LED (light-emitting diode) display system

Abstract

The invention discloses an LED (light-emitting diode) display system. The LED display system comprises an LED array, a control module, a row drive module, a column drive module and a voltage regulating module. The LED array comprises a row line, a column line and an LED lamp connected between the row line and the column line; the row drive module gates the row line under the control of the control module, and connects the gated row line to a high level VLED; the column drive module gates the column line under the control of the control module, and connects the gated column line to a low level VGND; and the voltage regulating module is used for controlling the output end voltage VOUT of the LED lamp to satisfy the following condition: VLED-VOUT<Vth, wherein the Vth is the threshold voltage of the LED lamp, the voltage regulating module comprises a first pull-up circuit and a second pull-up circuit which are connected in parallel. With the voltage regulating module, 'column carpenterworm' can be avoided, and simultaneously, by the two pull-up circuits, generation of inductance reversed high voltage can be avoided, and a high-voltage tube which both increases illumination and occupies area is not needed, so that cost is reduced.

Description

technical field [0001] The application belongs to the field of LED display screens, and in particular relates to an LED display system for eliminating row caterpillars. Background technique [0002] we use figure 1 The 3*3 LED array shown briefly introduces the display principle of the LED array. Such as figure 1 As shown, the anode of each LED lamp is connected to the corresponding row line, and the row line is connected to the LED power supply VLED through a switch. To turn on an LED, two conditions are required: first, the row line corresponding to the LED is connected to a high potential, and second, the column line corresponding to the LED is pulled to a low potential (usually between 0V~1V, to ensure LED has enough voltage difference to turn on). Both conditions must be satisfied at the same time, neither can be dispensable. Taking LED5 as an example, when switch SL2 is closed, row 2 is connected to V LED , if the switch SC2 is also closed at this time, pull colu...

AI Technical Summary

Problems solved by technology

But in reality, LED is easy to age and produce reverse leakage. Now suppose that LED1 ages and produces leakage. At this time, LED1 can be equivalent to an ideal diode and a resistor R LEAK connected in parallel, which will cause OUT3 to be pulled down to a low potential, forming a figure 2 The conduction loop shown by the dotted line in the middle makes the LED2 that should not be lit be turned on. When the entire LED array is working at high speed, when each row is alternately active, all the LEDs on column 3 will be lit. To the naked eye, a "column caterpillar" is formed

[0005] The "column caterpillar" makes the display effect of the LED screen worse, which is an abnormal phenomenon. In view of this situation, we propose this invention, which can solve this problem very well

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