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Thermal studies of high - power LED devices

Author: HanKai
Tutor: LiuMuQing
School: Fudan University
Course: Photovoltaic systems and control technology
Keywords: LED Thermal Resistance Operating junction temperature Sampling frequency Measuring current
CLC: TN312.8
Type: Master's thesis
Year: 2011
Downloads: 193
Quote: 0
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Abstract


Nineties of the last century, a blue LED successfully produced during power LED devices is increasing, and so far have been able to meet a need in the general illumination luminous flux high power LED, however, with its accompanying single LED hair The heat increases. As semiconductor devices, LED junction temperature has an important influence its efficiency and lifetime, so the LED devices, especially in the heat principle and its thermal structure of the high-power LED devices operating junction temperature accurate measurement of thermal LED applied to the face in the lighting field vital topic. This thesis is based on the high-power LED thermal studies discuss the theory of electrical measurement method involves measuring the LED thermal performance in a variety of basic questions, the article did major work as follows: 1, the paper through a semiconductor device The theoretical K-factor with the variation of measuring the current change, and validated using Keithley S2400-based measurement platform experiment. 2, used in this paper Keithley S2400-based measurement platform, using different sampling frequency and measure the current with a LED under the same cooling conditions, the junction temperature measurement, comparison, system analysis to measure current, the sampling frequency of the LED junction temperature measurement results RC network model with the analysis of the process of establishing the theory as well as the LED system explains why the LED junction temperature in the low sampling frequency will be underestimated Finally, based on these theories put forward an operating current as a measurement of the junction temperature of the measuring current method, and the junction temperature of a low sampling frequency measurement error compensation method. 3, the paper-based JESD51-1 electrical measurement method proposed to build a set NI 5922 data acquisition card as the core thermal measurement platform, research and actual measurement of non-ideal factors established in LABVIEW sets of data processing algorithms to these non-ideal factors are excluded from the measurement results, and finally through before repeating the S2400 platform on the sampling frequency, and measuring the current experiments, quantitative discussion of its impact on the LED junction temperature measurement of work to verify the results before , and also to some extent verify the accuracy of the new platform measurements. 4 In this paper, the RC network model analysis of the LED junction temperature measurement in the heating and cooling process, through the experimental measurement of LED current step voltage response, qualitative analysis of the relationship of the the LED heating curve and package structure, and in accordance with RC network The fitting model on the measurement results from the quantitative extraction of the heating curve of the LED showing the thermal resistance of the heat capacity parameters of the measured LED system, successfully obtained the same ETM actual measurement value, the actual physical model and its calculated value match.

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CLC: > Industrial Technology > Radio electronics, telecommunications technology > Semiconductor technology > Semiconductor diode > Diodes: structure and performance > Light-emitting diodes
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