Assessment of the validity of multi-domain LED model parameters in a broad current and temperature range

The paper reviews the theoretical and practical steps needed for modelling the electric, optical and thermal behaviour of LEDs. An amended combined thermal and optical measurement scheme is proposed for faster acquisition of model parameters in all domains. Physical considerations are presented which yield the equations for the electric and optical model; and also define the parameter set to be extracted for actual LED types. The valid range of parameters is specified and it is investigated how the unavoidable scatter in the parameter extraction process influences the model accuracy. Finally, novel procedures are shown for identifying the thermal properties of the external regions (board, heat sink) around the mounted device which also influence the accuracy of the packaged LED device model.