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An integrated floating-electrode electric micro-generator

Auteur(s) : W. Ma, R. Zhu, L. Rufer, Y. Zohar, M. Wong

Journal : Journal of Microelectromechanical Systems

Volume : 16

Issue : 1

Pages : 29-37

Doi : 10.1109/JMEMS.2006.885856

Microfabricated electric generators, scavenging ambient mechanical energy, are potential power sources for autonomous systems. Described presently are the design, modeling, and implementation of a single-wafer floating-electrode electric microgenerator, integrating a micromechanical resonator and a number of electronic devices. Forming a plate of a variable capacitor, the resonator is responsible for converting mechanical vibration to electricity. A sense transistor and a diode bridge are integrated, respectively, for monitoring the “charging” of the floating electrode and for rectification. A lumped electromechanical model of the generator is developed and expressed in terms of a set of nonlinear coupled state equations that are numerically solved. For small-amplitude excitation, a circuit based on a set of linearized equations is developed. The generator is realized using a compatible combination of standard complementary metal–oxide–semiconductor (CMOS) “floating gate” process and a post-CMOS photoresist molded electroplating process. Adequate agreement between model predictions and measurement results was obtained.