High efficiency step-down flyback converter using coaxial cable transformer

This paper proposes step-down flyback converter using coaxial cable transformer which has higher coupling than sandwich winding transformer. Proposed transformer converter has higher efficiency than conventional in same condition. The structure of the coaxial cable transformer is described and the results of the coupling of coaxial cable transformer and sandwich winding transformer are compared. Finally, performance of the proposed transformer is validated by the experimental results from a 35W single-output prototype and 35W multi-output prototype.