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

The input-parallel output-parallel (IPOP) DCDC converter is suitable for low-voltage and 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 paper, a coupled-inductor-based IPOP quasi-resonant (QR) single-stage DC-DC converter is proposed to mitigate 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. A 48V/1.8V 144W two-module QR single-stage converter prototype is made and tested to verify the analysis.