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Power Factor Controller, High-Efficiency, Enhanced for Lighting
8
1 SOIC−8 CASE 751
NCL2801
The 8−pin PFC controller NCL2801 is designed to drive PFC boost stages. It is based on an innovative Valley Count Frequency Fold−back (VCFF) method. The circuit classically operates in Critical conduction Mode (CrM) for high load values. When the load decreases a Discontinuous Conduction Mode DCM is forced by forcing a dead time which, by construction corresponds to a fixed number of valleys. The lower the output power, the higher the number of valleys corresponding to the dead time. After DCM works down to 6th valley switching and if the load continues to decrease, a dead time is continuously added to the 6th valley.