Design and analysis of high power LED light

Update:05 Jan 2019
Summary:

When using lighting fixtures outdoors, the power is typ […]

When using lighting fixtures outdoors, the power is typically many times greater than the power of the fixtures used indoors. Such as street lights, building outdoor landscape lights, stage lighting, roadway lights, explosion-proof headlights, etc., these lamps have a power of several hundred watts to kilowatts. High-power lamps are not only simple to stack many small LED lights, but also encounter various problems in actual use.

Like stage lighting, LEDs can get very good monochromatic light. That is, the red light we usually say is very red, and the green light is very green. Because of this feature, LED lights have been widely used in stage lighting. However, in order to obtain the effect of high-brightness spotlights, the LED lights are a little powerless, because multiple LEDs need to be combined to achieve sufficient brightness, but so many LEDs cannot be concentrated in one focus, so that they cannot be like traditional tungsten halogen lamps. In this way, the concentrating effect is achieved by a simple concentrator.

In addition, when high-power LED lamps are used, such as stage lighting, square lighting, LED street lights, etc., many LED lights are concentrated in the light, and the heat dissipation problem is revealed. Although the LED is a cold light source, it is only a light source that relies on heat to be converted into light. In fact, as the lighting power increases, the heat emitted by the LEDs will naturally become more obvious. The internal temperature of such lamps often reaches 70-80 ° C. Moreover, due to the structure of the LED solid-state package, the heat is concentrated in a very large size. On a small chip, the temperature rise will seriously affect the service life of the LED and the reliability will be reduced. Solving heat dissipation has become a prerequisite for high-brightness LED applications.

In order to reduce the junction temperature of the LED chip more effectively under the action of high current intensity, a good LED package and module design are needed to obtain a better heat conduction path for the LED.

The traditional way to dissipate heat is to use a heat sink, or to add air-cooled equipment, just like a computer's CPU cooling fan. This heat dissipation can only be used in a relatively closed space. High-power LED lamps are usually used outdoors, and the effects of weather such as rain and snow on the equipment should be fully considered. If the heat sink is greatly increased to achieve a better cooling effect, the manufacturing cost of the lamp and the quality of the lamp itself will increase. Therefore, it is an important problem to be overcome by high-power LEDs to balance the relationship between cost, quality and heat dissipation.