of Biomechanical Strain Variations.
abstract: Piezoelectricity-driven hot-electron injectors (p-HEI) are used for self-powered monitoring of mechanical activity in biomechanical implants and structures. Previously reported p-HEI devices operate by harvesting energy from a piezoelectric transducer to generate current and voltage references which are then used for initiating and controlling the process of hot-electron injection. As a result, the minimum energy required to activate the device is limited by the power requirements of the reference circuits. In this paper we present a p-HEI device that operates by directly exploiting the self-limiting capability of an energy transducer when driving the process of hot-electron injection in a pMOS floating-gate transistor. As a result, the p-HEI device can activate itself at input power levels less than 5 nW. Using a prototype fabricated in a 0.5- [Formula: see text] bulk CMOS process we validate the functionality of the proposed injector and show that for a fixed input power, its dynamics is quasi-linear with respect to time. The paper also presents measurement results using a cadaver phantom where the fabricated p-HEI device has been integrated with a piezoelectric transducer and is used for self-powered monitoring of mechanical activity.
authors.forename: Liang
authors.initials: L
authors.lastname: Zhou
authors.forename: Adam C
authors.initials: AC
authors.lastname: Abraham
authors.forename: Simon Y
authors.initials: SY
authors.lastname: Tang
authors.forename: Shantanu
authors.initials: S
authors.lastname: Chakrabartty
mesh_terms: D000465:Algorithms; D004583:Electrons; D004867:Equipment Design; D008962:Models, Theoretical; D008991:Monitoring, Physiologic / Q000295:instrumentation / Q000379:methods*; D012666:Semiconductors