Characterization of Junction Temperature of GaN Blue LED with Optimum Spectral Bandwidth

2015 ◽  
Vol 35 (1) ◽  
pp. 0130002 ◽  
Author(s):  
饶丰 Rao Feng ◽  
朱锡芳 Zhu Xifang ◽  
徐安成 Xu Ancheng ◽  
褚静 Chu Jing ◽  
张燕 Zhang Yan
Keyword(s):  
Junction Temperature ◽  
Spectral Bandwidth ◽  
Blue Led

Operating Temperature Analysis of LED with Cylindrical Cu Slug

2014 ◽  
Vol 487 ◽  
pp. 145-148 ◽  
Author(s):  
Rajendaran Vairavan ◽  
Zaliman Sauli ◽  
Vithyacharan Retnasamy
Keyword(s):  
Natural Convection ◽  
Operating Temperature ◽  
Simulation Method ◽  
Input Power ◽  
Junction Temperature ◽  
Temperature Analysis ◽  
Light Emitting ◽  
New Era ◽  
Lighting Systems

High power light emitting diodes is the new era of lighting due to momentous supremacy in terms of lighting efficacy over traditional lighting systems. The reliability of LED is dependent on its junction temperature. This study confers on the thermal and stress characterization of LED chip with copper cylindrical heat slug through simulation method. The simulation characterization was carried out with Ansys version 11 at ambient temperature of 25°C under natural convection condition. The LED package was powered with input powers of 0.1 W, 0.5 W and 1W .Results indicated that input power influences the junction temperature and stress of LED chip.

scholarly journals In-Place Characterization of On-State Voltage for SiC MOSFETs: Controlled Shoot-Through vs. Film Heater

Electronics ◽  
2021 ◽  
Vol 10 (22) ◽  
pp. 2745
Author(s):  
Alessandro Soldati ◽  
Matteo Dalboni ◽  
Roberto Menozzi ◽  
Carlo Concari
Keyword(s):  
Junction Temperature ◽  
Controlled Environment ◽  
Temperature Sensitive ◽  
Polyimide Films ◽  
Temperature Estimation ◽  
Electric Parameter ◽  
Conventional Procedure ◽  
Thermal Chamber ◽  
Characterization Procedure

The on-state voltage of MOSFETs is a convenient and powerful temperature-sensitive electric parameter (TSEP) to determine the junction temperature, thus enabling device monitoring, protection, diagnostics and prognostics. The main hurdle in the use of the on-state voltage as a TSEP is the per-device characterization procedure, to be carried out in a controlled environment, with high costs. In this paper, we compare two novel techniques for MOSFET junction temperature estimation: controlled shoot-through and direct heating by resistive heaters embedded in two Kapton (polyimide) films. Both allow in-place characterization of the TSEP curve with the device mounted in its final circuit and assembly, including the working heat sink. The two methods are also validated against the conventional procedure in a thermal chamber.

A non-contact method for determining the junction temperature of GaN-based blue light LED

2017 ◽  
Vol 31 (19-21) ◽  
pp. 1740023
Author(s):  
Guo Jie ◽  
Junshan Ma ◽  
Rao Feng
Keyword(s):  
Comparative Analysis ◽  
Standard Deviation ◽  
Blue Light ◽  
Junction Temperature ◽  
Contact Method ◽  
Forward Voltage ◽  
Spectral Parameters ◽  
Blue Led ◽  
Novel Method

A novel method to determine the junction temperature of GaN type blue light LED based on the spectral parameters is proposed. In this method, the relationships among LED junction temperature, centroid wavelength and FWHM are obtained in the lab, and then the junction temperature of operating LED of the same type can be derived from this relationship. A comparative analysis of the junction temperatures which are measured with the centroid wavelength-FWHM method and with the forward voltage method is performed. The standard deviation between these two methods is found to be about 2.3[Formula: see text]C. Therefore, the combination of centroid wavelength and FWHM can be used to determine the junction temperature of GaN-based blue LED.

Characterization of Short PM Raman Fiber Lasers with a Small Spectral Bandwidth

2011 ◽  
Author(s):  
Rainer Engelbrecht ◽  
Alexander Siekiera ◽  
Ralf Bauer ◽  
Ramona Neumann ◽  
Bernhard Schmauss
Keyword(s):  
Fiber Lasers ◽  
Spectral Bandwidth

scholarly journals Investigation of the Electroluminescence Mechanism of GaN-Based Blue and Green Light-Emitting Diodes with Junction Temperature Range of 120–373 K

2020 ◽  
Vol 10 (2) ◽  
pp. 444 ◽  
Author(s):  
Sai Pan ◽  
Chenhong Sun ◽  
Yugang Zhou ◽  
Wei Chen ◽  
Rong Zhang ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Radiation Power ◽  
Emission Peak ◽  
Junction Temperature ◽  
Dynamic Resistance ◽  
Electron Blocking Layer ◽  
Light Emitting ◽  
Blue Led ◽  
Peak Energy ◽  
Green Led

Junction temperature (Tj) and current have important effects on light-emitting diode (LED) properties. Therefore, the electroluminescence (EL) spectra of blue and green LEDs were investigated in a Tj range of 120–373 K and in a current range of 80–240 mA based on accurate real-time measurements of Tj using an LED with a built-in sensor unit. Two maxima of the emission peak energy with changing Tj were observed for the green LED, while the blue LED showed one maximum. This was explained by the transition between the donor-bound excitons (DX) and free excitons A (FXA) in the green LED. At low temperatures, the emission peak energy, full width at half maximum (FWHM), and radiation power of the green LED increase rapidly with increasing current, while those of the blue LED increase slightly. This is because when the strong spatial potential fluctuation and low exciton mobility in the green LED is exhibited, with the current increasing, more bonded excitons are found in different potential valleys. With a shallower potential valley and higher exciton mobility, excitons are mostly bound around the potential minima. The higher threshold voltage of the LEDs at low temperatures may be due to the combined effects of the band gap, dynamic resistance, piezoelectric polarization, and electron-blocking layer (EBL).

Growth and characterization of InGaN blue LED structure on Si(111) by MOCVD

2005 ◽  
Vol 285 (3) ◽  
pp. 312-317 ◽  
Author(s):  
Chunlan Mo ◽  
Wenqing Fang ◽  
Yong Pu ◽  
Hechu Liu ◽  
Fengyi Jiang
Keyword(s):  
Blue Led

Experimental and Computational Characterization of a Heat Sink Tester

2007 ◽  
Author(s):  
Aalok Trivedi ◽  
Nikhil Lakhkar ◽  
Madhusudhan Iyengar ◽  
Michael Ellsworth ◽  
Roger Schmidt ◽  
...  
Keyword(s):  
Heat Sink ◽  
Accurate Determination ◽  
Thermal Characterization ◽  
High Heat ◽  
Heat Fluxes ◽  
Thermal Design ◽  
Heat Sinks ◽  
Junction Temperature ◽  
Air Cooling

With the continuing industry trends towards smaller, faster and higher power devices, thermal management continues to be extremely important in the development of electronics. In this era of high heat fluxes, air cooling still remains the primary cooling solution in desktops mainly due to its cost. The primary goal of a good thermal design is to ensure that the chip can function at its rated frequency or speed while maintaining the junction temperature within the specified limit. The first and foremost step in measurement of thermal resistance and hence thermal characterization is accurate determination of junction temperature. Use of heat sinks as a thermal solution is well documented in the literature. Previously, the liquid cooled cold plate tester was studied using a different approach and it was concluded that the uncertainty in heat transfer coefficient was within 8% with errors in appropriate parameters, this result was supported by detailed uncertainty analysis based on Monte-Carlo simulations. However, in that study the tester was tested computationally. In this paper, testing and characterization of a heat sink tester is presented. Heat sinks were tested according to JEDEC JESD 16.1 standard for forced convection. It was observed that the error between computational and experimental values of thermal resistances was 10% for the cases considered.

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