6.9 A Self-Supplied Inertial Piezoelectric Energy Harvester with Power-Management IC

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 inde-pendent solutions in increasing the harvesting efficiency either on the mechani-cal harvester [1] or on its power management circuitry [2,3]. Recently, a piezo-electric MEMS harvester using AlN was demonstrated to generate enough ener-gy to autonomously power a wireless temperature sensor with a full-bridge rec-tifier 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