LED aging test solution that can monitor hundreds of channels simultaneously

The principle of LED lighting:

China's LED industry started in the 1970s. After more than 30 years of development, China's LED industry has initially formed a relatively complete industrial chain including the production of LED epitaxial wafers, the preparation of LED chips, the packaging of LED chips, and the application of LED finished products.

LED lighting is made of III-IV group compounds, such as GaAs (gallium arsenide), GaP (gallium phosphide), GaAsP (gallium arsenide phosphide) and other semiconductors, and its core is a PN junction. Therefore, it has the IN characteristics of a general PN junction, that is, forward conduction, reverse cutoff and breakdown characteristics. In addition, under certain conditions, it also has luminescence characteristics. Under forward voltage, electrons are injected from the N region into the P region, and holes are injected from the P region into the N region. A part of the minority carriers (minority carriers) that enter the other region recombine with the majority carriers (majority carriers) to emit light. Assuming that the luminescence occurs in the P region, the injected electrons directly recombine with the valence band holes to emit light, or are first captured by the luminescence center and then recombine with the holes to emit light. In addition to this luminescence recombination, some electrons are captured by the non-luminescence center (this center is between the conduction band and the intermediate band) and then recombine with the holes. The energy released each time is not large and cannot form visible light.

Market requirements for LED lighting products:

Some people call LED light sources long-life lamps, which means lights that never go out. Solid cold light sources, epoxy resin encapsulation, no loose parts in the lamp body, no filament burning, heat deposition, light decay and other shortcomings, the service life can reach 60,000 to 100,000 hours, more than 10 times longer than traditional light sources.

Therefore, to achieve this ideal state, anti-aging ability is particularly important.

1. Aging test of LED lighting products:

The long-term aging test of LED backlight and lighting products is a very important test. Through the aging test, the light decay, color temperature change, leakage and other faults that may occur in the long-term use of LED products can be discovered early, which is conducive to the stability of product performance. ITECH power supply and aging test software is mainly used for aging test of LED backlight and lighting products.

The results of the LED lighting product aging test are closely related to the equipment used. The aging equipment and LED lighting products must ensure adequate heat dissipation to determine the optimal aging time. The aging system monitors the data and performs analysis and comparison to obtain the most accurate test data, thereby achieving the purpose of production and testing.

2. Characteristics of the power supply and aging system used in LED aging test:

Since the working current of LED is very special, a professional test system is needed to obtain reliable data. In general, the power supply and aging system used in LED aging test should have the following characteristics:

1) High power ratio digital controlled DC power supply, with wide voltage and current utilization rate and wide application range;

2) It can automatically control the rate of change of voltage and current to minimize costs;

3) High precision and high resolution;

4) Low noise and ripple;

5) Minimize the volume to save space;

3. Construction of LED aging test system:

The LED aging test system is built by DC power supply and control software, as shown in the following figure:

Figure 1: LED aging test diagram of multiple IT6720 combined with IT9100 software.

Note: The power supply model used in the above figure is ITECH IT6720, and the aging control software model is ITECH IT9100

The following figure is a screenshot of the interface observed by the user during the aging test using the test system:

Figure 2: IT9100 software monitoring interface for LED aging.

In this interface, you can observe the aging of 16*32 channels of LED lighting or backlight products at the same time. There are 16 groups in total, each with up to 32 channels, and they are represented by arrays. Each square on the interface represents a channel. When the channel is configured, the square of the channel is gray. Using colors to distinguish different operating states enables users to observe any subtle changes more clearly, simply and quickly during use. Generally speaking, in order to conform to people's habits, the functions represented by different colors are as follows:

Gray: Already configured or stopped

Yellow: Communication failed

Red: An error occurred during operation

Green: Communication and operation are normal

4. Advantages of using this solution in LED aging test:

By selecting a power supply with flexible ratios and combining it with aging monitoring software that supports multiple channels, aging monitoring tests can be performed on hundreds of LEDs at the same time.

The advantages of this solution are:

1) The power supply is small and standard, and can be placed on a standard instrument cabinet. The aging system can be easily designed and placed according to the actual situation. This avoids the complicated work of customizing a special aging test system cabinet;

2) The programmable power supply used is easy to operate and has the characteristics of high precision and strong stability;

3) Intelligent fan control, low noise;

4) The aging value can be set in batches through software and the working status of each LED lighting product can be detected;

5) When the aging test bench works continuously for a long time, generally 72 hours, there is no need for on-duty personnel to be on duty;

6) Using monitoring software, data can be automatically recorded for easy analysis;

7) Reasonable price, simple construction, strong future scalability, very suitable for applications in this field.

V. Conclusion:

The characteristics of LED light emission put forward special requirements for the aging test scheme of LED lighting products. The LED aging test scheme introduced above can be widely used in the aging test of LED lighting and backlight products, and its performance is perfect. Selecting power supply and control software professionally applied to the LED industry and building the above test system can obtain the most accurate and effective data.