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What is the reason for the LED big screen chip circuit burning?
- Sep 15, 2018 -

What is the reason for the LED big screen chip circuit burning?



1. The power supply voltage is too large: the rated working voltage of the LED module is usually 4.5V-5V. The larger limit working voltage of the integrated chip on the module is generally not higher than 7V, and the larger reverse voltage of the LED lamp bead is also Below 7V. Therefore, the supply of 7V or more

The electrical voltage can damage the integrated chip and the LED tube. When the voltage reaches about 9V, conventional constant current/constant voltage driving chips tend to start to heat up sharply and may smoke. Normally, when the voltage is 10-11V, it will continue to be energized for about 2 seconds.

The chips will burn down to varying degrees. Since the LED large screen is powered by a constant voltage switching power supply with an output voltage of 5V, the possibility of overvoltage is not great. Even if the control circuit of the switching power supply fails, its output voltage is abnormal and reaches

The possibility of going above 9V is also very small (not to be impossible!). It is worth mentioning that some inferior switching power supplies, even high output voltage ripple can not cause the chip to burn out, it is enough to cause the chip function to fail.

2, The control signal is abnormal: full-color LED large screen appears a line of bright and bright fault phenomenon is also very common, often caused by abnormal cable contact or debugging parameters. Strictly speaking, well-designed LED large screen products should have

Avoid the protection circuit that is always bright and bright. If there is no protection circuit, after the line is bright and bright, if it is not eliminated in time, the module's row driver chip (such as 4953) may burn out due to the continuous high current operation and the temperature rises sharply.

Of course, compared with the previous products, the current full-color LED large-screen module, the drive power of the row driver chip is relatively low (below 2A), and the larger operating current of most row driver chips is around 3A. Modules appear frequently

The possibility of causing the line driver chip to burn out is relatively small. As a result, most products on the market no longer design protection circuits.

3. The positive and negative poles of the power supply are reversed: the electronic product designed according to the specification will have the "VCC" and "GND" marks (or "+" and "-") at the power terminal position, indicating the wiring positions of the positive and negative terminals respectively. . However, for operators who lack the basic knowledge of electric and electronic electronics, it is possible to reverse the positive and negative poles of the power supply due to unconsciousness. Even a qualified technician may operate incorrectly. The positive and negative poles of the power supply often cause most of the constant current/constant voltage driving chips on the module to burn.

Summary: In practical applications, most of the causes of chip smoke burning are reversed positive and negative, followed by abnormal control signals, but this situation will become less and less rare, and then there are very few power supply overvoltage conditions. Some of these faults are caused by humans. Whether it is a large LED screen manufacturer or a terminal user, it is necessary to improve the technical level of the operator in order to reduce the occurrence of full-color LED large-screen chip failure.


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