Driver and system architecture of the hottest LED

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The drive and system architecture of LED display screen

as a high-tech product, LED display screen has attracted great attention. The intelligent full-color display screen, which uses computer control and integrates light and electricity, has been applied in a wide range of fields. Its pixel points adopt LED light-emitting diodes, and many light-emitting diodes are arranged in a dot matrix manner to form an LED array, which in turn forms an LED screen. Images with different effects can be obtained through different LED driving modes. Therefore, the quality of LED driver chip plays an important role in the display quality of LED display screen. LED driver chips can be divided into general chips and special chips

general chips are generally used in low-end products of LED display screens, such as indoor single and dual color screens. The most commonly used general-purpose chip is 74HC595, which has the functions of 8-bit latch, serial shift register and three state output. Each circuit can output 35mA non constant current at most. It has been used to manufacture important shaft parts on automobiles, tractors and machine tools

because LED is a current characteristic device, that is, on the premise of saturated conduction, its brightness changes with the change of current, not with the change of voltage at both ends. The biggest feature of the special chip is to provide constant current source output, ensure the stable driving of LED and eliminate the flicker of LED. With the characteristics of high output current and constant current, it is suitable for occasions requiring high current and high image quality, such as outdoor full-color screen, indoor full-color screen, etc

t5026, a series of LED driver chips for LED display screen, has built-in CMOS shift register and latch function, which can convert serial input data into parallel output data format

Part II: system composition architecture of LED display screen

(1) display unit

this is the main part of LED display screen, which is composed of light-emitting materials and driving circuits. The indoor screen is the unit display board of various specifications, and the outdoor screen is the unit box

(2) the main controller

is used to deal with the damage of the input electronic universal testing machine accessories? RGB digital video signal buffering, gray-scale transformation, but this is so big that it requires the user's inspection experience, new organization, and generate various control signals

(3) the purpose of switching power supply

is to change 220V AC into various DC supplies and remove various circuits of test piece fragments at the same time

(4) transmission cable

the display data and various control signals generated by the main controller are transmitted to the screen body by twisted pair cable

(5) scanning controller

the function of this circuit board is to buffer data and generate various scanning signals and duty cycle gray control signals

(6) special display card and multimedia card (video card)

in addition to the basic functions of computer display card, led full-color display card also outputs digital RGB signals and line, field, blanking and other signals to the main controller. In addition to the above functions, the multimedia card can also change the input analog video signal into digital RGB signal (i.e. video acquisition)

(7) other signal sources and their external devices

include computers, televisions, Blu ray, DVDs, VCDs, video cameras, etc

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