An Extended Design Methodology for LED Lighting Systems Including Lifetime Estimation

Lighting systems based on light-emitting diodes (LEDs) are multivariable systems that involve electrical, thermal, and photometrical subjects. In addition, the knowledge about the system lifetime enhances the design procedure and helps the designer to predict the system behavior along their useful life. This paper proposes a simple methodology to estimate the lifetime of an LED-based system. The method is based on electrothermal characteristics and provides useful guidelines to LED lighting designers. In order to validate the methodology, two LED devices were experimentally tested and the comparison with theoretical results was satisfactory. In the end, two design examples of lighting systems are presented as an application to the proposed methodology.