onsemi NCP1622BECSNT1G, Power Factor Controller, 50 kHz, 30 V 6-Pin, TSOP

The 6-pin PFC controller NCP1622 is designed to drive PFC boost stages. It is based on an innovative Valley Synchronized Frequency Fold-back (VSFF) method. In this mode, the circuit classically operates in Critical conduction Mode (CrM) when control voltage exceeds a programmable value Vctrl,FF. When Vcontrol is below this preset level Vctrl,FF, the NCP1622 linearly decays the frequency down to about 30 kHz until Vcontrol reaches the SKIP mode threshold. VSFF maximizes the efficiency at both nominal and light load.

Critical Conduction Mode with frequency foldback
Optimizes conversion efficiency across load range
Valley Synchronized Frequency Fold-back (VSFF)
Enhanced efficiency at light load conditions compared to CrM PFC
Works with or without a transformer w/ ZCD winding
Reduced inductor cost and simplified design
Dynamic Response Enhancer
Improved transient response for line and load steps