A 130V Triboelectric Energy-Harvesting Interface in .18\mu\mathrm{m}$ BCD with Scalable Multi-Chip-Stacked Bias-Flip and Daisy-Chained Synchronous Signaling Technique

Triboelectric nanogenerators (TENGs) for collecting ambient mechanical vibration energy have gained popularity as a next-generation energy source owing to their numerous advantages including flexibility, high conversion efficiency, and low cost. However, ultra-high instantaneous open-circuit voltage (~110V) is the fundamental feature of TENGs, and thus they are not very compatible with integrated circuits. Recent TENG-harvesting chips [1]–[3] fabricated in a high-voltage BCD have been reported to be capable of handling up to 70V. Considering TENG's nature of producing a very low alternating current $(I_{\mathsf{T}})$ of several $\mu\mathsf{A}$ , the constrained tolerable voltage of the energy-harvesting (EH) interface ICs significantly limits the maximum extractable power to a sub-mW scale. Additionally, it is necessary to reduce the energy wasted to charge and discharge the parasitic capacitance $(C_{\mathsf{T}})$ of TENG whenever the polarity of $I_{\mathsf{T}}$ changes. To resolve this, several attempts [3], [4] have been made to apply parallel-synchronized switch harvesting on inductor (P-SSHI) of [5] into TENG-EH circuits. However, the conventional P-SSHI with a bias-flip rectifier can still be valid only within a limited voltage range that a single chip can accommodate.