Method for measuring relation curve of forward voltage and junction temperature of LED (Light Emitting Diode) in lamp

A technology of forward voltage and relationship curve, which is applied in the direction of lamp test and single semiconductor device test, etc., can solve the problem of inability to measure the junction temperature of PN junction, etc., and achieve junction temperature and thermal resistance that are convenient for actual work, easy to use, and high measurement accuracy Effect

Active Publication Date: 2011-09-21
SHANGHAI ALPHA LIGHTING EQUIP TESTING +3
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Problems solved by technology

However, after the LED is installed in the lamp, it is impossible to measure its PN j

Method used

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  • Method for measuring relation curve of forward voltage and junction temperature of LED (Light Emitting Diode) in lamp
  • Method for measuring relation curve of forward voltage and junction temperature of LED (Light Emitting Diode) in lamp
  • Method for measuring relation curve of forward voltage and junction temperature of LED (Light Emitting Diode) in lamp

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Embodiment Construction

[0014] The LED matrix in the luminaire using LED (see Figure 1a ) in a certain series LED group in the middle, a tested LED at or close to the middle part, that is, the two connecting wires of LED-2 in the figure are cut off, and are connected through three 2-knife 2-throw switching relays to form a Figure 1b , so that the LED under test is connected to the disconnected part or the constant current source of the above-mentioned series LED group through the three 2-knife and 2-throw switching relays, and the working position is when the tested LED is connected to the disconnected part of the above-mentioned series LED group , When the LED under test is connected to the constant current source, it is the measurement position. First, adjust the three 2-knife, 2-throw switching relays to the measurement position. At the heat sink of the LED (the LED comes with a small heat sink), stick a thermoelectric cube and connect the thermoelectric cube to the thermometer. Figure 1b Among...

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Abstract

The invention discloses a method for measuring a relation curve of a forward voltage and a junction temperature of an LED (Light Emitting Diode) in a lamp. In the invention, the method comprises the steps of obtaining a dropping amount of the forward voltage under a set measuring current within a unit measuring time; correcting the forward voltage drop of the measured LED by using the dropping amount of the forward voltage drop within the unit measuring time and an actual measuring time so as to improve the measuring accuracies of the forward voltage drop and the corresponding junction temperature of the measured LED; and measuring the forward voltage drop of the measured LED and figuring out the forward voltage drop of the measured LED at the moment of disconnecting the working current when the continuous working temperature of the LED lamp reaches heat balance. By using the method disclosed by the invention, the situation that the junction temperature of the measured LED obviously biases from a correct value due to the disconnection of the working current of the measured LED and fast dropping of the junction temperature of the LED can be effectively eliminated. The method disclosed by the invention has the advantages of convenience in use and high measuring accuracy; and the difficulty that the actual working junction temperature and the heat resistance of the LED in the traditional lamp cannot be accurately measured is solved.

Description

technical field [0001] The utility model relates to the field of lighting lamps, in particular to a method for measuring the relationship curve between LED forward voltage and junction temperature in a lamp. Background technique [0002] When LEDs are applied to lighting fixtures, because the service life of LEDs is generally very long, about tens of thousands of hours, it often takes more than 300 days to measure the light attenuation and life of lighting fixtures using LEDs according to the LM80 requirements of the US DOE. (6000h), but if you can accurately measure the two quantitative indicators of the PN junction temperature of the LED in the lamp and the thermal resistance from the PN junction to a specified point of the radiator, it will not only be able to measure the pros and cons of the heat dissipation characteristics of the lamp using the LED , can also qualitatively know the service life of various similar lamps using LEDs. In addition, it can also know under wha...

Claims

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Application Information

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IPC IPC(8): G01R31/26G01R31/44
Inventor 刘尔立杨樾施晓红汪钢黄习德俞安琪强耀根陈大国
Owner SHANGHAI ALPHA LIGHTING EQUIP TESTING
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