Why does the power supply of the LED display screen advertising need to be grounded? This is related to the working mode of switching power supply. The switching power supply for LED video display screen is a kind of device that can convert AC 220V into DC 5V DC power supply by a series of means such as filtering-rectifying-pulse modulation-output rectifying-filtering.
In order to ensure the stability of AC/DC conversion of power supply, according to the national 3C mandatory standard, the power supply manufacturer connects an EMI filter circuit from the firing line to the ground line in the circuit design of AC220V input terminal. In order to ensure the stability of AC220V input, so all power sources will have filter leakage, the leakage current of a single power source is about 3.5mA. The leakage voltage is about 110V. If the power supply of the LED display screen is not grounded, what will happen? Below is for your analysis and analysis.
First, the LED display screen is not grounded, leakage current may not only cause chip damage or lamp burnout. If more than 20 power sources are used, the accumulated leakage current can reach more than 70 mA, which is enough to damage the leakage protector and cut off the power supply. This is also why the LED display can not use leakage protector.
Secondly, if there is no leakage protection and the LED screen is not grounded, the leakage current superimposed by the power supply will exceed the safe current of the human body, and the voltage of 110V is enough to cause death. After grounding, the shell voltage of the power supply is close to 0, indicating that there is no potential difference between the power supply and the human body, and the leakage current is directed to the earth.
Summary: LED video display is the main component of LED and driver chip, which belongs to the aggregation of microelectronic products. The working voltage of LED is about 5V, and the general working current is less than 20mA. The working characteristics of LED display determine that its resistance to static electricity and abnormal voltage or current shocks is very fragile. In the process of production and use, we should recognize this point and pay enough attention to it, take measures to protect the LED display screen, and power grounding is the most commonly used protection method for the LED display screen. In order to use the product safely, the power supply of LED display must be grounded.