A self-powered zero-quiescent-current active rectifier for piezoelectric energy harvesting is proposed. It consists of two cross-biased PMOS transistors and two active diodes. To achieve zero quiescent-current, a biasfree clamping circuit is designed to clamp the drain-source voltage of the NMOS transistor of the active diode. Post-simulation and measurement results show that the proposed active rectifier achieves an efficiency improvement of more than 40% vs. the ordinary full-bridge rectifier; the power transferred by the rectifier from the piezoelectric energy harvester (PEH) to the storage capacitor is increased significantly, especially even when the output power of PEH is low.

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