400 w-pfc设计方案.pdf

AN2485 Application note 400 W FOT-controlled PFC pre-regulator with the L6563 Introduction This application note describes an evaluation board based on the Transition-mode PFC controller L6563 and presents the results of the bench evaluation. The board implements a 400 W, wide-range mains input, a PFC pre-conditioner suitable for ATX PSU, or a flat screen display. The chip is operated with Fixed-Off-Time control in order to use a low-cost device like the L6563 which is usually prohibitive at this power level. Fixed-Off-Time control allows Continuous Conduction Mode operation which is normally achieved with more expensive control chips and more complex control architectures. L6563 400W FOT PFC Demo board (EVAL6563-400W) March 2007 Rev 1 1/29 Contents AN2485 Contents 1 Main characteristics and circuit description . . . . . . . . . . . . . . . . . . . . . 4 2 Test results and significant waveforms . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.1 Harmonic content measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.2 Inductor current in FOT and L6563 THD optimizer . . . . . . . . . . . . . . . . . 10 2.3 Voltage feedforward . . . . . . . . . . .