A Single Stage Integrated Interface Circuit for Triboelectric Energy Harvester for Wearable Applications

Triboelectric generators (TEGs) are effective kinetic energy transducers with time-varying internal capacitances, posing challenges for efficient energy extraction. This work presents an integrated interface circuitry for triboelectric generators (TEGs) where rectification and regulation are combined in a single stage which minimizes the number of charge transfer stages and power losses in the front-end diode bridge rectifiers and thus results in improved efficiency. The proposed circuit also addresses the issue of the asymmetric TEG output during the positive and negative half-cycles. It performs active rectification of the low amplitude alternating current output generated during the negative half-cycle, corresponding to the release cycle of the device. The proposed circuit is designed and fabricated using 180nm CMOS BCD process. The experimental characterization of the fabricated integrated circuit (IC) is conducted by interfacing it with in-house fabricated TEG device. The developed harvesting system demonstrates an energy conversion efficiency of 75.6%. Overall, the proposed single-stage interface circuit presents a compelling alternative to the conventional two-stage interfacing approach in terms of simplicity, reliability, robustness and potentially lowered costs and power consumption. Additionally, the system supports cold start-up without an external power supply.