National Semiconductor Launches LED Driver Boasting Industry-Best Dimming Performance
LED driver with integrated phase dimming decoder and PFC ensuring flicker-free uniform dimming
– National Semiconductor Korea (CEO: Choi Chung-won) today introduced a new LED driver boasting industry-leading phase-based dimming performance in the high-brightness light-emitting diode (LED) field. The LM3450 LED driver integrates both a Power Factor Correction (PFC) controller and dimming decoding capabilities that provide uniform dimming and flicker-free lighting through a wide range of programmable dimming. Belonging to National’s PowerWise® energy-efficient product family, the LM3450 is ideal for high-performance LED lighting installations capable of phase dimming in the 10 W to 100 W output range.
Facilities equipped with phase-based dimmers among the lighting used in residential or commercial buildings require a circuit capable of accurately decoding phase-cut waveforms to properly adjust LED brightness. Currently available dimmable LED drivers fail to meet the minimum current requirements applied to forward-phase or TRIAC-based dimmers, frequently causing the dimmer to turn off or “malfunction” during operation. This results in inaccurate decoding of the phase angle, causing the LED to flicker, particularly at low dimming levels. To prevent this phenomenon, modern drivers continuously output power to reduce the LED dimming range or to prevent the dimmer from malfunctioning.
National Semiconductor attempted to solve the problem using proprietary technology by developing a new LM3450 controller that integrates a holding circuit that dynamically regulates the current flowing through the phase dimmer. The dynamic holding circuit, combined with a programmable intelligent dimming decoder, ensures smooth and constant lighting across the entire dimming range. This unique mode of operation enables the most efficient and consistent dimming. The LM3450 LED driver also features a PFC function, providing a high power factor that meets Energy Star® standards for residential and commercial buildings.
Technical Features of the National LM3450 Controller
The LM3450 LED driver accurately regulates the output while maintaining excellent power factor performance on the input side. The phase dimming decoder interprets the phase angle and converts it back into a 500 Hz PWM output that controls the brightness of the LED. This unique mode of operation is ideal for implementing offline LED drivers capable of phase dimming in load ranges from 10 W to 100 W.

Phase dimming decoders enhance design flexibility by utilizing programmable input-output mapping.