Measurement issues in LED characterization for Delphi4LED style combined electrical-optical-thermal LED modeling

Traditionally incandescent and fluorescent light sources were mostly used in a single operation point and their relevant characteristics was described by a few parameters in a datasheet. The emitted light of LED products depends on current and temperature heavily and the behavior of LEDs in actual use can be predicted only by complex models of physical roots. The paper summarizes the targets and methodology of the European Delphi4LED project aiming the elaboration of relevant measurements for identifying parameters of electrical-optical-thermal LED models. Measurement examples of high power LEDs are shown and the state-of-art of the modeling efforts is demonstrated in case studies. The two-diode Spice-like electro-thermal-optical model of LEDs is proposed to be extended with a serial resistor in the branch describing the light emission.