| Title |
High Efficiency and Small Size Switch Mode Line Transformer(SMLT) |
| Authors |
Jin-Hong Kim ; Jung-Woo Yang ; Du-Hee Jang ; Jeong-Il Kang ; Sang-Kyoo Han |
| DOI |
10.6113/TKPE/2019.24.4.237 |
| Keywords |
High efficiency; LLC resonant converter; Small size; SMLT(Switch Mode Line Transformer) |
| Abstract |
A high-efficiency and small-sized switched-mode line transformer (SMLT) is proposed in this study. The conventional structure of an adapter is composed of line transformer and rectifiers. This structure has a limit in miniaturizing due to low-frequency line transformer. Another structure is composed of power factor correction (PFC) and DC/DC converter. This structure has a limit in reducing volume due to two-stage structure. As the proposed SMLT is composed of an LLC resonant converter, a high-frequency transformer can be adopted to achieve isolation standards and size reduction. This proposed structure has different operation modes in accordance with line input voltage to overcome poor line regulation. In addition, the proposed SMLT is applied to the front of a conventional PFC converter, because the SMLT output voltage is restored to rectified sinusoidal wave by using a full-bridge rectifier in the secondary side. The design of the PFC converter is easy, because the SMLT output voltage is controlled as rectified sinusoidal wave. The validity of the proposed converter is proven through a 350 W prototype. |