The led display system and its line scan circuit which can eliminate the residual image of the led display screen

Abstract

The invention provides a light-emitting diode (LED) display system capable of eliminating the residual shadow of an LED display screen, and a line scanning circuit of the system. The line scanning circuit comprises a plurality of line switching tubes, a plurality of pre-discharge switches and line scanning control logic, wherein the first connecting end of each line switching tube is connected to supply voltage, and the second connecting end of each line switching tube is connected to a corresponding line; the first connecting end of each pre-discharge switch is connected to pre-discharge reference voltage, and the second connecting end of each pre-discharge switch is connected to the corresponding line; the line switching tube and the pre-discharge switch which are connected to the same line correspond to each other; the line scanning control logic is used for providing a plurality of line driving signals for the control ends of all the line switching tubes so as to control on or off of all the line switching tubes, and is used for providing a plurality of pre-discharge control signals for the control ends of all the pre-discharge switches so as to control on or off of all the pre-discharge switches. Pre-discharge is carried out on the lines in an LED array, so that the residual shadow of the LED display screen can be effectively eliminated.

Description

【Technical field】 [0001] The invention relates to the technical field of LED (Liquid Emitting Diode) display, in particular to an LED display system capable of eliminating afterimages on LED display screens and a row scanning circuit thereof. 【Background technique】 [0002] Generally, there are more or less afterimages (smearing / ghosting) in dynamic scanning LED displays, and the mechanism is due to the presence of parasitic capacitance at the chip output terminal, circuit board, and LED lamp port. When some devices are turned off at a certain moment, the corresponding parasitic capacitance will store residual charge, and the residual charge will be discharged through the channel at the next moment, so that the LED in the LED display screen that should not be lit is slightly bright, Afterimage phenomenon occurs. Please refer to figure 1 As shown, it is a schematic diagram of a partial circuit structure of an LED display screen using a 1 / 4 scan mode in the prior art. figur...

AI Technical Summary

Problems solved by technology

That is to say, due to the parasitic capacitance on the column line of the LED matrix, when the row is switched, the LED that should not be lit will be slightly brightened (that is, the so-called ghost image, which will affect the picture display effect of the LED display.

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