A Dynamic Threshold Cancellation Technique for a High-Power Conversion Efficiency CMOS Rectifier.

Zhuangde Jiang,António Godinho,Yumei Wen,Luís Gonçalves,Zhaochu Yang,Tao Dong,Ping Li,Paulo Mendes

doi:10.3390/s21206883

Abstract

Power conversion efficiency (PCE) has been one of the key concerns for power management circuits (PMC) due to the low output power of the vibrational energy harvesters. This work reports a dynamic threshold cancellation technique for a high-power conversion efficiency CMOS rectifier. The proposed rectifier consists of two stages, one passive stage with a negative voltage converter, and another stage with an active diode controlled by a threshold cancellation circuit. The former stage conducts the signal full-wave rectification with a voltage drop of 1 mV, whereas the latter reduces the reverse leakage current, consequently enhancing the output power delivered to the ohmic load. As a result, the rectifier can achieve a voltage and power conversion efficiency of over 99% and 90%, respectively, for an input voltage of 0.45 V and for low ohmic loads. The proposed circuit is designed in a standard 130 nm CMOS process and works for an operating frequency range from 800 Hz to 51.2 kHz, which is promising for practical applications.

Highlights

Energy harvesting appears as a promising reliable technology that can prolong the lifetime of batteries and power wireless sensor networks (WSNs) for environmental monitoring [1]
Because the output power of the vibrational energy harvester is low [4], the high forward voltage required by standard full-wave diode bridges and Schottky diode rectifiers limits their use on these low power restrict applications [8]
It consists of an negative voltage converter (NVC) and an active diode biased by a threshold cancellation circuit

Summary

Introduction

Energy harvesting appears as a promising reliable technology that can prolong the lifetime of batteries and power wireless sensor networks (WSNs) for environmental monitoring [1]. In these WSN applications, ambient vibrations are unpredictable, time-varying, and low amplitude, which restricts the available power of the energy harvesting system [2]. To overcome these drawbacks, research groups have been focusing on using piezoelectric harvesters due to their high power density and capability to integrate MEMS and CMOS technology, making it possible to develop all the systems (energy harvester and electronic system) in a single chip [3,4,5]. Designing the rectifier in CMOS technology is highly desirable to decrease the device’s form factor and integrate with the energy harvester while exploring new dynamic techniques to reduce the power consumption, achieve high PCE, and minimize leakage current [9,10]

Objectives

Methods

Conclusion