Why Must the Power Supply of the LED Display be Grounded?

Publisher: Supplier of LED Display Time: 2022-03-18 16:04 Views: 735

The main components of the LED display are LEDs and driver chips, which belong to a collection of microelectronic products. The operating voltage of the LED is about 5V, and the general operating current is below 20 mA. Its working characteristics determine that it is very vulnerable to static electricity and abnormal voltage or current shocks. This requires us to recognize this and pay enough attention to it in the process of production and use, and take measures to protect the LED display. The power grounding is the most commonly used protection method for LED displays.


Why is the power supply grounded? This is related to the working mode of the switching power supply. Our LED display switching power supply is a kind of conversion of AC (AC) 220V mains into DC (DC) 5V DC through a series of means such as filtering - rectification - pulse modulation - output rectification - filtering A device with stable power output.



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In order to ensure the stability of the AC/DC conversion of the power supply, the power supply manufacturer connects an EMI filter circuit from the live wire to the ground wire in the circuit design of the AC220V input terminal according to the national 3C mandatory standard. In order to ensure the stability of the AC220V input, all power supplies will have filter leakage during operation, and the leakage current of a single power supply is about 3.5mA. The leakage voltage is about 110V. When the display screen is not grounded, the leakage current may not only cause chip damage or lamp burnout. If more than 20 power supplies are used, the accumulated leakage current reaches more than 70mA.


It is enough to cause the leakage protector to act and cut off the power supply. This is also the reason why we cannot use leakage protectors for our display screens. If the leakage protection is not connected and the display screen is not grounded, the leakage current superimposed by the power supply will exceed the safety current of the human body, and the voltage of 110V is enough to cause death! After grounding, the voltage of the power supply shell is close to 0 to the human body. It shows that there is no potential difference between the power supply and the human body, and the leakage current is led to the ground. So the LED display must be grounded.