A Self-Powered Piezoelectric Energy Harvesting Circuit With an Optimal Flipping Time SSHI and Maximum Power Point Tracking

This brief presents an ultra low power IC design for piezoelectric (PE) energy harvesting, which integrates a maximum power point tracking (MPPT) circuit and a synchronized switch harvesting on inductor (SSHI) circuit. The proposed circuit also has three different operation modes to extend the range of the harvestable power level generated by a PE transducer. The circuit is designed in CMOS and fabricated in BiCMOS 0.25 μm technology with the die size of 2 mm ² . The measurement results indicate the circuit can harvest energy with the input power ranging from 10 to 34 μW during MPPT. It achieves peak efficiency of 77% under a PE cantilever voltage of 3.5 V and the battery voltage of 4.2 V.