The ON Semiconductor NCP1618CDR2G is an innovative multimode power factor controller. The circuit naturally transitions from one operation mode to another depending the switching period duration so that the efficiency is optimized over the line/load range. In very−light−load conditions, the circuit can enter the soft−SKIP mode for minimized losses. Housed in a SO-9 package, the circuit further incorporates the features necessary for robust and compact PFC stages, with few external components

A High-voltage start-up current source for VCC capacitor charge at startup
It has an internal compensation of the regulation loop
It offers Soft and Fast-overvoltage protection
It offers Line-Sag and Brown-out detection