Thermal Management
Thermal management is often not taken seriously, or even considered at all. That is, until something goes wrong – performance becomes unstable, characteristics drift, or field failures occur – and it becomes painfully apparent that electronic components and systems subjected to over-temperature stress and thermal cycling are prone to failure and unreliability. A recent high-profile case is the Xbox 360 “red ring of death”, where heat-related failure has been claimed to have cost Microsoft over $1bn.
This is just one example of the way in which thermal considerations are becoming more important in many main-stream products, which have higher operating frequencies, higher component packing densities and enclosure styling constraints. The resulting challenge of higher power dissipation in smaller volumes applies at all levels, from components and modules to data centres, and thermal issues are becoming increasingly important in a very wide variety of electronic products and in most application areas. BCC Research have estimated that the $4.1 billion world market for thermal management products in 2005 will approach $6.7 billion by 2011.
Choosing the most cost-effective approach is also becoming more difficult, demanding a wide knowledge of the available options and an ability to quantify problems using simulation rather than traditional empirical methods. This situation is made even more difficult by shortened product development cycles.
For challenging military/aerospace applications, managing heat flow has been important for many years, and has led to the development of simulation software and improvements in heat management techniques. For most applications, however, the approach has been less structured and more “rule of thumb”. However, the increasing complexity and power density of modern electronics, even in consumer applications, means that the traditional approach has severe limitations. Fortunately, the techniques and simulation software developed for demanding environments have become both more competent and more readily available.
So the engineer no longer has to risk heat-induced failure, provided, of course, that the thermal management issues have been tackled early in the product design life-cycle. In order to promote awareness of the need for thermal management, the availability of solutions, and the support available from their regional network, the Electronics KTN have commissioned this web-based material that aims to give an unbiased view of the challenges and the potential solutions.
The material is in five main sections, each containing one or more PowerPoint presentations by the EKTN team, with spoken narration and embedded transcription, which were converted into a web-accessible form that you can listen to, read, search and browse. [See this link for how to get the best from the Articulate Presenter format] There are also links to a number of additional resources from external contributors that are being added to as this project progresses. As with all the pages on this site, each of the concertina sections expands to give more detail and links to further web pages.
The need for thermal management
The comment at the very top of the page about thermal management often not being taken seriously, or even considered at all, is the starting point for a series of three presentations that between them attempt to scope the size of the problem and the trends in thermal dissipation that make thermal management more important, before looking in more detail at what heat does to the circuit, and promoting a structured and early approach to thermal design, rather than ignoring the challenge.
Web page: The need for thermal management »
Dealing with the heat
This brief section gives information about the ways in which heat is generated in an electronics product, before looking at some fundamentals of heat transfer. At this stage, the topic of removing heat is dealt with at only a superficial level, and there is much more about this in the section The practicalities of cooling. However, some of the fundamentals discussed are important foundations for the central section on thermal modelling.
Web page: Dealing with the heat »
Thermal modelling
This section is very much the heart of the material, and contains a main presentation, split into four elements, supported by a number of case studies. The focus moves from the basics of thermal modelling to the way in which models of heat-generating elements can be developed, and then used first to predict the thermal characteristics of a design and then to enhance product performance without the need to “cut metal”.
Web page: Thermal modelling »
The practicalities of cooling
Whilst the principal focus of early material has been to explain the rationale for thermal management and the methodology for different modelling solutions, our focus in this section is on practical ways by which excess heat can be removed from a product. Two presentations cover passive methods, using the board and heat sinks, and the use of forced ventilation. A third presentation suggests appropriate methods of dealing with the challenges given by applications with high levels of surplus heat energy.
Web page: The practicalities of cooling »
Implementing thermal management
This final section attempts to pull together the themes of the whole material, suggesting ways in which thermal design should be tackled and the most effective option selected, and making some suggestions for best practice approaches to embed thermal management within the design and development process.
Web page: Implementing thermal management »
Where the material came from
We are very grateful to the large number of people who have contributed to this material, and have acknowledged them and given their contact details on a separate page at this link. As far as is possible within the constraints of making a coherent argument, we have also retained the company badging of many contributions. However, in some cases, particularly where we have used generic illustrations, we have been unable to discover their original source. If you come across an image or idea that that you believe belongs to you and whose use is not acknowledged, please contact us and we will correct the omission.
How to take this further
If you have thermal issues with your products, and would like to access help from within the EKTN network, contact us on thermal@electronics-ktn.com, and we'll put you in touch with the most appropriate resource within the EKTN community.
Getting involved
Although the material is now complete, this will always be a work in progress, because we continue to look for case studies or examples (good or bad) to help amplify the message and ground it in reality. So, if you have an example of good practice thermal design that you would be prepared to share in the same way as others have, or there are problems you would like to highlight, do please get in touch with us on thermal@electronics-ktn.com to share your experiences and your learning. We would also like to know if there are any areas in this set of material that you think would benefit from additional material or explanation.
