A double-switch single-stage PFC offline switcher operating in CCM with high efficiency and low cost

A three-switched-networks SEPIC, PFC 350 W rectifier, utilizing magnetic integration at its input and operating in the continuous conduction mode (CCM) for every input and load condition, is presented. The proposed offline switcher shows convenient energy storage at low voltage, good load regulation, easy to implement output overvoltage and short-circuit protection, low inrush current and no heavy input filter. For all the above reasons, it assures high efficiency and low cost. Operation of the power converter, most of the design rules and procedures are described and some basic results from a laboratory prototype are also given.