PCB007 Magazine

PCB-Mar2015

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March 2015 • The PCB Magazine 51 THERMAL MANAGEMENT FOR LED LIGHTING APPLICATIONS continues As a general rule, IMS selection should be based on the specific requirements and use of the intended product. For example, high per- formance, premium IMS materials are very use- ful for down-lighters and will generally provide a lower operating temperature; however, you only gain the benefit if the associated heat-sink will dissipate the heat, so the heat sink must not already be at saturation point). Also, for appli- cations that require long warranties (e.g., tun- nel lighting), or are difficult to maintain (e.g., oil/gas rigs), it may be advisable to use an IMS even when a FR-4 option is acceptable, because generally, they will provide a reliably lower op- erating temperature (as they rely less on any secondary heat-sinking). Interestingly, recently one of the major LED fabricators also suggested that LED lighting manufacturers should review the overall sys- tem cost instead of focussing solely on the cost of the LEDs. They indicated that the improved reliability of the new generation of LEDs could be utilised by operating them at higher tem- peratures (by using smaller heat sinks and/or PCBs) and still obtain an acceptable product life. So adopting this approach would also form part of the selection criteria used for material selection. Although this will no doubt be help- ful for some applications, there are also many situations where low density (and even large format) PCBs are used primarily to eliminate LED 'spotting'. Even though LED technology improvements are making them more efficient and generate less thermal issues, they still present a range of thermal challenges on materials in order to provide the reliability and longevity the market expects and demands. In summary, when selecting the best mate- rial and technology for a specific application, it should be done based on a thorough under- standing of the application, including: lumi- naire design; any heat-sinking; TIMs; whether is it potted; maintenance requirements and war- ranty issues). It is critical to be involved at the early stages of design so that the optimum PCB layout, size, material, performance and cost-ef- fective solution may be selected. PCB Feature Les round is technical sales manager at Spirit Circuits. at the 2015 EIpC winter Conference in Mu- nich in february, EIpC Chairman alun Morgan (l) praised the efforts of two people, John Ling and pete Starkey (r), by presenting both with a plaque proclaiming their honorary fellowship, which had been conferred by the EIpC in rec- ognition of their loyal support and outstanding contribution to the pCB industry over many years. John Ling has been involved with the EIpC for many years and is the erudite editor of the EIpC's Speednews, amongst other ac- tivities in support of the institute. pete Starkey is a member of the EIpC confer- ence programme committee and is the distin- guished editor of many EIpC conference and workshop reviews. he also serves as technical editor for I-Connect007 publications. Both gentlemen also provide technical sup- port to the EIpC for the many Eu funded projects initiated from Brussels. regarding receiving the award, Starkey said, "It was totally unexpected and Ling and I were both totally flattered by the ges- ture. It's been an absolute pleasure to be of service to the EIpC, and to work with such a distinguished organization." The EIpC Summer Conference will be held June 18 & 19 in Berlin. for more information, click here. EIPC Honors Starkey and Ling as Valued Industry Fellows

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