A 63ns Flipping Time, 93.6% Voltage Flipping Efficiency Auto-Calibrated Ultrasonic Energy Harvesting Interface from −25 to 85°C

This work proposes the first ultrasonic PEH interface capable of operating up to 340kHz over a wide temperature range. As shown in Fig. 1, the major contributions include: 1) the proposed auto-calibration technique using $\mathrm{t}_{\text{flip}}/2$ detection and adaptive closed-loop timing calibration (ACTC) to achieve high accuracy and low power consumption; 2) a charge recycling (CR) bootstrap driver with fast body-biasing to reduce $\mathrm{E}_{\text{con}}$ and driving loss; and 3) a coarse/fine ACTC approach to eliminate the inherent timing offset and enhance the energy harvesting efficiency.