Drive and system architecture of LED display screen - Industry News - 奥马哈光电专业生产LED显示屏,户外表贴,室内表贴等全彩单双色产品


Drive and system architecture of LED display screen

        LED display as a high-tech product caused people's attention and controlled by computer, optical, electrical integrated intelligent full-color display has in a wide range of areas applied. Its pixel point using LED light-emitting diodes, a number of light-emitting diodes are arranged in a dot matrix to form a LED array, and thus constitute the LED screen. Different effects of image can be obtained by different LED driving mode. Therefore, the advantages and disadvantages of the LED driver chip plays an important role in the display quality of LED display. LED driver chip can be divided into general purpose and special chip.
        General general chip LED screens used in low-end products, such as indoor single and double color screen. The most commonly used general-purpose chip is 74HC595, with 8 bit latch, string together with the shift register and the three state output function. The current of the non constant current of the maximum output 35mA of each path.
        Because the LED is the current characteristic device, that is, under the premise of the saturation conduction, the brightness changes with the change of the current size, and not with the change of the voltage at both ends. The special chip is the most characteristic is to provide the constant current source output, to ensure the stability of the LED driver, eliminating the flicker of LED. Has the characteristics of large output current, constant current applicable on the occasions of high current, high quality requirements, such as outdoor full color display, indoor full color display, such as.
        LED display with the LED driver chip series CMOS built-in SMT5026.SMT5026 shift register and latch function, the serial input data can be converted into parallel output data format.
The second part: the system structure of LED display screen
       (1) display unit
       This is the main part of the LED display screen, which is composed of light emitting material and driving circuit. Indoor screen is a variety of specifications of the unit display panel, the outdoor screen is the unit box.
       (2) master controller
      The function is to input the RGB digital video signal buffer, gray transform, re organization, and produce a variety of control signals.
      (3) switching power supply
      Purpose is to change the 220V into a variety of DC power supply circuit.
      (4) transmission cable
     The display data generated by the master controller and various control signals are transmitted from the twisted pair cables to the screen body.
      (5) scanning controller
      The function of the circuit board is to buffer the data, and generate a variety of scanning signals and the duty cycle of the gray control signal.
      (6) special display card and multimedia card (video card)
      LED full color display card in addition to a computer display card basic functions, while the output digital RGB signal and line, field, eliminating hidden signal to the main controller. Multimedia card in addition to the above functions can also be input analog Video signal into a digital RGB signal (that is, video capture).
      (7) other signal sources and their external devices
     Including computers, televisions, Blu ray, DVD, VCD, video recorder, etc..

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