LED is a semiconductor device itself, all of the semiconductor device has a normal operating temperature requirements, including ambient temperature and operating temperature. Ambient temperature semiconductor devices generally have less than 80 degrees of normal, while the internal LED PN junction temperature reaches 140 degrees and they will fail. Normal working temperature of its own that comes out through the pin or special base, which can then be connected to the pin through the circuit board or aluminum plate dissipated to the surrounding air, in order to ensure the normal operation of the LED. In general, single power greater than 0.2W, should make the use of aluminum plate heat, then power should increase aluminum and aluminum heat sink. Of course, this entire LED lights inside the number and density, too focused on low-power LED also have to consider the thermal design. It's like on the side of every one of you electronic products, such as: televisions, monitors, computers and other hosts. Incorrect thermal design will directly lead to shortened life expectancy and accelerate LED light failure rate.
1 Now most of the junction temperature limit of 120 degrees can do about the current cree should be higher, at 150 degrees.
2 Lamp beads thermal structure, depending on the different packaging materials, some as high as tens of multi-chip, single-chip are generally single digits, at most a dozen, of course, directly related to the junction temperature can be regarded as related to the LED life, light effects and other important parameters of the.
3 Currently, most LED lighting design life is 20000 ~ 50000H, which is determined by many factors, such as the first IC lifetime limits the life of the whole lamp.
4 Issues in terms of structure and layout from the heat and the thermal contact resistance is actually a bottleneck, which involve more, not listed. Overall structure is one large area of ??good contact. PCB evenly distributed as possible above the lamp beads wants to avoid heat concentration.
5 Drive efficiency, of course the higher the better, as far as possible on the principle of maximum heat distribution, which is the LED lamp beads. Glue can be other ways to achieve the effect of thermal insulation is fixed.
Considering: Good thermal design temperature is best controlled at 35 or less. Junction temperature below 80. Theoretical life of 50,000 or more.
