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Proceedings Paper

Circuit requirements for MEMS-based mechanical-to-electrical power conversion
Author(s): Sungmuk Kang; Hyejoong Kim; Hoseong Kim; Changwook Baek
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Paper Abstract

Energy scavenging is a technology that derives required microwatt level power to drive electronics from ambient heat, light, radio, or vibration, that is otherwise wasted. In this study, we have investigated the circuit optimization strategy for vibration-based piezoelectric energy scavenging systems that supply the electric power to wireless sensors and electronics for ubiquitous sensor networks. In this paper, we assert that not only the mechanical to electrical energy conversion efficiency, but also the speed of energy storage is important in designing and evaluation of energy scavenging system, since the energy scavenging system with higher speed of energy storage has faster start up response to the mechanical input and can supply required power more frequently. Particularly in case of piezoelectric micropower generator, we show that the low reverse leakage current characteristic rather than the low forward voltage drop of the rectifying diodes is much more beneficial to improve conversion efficiency and that the storage capacitor should be as small as possible to reduce the time to store required amount of energy. Experimental and PSPICE results show that, when ultra-low leakage current diodes are adopted for a bridge rectifier, the mechanical-to-electrical energy conversion efficiency is doubled or more in some cases, and the charging speed is increased by 20%, compared to the circuit that adopts Schottky diodes. It is also found that, compared to the circuit with larger storage capacitor, the circuit with smaller storage capacitor requires shorter time to store the same amount of energy and can drive voltage regulator more frequently. This study suggests that low reverse leakage diode and small storage capacitor should be used to build efficient high performance piezoelectric energy scavenging systems for ubiquitous sensor networks.

Paper Details

Date Published: 28 February 2008
PDF: 8 pages
Proc. SPIE 6885, MEMS/MOEMS Components and Their Applications V. Special Focus Topics: Transducers at the Micro-Nano Interface, 68850H (28 February 2008); doi: 10.1117/12.762037
Show Author Affiliations
Sungmuk Kang, Chung-Ang Univ. (South Korea)
Hyejoong Kim, Chung-Ang Univ. (South Korea)
Hoseong Kim, Chung-Ang Univ. (South Korea)
Changwook Baek, Chung-Ang Univ. (South Korea)


Published in SPIE Proceedings Vol. 6885:
MEMS/MOEMS Components and Their Applications V. Special Focus Topics: Transducers at the Micro-Nano Interface
Srinivas A. Tadigadapa; Babak A. Parviz; Albert K. Henning, Editor(s)

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