30 April, 2018
Up until a few years ago, light-emitting diodes (LEDs) were mainly used in a few specific products and appliances. But technological advances have led to strong growth and quickened the pace of development within the LED market. These days, they’re now the standard in a number of public, industrial and personal appliances – used in everything from lamps to cars and horticultural spotlights. As a result, intelligent semiconductor-based LEDs will be the dominant lighting product for the foreseeable future.
The design of LED products, however, is a complex, multidisciplinary problem. The major challenge engineers face is ensuring that key components are kept within narrow temperature limits – given that nearly all of the electrical power in LEDs is converted to heat. This means that that thermal design is essential to both a device’s performance and lifecycle.
But with the correct thermal simulation tools, development teams are better able to deliver products that meet reliability, form factor, and performance targets.
For design engineers, the aim of thermal management is to transfer the heat generated by the device into the ambient air to prevent components overheating. The scope and complexity of thermal management depends on the amount of heat, the size of the source, and the anticipated ambient conditions. Dealing with these factors requires a clearly defined heat-transfer path.
Thermal simulation is the only way to assess different cooling concepts with known marginal conditions and loads. It allows designers to identify thermal issues and to experiment with different LED packages, PCB materials, and cooling devices – without the cost of creating prototypes. Using thermal simulation in this way lets LED designers ensure that their designs meet performance requirements.
A client of ours, Optimal Thermal Solutions (OTS) – an engineering company focused on the thermal management of electronics – has worked on numerous LED lighting projects for a range of manufacturers across various industries. While OTS conduct physical testing on all of its projects, thermal simulation tools have become central to the work they do.
Norbert Engelberts, Founder of Optimal Thermal Solutions, said: “Thermal simulation tools are absolutely essential. They are not just a “nice to have” anymore. One of the key drivers is that the average time-to-market for a product is now so short. So, while we continue to use simulation in tandem with physical testing, CFD tools are required to save significant time in the development process. There is simply not the time available to perform extensive physical experiments.”
As well as reducing the reliance on physical testing, OTS has realized a range of benefits from its use of dedicated thermal simulation software. It has witnessed a reduction of design risk and a 10-30% improvement in cooling for LED products. Overall, OTS estimates that it saves anything from a few weeks to several months in terms of total time to market for its clients.
There is simply no avoiding the fact that without the right thermal design, LED products will struggle to meet performance targets. However, optimizing the thermal design of any LED lighting product is a significant challenge, and designers need to have the right tools. If you are struggling with any of factors described above, then it is probably time to re-assess your simulation tools.
By: Tom Gregory, Product Manager