WHEN THE HEAT IS ON…
When heat becomes an issue in your LED displays, lots of things can happen and NONE of them are good! Heat will shorten the life of the diodes and components in your display. You will start seeing black diodes or single-color diodes. Heat can also cause uneven color distortion over time. It is imperative that you maintain sufficient heat management for your LED video display.
Here are a few ways you can do just that! This is not an exhaustive list, but it covers some of the major culprits when it comes to improper heat management in your LED video display system.
Individual LED’s or SMD’s should be of the highest millicandela possible. Also, it helps if the chip is of the highest diameter possible. These two things are present in the higher quality LED diodes and help ensure that the lowest milliamp is loaded on each LED lamp during times of highest brightness. Finally, high-quality copper is suggested for the lead-frame material instead of lower quality steel. Steel only offers about a third of the heat dissipation capability that copper does.
Power Supply Capacity & Performance
As the environment surrounding the LED module changes, so does the components of the module. Take the Power Supply Unit, as the temperature surrounding the PSU increases, the load capacity of the unit rapidly decreases. Eventually, it will decrease to a point where the automatic shut-down engages in order to prevent any permanent damage.
If your IC Chipset is working efficiently, it should, through a well-designed PCB assembly and an energy-efficient Power Supply Unit, easily convert 115/230 down to a forward voltage of 3V to the diode. Approximately 35% of the energy of the IC should be dissipated as heat and an efficient IC Chipset will achieve this easily.
Sufficient PCB Design and Assembly
Be sure that your LED modules have been designed and assembled with heat dissipation in mind. A good design will have enlarged traces. Each trace should be deeper and wider. This will serve to dissipate heat at the PCB level. Also, using a four(4)-layer board on an outdoor board as opposed to a two(2)-layer board, which is common on most indoor boards, will dissipate heat much better. This gives much needed heat-dissipation space to the heat-generating traces.
If the environment of the module is of a higher temperature, fans can be used to dissipate some of that heat away from the components of the modules. Fans with high RPM and CFM value (air movement capacity) should be used.
Metal cabinets, and in particular aluminum cabinets, offer a better heat dissipation coefficient than fiberglass, plastic or wood. Aluminum is also much better than steel or cast iron in exchanging heat with the ambient environment. Also, cabinet color plays a big role in dissipating heat. Cabinets should be white in color if they are exposed to direct sunlight. This reflects energy and reduces any heat-gain from solar energy.
The silicone applied to the front of the LED module can make a big difference in dissipating heat. Sometimes, depending on pitch, the difference can be up to 3-5 degrees. Many times, to dilute the cost, lower-tier suppliers mix a foreign substance into their silicone to create the illusion of a “heavier” weight. This foreign substance can create a barrier to heat-transfer that acts much like a nice warm winter coat on a cold day! Top-tier silicone will not be diluted with foreign substances and will provide the highest heat-transfer coefficient possible.
So, when you’re purchasing modules or video panels, ask for the specs! Ask questions. Make sure you know what you’re getting before you buy. LED video walls represent a sizeable investment. Make your investment last as long as possible! If you can think of something I left out, please comment below.
By Mike Kirkpatrick
Vice-President of Marketing
Azar Pixell, LLC
16531 Addison Rd.
Addison, TX 75001
Thank you to QST LED for some of the source material.