Materials
Effective thermal management of electronic devices and LEDs
Jade Bridges looks at thermal management solutions to increase reliability and prolong the working life of devices.
M
ost electronic components are low power and produce negligible amounts of heat in their operation, however some devices, such as LEDs, power transistors, CPUs and power diodes
produce a significant amount of heat. Failure to effectively dissipate this heat away from the component or device can lead to reliability concerns, reduced operational lifetimes and can even cause the device to fail.
Electrolube, a division of H K Wentworth Limited,
produces a range of thermal management solutions. The optically clear silicone resin, SC3001, has been specifically designed to meet heat transfer challenges facing the LED industry. The low viscosity, two- part encapsulation compound helps to dissipate heat generated from LEDs and provides a complete barrier for components against harsh and challenging environments, including moisture, chemicals and general contamination. Silicone or non-silicone thermally conductive pastes
can be applied to displace air from a component or heat sink interface.
Higher operating temperatures
Silicone-based pastes, such as Electrolube’s HTS and HTSP, have higher operating temperatures than their non-silicone alternatives, HTC and HTCP. Heat transfer compounds fill the gap between the device and the heat sink, and reduce the thermal resistance at the boundary between the two. This leads to faster heat loss to the heat sink and a lower operating temperature for the device.
Fig. 2. SC3001 has been specifically to meet heat transfer challenges facing the LED industry.
Heat transfer compounds can be of various types. The ‘P’ versions of Electrolube’s pastes have a higher filler loading and contain a special blend of different fillers to maximise thermal conductivity. Thermally conductive pastes remain as a paste and
this makes for easier disassembling of components for recovery or repair. It may be desirable in some circumstances to use a thermal transfer material, which cures up to a solid. Electrolube’s TCR is a silicone RTV filled with a proprietary blend of mineral fillers: when applied between the heat sink and the device it cures to a rubber under the influence of atmospheric moisture. Electrolube’s TBS is a two component epoxy resin
Fig. 1. The ever-increasing miniaturisation in electronics means that heat dissipation problems are becoming significantly more important.
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which cures to a tough solid and bonds the heat sink to the component. This may be an advantage with some designs of device, but will lead to problems with
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