New architecture development for energy harvesting

This research presents the design of an ultra-low power energy scavenging system capable of collecting and managing energy from ambient vibrations and RF electromagnetic waves. The main motive is to develop a self-powered system which is a substitute for remotely placed low power batteries with rare human interaction. Firstly, the energy transducers, commercial piezoelectric generators with a wide frequency range of 26 – 205Hz and the antenna with a center frequency of 916MHz are evaluated and characterized to maximize the efficiency. Both antenna and piezoelectric generator can form an array of each type to increase the energy being harvested. Secondly, the power electronic circuits involved in the energy harvesting are designed in 0.6um CMOS technology and the simulation results are presented. Charge pumps and rectifier were optimized to operate with low voltage ranges since the energy produced by the piezoelectric generator and the whip antenna is found to be in microwatts and less from the test results. The AC output from the piezoelectric generator is rectified and boosted to required output level using an AC-DC charge pump. A rectifier and DC-DC charge pump are adopted for the efficient conversion of voltage from the antenna. A back-up battery will be provided for the start-up of DC-DC charge pump at low input conditions. An LDO is designed to provide regulated output of 4.1 V to the battery. Finally, the collected energy will be stored in a 50uAh capacity thin film battery which is intended for low-voltage and low-power applications.