AN-6921 Datasheet PDF - Fairchild Semiconductor

This application note presents practical step-by-step design considerations for power supply system employing Fairchild’s FAN6921 PFC/PWM combination controller, which combines a Boundary Conduction Mode (BCM) Power Factor Correction (PFC) controller and QuasiResonant (QR) PWM controller. Figure 1 shows the typical application circuit, where the BCM PFC converter is in the
front end and the Quasi-Resonant flyback converter is in the back end.