Thermal Management
HOW TO MAKE HOT TECH COOL
Buyers are working more closely with engineers than ever before as engineers, procurement and suppliers collaborate to find the best possible options. As a result, buyers need a basic understanding of components’ functions to achieve an understanding of how a particular class of devices fits into the picture. Here, we discuss the basics of thermal management, some solutions that engineers commonly use, and why.
Thermal management is the practice
of managing heat buildup in electronics, and is critical to maintaining the proper operation of systems. Electronics components can generate more heat than appears possible in those tiny black packages; enough literally to burn your finger. Not only can they burn you, but they can burn themselves up, damage other components around them and even generate smoke. Too much heat can lead to total failure, plain poor performance, or erratic and unpredictable performance.
It’s difficult to imagine
The Wakefield 882 series radial fin heat sink for star type LED packages
26 July/August 2014
exactly how much heat electronic components can produce. To get a feel for how hot it can get, we used a Fluke TI‐400 to take images of several items for comparison. The included Fluke software package allows you to mouse over areas in the image and see the variation in temperatures from when they were recorded or captured by the Fluke. Figure 1 shows the heat image of a server computer’s power case.
If operating above maximum specified
temperatures, electronics can perform poorly or fail altogether. It is also possible for a device to get somewhat damaged by excess heat, yet continue to operate, although it will no longer operate in the same way. It might become slower or performance will somehow be compromised. However, there are several ways to keep hot electronics from getting too hot. One is to buy products that are rated for high temperatures, but these come at a premium. Another is to cool the devices by
external means. Two main
components commonly used in thermal management are fans and heat
Overheating components can cause many different problems. Lynnette Reese of Mouser Electronics summarizes ways of keeping system temperatures under control
The Fluke TI-400 thermal imaging camera
sinks. Let’s cover
fans first. Active devices with
moving parts like fans and blowers can be used to maintain safe operating temperatures. Moving parts consume energy, so a temperature sensor can be used to determine when to turn the fan on and when to turn it off. Ebm‐papst is a well‐known fan manufacturer with many options for low noise, power‐ efficient fans.
Besides using a fan to remove excess
heat, there are additional devices that can remove heat build‐up, such as heat sinks. A heat sink has no moving parts. It is a heat‐conducting element, usually a base (like a trivet under a hot plate) that absorbs heat and disperses it over the whole area of the heat sink so it is not concentrated in one area. Typical heat sinks are fairly inexpensive, easy to use and very common, but they also add weight and bulk. It is important to note that too much heat on an integrated circuit, even in a small area of the chip (called a “hot spot”), can cause permanent damage. Heat sinks are excellent at dispersing hot spots and do not consume energy. Many ICs are designed to run hot and designers may integrate a heat sink into the IC
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