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P2.5 LED display brightness control method
P2.5 LED display has two methods to control the brightness: one is to change the current flowing through the LED display, the general LED display tube allows a continuous working current of about 20 mA, except that the single red LED display has saturation The brightness of other LED displays is basically proportional to the current flowing through;
P2.5 LED display screen Another method is to use the visual inertia of the human eye, using pulse width modulation method to achieve gray control, that is, periodically change the light pulse width (ie, duty cycle), as long as the repeated light The period is short enough (ie, the refresh rate is high enough) that the human eye cannot feel the jitter of the luminescent pixel. Since pulse width modulation is more suitable for digital control, today, microcomputers are generally used to provide LED display content. Almost all LED display screens use pulse width modulation to control gray levels.
P2.5 LED display control system usually consists of three main parts: main control box, scan board and display and control device. The main control box gets the brightness data of each pixel of a screen from the computer's display card, and then re-allocates to several blocks. The scanning board, each scanning board is responsible for controlling several rows (columns) on the LED display screen, and the LED display display control signal is transmitted in a serial manner on each row (column).
Currently, there are two ways to serially transmit display control signals: one is to centrally control the grayscale of each pixel on the scanning board, and the scan board decomposes the luminance values ​​of the pixels in each row from the control box (ie, pulse width modulation). Then turn on the signal of LED display of each line in the form of pulse (lighting is 1, not bright is 0) according to the line to transmit to the corresponding LED display screen in series, control whether it is lit. This method uses fewer devices, but the amount of data transferred in series is larger because each pixel requires 16 pulses at 16 levels of gray in a repetitively lit period, requiring 256 levels of gray. 256 pulses, due to device operating frequency limitations, generally only allow the LED display screen to achieve 16 gray levels.
Another method is that the content of the serial transmission of the scan board is not the switching signal of each LED display but an 8-bit binary brightness value. Each LED display has its own pulse width modulator to control the lighting time. In this way, in a repetitively lit period, each pixel point needs only 4 pulses under 16 gray levels, and only 8 pulses under 256 gray levels, which greatly reduces the serial transmission frequency. With this method of decentralized control of the LED display screen grayscale can easily achieve 256 grayscale control.
The above is the P2.5 LED display brightness control method shared by Shenzhen Siweixin Optoelectronics. Hopefully it will help you. If you are interested in P2.5LED display price, please call for more relevant information.