Integrated metal substrates improve LED thermal management

Oct. 19, 2007
Compared with standard FR4, integrated metal substrates deliver valuable thermal management improvements for LEDs, enabling higher light output and greater reliability, writes Nico Bruijnis.
As with power transistors, the performance and longevity of high-brightness LEDs depends upon effective thermal management. Accordingly, LED manufacturers are adopting similar package design techniques to those now seen in surface-mounted power devices.
However, thermal management between the boundaries of the package and the ambient environment is equally important, and systems integrators are also adopting power electronics techniques to achieve cost-effective solutions.

Effective thermal management influences both the quality and quantity of light available from a high-brightness (HB) LED. Since the emitted wavelength increases linearly with the temperature of the die, maintaining a stable die temperature for consistent colour output is important in assemblies containing large numbers of LEDs. This is particularly important with the emerging families of white LEDs, as the human eye is able to differentiate very small colour changes in white light.

Also, the intensity of the emitted light is heavily dependent on the forward current supplied, and higher current causes the die temperature to increase. Good thermal management techniques are required to achieve bright light without exceeding the recommended maximum die temperature.


This article was published in the September/October 2007 issue of LEDs Magazine.

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