Design of MHz Level Planar Transformer and Analysis of Leakage and Loss

Planar transformer is an important factor to achieve high power density and high efficiency of switching power supply. In this paper, a MHz level planar transformer is designed based on flyback converter. First of all, according to the smallest structural constant of PCB core, the magnetic core is selected. The working flux density is selected preliminarily based on the relationship between magnetic core loss and temperature rise, and the number of primary side turns and line width is further calculated. The design of planar transformer structure is further accomplished in the magnetic element design software Ansoft Pexprt, and the leakage inductance and loss of planar transformer is simulated in the finite element analysis software Maxwell 2D. According to the simulation design, the layout of the printed circuit board of transformer is made, and the leakage loss is tested and calculated. The correctness of the design of planar transformer is verified.