High-Voltage Triboelectric Energy Harvesting Using Multi-Shot Energy Extraction in 70-V BCD Process

Triboelectric Nanogenerators (TENG) suitable for mechanical energy harvesting typically have ultra-high open-circuit voltage in several hundreds of volts, challenging the energy extraction circuit (EEC) design required for charging load battery/capacitor. Here, we present a novel multi-shot switched EEC that extracts energy in multiple discrete steps to regulate the TENG voltage below the breakdown limit of the technology (70 V in our case), making it suitable for Integrated Circuit (IC) implementation. The proposed strategy maintains high TENG voltage just below the breakdown limit to offer a high electrostatic retardation, enhancing the work done against it by the mechanical source in the form of transduced electrical energy. Mathematical derivation of the circuit's output shows a constant transduction power at all load voltages, fully eliminating Maximum Power Point (MPP) Tracking and saving power for the same. The design and simulation of the proposed EEC in TSMC 0.18 $\mu \text{m}$ BCD process achieve a maximum power conversion efficiency of 63.3% and a 1.91x gain over even an ideal conventional Full Wave Rectifier (FWR) circuit at its optimal MPP load (gain will be higher for a real FWR implementation).