Research On Active Clamp Utilized For Flyback Switch Mode Power Supply

Compared to other DC/DC converters, the flyback converter has irreplaceableadvantages, which has the simplicity of circuit topology and control policy, low EMI,economy, and so on. At present, all low power applications are taking advantage of flybackconverter, which most of them are closely connected to people’s daily life, for instance,charger for cell phone, power adapter for laptop. Unfortunately, traditional flyback converterhas its faults, the worst thing is low efficiency. As the most widely used converter for ourlives, the flyback converter has a huge number of utilities. The energy saving and emissionreduction is strongly suggested at present, as a result, improve the efficiency of flybackconverter is on top priority, which has significance for the social development, andenvironmental protection.This paper reviews the history of development of the flyback converter briefly, as well ascontributions engineers made to improve the efficiency of the flyback converter for now.Analyzes the factor made the flyback converter low efficiency, which is the loss ofaccumulated energy of transformer’s leakage inductance. The efficiency of flyback could befurther improved if recycle these energy is possible. Introduces the circuit topology of activeclamp. Analyzes the active clamp employed for the forward converter in detail. Presents theconcept of utilize the active clamp in the flyback converter. Analyzes the different effects ofactive clamp between forward and flyback converter. Expounds the universal active clamp forflyback converter, analyzes its working process. Put forward to the dual-tube clamp topology,which presented in this paper. Explains the meaning of this topology, analyzes its workingprocess and principle, as well as the evidence of dual-tube belongs to the active clamp. Addsthe ZVS quasi-resonant topology for further improve the efficiency of the flyback converter,analyze its working status. Eventually proves the advantages of flyback converter employ thedual-tube clamp and quasi-resonant with experiment data.Introduce the dual-tube clamp and quasi-resonant into the flyback converter, which hasmassive quantity of inventory in the world, could be a significance of increase the efficiencyof flyback converter, as well as for humanity to construct the conservation-minded societyand protect the environment.