Development of thermal LED Model

One of the main tasks of modern lighting technology is to increase the reliability of LED technology. In order to solve this problem, it is necessary to ensure an effective cooling of LEDs, since the values of their parameters depend substantially on the temperature of a crystal. This dependence makes a significant effect on the reliability of a lamp or a luminaire. Thus, in order to increase the reliability of LED technology, it is necessary to calculate the thermal operating conditions of LEDs at the design stage, taking into account a cooling system in use. There are many programs designed to simulate thermal processes, however, such programs use primitive, substantially simplified LED models, and do not allow to recreate electrical and thermal regimes close to real ones. In order to conduct a more accurate simulation, it is required to create new electric and thermal models of LEDs, which are based on real values of the electric-physical and geometric parameters of the instruments. The article considers the thermal model of LED produced by the company SemiLEDs developed in the Multisim program. They performed the calculation of the processes taking place in the light-emitting diodes during their work in a luminaire. The obtained results indicate the possibility of the used approach application for the analysis of various LED light sources. The created models will allow to reveal unfavorable thermal operating modes for LEDs and, accordingly, to take measures to increase the reliability of fixtures.Keywords: temperature dependence of characteristics, high-power LED, current-voltage characteristic, flux-current characteristic

Sub-nanosecond Pulse Generation from a Two-section Laser-thyristor: Theoretical Analysis

We have developed a theoretical model of a two-section laser-thyristor. It is shown that using a 4 µm weakly doped p-base can increase blocking voltage up to 50 V, which makes it possible to generate 2 ns 10 A current pulses. It is demonstrated that the proposed device utilizes passive Q switching to generate high-power short optical pulses that account for up to 80% of output power. By picking the optimal passive section length, we have achieved optical pulses of ∼30 ps full width at half maximum (FWHM) and ∼100 W peak power.     Keywords: pulsed laser, semiconductor N-p-N-i-P heterostructure, laser-thyristor, dynamic model of pulsed lase