PFC module
National Semiconductor

The LM3450 is a power factor controller (PFC) with separate phase dimming decoder. The PFC regulates an accurate output voltage while maintaining excellent power factor at the input. The phase dimming decoder interprets the phase angle and remaps it to a 500Hz PWM output. This combination of features is ideal for implementing a dimmable off-line LED driver for 10-100W loads.

The phase dimming decoder has several unique features. A programmable mapping from input to output increases design flexibility, while a dynamic filter and variable sampling rate provide a fast, smooth response to dimmer movement. A dynamic hold circuit ensures that the phase dimmer angle is decoded properly while minimizing the extra power losses associated with holding current.

Applications
- Dimmable downlights, troffers, and lowbays
- Indoor and outdoor area SSL
- Power supply PFC