Affect the configuration of the power LED integrating sphere test system tests

As we are familiar with laptop backlight, is a combination of a number of LED lamp beads , the color problem has become increasingly evident . If the LED is not using the same batch of beads , then easily lead to different wavelengths , color and so on, even though this problem is to use the same batch of LED lamp beads are inevitable. For the LED chip test , commonly used test systems integrating sphere .

Using an integrating sphere to measure parameters such as flux , make measurements more reliable. And removing the integrating sphere can reduce the error caused by the shape of the light diverging angle caused by the difference . This high -precision and careful measurements, but also to promote the LED manufacturer integrating sphere increasingly tend to choose higher-performance power configuration in the system used to power the LED under test .

LED test systems integrating sphere

LED sphere mainly to measure the luminous efficiency of LED lights , LED light source characterization parameters of performance indicators , such as color and color . In a large daily volume production line testing , always faced with two questions: First, how to improve the efficiency of the second test is a measure of how to better protect the test LED.

It is understood in the power industry , light from the LED to turn on the power supply to the control system software acquisition value back to a stable voltage and current , the total time is about 600ms, and that on the basis of whether there is a possibility to break it ? The answer is yes. So by what method to achieve it ? In fact, the system is configured to be tested for LED power supply plays an important role in it .

A Configuration Professional Power inhibit overshoot and improve test efficiency

General power in the boot moment , due to the presence of the loop response time, the power output of the output voltage reaches the set value is not to stop output. Therefore, in this time, the voltage overshoot . Excessive overshoot voltage LED life will have an impact , even serious breakdown LED.

For typically between tens to hundreds of milliamps low-power LED lights , constant operating current. When a small current , and a current and a voltage drop corresponding to climb speed , sometimes LED lighting time , even more than the normal power to the LED from the control system software to collect current values ​​back to a stable voltage but also the time required to add longer .

The face of the above two questions , if in order to speed up the climb speed , improve test efficiency improvement measures to improve the speed of the loop , it is usually more serious overshoot . However, if the overshoot in order to take care of the problem, the overall test efficiency will drop. Such problems can be configured to professional test LED power to achieve, such as the power supply will be able to ITECH IT6874A this problem solved. The following two figures are IT6874A DC power supply to 80V/20mA and 80V/400mA the LED supply voltage rising phase waveforms .

Seen from the figure ITECH IT6874A DC power supply, basically within the 100ms time while satisfying high speed and without overshoot test requirements , and general power requires about 600ms time ITECH IT6874A DC power supply will this figure increased nearly six -fold , to test the efficiency improvement has great significance.

A Configuration professional power test system allows integrating sphere collected more stable value

When tested using an integrating sphere , the stability of the power supply system is also very important. Stability is mainly reflected in:

Error range ( 1 ) power supply

When integrating sphere test, if the use of higher power accuracy , measuring more data when the batch testing tends to the true value , the deviation between the measured LED tends accurate. For example , for testing LED lamps , so the assumption of power back to reading the tolerance range is 20mV, while simultaneously measuring two LED lights ( theoretical indicators are rated 350mA) when , # 1-LED measured values ​​might as 330mA, # 2 -LED measured values ​​might as 370mA. Assuming that the true value of the two LED lights are 352mA, 330mA and 370mA is visible far from the true value of value and performance also led two LED lights large deviations . And if using a higher accuracy power supply voltage readback assumed error range allowed for the value of 10mV power test , the test is likely to be the same for the two LED light value between 342mV and 362mV, the closer the value consistency of performance deviation can compare a true reflection of the individual LED lights and a plurality of LED between .

The power supply voltage ITECH IT6874A series accuracy up to five ten , current accuracy of up to one-thousandth of such high precision can bring more accurate test results to the test .

Stability ( 2 ) the value of the acquisition

What is the stability of the acquisition value mean? Let's take an example. For example, the power can be lit LED lights ( LED lights tested parameters for 80V/20mA) within 400mS time , this time integrating sphere test system software to capture the voltage value is 80.099V. LED lights when closed and opened again , it is possible to read the value of the software is 82.152V. So simply using an oscilloscope , we can see the waveform rise to the rated current and voltage values, but does not guarantee the value of the software is also collected to reach a stable range. This will in LED production testing, due to the unstable power value , resulting in test performance index of LED lights . Under normal circumstances , the software developers will delay the project to 500-600ms, in order to ensure numerical stability during sequential read operation. Therefore , the time required for integrating sphere test is about 600ms, instead of oscilloscope measurements to 400ms.

The ITECH IT6874A DC power supply, LED lights from the lighting to ensure the stability of time to read the voltage and current values ​​is less than 150ms.

Thus, the test configuration professional LED power supply for LED test systems integrating sphere has important significance. ITECH IT6874A DC power supply applications broke the defects in the general sphere LED test system, capable of inhibiting the perfect moment to start overshoot , and greatly improve the efficiency of the test ....
[http://www.dealightstore.com/led-lights.html:title=
led strip light] led tape flexible led strip led strips