High-Efficiency AC-DC Switch-Mode Power Supply Using FullBridge Converter Circuits

Abstract

This paper presents a high-efficiency AC-DC switch-mode power supply (SMPS) using the full-bridge converter circuits. The proposed converter utilizes three full-bridge converter circuits: two full-bridge diode converter circuits and one full-bridge MOSFET converter circuit. The two full-bridge converters are utilized at the primary AC input and the secondary DC output, respectively, and the full-bridge MOSFET converter is used to convert a DC voltage to a high-frequency AC voltage that is converted to another DC voltage with the transformer and the secondary full-bridge diode converter, which is simply referred to as the full-bridge DC-DC converter. However the conventional full-bridge converter has a limit in its operating duty ratio in normal operation, because it results in more conduction loss in light load operation. Therefore, the proposed converter resolves the drawbacks of the conventional full-bridge converter using a modified full-bridge circuit with a DC blocking capacitor in the primary. Thus, the proposed converter has improved total efficiency and performance. The operation principle of the proposed converter is described in detail, and a design example of a prototype is shown. The good performance of the proposed converter is demonstrated through experimental results of the implemented prototype based on the design example.