Due to their brightness, long life, and lighting efficiency, LEDs are becoming increasingly
popular in lighting and signage applications.
LEDs have very high heat flux values, meaning that the heat they dissipate is dissipated
over very small areas. LEDs can dissipate from 1W—8W and this is done over very small
areas. The maximum allowable junction temperatures for these devices is also relatively
low (from 120C - 185C), thus cooling and thermal management for these devices becomes
critical to their design and proper operation.
LED cooling can take various forms depending on their applications. It is often desired
to avoid active cooling systems in order to maintain high system reliability, however,
this limits the heat extraction possible. In some cases, passive cooling is highly
desirable so as to minimize maintenance (ex. in hard to access places or areas where
maintenance down-time is unacceptable). In other cases, the high heat fluxes resulting
from the illumination requirements will mandate active cooling systems. As an example,
an automotive LED headlamp with high under hood ambient conditions of 85 C or higher
would likely require an active cooling system such as a fan or a liquid cooling system.
There are a number of factors that drive the thermal design for LED applications.
In general, thermal contact resistance, and spreading resistance will play a significant
role. Insulated metal substrate boards will often be used with LEDs to help reduce
the spreading resistance associated with FR4 PCBs. Also, highly conductive thermal
interface materials will often be used to help reduce the junction temperature of
TDMG has been involved in a number of LED product development programs. Our thermal
design and analysis experience with LED systems can help us identify the proper solution
for your LED application. As a heatsink manufacturer we can produce the cooling solution
you require for your LED system.
Figure 1: Typical LED lighting applications
If you have any questions regarding the above or for a specific design question which
you may have, please contact us and we will be pleased to help you.