Comparison between Control Methods of Active Clamp Flyback for Adaptor Application

High efficiency and high switching frequency are the key points for the miniaturization of the power adapter. The ACF (Active Clamp Flyback) can achieve ZVS (zero voltage switching) and recycle the leakage energy at all load and line conditions. This paper presents the comparison between the ACF with the complementary control mode and the ACF with the non-complementary control mode. Key differences between the two control modes at all load and line conditions are analyzed. Performances of the ACF with the two control modes are verified on a sample of prototype adaptor with 65W (19.5V, 3.33A) output.