An Improved Synchronous Charge Extraction Rectifier for Piezoelectric Energy Harvesting from Low-Amplitude Vibrations

Abstract

There is growing interest in developing wireless, battery-free sensors which are powered solely through ambient vibrations, using piezoelectric transducers. In order to power conventional electronics, the output of a piezoelectric transducer must be converted to a steady voltage using a rectifier circuit. Conventional passive rectifiers exhibit poor performance when used with piezoelectric transducers, leading to the advent of specialized switching circuits such as bias-flip and synchronous charge extraction designs. These switching circuits also have their drawbacks, as switching typically requires a power source. Recent developments in the field include switching circuits built on electronic breaker technology, which can self-power their own switching apparatus. This work presents a novel synchronous charge extraction circuit, built with electronic breakers, that exhibits improved performance in low-vibration conditions. In addition, this work investigates the use of germanium transistors to improve the efficiency of electronic breaker circuits. The proposed designs offer significant improvement over existing electronic breaker designs, which were replicated and tested under identical conditions for consistency.