CN117292637A

CN117292637A - Driving circuit and display device

Info

Publication number: CN117292637A
Application number: CN202311321798.5A
Authority: CN
Inventors: 刘乾乾; 毕鑫
Original assignee: BOE Technology Group Co Ltd; Chengdu BOE Optoelectronics Technology Co Ltd
Current assignee: BOE Technology Group Co Ltd; Chengdu BOE Optoelectronics Technology Co Ltd
Priority date: 2023-10-12
Filing date: 2023-10-12
Publication date: 2023-12-26

Abstract

The invention discloses a driving circuit and a display device. The driving circuit comprises a signal output end, a first voltage source, a second voltage source, a pull-down switch, a protection switch and a control signal end. The signal output terminal is used for outputting a driving signal to drive the pixel circuit. The first voltage source is electrically connected with the signal output end through the pull-down switch. The second voltage source is electrically connected with the control electrode of the pull-down switch through the protection switch. Under the condition that the protection switch is on, the pull-down switch is off. The control signal end is used for accessing control signals, and the control signal end is electrically connected with the control electrode of the protection switch. Before the drive circuit drives the light-emitting device to emit light, the control signal is firstly used for controlling the protection switch to be turned on, so that negative charges accumulated on the insulating film of the transistor of the protection switch are released, the control signal is used for controlling the protection switch to be turned off, and one frame of control signal before the drive circuit drives the light-emitting device to emit light is used for controlling the protection switch to be turned off, so that the normal work of the light-emitting device is prevented from being influenced when the drive circuit drives the light-emitting device to emit light.

Description

Driving circuit and display device

Technical Field

The invention relates to the technical field of displays, in particular to a driving circuit and a display device.

Background

In the related art, an array substrate gate driver (GOA) circuit of a display device includes a signal output terminal and a pull-down switch, the signal output terminal being electrically connected to the pull-down switch. In the case of abnormal shutdown of the display device, for example, in the case of instantaneous disassembly of the battery of the display device, the pull-down switches of all the driving circuits are turned on, so that the signal output ends of all the driving circuits in the display device are pulled down to a low level, the light emitting diodes of the pixel circuits of the driving display device emit light, and the display device flashes.

In order to avoid the flicker of the display device, each driving circuit comprises a protection switch, and the protection switch can control the pull-down switch to be turned off under the condition that the display device is abnormally turned off, so that the condition that the display device flicker is caused by the fact that the signal output ends of all the driving circuits are pulled down to a low level is avoided.

Under the condition that the driving circuit normally drives the light emitting diode to emit light, the protection switch is turned off and is in a positive pressure bias state, so that the phenomenon that the driving circuit drives the pixel circuit is avoided because the protection switch forcibly controls the pull-down switch to be turned off. The protection switch works in a positive pressure bias state for a long time, negative charges can be accumulated on a transistor insulating film of the protection switch, and the protection switch cannot be normally turned off after being turned on.

Disclosure of Invention

The embodiment of the invention provides a driving circuit and a display device. The driving circuit comprises a signal output end, a first voltage end, a second voltage end, a pull-down switch, a protection switch and a control signal end. The signal output terminal is used for outputting a driving signal to drive the pixel circuit. The first voltage terminal is used for providing a first level signal. The first voltage end is electrically connected with the signal output end through the pull-down switch, and under the condition that the pull-down switch is conducted, a first level signal provided by the first voltage end is written into the signal output end. The second voltage terminal is used for providing a second level signal. The second voltage end is electrically connected with the control electrode of the pull-down switch through the protection switch. And under the condition that the protection switch is turned on, the second voltage end is used for providing a second level signal for the control electrode of the pull-down switch so that the pull-down switch is turned off. The control signal end is used for accessing a control signal, the control signal end is electrically connected with the control electrode of the protection switch, and the control signal is used for controlling the protection switch to be turned on or turned off. The pixel circuit includes a light emitting device. Before the driving circuit drives the light emitting device to emit light, the control signal is used for controlling the protection switch to be turned on and then controlling the protection switch to be turned off.

Before the driving circuit drives the light emitting device to emit light, the control signal can be used for controlling the protection switch to be turned on, and the protection switch is in a negative pressure bias state. Under the condition that the protection switch is in a negative pressure bias state, negative charges accumulated by the transistor insulating film of the protection switch are released, and the influence of the negative charges accumulated by the transistor insulating film of the protection switch on the protection switch can be eliminated, so that the protection switch can be normally turned off after being turned on.

Before the driving circuit drives the light emitting device to emit light, the control signal also controls the protection switch to be switched from the on state to the off state. Under the condition that the driving circuit works normally, the protection switch keeps on to enable the pull-down switch to be turned off, the driving signal output by the signal output end is influenced, and the driving circuit is influenced to drive the light emitting device to emit light.

In summary, before the driving circuit drives the light emitting device to emit light, the control signal controls the protection switch to be turned on, the protection switch is in a negative voltage bias state, and negative charges accumulated in the transistor insulating film of the protection switch are released. After negative charges accumulated by the transistor insulating film of the protection switch are released, the control signal controls the protection switch to be turned off again, and the protection switch is in an off state before the light emitting device emits light, so that the normal work of the light emitting device is prevented from being influenced when the driving circuit drives the light emitting device to emit light.

In some embodiments, a frame of control signal is used to control the protection switch to turn off before the driving circuit drives the light emitting device to emit light.

The protection switch needs to be controlled to be turned off by a frame of control signal before the driving circuit drives the light emitting device to emit light, so that the protection switch is still in a conducting state when the driving circuit drives the light emitting device to emit light, and the pull-down switch is turned off, so that the driving circuit is influenced to drive the light emitting device to emit light.

In some embodiments, the drive circuit further includes a start signal terminal, a first clock signal terminal, and a first switch. The starting signal end is used for accessing a starting signal, and the first clock signal end is used for accessing a first clock signal. The starting signal end is electrically connected with the control electrode of the pull-down switch through the first switch. The control electrode of the first switch is electrically connected with the first clock signal end. The first switch is turned on or off according to the first clock signal, and is used for applying the starting signal to the control electrode of the pull-down switch under the condition of conduction so as to control the pull-down switch to be turned on or off.

In the case where the driving circuit drives the light emitting device to emit light. The first clock signal and the start signal can be used for controlling the on or off of the pull-down switch, and further controlling the driving signal output by the signal output end. The protection switch is in an off state, so that the phenomenon that the first switch and the protection switch are simultaneously conducted to cause short circuit between the starting signal end and the second voltage end to influence the driving signal output by the signal output end is avoided.

In some embodiments, a frame of the control signal is used to control the protection switch to turn off before the start signal is received by the start signal.

In some embodiments, the control signal is used to control the protection switch to be turned off when the control signal is in the first level state. And under the condition that the control signal is in a second level state, the control signal is used for controlling the protection switch to be conducted. And under the condition that the control signal is in a third level state, the control signal is used for controlling the protection switch to be turned off. After the control signal is switched from the first level state to the second level state, the control signal is switched from the second level state to the third level state. The control signal is switched from the second level state to the third level state one frame before the start signal is received by the start signal.

The time from the start signal receiving the start signal to the time before the driving circuit drives the light emitting device to emit light can be freely set for the time when the protection switch is in the on state, so that the negative charge accumulated in the transistor insulating film of the protection switch is sufficiently released.

In some embodiments, the level of the control signal is pulled low in the event that the control signal switches from the first level state to the second level state. In the case where the control signal is switched from the second level state to the third level state, the level of the control signal is pulled up.

In some embodiments, the driving circuit further includes a second switch, a third switch, a fourth switch, a first capacitor, and a second clock signal terminal. The second clock signal terminal is used for accessing a second clock signal. The control electrode of the second switch is electrically connected with the first clock signal end. The first voltage end is electrically connected with the control electrode of the third switch through the second switch. The second voltage terminal is electrically connected with the second clock signal terminal through the third switch and the fourth switch. One end of the first capacitor is electrically connected between the third switch and the fourth switch, the other end of the first capacitor is electrically connected with the control electrode of the fourth switch, and the control electrode of the fourth switch is electrically connected with the control electrode of the pull-down switch.

In the case where the driving circuit normally drives the light emitting device to emit light. The first clock signal, the second clock signal and the starting signal can be used for controlling the on or off of the pull-down switch, so as to control the driving signal output by the signal output end.

In some embodiments, the drive circuit further comprises a fifth switch having a control electrode electrically connected to the control electrode of the pull-down switch. The first clock signal end is electrically connected with the control electrode of the third switch through the fifth switch.

The start signal and the first clock signal can also control the driving signal output by the signal output end by controlling the on or off of the fifth switch and further controlling the on or off of the pull-down switch.

In some embodiments, the drive circuit further includes a pull-up switch and a sixth switch. The second voltage end is electrically connected with the signal output end through the pull-up switch, and under the condition that the pull-up switch is conducted, the first voltage provided by the second voltage end is connected with the signal output end. The second voltage end is electrically connected with the control electrode of the pull-up switch through the sixth switch, and the control electrode of the sixth switch is electrically connected with the control electrode of the pull-down switch.

The sixth switch can control the turn-off of the pull-up switch so that the signal output terminal cannot output a high level. Under the condition that the protection switch is turned on, the sixth switch can be controlled to be turned off, and then the signal output end can output high level.

In some embodiments, the driving circuit further includes a second capacitor, and the second capacitor is electrically connected to the second voltage terminal and the control electrode of the pull-up switch, respectively.

The second capacitor can be used as a voltage stabilizing capacitor, and can stabilize the voltage of the control electrode of the pull-up switch, so as to control the turn-on or turn-off of the pull-up switch and control the output signal of the signal output end.

In some embodiments, the driving circuit further includes a second switch, a seventh switch, an eighth switch, a third capacitor, and a second clock signal terminal. The second clock signal terminal is used for accessing a second clock signal. The control electrode of the second switch is electrically connected with the second clock signal end. The first voltage end is electrically connected with the control electrode of the seventh switch through the second switch. The second clock signal end is electrically connected with the control electrode of the pull-up switch through the seventh switch and the eighth switch, and the control electrode of the eighth switch is electrically connected with the second clock signal end. One end of the third capacitor is electrically connected between the seventh switch and the eighth switch, and the other end of the third capacitor is electrically connected with the control electrode of the seventh switch.

In the case where the driving circuit normally drives the light emitting device to emit light. The first clock signal, the second clock signal and the starting signal can be used for controlling the on or off of the pull-up switch, so as to control the driving signal output by the signal output end.

An embodiment of the present invention provides a display device including the driving circuit and the pixel circuit of any one of the above embodiments.

In the driving circuit and the display device of the embodiment of the invention, the driving circuit comprises a signal output end, a first voltage end, a second voltage end, a pull-down switch, a protection switch and a control signal end. The signal output terminal is used for outputting a driving signal to drive the pixels. The first voltage terminal is used for providing a first level signal. The first voltage end is electrically connected with the signal output end through the pull-down switch, and under the condition that the pull-down switch is conducted, a first level signal provided by the first voltage end is written into the signal output end. The second voltage terminal is used for providing a second level signal. The second voltage end is electrically connected with the control electrode of the pull-down switch through the protection switch under the condition that the protection switch is turned on, and the second voltage end is used for providing a second level signal for the control electrode of the pull-down switch so that the pull-down switch is turned off. The control signal end is used for accessing a control signal, the control signal end is electrically connected with the control electrode of the protection switch, and the control signal is used for controlling the connection or disconnection of the protection switch. Before the driving circuit drives the light emitting device to emit light, the control signal is used for controlling the protection switch to be turned on and then used for controlling the protection switch to be turned off.

Before the driving circuit drives the light emitting device to emit light, the control signal can be used for controlling the protection switch to be turned on, negative charges accumulated in the transistor insulating film of the protection switch are released, the influence of the negative charges accumulated in the transistor insulating film of the protection switch on the protection switch can be eliminated, and the protection switch can be normally turned off after being turned on. Before the driving circuit drives the light emitting device to emit light, the control signal also controls the protection switch to be switched from the on state to the off state. Under the condition that the driving circuit normally drives the light-emitting diode to emit light, the protection switch is kept on so that the pull-down switch is turned off, the driving signal output by the signal output end is influenced, and the driving circuit is further influenced to drive the light-emitting device to emit light.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

The foregoing and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, in which:

fig. 1 is a schematic diagram showing connection between a driving circuit and a pixel circuit according to an embodiment of the present invention;

FIG. 2 is a schematic circuit diagram of a driving circuit according to an embodiment of the present invention;

fig. 3 is a timing diagram of control signals according to a first embodiment of the present invention;

FIG. 4 is a timing diagram of control signals according to a second embodiment of the present invention;

fig. 5 is a schematic view of a display device according to an embodiment of the present invention.

Detailed Description

Embodiments of the present invention are described in detail below, which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary only for explaining the present invention and are not to be construed as limiting the present invention.

In the related art, an array substrate gate driver (GOA) circuit of a display device includes a signal output terminal and a pull-down switch, the signal output terminal being electrically connected to the pull-down switch. Under the condition that the display device is abnormally closed, for example, under the condition that a battery of the display device is instantaneously disassembled, the pull-down switches of all the driving circuits are conducted, so that signal output ends of all the driving circuits in the display device are pulled down to a first voltage, the light emitting diodes of the pixel circuits of the driving display device emit light, and the display device flashes.

Referring to fig. 1, an embodiment of the invention provides a driving circuit 100. The driving circuit 100 is for driving a pixel circuit 200 including a light emitting device 210. The driving circuit 100 includes a signal output terminal 110, a first voltage terminal 121, a second voltage terminal 122, a pull-down switch 130, a protection switch 131, and a control signal terminal 123. The signal output terminal 110 is used for outputting a driving signal to drive the pixel circuit 200. The first voltage terminal 121 is used for providing a first level signal. The first voltage terminal 121 is electrically connected to the signal output terminal 110 through the pull-down switch 130, and the first level signal provided by the first voltage terminal 121 is written into the signal output terminal 110 in a state that the pull-down switch 130 is turned on. The second voltage terminal 122 is used for providing a second level signal. The second voltage terminal 122 is electrically connected to the control electrode of the pull-down switch 130 through the protection switch 131, and in case that the protection switch 131 is turned on, the second voltage terminal 122 is configured to provide a second level signal to the control electrode of the pull-down switch 130, so that the pull-down switch 130 is turned off. The control signal end 123 is used for accessing a control signal, the control signal end 123 is electrically connected with the control electrode of the protection switch 131, and the control signal is used for controlling the protection switch 131 to be turned on or off. Before the driving circuit 100 drives the light emitting device 210 to emit light, the control signal is used to control the protection switch 131 to be turned on and then to control the protection switch 131 to be turned off. A frame control signal before the driving circuit 100 drives the light emitting device 210 to emit light is used to control the protection switch 131 to be turned off.

Specifically, the pixel circuit 200 includes a driving transistor and a light emitting device 210, wherein the driving transistor may be a transistor or a MOS transistor, and the light emitting device 210 may be a light emitting diode. The driving circuit 100 may be a GOA circuit. The driving signal output from the signal output terminal 110 may be connected to the control electrode of the driving transistor, and the light emitting device 210 is controlled to emit light by controlling the on or off of the driving transistor.

Further, the circuit configuration of the driving circuit may refer to fig. 2. The signal output terminal 110 may be an OUT terminal, the first voltage terminal 121 may be electrically connected to the first voltage signal line V1, and the pull-down switch 130 may include a tenth switching element T10. A first pole of the tenth switching element T10 is electrically connected to the first voltage terminal 121, and a second pole of the tenth switching element T10 is electrically connected to the signal output terminal 110. The control electrode of the tenth switching element T10 is electrically connected to the second node N2. The first signal line V1 may provide a first level signal, such as a low level signal VGL.

A first pole of the twelfth switching element T12 is electrically connected to the first node N1, a second pole of the twelfth switching element T12 is electrically connected to the second node N2, and a control pole of the twelfth switching element T12 is electrically connected to the first voltage terminal 121. The control electrode of the twelfth switching element T12 may be electrically connected to the first voltage signal line V1 through the first voltage terminal 121, and the level signal VGL is written into the control electrode of the twelfth switching element T12, so that the twelfth switching element T12 is turned on for a long time, and the voltage of the second node N2 may be stabilized, thereby avoiding a large signal deviation.

The control signal terminal 123 may include an NCX terminal, the second voltage terminal 122 may be electrically connected to the second signal line V2, and the protection switch 131 may include a thirteenth switching element T13. The first pole of the thirteenth switching element T13 is electrically connected to the second voltage terminal 122, the second pole of the thirteenth switching element T13 is electrically connected to the first node N1, and the control pole of the thirteenth switching element T13 is electrically connected to the NCX terminal. The second signal line V2 may provide a second level signal, such as a high level signal VGH.

With the tenth switching element T10 turned on, the low level signal VGL is written to the OUT terminal for driving the pixel circuit 200.

The thirteenth switching element T13 may be used to control the tenth switching element T10 to be turned off. With the thirteenth switching element T13 turned on, the high-level signal VGH is written to the first node N1. The low level signal VGL is written into the control electrode of the twelfth switching element T12, so that the twelfth switching element T12 is turned on, and further, the high level signal VGH is written into the second node N2, that is, the control electrode of the tenth switching element T10, while being written into the first node N1, so that the tenth switching element T10 is turned off.

The signal of the NCX access may be used to control the thirteenth switching element T13, and the thirteenth switching element T13 is turned off when the NCX access is a high level signal. When the NCX terminal is connected to a low level signal, the thirteenth switching element T13 is turned on. When the signal connected to the NCX terminal controls the thirteenth switching element T13 to be turned on, as described above, the high level signal VGH is written into the first node N1, and if the twelfth switching element T12 is turned on at this time, the high level signal VGH is written into the second node N2, i.e., the control electrode of the tenth switching element T10, so that the tenth switching element T10 is turned off.

When the driving circuit 100 normally drives the light emitting device 210 to emit light, the thirteenth switching element T13 is turned off and is in a positive voltage bias state. The driving circuit 100 drives the light emitting device 210 to emit light for a long period of time, and the control of the thirteenth switching element T13 is written with a high level signal most of the time, and the transistor insulating film of the thirteenth switching element T13 may accumulate a certain negative charge under a positive bias for a long period of time. In the case where there is fluctuation in the manufacturing process of the thirteenth switching element T13, there may be a problem in that the thirteenth switching element T13 has a threshold shift or an insulating layer thickness is not uniform, so that the threshold voltage of the thirteenth switching element T13 increases.

After the display device is abnormally turned off, if the display device needs to be continuously started, the display device can normally display and work, and the thirteenth switching element T13 needs to be switched from the on state to the off state. At this time, since the threshold voltage of the thirteenth switching element T13 increases, it is difficult for the signal connected to the NCX terminal to immediately turn off the thirteenth switching element T13, and thus, the high-level signal VGH is written into the second node N2 to cause the tenth switching element T10 to be turned off, resulting in a problem that the display device displays an abnormality.

Before the OUT terminal outputs the driving signal to drive the light emitting device 210 to emit light, the signal connected to the NCX terminal may first control the thirteenth switching element T13 to be turned on for a period of time, so that the negative charge accumulated on the transistor insulating film of the thirteenth switching element T13 is released, and the influence of the negative charge accumulated on the transistor insulating film of the thirteenth switching element T13 on the threshold voltage of the thirteenth switching element T13 is eliminated, so that the NCX terminal can normally control the thirteenth switching element T13 to be turned off.

After the thirteenth switching element T13 is turned on for a period of time, the signal connected to the NCX terminal controls the thirteenth switching element T13 to be turned off. The thirteenth switching element T13 is switched from on to off before the OUT terminal outputs the driving signal to drive the light emitting device 210 to emit light, so that abnormal display of the display device is avoided due to the fact that the thirteenth switching element T13 is turned on when the light emitting device 210 emits light.

Further, the timing diagram of the control signal to which the NCX terminal is connected may refer to fig. 3, and the control signal to which the NCX terminal is connected may have three level states before the OUT terminal outputs the driving signal to drive the light emitting device 210 to emit light. Before the time T0, the level of the control signal accessed by the NCX terminal is in the first level state NCX1. And the level of the control signal accessed by the NCX terminal is in a second level state NCX2 from the time T0 to the time T1. After the time T1, the level of the control signal accessed by the NCX terminal is in a third level state NCX3.

At time T0, the level of the control signal connected to the NCX terminal is switched from the first level state NCX1 to the second level state NCX2, and the thirteenth switching element T13 is switched from the off state to the on state. At the timings T0 to T1, the thirteenth switching element T13 is in an on state. As described above, the signal received by the NCX terminal can control the thirteenth switching element T13 to be turned on for a period of time, so that the negative charge accumulated on the transistor insulating film of the thirteenth switching element T13 is released, and the influence of the negative charge accumulated on the transistor insulating film of the thirteenth switching element T13 on the threshold voltage when the thirteenth switching element T13 is turned off is eliminated, so that the NCX terminal can normally control the thirteenth switching element T13 to be turned off.

At time T1, the level of the control signal connected to the NCX terminal is switched from the second level state NCX2 to the third level state NCX3, and the thirteenth switching element T13 is switched from the on state to the off state. After time T1, the thirteenth switching element T13 is in an off state. As described above, after the thirteenth switching element T13 is turned on for a period of time, the signal applied to the NCX terminal controls the thirteenth switching element T13 to be turned off again. The thirteenth switching element T13 is switched from on to off before the OUT terminal outputs the driving signal to drive the light emitting device 210 to emit light, so that abnormal display of the display device is prevented from being caused by the conduction of the thirteenth switching element T13 when the light emitting device 210 is driven.

In some embodiments, the driving circuit 100 further includes a first clock signal terminal 124, a start signal terminal 125, and a first switch 132. The first clock signal terminal 124 is electrically connected to a first clock signal line CK, and the first clock signal line CK may provide the first clock signal to the first clock signal terminal 124. The start signal terminal 125 is electrically connected to a start signal line STV, which provides a start signal to the start signal terminal 125. A first pole of the first switch 132 is electrically connected to the start signal terminal 125, and a second pole of the first switch 132 is electrically connected to the first node N1. The control electrode of the first switch 132 is electrically connected to the first clock signal terminal 124. The first switch 132 is turned on or off under the control of the first clock signal, and the first switch 132 is configured to write a start signal into the first node N1 when turned on, so as to control the pull-down switch 130 to be turned on or off.

In the case that the driving circuit 100 drives the light emitting device 210 to emit light, the protection switch 131 is in an off state, so that the short circuit between the start signal terminal 125 and the second voltage terminal 122 caused by the simultaneous conduction of the first switch 132 and the protection switch 131 is avoided, the normal operation of the driving circuit 100 is affected, and the display device is prevented from abnormal display.

Specifically, referring to fig. 2, the first switch 132 may include a first switching element T1. The first pole of the first switching element T1 is electrically connected to the start signal terminal 125, and the second pole of the first switching element T1 is electrically connected to the first node N1 node. The start signal terminal 125 may be electrically connected to a start signal line STV to supply a start signal to the driving circuit 100.

The first clock signal terminal 124 may be electrically connected to a first clock signal line CK, and the first clock signal provided by the first clock signal line CK may control the first switching element T1 to be turned on or off. In case the first clock signal controls the first switching element T1 to be turned on, the start signal may be written into the first node N1. Since the twelfth switching element T12 is in the on state, the signal of the first node N1 can be written into the second node N2 at this time, and thus the on or off of the tenth switching element T10 can be controlled.

In the case where the driving circuit 100 drives the light emitting device 210 to emit light, it is necessary to ensure that the thirteenth switching element T13 is in an off state. If the thirteenth switching element T13 is turned on, the start signal terminal 125 is shorted with the second voltage terminal 122 when the first switching element T1 is turned on, and the second voltage signal line V2 can write the high level signal VGH to the start signal terminal 125 through the second voltage terminal 122. Therefore, in the case where the start signal terminal 125 is shorted with the second voltage terminal 122, the driving signal output from the OUT terminal is abnormal, and the display device may have a flicker phenomenon.

In some embodiments, a frame of control signal is used to control the protection switch 131 to turn off before the driving circuit 100 drives the light emitting device 210 to emit light.

As described above, when the control signal controls the protection switch 131 to be turned on, negative charges accumulated on the transistor insulating film of the protection switch 131 are released. The longer the protection switch 131 is turned on, the more the negative charge accumulated on the transistor insulating film of the protection switch 131 is released.

And the protection switch 131 needs to be in an off state before the driving circuit 100 outputs the driving signal to drive the light emitting device 210 to emit light. A frame of control signal, which may be used to control the protection switch 131 to switch from on to off before the driving circuit 100 drives the light emitting device 210 to emit light, may make the protection switch 131 on long enough, and the accumulated negative charges on the transistor insulating film of the protection switch 131 may be sufficiently released.

Further, in some embodiments, a frame of control signal is used to control the protection switch 131 to turn off before the start signal terminal 125 receives the start signal.

Specifically, referring to fig. 2, as previously described, the signal output terminal 110 may include an OUT terminal. The start signal terminal 125 may be electrically connected to a start signal line STV to supply a start signal to the driving circuit 100. The signal control terminal 123 may include an NCX terminal, and the protection switch 131 may include a thirteenth switching element T13.

Referring to fig. 4, the STV receives the start signal at time T2. The level of the control signal one frame before the time T2, i.e. one frame before the STV receives the start signal, is in the third level state NCX3, and the control signal can control the thirteenth switching element T13 to be turned off.

The thirteenth switching element T13 is in an off state before the OUT terminal outputs the driving signal to drive the light emitting device 210 to emit light, so that it is possible to prevent the thirteenth switching element T13 from being turned on at the time of driving the light emitting device 210, resulting in abnormal display of the display device.

Further, in some embodiments, the control signal is used to control the protection switch 131 to be turned off when the control signal is in the first level state. In the case that the control signal is in the second level state, the control signal is used to control the protection switch 131 to be turned on. In the case that the control signal is in the third level state, the control signal is used to control the protection switch 131 to be turned off. After the control signal is switched from the first level state to the second level state, the control signal is switched from the second level state to the third level state. A frame of control signals is switched from the second level state to the third level state before the start signal is received by the start signal.

Specifically, the control signal accessed by the NCX terminal may have three level states. Before the time T0, the level of the control signal accessed by the NCX terminal is in the first level state NCX1. And the level of the control signal accessed by the NCX terminal is in a second level state NCX2 from the time T0 to the time T1. After the time T1, the level of the control signal accessed by the NCX terminal is in a third level state NCX3.

At time T0, the level of the control signal connected to the NCX terminal is switched from the first level state NCX1 to the second level state NCX2, and the thirteenth switching element T13 is switched from the off state to the on state. The thirteenth switching element T13 is in an on state from the time T0 to the time T1. At time T1, the level of the control signal connected to the NCX terminal is switched from the second level state NCX2 to the third level state NCX3, and the thirteenth switching element T13 is switched from the on state to the off state. The thirteenth switching element T13 is in an off state from the time T1 to the time T2.

The time T1 may be set at any time before the time T2 by one frame of the control signal, which may ensure that the one frame of the control signal before the time T2 is in the third level state NCX3, and the control signal may control the thirteenth switching element T13 to be turned off. The time T0 may be set at any time before the time T1. Thus, the time length from the time T0 to the time T1 can be arbitrarily set. Since the thirteenth switching element T13 is in the on state at the timings T0 to T1, the length of time the thirteenth switching element T13 is in the on state can be arbitrarily set.

By setting the time length from the time T0 to the time T1, the period of time during which the thirteenth switching element T13 is turned on can be set so that the negative charge accumulated on the transistor insulating film of the thirteenth switching element T13 is released.

Further, in some embodiments, in the event that the control signal switches from the first level state to the second level state, the level of the control signal is pulled low. In the case where the control signal is switched from the second level state to the third level state, the level of the control signal is pulled up.

At time T0, the level of the control signal connected to the NCX terminal is switched from the first level state NCX1 to the second level state NCX2, and the level of the control signal connected to the NCX terminal is pulled down, that is, the signal connected to the control electrode of the thirteenth switching element T13 is pulled down, so that the thirteenth switching element T13 is switched from the off state to the on state.

At time T1, the level of the control signal connected to the NCX terminal is switched from the second level state NCX2 to the third level state NCX3, and the level of the control signal connected to the NCX terminal is pulled high, that is, the signal connected to the control electrode of the thirteenth switching element T13 is pulled high, so that the thirteenth switching element T13 is turned on from the off state to the off state.

In some embodiments, the driving circuit 100 further includes a second switch 133, a third switch 134, a fourth switch 135, a first capacitor 136, and a second clock signal terminal 126. The second clock signal terminal 126 is electrically connected to a second clock signal line CB, which may provide a second clock signal to the second clock signal terminal 126. The control electrode of the second switch 133 is electrically connected to the first clock signal terminal 124. The first voltage terminal 121 is electrically connected to a first pole of the second switch 133, and a second pole of the second switch 133 is electrically connected to a control pole of the third switch 134. The second voltage terminal 122 is electrically connected to a first pole of the third switch 134, a second pole of the third switch 134 is electrically connected to a first pole of the fourth switch 135, and a second pole of the fourth switch 135 is electrically connected to the second clock signal terminal 126. One end of the first capacitor 136 is electrically connected to the second pole of the third switch 134, the other end of the first capacitor 136 is electrically connected to the control pole of the fourth switch 135, and the control pole of the fourth switch 135 is electrically connected to the control pole of the pull-down switch 130.

Specifically, referring to fig. 2, the second switch 133 may include a third switching element T3, the third switch 134 may include a fifth switching element T5, the fourth switch 135 may include a fourth switching element T4, and the first capacitor 136 may include a third capacitive element C3.

The first pole of the fourth switching element T4 is electrically connected to the second clock signal terminal 126. The second pole of the fourth switching element T4, the first pole of the fifth switching element T5, the control pole of the fourth switching element T4, and the first pole of the third capacitive element C3 are electrically connected to the second node N2. The second terminal of the fifth switching element T5 is electrically connected to the second voltage terminal 122, and the second pole of the third capacitive element C3 and the control pole of the fifth switching element T5 are electrically connected to the third node N3.

When the third switching element T3 is turned on, the low level signal VGL connected to the first voltage terminal 121 is written to the third node N3, and the fifth switching element T5 is turned on or off according to the voltage written to the third node N3. The fourth switching element T4 is turned on or off according to the voltage written at the second node N2.

In some embodiments, the driving circuit 100 further includes a fifth switch 137, and a control electrode of the fifth switch 137 is electrically connected to a control electrode of the pull-down switch 130. The first clock signal terminal 124 is electrically connected to a first pole of a fifth switch 137, and a second pole of the fifth switch is electrically connected to the third node N3.

Specifically, referring to fig. 2, the fifth switch 137 may include a second switching element T2, a first pole of the second switching element T2 is electrically connected to the first clock signal terminal 124, a second pole of the second switching element T2 is electrically connected to the third node N3, and a control pole of the second switching element T2 is electrically connected to the second node N2.

The first clock line CK may write a first clock signal to the first pole of the second switching element T2 through the first clock signal terminal 124, the second switching element T2 is turned on or off according to the voltage written to the second node N2, and the first clock signal may be written to the third node N3 in case that the second switching element T2 is turned on.

In some embodiments, the drive circuit 100 further includes a pull-up switch 138 and a sixth switch 139. The second voltage terminal 122 is electrically connected to the signal output terminal 110 through the pull-up switch 138, and the first voltage provided by the second voltage terminal 122 is connected to the signal output terminal 110 when the pull-up switch 138 is turned on. The second voltage terminal 122 is electrically connected to the control electrode of the pull-up switch 138 through a sixth switch 139, and the control electrode of the sixth switch 139 is electrically connected to the control electrode of the pull-down switch 130.

Specifically, referring to fig. 2, the pull-up switch 138 may include a ninth switching element T9, and the sixth switch 139 includes an eighth switching element T8. The second voltage terminal 122 is electrically connected to a first pole of the ninth switching element T9, and a second pole and an OUT terminal of the ninth switching element T9 are electrically connected to the fifth node N5. The VGH terminal is electrically connected to the first pole of the eighth switching element T8, the second pole of the eighth switching element T8 and the control pole of the ninth switching element T9 are electrically connected to the fourth node N4, and the control pole of the ninth switching element T9 is electrically connected to the first node N1.

With the thirteenth switching element T13 turned on, the high-level signal VGH is written to the first node N1, i.e., the control electrode of the eighth switching element T8, so that the eighth switching element T8 is turned off.

In some embodiments, the driving circuit 100 further includes a second capacitor 140, and the second capacitor 140 is electrically connected to the second voltage terminal 122 and the control electrode of the pull-up switch 138, respectively.

Specifically, referring to fig. 2, the second capacitor 140 may include a second capacitive element C2. The first pole of the second capacitive element C2 is electrically connected to the fourth node N4, and the second pole of the second capacitive element C2 is electrically connected to the fifth node N5.

The second capacitive element C2 may be used as a voltage stabilizing capacitor, the high level signal VGH is written into the fifth node N5, the second capacitive element C2 may stabilize the voltage written into the fourth node N4, that is, the voltage of the control electrode of the ninth switching element T9, and thus the on or off state of the ninth switching element T9 may be kept stable.

In some embodiments, the driving circuit 100 further includes a second switch 133, a seventh switch 141, an eighth switch 143, a third capacitor 142, and a second clock signal terminal 126. The second clock signal terminal 126 is used for accessing the second clock signal. The control electrode of the second switch 133 is electrically connected to the second clock signal terminal 126. The first voltage terminal 121 is electrically connected through the control electrodes of the second switch 133 and the seventh switch 141. The second clock signal terminal 126 is electrically connected to the control electrode of the pull-up switch 138 through a seventh switch 141 and an eighth switch 143, and the control electrode of the eighth switch 143 is electrically connected to the second clock signal terminal 126. One end of the third capacitor 142 is electrically connected between the seventh switch 141 and the eighth switch 143, and the other end of the third capacitor 142 is electrically connected to the control electrode of the seventh switch 141.

Specifically, referring to fig. 2, the seventh switch 141 may include a sixth switching element T6, the eighth switch 143 may include a seventh switching element T7, and the third capacitor 142 may include a first capacitive element C1.

The control electrode of the eleventh switching element T11 is electrically connected to the first voltage terminal 121, and the low-level signal VGL may be written into the control electrode of the eleventh switching element T11 through the first voltage terminal 121, so that the eleventh switching element T11 is turned on. The first pole of the eleventh switching element T11 is electrically connected to the third node N3, and the second pole of the eleventh switching element T11 is electrically connected to the sixth node N3. Since the eleventh switching element T11 is in the on state, the voltage written by the third node N3 is the same as the voltage written by the sixth node N6.

A first pole of the sixth switching element T6 is electrically connected to the second clock signal terminal 126, and a second terminal of the sixth switching element T6 is electrically connected to the seventh node N7. A first pole of the first capacitive element C1 is electrically connected to the sixth node N6, and a second pole of the first capacitive element C1 is electrically connected to the seventh node N7. The first pole of the seventh switching element T7 is electrically connected to the seventh node N7, the second pole of the seventh switching element T7 is electrically connected to the fourth node N4, and the control pole of the seventh switching element T7 is electrically connected to the second clock signal terminal 126.

The sixth switching element T6 is turned on or off according to the voltage written at the sixth node N6, and the second clock signal is written at the seventh node N7 when the sixth switching element T6 is turned on. The seventh switching element T7 is turned on or off under the control of the second clock signal, and when the seventh switching element T7 is turned on, the voltage of the seventh node N7 is the same as the voltage of the fourth node N4.

Referring to fig. 5, an embodiment of the present invention provides a display device 1000, and the display device 1000 includes the driving circuit 100 and the pixel circuit 200 according to any of the embodiments described above.

Specifically, the embodiments of the driving circuit 100 may refer to the above embodiments, and the embodiments of the display device 1000 include the driving circuit 100 of any one of the embodiments, and the beneficial effects of the display device 1000 include all the beneficial effects of the driving circuit 100, which are not described herein.

The display device 1000 may be any device that displays either motion (e.g., video) or stationary (e.g., still image) and whether text or image. More particularly, the display device 1000 may be one of a variety of electronic devices in or with which embodiments may be implemented. A variety of electronic devices such as, but not limited to, mobile phones, wireless devices, personal data assistants (PS 1), handheld or portable computers, GPS receivers/navigators, cameras, MP4 video players, video cameras, game consoles, wrist watches, clocks, calculators, television monitors, flat panel displays, computer monitors, auto displays (e.g., odometer display, etc.), navigators, cabin controllers and/or displays, camera view displays (e.g., display of a rear view camera in a vehicle), electronic photographs, electronic billboards or signs, projectors, architectural structures, packaging, and aesthetic structures (e.g., display of images on a piece of jewelry), and the like. The embodiment of the present disclosure does not particularly limit the specific form of the display device 1000 described above.

In the description of the present specification, reference is made to the terms "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., meaning that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

Furthermore, the term "coupled" is to be broadly interpreted and includes, for example, either permanently coupled, detachably coupled, or integrally coupled; can include direct connection, indirect connection through intermediate media, and communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps of the process, and further implementations are included within the scope of the preferred embodiment of the present invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order from that shown or discussed, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the embodiments of the present invention.

While embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the invention.

Claims

1. A driving circuit for driving a pixel circuit, the driving circuit comprising:

the signal output end is used for outputting a driving signal to drive the pixel circuit;

the first voltage end is used for accessing a first level signal;

The pull-down switch is electrically connected with the first voltage end through the pull-down switch and the signal output end, and under the condition that the pull-down switch is conducted, a first level signal accessed by the first voltage end is written into the signal output end;

the second voltage end is used for accessing a second level signal;

the second voltage end is electrically connected with the control electrode of the pull-down switch through the protection switch, and is used for providing the second level signal for the control electrode of the pull-down switch under the condition that the protection switch is turned on, so that the pull-down switch is turned off;

the control signal end is used for accessing a control signal, the control signal end is electrically connected with the control electrode of the protection switch, and the control signal is used for controlling the protection switch to be turned on or turned off;

the pixel circuit comprises a light emitting device, and the control signal is used for controlling the protection switch to be turned on and then controlling the protection switch to be turned off before the driving circuit drives the light emitting device to emit light;

and one frame of the control signal is used for controlling the protection switch to be turned off before the driving circuit drives the light emitting device to emit light.

2. The drive circuit of claim 1, wherein the drive circuit further comprises:

the starting signal end is used for accessing a starting signal;

the first clock signal end is used for accessing a first clock signal;

the first switch is used for writing the starting signal into the control electrode of the pull-down switch under the condition of being conducted so as to control the pull-down switch to be conducted or cut off.

3. The drive circuit of claim 2, wherein a frame of the control signal is used to control the protection switch to turn off before the start signal is received at the start signal.

4. A driving circuit according to claim 3, wherein the control signal is for controlling the protection switch to be turned off in case the control signal is in a first level state, for controlling the protection switch to be turned on in case the control signal is in a second level state, and for controlling the protection switch to be turned off in case the control signal is in a third level state;

After the control signal is switched from the first level state to the second level state, the control signal is switched from the second level state to the third level state;

the control signal is switched from the second level state to the third level state one frame before the start signal is received by the start signal.

5. The driver circuit according to claim 4, wherein in the case where the control signal is switched from the first level state to the second level state, the level of the control signal is pulled down;

in the case where the control signal is switched from the second level state to the third level state, the level of the control signal is pulled up.

6. The drive circuit of claim 2, further comprising a second switch, a third switch, a fourth switch, a first capacitor, and a second clock signal terminal;

the second clock signal end is used for accessing a second clock signal;

the control electrode of the second switch is electrically connected with the first clock signal end, the first voltage end is electrically connected with the control electrode of the third switch through the second switch, the second voltage end is electrically connected with the second clock signal end through the third switch and the fourth switch, one end of the first capacitor is electrically connected between the third switch and the fourth switch, the other end of the first capacitor is electrically connected with the control electrode of the fourth switch, and the control electrode of the fourth switch is electrically connected with the control electrode of the pull-down switch.

7. The drive circuit of claim 6, further comprising a fifth switch having a control electrode electrically connected to the control electrode of the pull-down switch, the first clock signal terminal being electrically connected to the control electrode of the third switch through the fifth switch.

8. The drive circuit of claim 1, wherein the drive circuit further comprises:

the second voltage end is electrically connected with the signal output end through the pull-up switch, and when the pull-up switch is conducted, the first voltage provided by the second voltage end is written into the signal output end;

and the second voltage end is electrically connected with the control electrode of the pull-up switch through the sixth switch, and the control electrode of the sixth switch is electrically connected with the control electrode of the pull-down switch.

9. The drive circuit of claim 8, further comprising a second capacitor electrically connected to the second voltage terminal and the control electrode of the pull-up switch, respectively.

10. The drive circuit of claim 9, further comprising a second switch, a seventh switch, an eighth switch, a third capacitor, and a second clock signal terminal;

The second clock signal end is used for accessing a second clock signal;

the control electrode of the second switch is electrically connected with the second clock signal end, the first voltage end is electrically connected with the control electrode of the seventh switch through the second switch, the second clock signal end is electrically connected with the control electrode of the pull-up switch through the seventh switch and the eighth switch, the control electrode of the eighth switch is electrically connected with the second clock signal end, one end of the third capacitor is electrically connected between the seventh switch and the eighth switch, and the other end of the third capacitor is electrically connected with the control electrode of the seventh switch.

11. A display device comprising the drive circuit according to any one of claims 1 to 10 and a pixel circuit.