Hybrid CMOS Rectifier Based on Synergistic RF-Piezoelectric Energy Scavenging

摘要

This paper presents a novel CMOS hybrid rectifier that can simultaneously and efficiently scavenge energy from a low-amplitude radio-frequency (RF) signal and a low-frequency, low-energy signal from a piezoelectric (PZT) transducer. The piezoelectric signal is used for biasing a complimentary, cross-coupled rectifier (CCCR) chain to an operating point such that the RF signal energy can be efficiently harvested, even if its amplitude is well below the threshold voltage of the rectifier transistors. The device sizes for the proposed design have been optimized to achieve the maximum DC output voltage and the proposed design is shown to effectively eliminate dead-zones in the rectifier response. The measurement results show that a 6-stage hybrid rectifier (HR) can generate up to 1 V DC output voltage at a load current of 3 when a 300 mV peak-to-peak, 13.56 MHz RF signal is applied in conjunction with a 10 KHz, 2 V piezoelectric signal. Using measured results from prototypes fabricated in a 90 nm CMOS process, the proposed HR is shown to yield a significant improvement in power conversion efficiency (PCE) for low levels of input power when compared to a conventional CCCR that has been implemented on the same die.