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Outdoor LED display switching power supply design concept analysis
The study of the led display uses a dot matrix display with a screen of 88, focusing on the dynamic processing method. Due to the limitations of the display screen, only English and numbers can be displayed in this research design. A basic led screen consists of 8 rows and 8 columns with a total of 64 LEDs. The display has two connections: common and common. For a led display consisting of 88 dots, the general data end is connected to the 8-bit parallel data port of the microprocessor, and the strobe end is enabled one by one (strobe), selecting a column to be lit, and passing The time multiplexing method realizes the dynamic display effect. There are two general strobe modes: independent strobe and decode strobe. If the screen is small and the processor has enough I/O ports available, you can connect one strobe to each I/O port. If the screen is large, or the processor's I/O port is not very rich, you can pass The decoding method is used to strobe. For example, when 8 pieces of 88 dot matrix LEDs form a 8128 dot matrix led screen, the direct strobe mode requires 64 I/O ports, and the decoding strobe mode requires only 6 I/O ports. Software design: 88 dot matrix led screen display characters need to be converted into actual display data by means of modulo, this process can be realized by PctoLCD2002 software, PctoLCD2002 is a kind of LCD font generation software, also suitable for dot matrix led The screen performs font generation. The size of the English characters generated here is 88 dot matrix, and the mode of setting is set to cathode (lighting bit is 1), column by column and forward direction (high order first). Hardware circuit: In the LED display system, an 88 display is used, so 8 strobe I/O ports are used, and the strobe mode is independent strobe mode. The signal is supplied to the strobe through the I/O port of the software Atmega16. Atmega16 does not need to add its driver line, software atmega16 has direct drive capability. By studying the display system of the led display screen, focusing on the display dynamics of the LED large screen, two timers are used to control the brightness of the display screen and the dynamic shift speed of the displayed characters. The schematic diagram of the led large-screen display system is designed under DXP2004. The displayed characters can be modeled by PctoLCD2002 software. In the design of the system, according to the actual LED screen type and circuit connection settings, the appropriate cathode mode is selected. The use of led switching power supply, applicable laws and regulations and standards, laid the foundation for evaluating and reviewing the design safety of new development products, scientifically and effectively monitoring product quality; actively responding to technical trade barriers, helping enterprises to improve quality management and quality control capabilities And the ability to deal with the broken wall has great guiding significance.