Operating temperature reduction of low-profile transformer in LLC resonant converter for PDP

Nowadays high power density, high performance, and high efficiency converters become a hot issue of the PDP TV. For meeting requirements, the design and implementation of LLC resonant converter using low-profile magnetic component for PDP is proposed in this paper. In order to use a flat transformer, it is necessary to operate the converter at high switching frequency. In the LLC resonant converter, soft-switching operations of main switches and diode rectifiers can be achieved. Therefore, the switching loss is reduced and we can operate the converter at higher switching frequency. However, it is a problem that low-profile transformer temperature becomes high at high switching frequency. Based on the theoretical analysis, simulation and experimental results, the design for reducing operating temperature of low-profile transformer is proposed in this paper. As a result, temperature inside of transformer repressed to 61 °C and an overall efficiency of about 97.8% was obtained.