Non-control-lightening-free shadow elimination circuit for LED (Light Emitting Diode) display screen

Abstract

The invention discloses a non-control-lightening-free shadow elimination circuit for an LED (Light Emitting Diode) display screen, which is arranged in a row driving circuit of the LED display screen arranged on a 1 / 4 scanning rank branch console. The non-control-lightening-free shadow elimination circuit is characterized in that a triode switching circuit is arranged among a row control line output end of a corresponding decoding chip, a row line output end of a field-effect tube and a public ground; when a level of the row control line output end is changed into a high level from an output low level, the row line output end is used for rapidly pulling a row power supply down; an isolation capacitor is charged and the connection with the public ground is switched off; device parameters are selected so that overlapping time of about 30ns exists between the front row and the next row in one frame of an image and the overlapping time is similar to the descending time of the row power supply. The circuit is simple and low in cost; the non-control lightening of LEDs on the other rows of the same line under the driving of the row power supply can be eliminated effectively; even if the non-control lightening of LEDs, caused by the electric leakage of the LEDs, happens, the trailing phenomenon of the LED display screen can be improved obviously so that human eyes cannot identify the effect that the front rows of the LEDs are slightly bright.

Description

technical field [0001] The invention relates to an LED display screen, in particular to a non-controlling lighting and disappearing circuit for the LED display screen. Background technique [0002] Most of the light-emitting diode (Light Emitting Diode, abbreviated as LED) display adopts the scanning method. The general control method of the scanning screen is the row and column control method, which is commonly referred to as the scanning method. The multi-scanning mode of the LED display usually includes 1 / 2 scanning mode, 1 / 4 scanning mode, 1 / 8 scanning mode and 1 / 16 scanning mode, the LED reverse leakage improvement circuit structure in these scanning modes is similar, the following takes the 1 / 4 scanning mode as an example for the existing LED The reverse leakage improvement circuit will be described. The row drive power tube in the drive circuit of the LED display is basically a dual P-channel metal-oxide-semiconductor field effect transistor (Metal-Oxide-Semiconduct...

AI Technical Summary

Problems solved by technology

[0009] When the column power tube is turned off, during the sequential output of the row lines H1, H2, H3 and H4 in the 1 / 4 scanning LED dot matrix display, the LEDs on other rows of the same column will pass through the reverse leakage LEDs of the same column And the grounding resistor connected to the row line corresponding to the reverse leakage LED is connected to the common ground to form a loop. Under the output of the row line of the field effect transistor MOSFET1 and MOSFET2, that is, the LEDs on other rows of the same column will not be controlled under the drive of the row power supply. If the number of LED points that are not controlled is greater than 1 / 10000, it will affect the display effect of the LED display

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