A self-supplied inertial piezoelectric energy harvester with power-management IC

Abstract

Harvesting energy from ambient vibrations is a promising technology for fully autonomous wireless sensor nodes, which can give birth to new applications in biomedical, industrial, and environmental monitoring. There have been independent solutions in increasing the harvesting efficiency either on the mechanical harvester [1] or on its power management circuitry [2,3]. Recently, a piezoelectric MEMS harvester using AlN was demonstrated to generate enough energy to autonomously power a wireless temperature sensor with a full-bridge rectifier built with off-the-shelf components [1]. Meanwhile, AC-DC converters for piezoelectric harvesters have been designed to enable efficient power extraction [2], or efficient rectification of low-voltage outputs [3], and have been tested with commercial meso-scale piezoelectric beams. However, to realize an efficient stand-alone energy generator platform, it is necessary to integrate these efforts into a single low-volume system. This paper presents a self-supplied energy generator, which includes a MEMS harvester hybridly integrated with its power management circuitry for autonomous charging of an energy reservoir (Fig. 6.9.1). The proposed packaging of the generator is <0.3cm3. Initial testing results are obtained with an unpackaged MEMS harvester.