Light-emitting diode junction temperature detection device and detection method thereof
A technology of light-emitting diodes and detection devices, which is applied in the direction of measuring devices, electric devices, thermometers, etc., can solve problems such as deviations in measurement results, and achieve the effects of improving accuracy and reducing the impact of heat generation on junction temperature testing
Active Publication Date: 2014-04-30
RESEARCH INSTITUTE OF TSINGHUA UNIVERSITY IN SHENZHEN
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[0004] However, in the above method, in order to ensure the stability of the voltage measurement, a large current is usually required to flow through the light emitting diode, and the above method ignores the inevitable self-heating phenomenon when the large test current passes through the light emitting diode (internal resistance). The effect of the junction temperature of the light-emitting diode, which leads to deviations in the measurement results
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[0020] See figure 1 , it can be known from the knowledge of semiconductor physics that figure 1 The reverse saturation current I of the LED 10 in 0 The relationship between and the junction temperature T is:
[0021] (1)
[0022] In the formula, A is a coefficient related to the type, doping concentration, geometric size, and material of the PN junction of the light-emitting diode 10, n is an ideality factor, k is Boltzmann's constant, and q is an electronic charge, T is the temperature, E G (T) is the energy band width of the PN junction at temperature T, and its first-order approximation is:
[0023] (2)
[0024] In the formula, β is the temperature coefficient.
[0025] When the heating effect of the test current I on the internal resistance R of the light-emitting diode 10 is not considered, the relationship between the forward current I and the forward voltage drop V is:
[0026] (3)
[0027] considering , the above formula can be written as,
[0028] (...
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A light-emitting diode junction temperature detection device comprises a drive module, a test constant current source module, a microprocessor module, a voltage drop detection module and a data processing module, wherein the drive module is used for providing working current needed when a light-emitting diode works normally; the test constant current source module is used for providing test current I and test current I+delta I for the light-emitting diode; the microprocessor module is used for controlling the drive module and the test constant current source module to provide current for the light-emitting diode in a time-sharing mode; the voltage drop detection module is used for detecting voltage drops of the light-emitting diode when the test currents are I and I+delta I; the data processing module is used for calculating the junction temperature of the light-emitting diode according to the difference value of the voltage drops detected by the voltage drop detection module when the test currents are I and I+delta I. The invention further relates to a method for detecting the junction temperature of the light-emitting diode by the adoption of the light-emitting diode junction temperature detection device.
Description
technical field [0001] The invention relates to a light-emitting diode detection device, in particular to a light-emitting diode junction temperature detection device and a detection method thereof. Background technique [0002] Light-emitting diode (Light-emitting Diode) solid-state light source has the advantages of high efficiency and long life, and has been widely used in the field of lighting. Most of the electrical energy consumed by light-emitting diodes is converted into thermal energy, which leads to a significant increase in chip temperature. The change of PN junction temperature (hereinafter referred to as junction temperature) of light-emitting diodes directly affects the performance and service life of light-emitting diode products. Therefore, how to accurately measure the junction temperature of light-emitting diodes so as to control its temperature rise range is extremely important for improving the performance stability and service life of light-emitting dio...
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IPC IPC(8): G01K7/00
Inventor 胡益民佘露刘岩敬刚张志甜刘淮源陆兆隆曹鸣皋袁文龙肖文鹏梁荣丁钊曹广忠汤皎宁张超朱惠忠
Owner RESEARCH INSTITUTE OF TSINGHUA UNIVERSITY IN SHENZHEN