Wednesday, March 28, 2007
Rebel with a cause
Lumileds (Philips now) has finally released the latest and greatest in low form factor power led's. The high efficacy (upt 72 lm/W) LED boasts a high Tj of 150 deg C. This is quite an innovation and can provide a much needed shot in the arm for LED general illumination space. Alternate Lighting (where i work) has already created some reference designs that will use this semiconductor. Currently this led is seen to have a large potential in the solar lighting and AC dowlighting (MR16, 11 etc) markets.
From the article in LED mag
The Rebel contains a 1x1 mm2 chip and has a footprint of just 3mm x 4.5mm, considerably smaller than rival power LEDs. The chip is mounted on a ceramic substrate and has a hemispherical silicone lens. The Rebel is engineered for operation between 350 mA and 1000 mA, and is the first power LED to offer guaranteed minimum performance (many datasheets for other LEDs specify typical performance values). Lumileds says that its minimum performance specifications enable greater design and manufacturing consistency, and allow customers to purchase the light output performance appropriate for each application.
The Rebel white binning structure includes a CCT range from 2670K to 3500K for warm-white, 3500K to 4500K for neutral-white, and 4500K to 10000K for cool-white. Sampling of the warm-white and neutral-white products begins immediately with volume production later this year.
For each CCT range, there are several bins with different minimum performance; 40, 50, 70 and 80 lm at 350 mA for cool- and neutral-white. With a forward voltage of 3.15 V, the highest bin has an efficacy of around 72 lm/W.
At higher drive currents, the datasheet shows that the top bins deliver 145 lm at 700 mA in cool- and neutral-white (57 lm/W), and 110 lm for warm-white (43 lm/W).
Typical color-rendering index (CRI) is 80 for warm-white, 75 for neutral-white, and 70 for cool-white.
The package's small footprint and low profile of just 2.1mm should enable significantly reduced color mixing and diffusion depths. This will allow luminaire designs that are significantly thinner than those using alternative power LED packages.