A Coupled-Inductor-Based Input-Parallel Output-Parallel Quasi-Resonant Single-Stage DC–DC Converter to Mitigate Current Difference

The input-parallel output-parallel (IPOP) dc–dc converter is suitable for high-current applications, such as voltage regulator module. However, the parameter mismatch in the IPOP converter causes uneven current sharing between the constituent modules, which makes the IPOP converter unreliable for practical use. In this article, a coupled-inductor-based IPOP quasi-resonant (QR) single-stage dc–dc converter is proposed to mitigate the current difference. The coupled inductor integrates the discrete external inductors of parallel modules to automatically balance the primary currents between modules and act as resonant inductors, which can reduce the number of magnetic components and simplify the control strategy. Besides, primary switches of QR single-stage converter can achieve zero-voltage switching (ZVS), and synchronous rectifiers can achieve ZVS and zero-current switching with the resonance, resulting in the efficiency improvement. What is more, the current sharing method can be extended to an
N
-module converter with an
N
-phase coupled inductor. Finally, a 48-V/1.8-V 144-W two-module QR single-stage converter prototype is made and tested to verify the analysis.