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34 The PCB Design Magazine • October 2014 According to a June 2012 report from the Climate Group, many commercially available, outdoor light-emitting diode (LED) products offer high-quality light, durability, and signifi- cant electricity savings in the range of 50–70%. More European cities are adopting LED street- lights because LEDs can save energy costs, while exceeding local lighting standards. They last 50,000 to 100,000 hours, change little in col- or, and have a failure rate of around 1%, com- pared, for example, to up to 10% for ceramic metal halide fixtures over a similar time period. LED streetlights are a gateway technology— when LED designers solve the current problems of reducing cost and thermal challenges, they'll be paving the way for wider adoption and the energy-saving potential of LEDs. Thermal management is one of the more complex areas of LED system design. And until a few years ago, the methods and technology to scientifically characterize the thermal behavior of the component, as well as its systems and subsystems, were not available. Instead, most engineers calculate their thermal needs from data sheets published by component manufac- turers. Understandably, having data available to engineers on the specific thermal mechan- ics of LED-based devices within the system in which they are being used could be a huge step forward for future lighting designs. This article describes a method that com- bines hardware measurement (a thermal tran- sient tester), and computational fluid dynamics (CFD) software to provide high measurement throughput, which enables systems integrators to verify a vendor's thermal resistance data dur- ing design and to test incoming commercial off-the-shelf parts before they are introduced into production. This data can be used during the design and product development phase to accurately capture the thermal response of an LED lighting system. Thermal Characterization of LEDs: Enabling the Upcoming Lighting Revolution article by Dr. John Parry MEnTOr GraPHICS