A Leakage-Suppressing Differential-Drive Rectifier for Sporadic Wearable Triboelectric Energy Harvesting

This brief presents a leakage-suppressing differential-drive rectifier for triboelectric energy harvesting from sporadic human motions. Unlike triboelectric energy harvesting in the ambience (e.g., from wind, tide, mechanical motions) that allows for larger triboelectric nanogenerator (TENG) form factor and higher vibrational frequency, wearable triboelectric energy harvesting from human motions is area-constrained, sporadic and low-frequency. Such characteristics result in low power generation and low-frequency excitations with long inactive period, challenging the harvester interface circuit design. In this work, a leakage-suppressing differential-drive rectifier is proposed, which enables the reduction of reverse leakage of differential-drive rectifier by 5 orders of magnitude during the inactive period, while improving the power conversion efficiency (PCE) during the harvesting period. The passive structure does not incur additional power overhead, making it suitable for nW-level power scavenging. Fabricated in 40 nm CMOS, the proposed rectifier achieves a maximum PCE of 91.8 Hz and nW-level TENG power harvested from body motions.