onsemi NCP1622 Power Factor Controller

onsemi NCP1622 Power Factor Controller can drive PFC boost stages and 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 (versions [B**] and [D**]) 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 loads. Standby losses are reduced to a minimum. Like in FCCrM controllers, internal circuitry allows near-unity power factor even when the switching frequency is reduced. The circuit is housed in a TSOP6 package and incorporates the features necessary for robust and compact PFC stages, with few external components.