High efficiency active rectifier with low-power self-biased comparator for low-frequency piezoelectric vibration energy harvesting of AUV

Abstract

This paper proposes an Active Rectifier for low-frequency vibration piezoelectric (PZE) energy harvesting of Autonomous Underwater Vehicle (AUV). By using the cross-coupled NMOS transistors and active driven PMOS transistor, the turned-on resistance across the transistors could be minimized such that the voltage conversion efficiency is improved. Besides, the problem of the reverse current is avoided. Moreover, the novel self-biased low power comparator operated in subthreshold region is employed to reduce the power consumption. Only 6 MOS transistors and 1 resistor are required in the proposed self-biased comparator. The proposed design is implemented with a 0.18μm HV process. Based on the measurement results, the peak voltage conversion efficiency (VCE) and the peak power conversion efficiency (PCE) are 97.63% and 96.26%, respectively, at 50 KΩ loads and 20 Hz vibration frequency. The maximum output power is 14.1 mW with the load of 1 KΩ.