Abstract: The optimal design of the magnetic integration and integrated printed circuit board（PCB）winding

based on a high-frequency high-density LLC resonant converter was studied. Both the transformer and resonant

inductor were integrated into only one magnetic core. By configuring the resonant inductor on the secondary side of the transformer，larger phase difference can be achieved. According to the finite element analysis（FEA）simulation results，compared with the separate cores，the volume is 12% lower and the core loss is 23% lower after integration. In addition，to reduce the common-mode（CM）noise，a symmetrical integrated PCB winding for full-bridge rectifier was proposed. Part of the shielding windings worked as the primary winding to improve the winding utilization.Finally，a 1.2 MHz-750 W-270 V / 48 V LLC resonant converter was built with a peak efficiency of 96.6% and the power density of 44 W/mm3. The comparison test results of the CM current also prove the effectiveness of the proposed integrated PCB winding structure.

      Key words: LLC resonant converter；matrix transformer；printed circuit board（PCB）winding；shielding；

magnetic integration