New Dynamic Photo-Electro-Thermal Modeling of Light-Emitting Diodes With Phosphor Coating as Light Converter Part I: Theory, Analysis, and Modeling

Abstract

Phosphor-coated light-emitting diode (PC-LED) is the dominant LED technology for public lighting. This paper presents a comprehensive theory for analyzing and modeling phosphor coating (PC) in white LEDs as a dynamic light converter. The new PC-LED model not only obeys the traditional diode equation but also includes the energy storage and transient effects of the PC. Major control variables include energy storage in and the luminous flux from the PC. This new model enables the dynamic variations of luminous flux and energy storage and power loss in PC to be accurately predicted. Part I of this paper provides the details of the theory and analysis leading to the new PC-LED model under the framework of the photo-electro-thermal theory. The details of the model parameter determination, model setup, and experimental verification are included in Part II. The model offers the important power loss equation of the PC which highlights the factors affecting the heat loss and the coating's blackening effects. This equation can be used by engineers to design LED drivers in order to reduce the coating temperature and the blackening effects and to prolong LED lifetime. © 2013 IEEE.