CN102968975B - Liquid crystal display device and gate driving circuit voltage control method and control circuit thereof - Google Patents

Abstract

The present invention provides a liquid crystal display device and its gate drive circuit voltage control method and control circuit, wherein the control method includes: when the liquid crystal display device is turned off, it is detected that the boost voltage of the boost circuit connected to the gate drive circuit has dropped to one When the preset value is set, the control circuit connected to the gate drive circuit is turned on; when it is detected that the voltage signal output by the control circuit drops to 0V, the gate drive circuit is controlled to open all gate lines, so that the gate lines generate The charge neutralizes all charges in the pixel. The solution of the present invention can avoid slow charging (or discharging) or white screen phenomenon of the liquid crystal display device caused by switching on and off.

Description

Liquid crystal display device and its gate drive circuit voltage control method and control circuit

technical field

The invention relates to the field of circuits, in particular to a liquid crystal display device and a method for controlling voltage of a gate drive circuit thereof and a control circuit thereof.

Background technique

Generally, when the liquid crystal display device (LCD) is turned off, the equipment operating voltage (VDDIN) is powered off first, and then the control voltage XON signal of the control circuit of the gate drive circuit (Gate IC) of the liquid crystal display device detects that VDDIN is powered off When it reaches a certain value (such as 5V power down to 4.5V), the control circuit starts to work. After receiving the XON signal and changing to 0V, the Gate IC will open all the gate lines and neutralize all the charges in the pixel to cover up the shutdown. When the screen is abnormal and afterimage phenomenon occurs when starting up. But at this time, a large shutdown current will inevitably be generated, and the boost voltage VON output by the boost circuit (such as DC/DC IC) connected to the Gate IC will instantly generate a large current of 200mA~500mA, such a large current will often burn it out. The VON wiring on the LCD device causes slow charging (or discharging) or white screen phenomenon.

Contents of the invention

The technical problem to be solved by the present invention is to provide a liquid crystal display device and its gate drive circuit voltage control method and control circuit, which can effectively prevent the boost voltage VON wiring from being burned, and avoid slow charging of the liquid crystal display device caused by switching on and off (or discharge) or white screen phenomenon.

In order to solve the above technical problems, an embodiment of the present invention provides a voltage control method for a gate drive circuit of a liquid crystal display device, including:

When the liquid crystal display device is turned off, when it is detected that the boost voltage of the boost circuit connected to the gate drive circuit drops to a preset value, the control circuit connected to the gate drive circuit is turned on;

When it is detected that the voltage signal output by the control circuit drops to 0V, the gate drive circuit is controlled to turn on all the gate lines, so that the charges generated by the gate lines neutralize all the charges in the pixel.

Wherein, the preset value is less than 15V.

Wherein, the boost circuit is a DC/DC IC, and the voltage signal output by the control circuit is an in-band XON voltage signal working between terminals.

Wherein, the boost circuit is connected to the working power supply VDDIN.

Embodiments of the present invention also provide a control circuit connected to the gate drive circuit of the liquid crystal display device, including:

The first detection terminal is used to activate the second detection terminal of the control circuit when it detects that the boost voltage of the boost circuit connected to the gate drive circuit has dropped to a preset value when the liquid crystal display device is turned off;

The second detection terminal is used to control the gate drive circuit to open all the gate lines when the output voltage signal of the control circuit drops to 0V, so that the charges generated by the gate lines neutralize all the charges in the pixel.

Wherein, the first detection terminal is connected to the boost circuit connected to the gate drive circuit; the second detection terminal is connected to the gate drive circuit; wherein, the first detection terminal is connected to the boost circuit through the first voltage dividing resistor connected to the RSTIN terminal, and also connected to the RST terminal of the boost circuit through the second voltage dividing resistor.

Wherein, the first detection terminal is connected to the second detection terminal through a printed circuit board.

Wherein, the boost circuit is a DC/DC IC, the voltage signal output by the control circuit is an in-band XON voltage signal working between terminals, the RSTIN terminal of the boost circuit is used as the input of the XON signal, and RST is used as the XON signal Signal output; the boost circuit is connected to the working power supply VDDIN.

Wherein, the preset value is less than 15V.

An embodiment of the present invention also provides a liquid crystal display device, including the above-mentioned control circuit.

The beneficial effects of above-mentioned technical scheme of the present invention are as follows:

In the above solution, by adjusting the control circuit XON detection signal from the power supply operating voltage XON to the output voltage VON of the boost circuit connected to the gate drive circuit; when the VON voltage drops to a certain value, XON starts to work, and the gate drive circuit Gate After the IC receives the XON signal and changes to 0V, it turns on all the gate lines, so that the charge generated by the gate lines neutralizes all the charges in the pixel, which can effectively prevent the VON value from being too large when XON is working, resulting in Large current, thus causing the probability of VON wiring (VON Pin) burning, and avoiding the phenomenon of slow charging (or discharging) or white screen of the liquid crystal display device caused by VON Pin burning when switching on and off.

Description of drawings

1 is a schematic flow diagram of a gate drive circuit voltage control method of a liquid crystal display device of the present invention;

FIG. 2 is a schematic structural diagram of a gate drive circuit voltage control circuit of a liquid crystal display device of the present invention;

FIG. 3 is a schematic diagram of a specific embodiment of the connection between the control circuit shown in FIG. 2 and the booster circuit.

detailed description

In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will describe in detail with reference to the drawings and specific embodiments.

As shown in FIG. 1 , an embodiment of the present invention also provides a method for controlling the voltage of a gate drive circuit of a liquid crystal display device, including:

Step 11, when the liquid crystal display device is turned off, when it is detected that the boost voltage of the boost circuit connected to the gate drive circuit drops to a preset value, the control circuit connected to the gate drive circuit is turned on;

Step 12, when it is detected that the voltage signal output by the control circuit drops to 0V, control the gate drive circuit to turn on all the gate lines, so that the charges generated by the gate lines neutralize all the charges in the pixel.

Wherein, the preset value is less than 15V. The boost circuit is a DC/DC IC, and the voltage signal output by the control circuit is an in-band XON voltage signal working between terminals. The boost circuit is connected to the working power supply VDDIN.

In the above embodiment of the present invention, by adjusting the XON detection signal, the original operating voltage VDDIN of the detection working power is changed to the output circuit VON of the detection booster circuit; and the booster circuit (DC/DCIC) is powered by the working power supply, When the LCD is turned off, the working power will be powered off. At this time, the output voltage of VON will also drop. When the output voltage of VON drops to a certain value (generally, the VON signal is a signal similar to AC, and the voltage value is changed from 27V change to 15V), this voltage value is required to be smaller than the voltage after angle elimination (such as 15V), such as 10V, at this time the control circuit XON starts to work, and after the Gate IC receives the XON signal and changes to 0V, all gates The lines are all turned on, so that the charge generated by the gate line neutralizes all the charges in the pixel. When all row gate lines are turned on, the VON voltage value is 10V, which is a very small value, and the current required to neutralize the charge in the pixel will also be reduced, and the current flowing from the VON Pin (VON line) will not burn out Von pin, no matter how many times the power is turned on and off, there will be no slow charging or white screen.

As shown in Figure 2, the embodiment of the present invention also provides a control circuit 23, which is connected to the gate drive circuit 24 of the liquid crystal display device, including:

The first detection terminal is used to activate the second detection terminal of the control circuit when the boost voltage VON of the boost circuit 22 connected to the gate drive circuit 24 is detected to drop to a preset value when the liquid crystal display device is turned off. ;

The second detection terminal is used to control the gate drive circuit (Gate IC) to open all gate lines (Gate) 25 when the output voltage signal XON of the control circuit drops to 0V, so that the charge generated by the gate lines 25 Neutralizes all charges within the pixel.

Wherein, the first detection terminal is connected to the boost circuit (RSTIN terminal and RST terminal) connected to the gate drive circuit; the second detection terminal is connected to the gate drive circuit. Specifically, the first detection terminal of the control circuit is connected to the RSTIN terminal of the boost circuit through the first voltage dividing resistor, and is also connected to the RST terminal of the boost circuit through the second voltage dividing resistor.

Wherein, the boost circuit is a DC/DC IC, and the voltage signal output by the control circuit is an in-band XON voltage signal working between terminals; the RSTIN terminal is used as the input of the XON signal, and RST is used as the output of the XON signal; The boost circuit is also connected to the working power supply (VDDIN) 21 .

In addition, the first detection terminal is connected to the second detection terminal through a printed circuit board. The preset value is less than 15V.

The boost circuit in this control circuit embodiment of the present invention is as shown in Figure 3, the RSTIN end is used as the input of the XON signal, and RST is used as the output of the XON signal, and the RSTIN end and the RST end are connected with the first detection end of the control circuit, through Adjust the XON detection signal from the original detection working voltage VDDIN of the working power supply to the output circuit VON of the detection boost circuit; and the boost circuit (DC/DC IC) is powered by the working power supply;

When the LCD is turned off, the working power supply VDDIN will lose power. At this time, the output voltage of the boost circuit VON will also drop. When the output voltage of VON drops to a certain value (generally, the VON signal is a signal similar to AC, The voltage value changes from 27V to 15V), this voltage value is required to be smaller than the voltage after angle reduction (such as 15V), such as 10V, then the control circuit XON starts to work, and the Gate IC changes to 0V after receiving the XON signal , turn on all the gate lines, so that the charges generated by the gate lines neutralize all the charges in the pixel. When all row gate lines are turned on, the VON voltage value is 10V, which is a very small value, and the current required to neutralize the charge in the pixel will also be reduced, and the current flowing from the VON Pin (VON line) will not burn out Von pin, no matter how many times the power is turned on and off, there will be no slow charging or white screen.

An embodiment of the present invention also provides a liquid crystal display device, including the above-mentioned control circuit.

The above description is a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (7)

1. A gate drive circuit voltage control method of a liquid crystal display device, characterized in that, comprising: When the liquid crystal display device is turned off, when it is detected that the boost voltage of the boost circuit connected to the gate drive circuit drops to a preset value, the control circuit connected to the gate drive circuit is turned on; the preset value is less than 10V; When it is detected that the voltage signal output by the control circuit drops to 0V, the gate drive circuit is controlled to open all the gate lines, so that the charges generated by the gate lines neutralize all the charges in the pixel; the boost circuit is DC/DC IC, the voltage signal output by the control circuit is an in-band XON voltage signal working between terminals; the XON voltage signal is used to detect the boosted voltage VON of the booster circuit. 2 . The method for controlling the gate drive circuit voltage of a liquid crystal display device according to claim 1 , wherein the boost circuit is connected to a working power supply VDDIN. 3 . 3. A control circuit, connected with the gate drive circuit of the liquid crystal display device, is characterized in that, comprising: The first detection terminal is used to start the second detection terminal of the control circuit when detecting that the boost voltage of the boost circuit connected to the gate drive circuit drops to a preset value when the liquid crystal display device is turned off; The preset value is less than 10V; the boost circuit is a DC/DC IC; The second detection terminal is used to control the gate drive circuit to open all the gate lines when the output voltage signal of the control circuit drops to 0V, so that the charges generated by the gate lines neutralize all the charges in the pixel; The voltage signal output by the control circuit is an in-band XON voltage signal working between the terminals; the XON voltage signal is used to detect the boosted voltage VON of the booster circuit. 4. The control circuit according to claim 3, wherein the first detection terminal is connected to a booster circuit connected to the gate drive circuit; the second detection terminal is connected to the gate drive circuit; wherein, the first detection terminal is connected to the gate drive circuit; A detection terminal is connected to the RSTIN terminal of the boost circuit through the first voltage dividing resistor, and is also connected to the RST terminal of the boost circuit through the second voltage dividing resistor. 5. The control circuit according to claim 4, wherein the first detection terminal is connected to the second detection terminal through a printed circuit board. 6. The control circuit according to claim 4 or 5, wherein the RSTIN terminal of the boost circuit is used as the input of the XON signal, and RST is used as the output of the XON signal; the boost circuit is connected to the working power supply VDDIN. 7. A liquid crystal display device, characterized by comprising the control circuit according to any one of claims 3-6.