A Self-Powered High-Efficiency Rectifier With Automatic Resetting of Transducer Capacitance in Piezoelectric Energy Harvesting Systems

Abstract

This paper presents a self-powered rectifier for piezoelectric energy harvesting applications, and the key idea of the proposed system is to reset the transducer capacitor at optimal instants to maximize the extracted power. The proposed rectifier consists of two switches and two active diodes. The switches discharge the transducer capacitor at optimal instants two times for every cycle. The active diodes are based on op-amps with a preset dc offset, which reduces the voltage drop and the leakage current and avoids instability. In addition, the controller for the proposed rectifier is simple to reduce the circuit complexity and the power dissipation. The proposed rectifier was designed and fabricated in 0.18-mu m CMOS technology. Measured results indicate that it achieves power efficiency of 91.2%, and the amount of power extracted by the proposed rectifier is 3.5 times larger when compared with the conventional rectifiers. The proposed rectifier does not require any off chip components to enable a full chip integration, and the die area of the proposed circuit is 0.08 x 0.20 mm(2).