Board-Level Power Management Circuits for Triboelectric Nanogenerators: A Review

Triboelectric nanogenerators (TENGs) have emerged as a promising solution for powering Internet of Things (IoT) sensor nodes and wearable electronics, owing to their use of low-cost, lightweight, and environmentally friendly materials. However, the distinctive characteristics of their electrical output, such as high voltage and time-varying internal capacitance, pose significant challenges for the design of efficient power management circuits (PMCs). The high output voltage of TENGs, which often exceeds the safe operating limits of integrated-circuit (IC) technologies, renders conventional IC-based PMCs unsuitable for optimal energy extraction. As a result, board-level PMCs, free from these voltage constraints, are essential for effectively managing the output power of TENGs. This article presents a comprehensive classification and critical review of recent board-level PMC designs tailored for TENG applications. Using a generic block diagram as a framework, various implementation strategies for each functional block are analyzed, highlighting their respective benefits and limitations. Particular focus is given to switching-stage configurations around the rectifier, which enable advanced techniques such as synchronous electric charge extraction (SECE) and synchronous switched harvesting on inductor (SSHI). A comparative analysis of representative PMCs is conducted based on key mechanical and electrical performance metrics. Finally, unresolved challenges and promising research directions are discussed, providing insights into future development of high-efficiency TENG-based energy harvesting systems.