As the application of LED display screens becomes more and more widespread, the electrical parameters of LED display screens are increasingly valued and concerned by consumers. Everyone knows that LED display screens are made up of LED modules one by one, and the back of the screen is connected to the LED power supply, and then the power cord and signal line are connected.
So how to calculate the number of power supplies for LED display screens?
LED display screen modules are processed and produced by combining raw materials such as LED lamp beads, PCB circuit boards, ICs, and kits. The working principle of LED display screen modules is that constant current IC drives the light-emitting chip in the LED lamp beads to display colors.
In terms of display color, LED display screen modules are divided into three types: single color, two-color, and full color. In terms of application range, LED modules are divided into indoor modules and outdoor modules.
Generally speaking, the current of full-color LED modules is large, the current of single-color and two-color LED modules is relatively small, the current of outdoor LED modules is large, and the current of indoor LED modules is relatively small. However, when the factory is debugging the “white balance” of the LED module, the working current of a conventional single LED display screen module is generally below 10A.
First, we need to measure the current of a single LED module.
We can use a multimeter to connect to the circuit to measure the actual current parameters of the LED module. Today, we will take the P10-4S outdoor LED display module as an example to explain how to measure the module current parameters step by step.
Step 1, prepare equipment and items
We prepare several P10-4S outdoor LED display modules, a multimeter (can measure DC current within 10A), several wires, electrical tape, wire strippers, LED display control card, LED display power supply.
Step 2, connect correctly
In this measurement experiment, we use the multimeter as a DC ammeter. The maximum range of the multimeter to measure DC current is 10A. We connect the multimeter in series to the circuit of the LED module.
The specific wiring sequence is:
1. Connect AC 220V to the input end of the LED power supply (equivalent to the role of a transformer, transforming 220V AC into 5V DC)
2. Connect a wire from the positive pole of the output end to the red wire pen (positive pole) of the multimeter
3. Plug the red wire into the red “10A” hole on the multimeter
4. Connect the black wire pen to the red wire (positive pole) of the module power cord
5. Plug the module power cord into the module normally
6. Connect the black wire (negative pole) of the module power cord back to the negative pole of the output end of the LED power supply.
Step 3, measure the reading
We can see that when the input power socket is plugged in and the entire LED display is lit, the current of a single module is not very large. As the playback content changes, the reading on the multimeter also fluctuates, basically maintaining at 1-2A.
We press the test button on the control card to switch the screen state and get the following experimental data:
a. The current is the largest when “all white”, about 5.8A
b. The current is 3.3A in red and green states
c. The current is 2.0A in blue state
d. When switching back to normal program content, the current fluctuates between 1-2A.
Step 4, calculation
Now we can calculate how many LED modules an LED power supply can carry based on the above measurement results. The specific calculation method is: Each LED power supply is essentially a transformer. Taking our commonly used 200W switching power supply as an example, the manufacturer gives the load parameters as “output 5V40A” and “effective conversion rate 88%”.
The effective power provided by the LED switching power supply: P=88% x 200W=176W. According to the formula: P=UI, the maximum power consumption of a single LED module can be obtained: P1=UI=5V x 5.8A=29W. From this, the number of modules that a single LED switching power supply can carry can be calculated: n=P/P1=176W/29W≈6.069
Based on the above calculation, we know that when the number of LED modules carried does not exceed 6, the LED power supply is not overloaded.
The current we calculated is the maximum current when the LED module is “all white”, and the working current during normal playback is often only 1/3-1/2 of the maximum current. Therefore, the number of loads calculated according to the maximum current is the safe load number. Then how many LED modules are spliced together to form a whole large LED display screen, and then divided by this safe load number, we can get how many LED power supplies are used in a LED display screen.
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Post time: Jul-20-2024