DOES A SINGLE LED BIN REALLY REPRESENT A SINGLE LED TYPE?

摘要

In a recent H2020 European wide research project (Delphi4LED, www.delphi4LED.eu) extensive study for generating multi-domain compact LED models based on measurement data was concluded. In this context combination of the latest LED testing standards and recommendations of JEDEC and CIE have been applied in testing and new models and modelling methods have been developed in order to capture the multi-domain operation of LEDs for the purpose of simulation. A valid question is: how representative a model is for a type of an LED package, how to select a nominal LED device for modelling and how to capture the inherent variation of LED operating parameters. We had specific tasks dedicated to measure and model these variations. Findings related to capturing, quantifying and modelling of the thermal features of the mechanical structure of LED packages have already been published. In this paper we report about the measured variances of the multi-domain chip level operation of LEDs and the way how to model them. During this analysis we were confronted with the issue of having various parameter distributions in a LED population purchased from the same bin. This raises the question: LEDs belonging to a given binning class really represents a single LED type if their multi-domain behaviour is different.