onsemi NCP1622 power factor controller

The 6-pin PFC controller NCP1622 is designed to drive PFC boost stages. It is based on an innovative Valley Synchronized Frequency Fold-back method.VSFF maximizes the efficiency at both nominal and light load. In particular, the stand-by losses are reduced to a minimum. Like in FCCrM controllers, internal circuitry allows near-unity power factor even when the switching frequency is reduced. Housed in a TSOP6 package, the circuit also incorporates the features necessary for robust and compact PFC stages, with few external components.

Key features

• Critical Conduction Mode with frequency foldback
• Valley Synchronized Frequency Fold-back (VSFF)
• Works with or without a transformer w/ ZCD winding
• Dynamic Response Enhancer

Additional features

• Critical Conduction Mode with frequency foldback
• Valley Synchronized Frequency Fold-back (VSFF)
• Works with or without a transformer w/ ZCD winding
• Dynamic Response Enhancer

Applications

• Offline Power supply
• Flat panel TV
• High power adapters
• PC Power Supplies
• Lighting Ballasts
• Flat Screen TV
• All off line applications requiring power factor correction

Available tools

The NCP1622 Evaluation Board implements a complete 160W/390 Vdc nominal Power Factor Correction Stage and operates from 90-265 Vac. The board illustrates a low profile (<13 mm height) that might be used in a flat TV or All-in-One PC Application. The target efficiency and power factor at full load for this board is >95% with a PF > 0.95 and meets EN61000-3-2 Class C and Class D requirements.

The NCP1622 is active power factor corrected (PFC) controller specifically designed for use as a boost pre-converter in ac-dc adapters, flat TVs, lighting ballasts and other medium powered offline applications. The controller 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 the inductor current exceeds a programmable value. When the current is below this preset level, the NCP1622 linearly reduces the frequency down to about 20 kHz when the current is at a null. VSFF maximizes the efficiency at both nominal and light load. In particular, the standby losses are reduced to a minimum. The controller features a robust suite of protection features to properly handle an array of power supply operating and fault conditions.