Design on topologies for high efficiency two-stage AC-DC converter

Design on topologies for high efficiency 60W level two-stage AC-DC adapter is proposed in this paper. Conventional 60W level single-stage AC-DC converter has wide input range. And flyback topology has low efficiency characteristic. Therefore, conventional 60W single-stage AC-DC adapter has low efficiency characteristic. In order to develop small and high efficiency AC-DC converter, propose two-stage AC-DC converter structure. Two-stage AC-DC converter is added PFC stage. But DC-DC stage easy to design Because input voltage fixed link capacitor voltage. Moreover, size of input-filter decrease due to PFC stage effect. Therefore, two-stage AC-DC converter has high efficiency. And it is possible to put in conventional single-stage AC-DC adapter case. Design procedures and experimental results for boost PFC, flyback, forward and LLC DC-DC converters are presented to select the suitable topologies of two-stage AC-DC converter.