LED (Light Emitting Diode) scanning screen blanking method, device and LED scanning screen

Abstract

The invention relates to an LED (Light Emitting Diode) scanning screen blanking method, a device and an LED scanning screen. The method comprises the following steps: detecting a data latch signal for leading the LED screen to drive the data transmission; and discharging parasitic capacitance of each LED when a high-level signal of the data latch signal is detected. In the invention, when the high-level signal of the data latch signal is detected, the parasitic capacitance of each LED is discharged through detecting the data latch signal for leading the LED screen to drive the data transmission; when an output enable signal is at high level, all PMOS (Channel Metal Oxide Semiconductors) are cut off according to the time sequence of an LED screen module data interface; when a data latch signal LE is at high level, the signal enable signal also is at high level so as to ensure that when the parasitic capacitance is discharged under the situation that the data latch signal LE is at the high level, all PMOS are cut off to realize the effect that the parasitic capacitance is discharged under the situation that all the PMOS tubes are cut off, therefore, the conditions of generating the darkness and the brightness are damaged, and the dark and bright phenomena are eliminated.

Description

technical field [0001] The invention relates to a blanking method and device for an LED scanning screen and an LED scanning screen. Background technique [0002] like figure 1 As shown, it is a schematic diagram of the principle of the LED scanning screen. The basic implementation method is to quickly control the switching of multiple PMOS tubes and share a constant current source chip to achieve the purpose of saving costs. In the actual application of the existing LED scanning screen, there is a phenomenon that when the oblique line is output on the LED screen, there is a phenomenon that the oblique line has a faint shadow, which affects the output effect. There are many reasons for this phenomenon, the main reason is that the LED has a certain parasitic capacitance, and the parasitic capacitance forms a weak current through the discharge of the LED, causing the LED to dim. When the constant current source is turned off, control the PMOS tube to turn on. Although the LED...

AI Technical Summary

Problems solved by technology

According to this method, dark and bright can be effectively eliminated, but there are still many disadvantages: first, as long as the PMOS transistor is turned on, there must be a current flowing through the resistor, which will cause unnecessary energy consumption to increase; second, when a current is connected in parallel When one of the several LEDs in the source is reversely broken down, the function of the discharge resistor is equivalent to connecting a resistor in parallel with the constant current source. image 3 The schematic diagram of the equivalent circuit when reverse breakdown occurs is shown in . At this time, all other LEDs can form a current loop through this resistor. Even if the constant current source is turned off, current can still flow through the LED. At this time, the relevant The LED will be out of control, and the specific performance is that the LED screen is always on

Images