A new winding interleaving structure for MHz regulated DC Transformer (RDCX) is proposed in this paper, which can greatly reduce the PCB-winding loss produced by high-frequency eddy current. Due to the characteristic of the partial power regulation and transformer integration, the distribution of the magnetic field will be greatly affected by the regulated output voltage in the winding window, which in turn will increase the winding loss. This paper proposes a winding arrangement to optimize the magnetomotive force (MMF) distribution in the winding window, no matter how the output voltage changes. An experimental prototype was built for verification, whose charging efficiency increased by 0.6%.