LED cooling design

by / Thursday, 22 March 2018 / Published in Company Blog

From a thermal design point of view, a typical LED lamp includes an LED light source, a printed circuit board (PCB), and a cooling system. The LED light source includes a semiconductor chip (light emitting portion), an optical element, a package, and a heatsink for taking the heat of the chip. The heatsink is soldered on the PCB board. To shorten the development cycle of LED lamps, it is necessary to estimate the temperature of the LED light source in the lamp. With the increase of high-power and high-lumen packaged products, LED cooling has become a challenge. Thermal designs has become an integral part of the LED lamp R&D process.

LED light sources are very efficient, and thermal management can be said to be the most challenging part of the design process. Proper cooling system design is critical to LED lamp. The heat dissipation of the LED was not a problem at first, because the main power used were the low power LED. However, with the use of high-power LEDs, their heat output is greatly increased. In order to ensure the high efficiency, reliability, and long life of LEDs, the heat dissipation problem must be solved.

The figure below shows a simplified model of a LED lamp based on several basic output parameter simulations.

Cooling system

Excessive heat will directly affect the short-term and long-term performance of the LED light source.

Ÿ Short-term: color drift, reduced light output

Ÿ Long-term: accelerated decay and shorter lifetime

People usually use natural (passive) and artificial (active) cooling systems to dissipate heat.

 

The most common passive cooling system in LED fixtures is the heatsink. Generally speaking, the heatsink consists of many sets of metal blades, which can quickly to conduct the heat gathered in the LED light source. Since the heatsink itself does not consume energy, it is the most energy-efficient cooling system. However, with the increase of the power of LED light sources, the heat dissipation area is required to be larger and larger, which requires the design of a heatsink with a complicated shape, which bring disadvantages to the lamps and lanterns. When designing such a system, several major factors must be considered, such as the layout of the LED light source, the properties of the lamp material, the shape of the heatsink, and the surface treatment. Aluminum is a common material for the production of heat sinks, not only because of its high cost performance, but also because of the ease of aluminum processing, die casting, and extrusion.

Share Button
TOP