The Novel Quasi-Resonant Flyback Converter with Auto Regulated Structure for Parallel/Serial Input

In the present paper, a novel quasi-resonant flyback converter that mainly comprises two modules of flyback converters is proposed. A relay is connected in series to the input terminals of two transformers, and the transformer input structure is adjusted according to the input voltage to improve the conversion efficiency. In addition, a novel frequency-limiting quasi-resonant control strategy for solving the limitations of the conventional quasi-resonant control strategies is proposed, wherein the switching frequency is increased under light load conditions. Here, the current-mode pulse width modulation IC is used as the core controller. The operating principle and design parameters of the converter are analyzed and discussed in detail. The experimental results prove the feasibility of the proposed circuit.