Solution to the heat dissipation problem of high-power LED tube
Whether the high-power LED tube can work normally, the quality of the lamp beads is directly related to the heat dissipation of the high-power LED tube. Now the heat dissipation of the high-power LED tube is natural heat dissipation. The effect is not ideal. High-power LED The lamp bead is composed of LED; heat dissipation structure; driver; lens. The heat dissipation part is a very important part. The quality of heat dissipation directly affects the service life and conditions of high-power LED tubes.
1. Regarding metal heat dissipation substrates, currently there are aluminum substrates and copper substrates. As a professional manufacturer of metal substrates, it is recommended that you use cost-effective aluminum substrates. The price of copper substrate and aluminum substrate are quite different. Copper substrate is better than aluminum in terms of thermal conductivity, but the cost and weight are much higher than aluminum. Aluminum substrate is recommended. Furthermore, some manufacturers of high-power LED lamp beads add a temperature control switch to the high-power LED lamps and set the temperature value, and when the temperature here is higher than this value, the current is reduced. The disadvantage is that the light will be darker, but the effect is not big, so this method is still feasible
Temperature protection is a must. The product is not only required but also responsible for the customer. How much temperature protection is appropriate? Calculate it. The maximum ambient temperature is 40°C in summer, 50°C in summer light exposure, and 50°C ambient temperature is practical. Refer to the general high-power LED lamp bead specifications. The junction temperature is acceptable at 120°C. The thermal resistance from the chip to the aluminum substrate, The specification generally recommends 10-15℃, and the LED substrate should be guaranteed to be at 120-15=105℃. Good, the retained temperature difference is taken as the intermediate value of 50-105°C, 77.5°C. Generally, the operating temperature of electronic components is reliable at 85°C, and 77°C is in line with this principle. It is recommended to start the protection at 77°C, reduce the current drastically before 85°C, and complete the product temperature protection function at 90°C.
A question worth remembering: why not control a smaller current before the temperature rises? In this way, the user will not feel discomfort, and the temperature will not rise very quickly, or even reach an excessively high temperature.
I think it is unrealistic to reduce the current to reduce heat generation without reducing the brightness. In this way, there is a combination of 1W and 3W high-power LED lamp beads. That is, when the high-power temperature rises to a certain high, the high-power is reduced from 3W to 1W so that the temperature will not continue to rise, which effectively controls the temperature problem of the high-power LED lamp beads.
In general: 1. Improve its luminous efficiency. Now the high-power LED lamp beads have reached 50-70LM/W, and the development direction will reach 140lm/W or even higher. It is conceivable that this will fundamentally improve the heat problem.
2. Strengthen heat dissipation. This is an effective solution under the current circumstances.
I use an LED lamp bead for bedside lighting. But it is not a high-power type. It is made of white LED lamp beads by itself. At first, the current is too large, and the lamp is always burnt. The effect of adding heat dissipation holes is not very satisfactory. After calculation, it is found that the current reaches 56mA (divided into two channels, each of which is about 28mA). Later, the current was recalculated, the components were changed, and the current was controlled to about 15mA, which greatly improved the heat. Of course the brightness is also different.
The solution I have seen is for high-power street lamps, mainly using aluminum substrates. Copper substrates are less economical, but copper heat pipes can be added.
There is also a fan. Although the life of the fan is a little bit worse, it is more cost-effective than changing the LED lamp beads. There are two fans with temperature protection. After the temperature is over, the two fans are gradually turned on, and then it can be overheated at the same time Turning off part of the LED lamp beads to reduce the total power is actually similar to the effect of reducing the current.
The so-called high-power LED lamp beads are only relative to the previous LED lamp beads, the actual power is not very large, generally only 1~2W. Most of them are superimposed on chips. Now many companies are launching this kind of LED lamp beads. You only need to search for LED lamp beads on the website of Electronic Engineering Album, and you will find that most of the newly launched LEDs are high-power LEDs. Lamp beads.
When the current of the LED is less than 150mA, it is a low-power LED lamp (also called LED). When the current flowing through the LED is greater than 150mA, it is called a high-power LED (HBLED) lamp.
You can also consider the heat conduction of the heat pipe. There are liquid single-phase and liquid/gas two-phase. If the power is large, this must be used. CPU cooling is now in use. LED heat dissipation is occasionally used by someone.
