Cree, Inc. announced the commercial availability of its high-voltage XLamp(R) XT-E and XM-L LEDs. The release is apparently an attempt to go after the small form-factor replacement lamp market in which no CFL alternatives exist. This market includes B10 (candelabra), E17 (down-sized A-lamps) or GU10s (like MRs, but run on line voltage). This application allows very limited space to dissipate any heat. Since LEDs typically run around 3V, and it's more efficient the less you need to step voltage down, a standard strategy is to string a bunch of LEDs together to align them with a higher input voltage. These kinds of small lamps don't have enough LEDs to string together, and are the most demanding of an efficient driver.
Cree's design strings together a single 16 die LED, wired differently so it can accept a 46v input. The packages measure 3.5mm x3.5mm and 5mm x 5mm. According to Cree, the XLamp(R) XT-E and XM-L LEDs can enable the use of more efficient, smaller drivers to lower cost for compact lighting applications such as candelabras and retrofit lamps.
The XLamp XM-L LED provides up to 600 lm in Cool White (6000K) and up to 462 lm in Warm White (3000K) at 6W, 85 deg C. The XLamp XT-E LED delivers up to 300 lm in Cool White (6000K) and up to 228 lm in Warm White (3000K) at 6W, 85 deg C. Both LEDs have a typical voltage of 46V at binning conditions.
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