Design consideration of flat transformer in LLC resonant converter for low core loss

Low-profile, high efficiency power supply is today´s industry trend for Plasma Display Panel (PDP) application system. Transformer is the major challenge and bottleneck for achieving low-profile, high power density converter. Generally, it is necessary for low-profile converter to operate it at high switching frequency. However, it is very difficult to design converter using flat magnetic component because flat transformer temperature becomes high at high switching frequency. In this paper, the design and analysis of flat transformer in LLC resonant converter for the PDP TV is proposed to reduce temperature of the transformer. In this proposed converter, flat transformer is integrated into advanced power conversion application systems. Low-profile power module of profile of about 14mm is achieved. Temperature inside of transformer repressed to 71^oC and an overall efficiency of about 96.6% was obtained.