White Papers

Unlike incandescent lighting that relies on heat to cause a filament to glow and produce light as hot black body, light emitting diodes (LEDs) are semiconductors and as such must be kept cool. When LEDs produce light, heat is a by-product. Heat generated in an LED increases its temperature. As the LED’s temperature increases, the light output decreases, the light changes color, and the lifetime of the LED reduces. Temperature adversely affects both the functional performance of the LED and its longevity. As a consequence, thermal management has become the most predominant issue in solid state lighting (SSL) design.

Using the JEDEC standard static test method for transient thermal measurements in accordance with JESD51-14 and CIE 127-2007 has increased the level of accuracy in light-emitting diodes (LEDs) thermal characterization. These higher standards have resulted in increased customer confidence and market share. In compliance with these standards, the Mentor Graphics T3Ster system can complete more than 100 LED thermal measurements in a single day, and it is the most accurate. The T3Ster post-processing software fully supports the latest thermal testing standard (JEDEC JESD51-14) for junction-to-case thermal resistance measurement. This paper discusses the importance of more accurate thermal characterization to the rapidly evolving marketplace and how the T3Ster and TERALED systems are meeting this challenge for lighting manufacturers and their customers.

 Best practices for CFD analysis in gas mixing with new CAD-embedded tools.

Using IP blocks in designs requiring DO-254 compliance is becoming more popular as a way to reduce costs and schedules. However, the use of IP comes with its own problems and pitfalls. A good methodology to better screen this IP before its usage can significantly reduce unexpected problems and lower risk, especially on safety critical designs. The most important soft IP screening technologies are automatic formal check and clock domain crossing analysis. This paper will provide a background explanation of IP, including: what types exist in the market; caveats to their usage; and suggestions to better analyze IP before it is used in a design, thus lowering risk and improving product safety. (Note: This paper does not address IP compliance issues. For more information on that topic, please refer to the DO-254 User Group paper "Use of Intellectual Property (IP) Cores in Airborne Electronic Hardware".

Computational Fluid Dynamics (CFD) analysis is no longer a discipline reserved only for highly trained practitioners. A new class of CFD analysis software known as “Concurrent CFD” is proving to be greatly effective at performing pressure drop analysis, enabling mechanical engineers to accelerate key decisions at their workstations, without the need for CFD specialists. Embedded into the MCAD environment, this intuitive process allows designers to optimize a product during the design stages, reducing manufacturing costs across a wide range of mechanical designs and systems.

Mini-fridges, commonly filled with beer and the occasional moldering sandwich, have become a ubiquitous fixture in college dorm rooms and office break areas. But for some reason they never seem to cool their contents as well as their full-size cousins in the kitchen. This paper, based on a series of blog entries, presents a light-hearted look at the problem and offers a solution. In doing so, it demonstrates some practical thermal analysis methods using Mentor Graphics FloTHERM and proves that thermal simulation can help engineers design better products for consumers.