National Semiconductor's constant-current controller enables off-line, uniform, flicker-free dimming of high-brightness light-emitting diodes (LEDs) with a conventional TRIode for Alternating Current (TRIAC) forward or reverse phase-control wall dimmer. 

The LM3445 TRIAC dimmable LED driver enables a full 100:1 range of dimming capability and can maintain greater than 1A of constant current to large strings of LEDs in a variety of residential, architectural, commercial and industrial applications.

The driver maximizes the light output for systems while maintaining Energy Star power factor requirements, placing it in National’s PowerWise range of energy-efficient products. 

Today's TRIAC wall dimmers are designed to interface with a resistive load such as incandescent or halogen light bulbs. Since an LED bulb does not appear as a resistive load to the TRIAC wall dimmer, dimming an LED bulb using a conventional TRIAC wall dimmer does not yield optimal dimming performance. LED drivers available today cause either a 120Hz flicker of the LEDs or do not enable the full 100:1 dimming range. 

National's LM3445 translates the TRIAC-chopped waveform to a DIM signal and decodes it for a full-range of uniform, flicker-free dimming. The driver's control architecture maintains constant ripple through the LEDs, which extends the life of the LEDs. 

The LM3445 LED driver enables direct LED bulb replacement of existing incandescent or halogen bulb systems connected to standard TRIAC wall dimmers.  In addition, the LM3445 allows master-slave operation, enabling control of multiple strings of LED bulbs.

More information: http://www.national.com/pf/LM/LM3445.html