The LED junction temperature control in a certain range is to ensure that the service life of the lamp and luminous efficiency of LED key. This paper discusses the LED junction temperature measuring method is presented, reishi dab6d23ck through the single-chip microcomputer real-time measurement of LED light source junction temperature, the temperature exceeds the set value generated PWM signal to adjust the power output power. In this paper by using LM3404 and PIC12F675 composition based on node temperature protection power supply schematic diagram and program block diagram. Experiments show that, based on node temperature protection for the LED drive, can make the LED lamp reliability effectively improve.
With LED epitaxial materials, chip technology and packaging technology progress, the luminous efficiency of LED continues to increase, which makes the LED light source to replace the traditional light source become possible. In theory, LED has the advantages of long service life, high efficiency advantages, but in some practical applications but it leaves a large decline, DVD to PSP the short life of the impression, which greatly affected the popularization and promotion of semiconductor lighting. Investigate its reason, mainly is the LED driving power supply problems.
LED long life, high efficiency is a premise, namely appropriate working conditions. The influence of the service life and the luminous efficiency is the main factor of LED operating junction temperature. From the mainstream LED manufacturers to provide test data show that, the luminous efficiency of LED and junction temperature almost inversely, life with the junction temperature rise almost exponentially decreasing. Therefore, the junction temperature control in a certain range is to ensure that the LED service life and the luminous efficiency of the key. The junction temperature control in a certain range by means of removing cooling measures, Android TV remote the junction temperature into electric power control parameter is very necessary.
1LED junction temperature detection
LED junction temperature is a PN junction temperature, actual measurement of LED junction temperature is more difficult, but can be based on LED temperature characteristics of indirect measurement.