Compact Modelling of Electrical, Optical and Thermal Properties of Multi-Colour Power LEDs Operating on a Common PCB

Abstract

This paper concerns the problem of modelling electrical, thermal and optical properties of multi-colour power light-emitting diodes (LEDs) situated on a common PCB (Printed Circuit Board). A new form of electro-thermo-optical model of such power LEDs is proposed in the form of a subcircuit for SPICE (Simulation Program with Integrated Circuits Emphasis). With the use of this model, the currents and voltages of the considered devices, their junction temperature and selected radiometric parameters can be calculated, taking into account self-heating phenomena in each LED and mutual thermal couplings between each pair of the considered devices. The form of the formulated model is described, and a manner of parameter estimation is also proposed. The correctness and usefulness of the proposed model are verified experimentally for six power LEDs emitting light of different colours and mounted on an experimental PCB prepared by the producer of the investigated devices. Verification was performed for the investigated diodes operating alone and together. Good agreement between the results of measurements and computations was obtained. It was also proved that the main thermal and optical parameters of the investigated LEDs depend on a dominant wavelength of the emitted light.

Modelling of Transmission Lines Inside Modern Integrated Semiconductor and Test Boards

“…However, it is interesting that this frequency cannot be simply used to estimate other parameters. The determined line model cannot be directly used for higher frequencies -the variation of material properties using a multiple-pole Debye, Drude, or Lorentz medium model with polarisation current should be also introduced for this purpose (see also [46]). We have developed a dedicated tool for the generation of the distributed electromagnetic models using the set of ODEs as part of our research work (section IV).…”

Comparison of Properties for Selected Experimental Set-Ups Dedicated to Measuring Thermal Parameters of Power LEDs

“…The value of this increase depends on the power losses in the considered device, on the power dissipated in the other semiconductor devices situated on the common substrate with the tested device, and on the efficiency of generated heat removal in these devices. This efficiency is characterised by such thermal parameters as the steady state thermal resistance R th , transient thermal impedance Z th (t), and transfer transient thermal impedances Z tht (t) between the tested device and other devices thermally coupled with the tested one [7][8][9][10][11].…”

“…Paper [21] compares the results of measurements of transient thermal impedance of selected LEDs containing single semiconductor structures obtained with the use of both set-ups. However, LED light sources containing more semiconductor dies placed in a common housing [22] or on a common substrate [10,18,23] are often used. Thermal couplings characterized by mutual thermal impedances Z tht (t) occur between these dies.…”

Understanding multi-domain compact modeling of light-emitting diodes

“…Energy departments across the world recommend that a minimum set of key parameters be reported by SSL manufacturers to accurately reflect their LED product performance (Baran et al, 2020;Reporting LED luminaire product performance, 2008). There exists contemporary work on modeling LEDs in multiple domains (Alexeev et al, 2019;Górecki & Ptak, 2021Janicki et al, 2020;Pohl et al, 2020), however, the approach followed in this work is simple and easily understood.…”