Abstract：The explosive growth of data and computing demand has significantly increased data center energy consumption. As the 48 V bus architecture gradually replaces the conventional 12 V distribution system, power supplies must deliver ultra-low output voltages and high currents while maintaining high efficiency and high power density. Conventional two-stage architectures, which consist of a bus converter followed by a point-of-load regulator, suffer from two-stage efficiency losses and limited power density. Consequently, single-stage solutions have gained increasing attention. Among these, the current-doubler rectifier (CDR) topology has been widely studied due to its simple structure and suitability for low-voltage, high-current applications. However, challenges remain in scalability, magnetic integration, and optimization of conduction loss. Therefore, this paper proposes a high-density matrix-magnetic-integration method for CDR converters. The proposed method splits the non-winding leg of a conventional CDR integrated magnetic core. This design exploits underutilized regions of the winding window where current distribution is minimal, thereby reducing both the footprint and the winding length of each integrated inductor-transformer unit. Accordingly, a matrix expansion scheme is introduced to enable the modular combination of multiple sub-transformer units. The optimized configuration of cores and windings achieves a balance between scalability and simplified routing while reducing magnetic and conduction losses. To guide the design, the flux distribution characteristics of negatively coupled transformers in the matrix magnetic integration structure are analyzed, and a design approach for magnetic parameters is developed with the minimum footprint of the integrated magnetic component as the primary objective. The proposed method is validated through finite-element simulations and a prototype featuring a 10-layer printed circuit board (PCB) winding structure. The prototype was tested with a 48 V input and a 0.8 V to 1.2 V, 150 A output. Experimental results indicate a peak efficiency of 91.88% and a power density of 800 W/in3. Compared with a conventional EI-core design, the proposed structure reduces the footprint by approximately 11% and core loss by approximately 10%. Thermal imaging at full load (150 A) indicates a maximum hot-spot temperature of 73.5℃. In conclusion, the matrix-transformer-based CDR converter enables direct conversion from a 48 V bus to low-voltage, high-current outputs while maintaining high efficiency and power density. The proposed matrix magnetic integration method effectively reduces the size of each unit core and minimizes losses, demonstrating strong potential for application in high-performance computing power supply systems. In addition, the matrix structure provides a pathway for further current scalability. This paper offers a practical and reliable solution to future low-voltage, high-current power-delivery requirements.
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2026, Vol. 41 
