A Merged Backside Series/Parallel Hybrid Piezoelectric-Resonator-Based DC-DC Converter

This study introduces a hybrid Backside Series/Parallel Piezoelectric-Resonator-based (BSPPR) DC-DC converter that improves the performance of conventional piezoelectric-resonator-based (baseline PR) converters at large step-down ratios. The proposed converter incorporates a 2:1 series-parallel switched capacitor (SC) network to the output of the baseline PR converter, enabling a more efficient step-down conversion while placing the piezoelectric resonator (PR) on the high voltage side, which leads to reduced PR resonant current and PR vibration losses (I ² R losses). Moreover, due to the merged hybrid converter concept, the operational principle remains unchanged, preserving all the benefits of the baseline PR converter, including zero-voltage-switching (ZVS) and soft charging. A prototype of the BSPPR converter, employing disk-shaped lead zirconate titanate (PZT) PRs, is constructed and achieves a peak efficiency of 95.8%.