A Rectifier-Reusing Bias-Flip Energy Harvesting Interface Circuit with Adaptively Reconfigurable SC converter for Wind-Driven Triboelectric Nanogenerator

The energy harvesting interface circuit is proposed for wind-driven triboelectric nanogenerator (WD-TENG). To extract power from the WD-TENG maximally and deliver power to the output (battery) efficiently, a rectifier-reusing bias-flip (RRBF) technique and a multi-phase reconfigurable switched-capacitor converter (MRSCC) are developed. In the RRBF, the low-side switches of the rectifier are reused as switches for bias-flip without additional components. The MRSCC delivers power to the battery efficiently by reducing switching loss including overlap loss. Furthermore, the MRSCC maintains a rectified voltage ( $V_{RECT}$ ) as high as a breakdown voltage ( $V_{BR}$ ) of a switch by adaptive conversion control and multi-phase operation to extract maximized power from the WD-TENG in a given process, even if the battery voltage is varied from 2.7 V to 4.2 V. Owing to the proposed techniques, the maximum extracted power to the output is 238 μW and peak power delivering efficiency of the MRSCC is 79.3%. The chip was fabricated in 0.18 μm BCD process.