Display driving circuit and display device

Abstract

The invention discloses a display driving circuit and a display device.The display driving circuit comprises a source electrode driving chip and a gamma chip, the source electrode driving chip comprises a plurality of source electrode signal driving modules, a first short circuit module, a first comparator, a second comparator and a logic judgment module, each source electrode signal driving module comprises a first switch, and each first short circuit module comprises a second switch. The first short circuit module comprises a second switch and a plurality of third switches, the receiving end of the logic judgment module is connected with the output end of the first comparator and the output end of the second comparator, and the output end of the logic judgment module is connected with the control ends of the first switch, the second switch and the third switches. And the first switch, the second switch and the third switch are controlled to be switched on and off according to output results of the first comparator and the second comparator. Through the above design, the problems of large pumping current and transient voltage difference of the common electrode signal and the source electrode driving signal in the power-on and power-off processes can be improved.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to a display driving circuit and a display device. Background Art

[0002] As consumers have higher and higher requirements for LCD panels, terminal manufacturers have lower and lower tolerance for the instantaneous screen flickering phenomenon when the LCD panel is turned on and off. This situation makes the source driver chip (SourceDriver) manufacturers design driver chips to make a power on / off reset function (POF) for the LCD panel when it is turned on and off. When the power is turned on (power on) or off (power off), all the output channels of the source driver chip are short-circuited together, and then short-circuited to the common electrode signal channel (CFVCOM) or the system ground (VSS). This can release the charge in the LCD panel as much as possible and ensure that the voltage between the electrodes on both sides of the liquid crystal (pixel electrode and common electrode) is consistent.

[0003] However, with the current power on / off reset structure design, during the power-on and power-off process of the LCD panel, the common electrode signal will experience a large current draw, and a short voltage difference will occur between the common electrode signal and the source drive signal, causing the LCD panel to flicker. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a display driving circuit and a display device to improve the problems of large current draw and short-term voltage difference between the common electrode signal and the source driving signal during power-on and power-off.

[0005] The embodiment of the present application discloses a display driving circuit, the display driving circuit includes a source driving chip and a gamma chip, the gamma chip is connected to the source driving chip through multiple gamma channels and a common electrode signal channel, the source driving chip includes multiple source signal driving modules, a first short-circuit module, a first comparator, a second comparator and a logic judgment module, the source signal driving module includes a first switch, the input end of the first switch is connected to the gamma channel correspondingly, and the output end of the first switch is connected to the data line in the display panel correspondingly; the first short-circuit module includes a second switch and multiple third switches, the input end of the second switch is connected to the common electrode signal channel, and the output end of the second switch is respectively connected to the corresponding source electrode through the third switch. The signal driving module is connected; the positive input terminal of the first comparator receives the reference voltage, and the negative input terminal of the first comparator receives the power supply voltage; the positive input terminal of the second comparator receives the power supply voltage, and the negative input terminal of the second comparator receives the first standard voltage; the receiving end of the logic judgment module is connected to the output end of the first comparator and the output end of the second comparator, and the output end of the logic judgment module is connected to the control end of the first switch, the second switch and the third switch, and the opening and closing of the first switch, the second switch and the third switch are controlled according to the output results of the first comparator and the second comparator; wherein the first standard voltage is the voltage of the display panel in the initial stage of power-on or the voltage of the display panel in the final stage of power-off.

[0006] Optionally, when the power supply voltage is lower than the first standard voltage, the logic determination module controls the second switch and the third switch to be turned on, and controls the first switch to be turned off.

[0007] Optionally, the display driving circuit also includes a second short-circuit module, which includes a fourth switch and multiple fifth switches, the input end and the output end of each of the fifth switches are respectively connected to two adjacent source signal driving modules, and all the fifth switches are grounded through the fourth switch; the output end of the logic judgment module is also connected to the control end of the fourth switch and the fifth switch, and the opening and closing of the first switch, the second switch, the third switch, the fourth switch and the fifth switch are controlled according to the output results of the first comparator and the second comparator.

[0008] Optionally, when the power supply voltage is lower than the first standard voltage, the logic judgment module controls the second switch and the third switch to open, and controls the first switch to open; or, when the power supply voltage is lower than the first standard voltage, the logic judgment module controls the second switch, the third switch, the fourth switch and the fifth switch to open, and controls the first switch to open.

[0009] Optionally, the display driving circuit also includes a third comparator, the positive input terminal of the third comparator receives the power supply voltage, the negative input terminal of the third comparator receives the second standard voltage, and the second standard voltage is the voltage of the display panel in the secondary stage of power-on or the voltage of the display panel in the penultimate stage of power-off; the output terminal of the third comparator is connected to the receiving end of the logic judgment module, and the logic judgment module controls the opening and closing of the first switch, the second switch, the third switch, the fourth switch and the fifth switch according to the output results of the first comparator, the second comparator and the third comparator.

[0010] Optionally, when the reference voltage is lower than the power supply voltage, and the power supply voltage is lower than the first standard voltage, the logic determination module controls the second switch and the third switch to be turned on, and controls the first switch, the fourth switch, and the fifth switch to be turned off; when the reference voltage is lower than the power supply voltage, and the power supply voltage is higher than the first standard voltage and lower than the second standard voltage, the logic determination module controls the second switch, the third switch, the fourth switch, and the fifth switch to be turned on, and controls the first switch to be turned off; when the reference voltage is lower than the power supply voltage, and the power supply voltage is higher than the second standard voltage, the logic determination module controls the fourth switch and the fifth switch to be turned on, and controls the first switch, the second switch, and the third switch to be turned off When the reference voltage is greater than the power supply voltage and the power supply voltage is less than the first standard voltage, the logic determination module controls the second switch and the third switch to be turned on, and controls the first switch, the fourth switch and the fifth switch to be turned off; when the reference voltage is greater than the power supply voltage and the power supply voltage is greater than the first standard voltage and less than the second standard voltage, the logic determination module controls the second switch, the third switch, the fourth switch and the fifth switch to be turned on, and controls the first switch to be turned off; when the reference voltage is greater than the power supply voltage and the power supply voltage is greater than the second standard voltage, the logic determination module controls the first switch to be turned on, and controls the second switch, the third switch, the fourth switch and the fifth switch to be turned off.

[0011] Optionally, the first short-circuit module also includes a sixth switch, the input end of the sixth switch is connected to the input end of the second switch, the output end of the sixth switch is grounded, and the control end of the sixth switch is connected to the output end of the logic judgment module, and the logic judgment module controls the opening and closing of the first switch, the second switch, the third switch, the fourth switch, the fifth switch and the sixth switch according to the output results of the first comparator, the second comparator and the third comparator; when the reference voltage is less than the power supply voltage, and the power supply voltage is greater than the first standard voltage and less than the second standard voltage, the logic judgment module controls the second switch, the third switch, the fourth switch, the fifth switch and the sixth switch. The logic judgment module controls the fourth switch, the fifth switch and the sixth switch to be turned on, and controls the first switch to be turned off; when the reference voltage is lower than the power supply voltage, and the power supply voltage is higher than the second standard voltage, the logic judgment module controls the fourth switch, the fifth switch and the sixth switch to be turned on, and controls the first switch, the second switch and the third switch to be turned off; when the reference voltage is higher than the power supply voltage, and the power supply voltage is higher than the first standard voltage and lower than the second standard voltage, the logic judgment module controls the second switch, the third switch, the fourth switch, the fifth switch and the sixth switch to be turned on, and controls the first switch to be turned off.

[0012] Optionally, the first short-circuit module further includes a first resistor, and the input end of the second switch is connected to the common electrode signal channel through the first resistor.

[0013] Optionally, the gamma chip is connected to the source driver chip through n gamma channels and a common electrode signal channel; the gamma chip includes a fourth comparator, the positive input end of the fourth comparator receives the power supply voltage, the negative input end of the fourth comparator receives the third standard voltage, and the output end of the fourth comparator is connected to the receiving end of the logic judgment module; wherein the third standard voltage is 70% of the power supply voltage; the gamma chip also includes n seventh switches and n-1 eighth switches, the gamma channel and the common electrode signal channel are connected to the source driver chip through the corresponding seventh switch; two adjacent gamma channels are connected through one eighth switch, and the common electrode signal channel and the adjacent gamma channel are also connected through one eighth switch; the control ends of the seventh switch and the eighth switch are connected to the output end of the logic judgment module, and the logic judgment module controls the opening and closing of the seventh switch and the eighth switch according to the output result of the fourth comparator.

[0014] An embodiment of the present application further discloses a display device, which includes a display panel and the display driving circuit as described above, wherein the display driving circuit is used to drive the display panel.

[0015] The beneficial effects of the embodiments of the present application are as follows: the embodiments of the present application provide a source signal driving module, a first short-circuit module, a first comparator, a second comparator and a logic determination module in the source driving chip of the display driving circuit; the logic determination module determines whether the current state is power-on or power-off according to the comparison result of the first comparator between the reference voltage and the power supply voltage; at the same time, the logic determination module determines which stage of power-on or power-off the current state is according to the comparison result of the second comparator between the power supply voltage and the first standard voltage; the logic determination module controls the switches in the source signal driving module and the first short-circuit module according to the comprehensive results of the first comparator and the second comparator, so that the ports corresponding to the gamma channel and the common electrode signal channel in the source driving chip can be short-circuited in a targeted manner at different stages of power-on or power-off, thereby realizing rapid discharge of the common electrode and the pixel electrode, and avoiding the problems of large current extraction and short-term voltage difference between the common electrode signal and the source driving signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The included drawings are used to provide a further understanding of the embodiments of the present application, which constitute a part of the specification, are used to illustrate the implementation methods of the present application, and together with the text description, explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0017] Figure 1 is a schematic diagram of a driver chip provided by the present application;

[0018] Figure 2 This application provides a Figure 1 Timing diagram of the structure during power-on;

[0019] Figure 3 This application provides a Figure 1 Timing diagram of the structure during power-off;

[0020] Figure 4 is a schematic diagram of a display driving circuit provided in the first embodiment of the present application;

[0021] Figure 5 is a schematic diagram of a display driving circuit provided in a second embodiment of the present application;

[0022] Figure 6 is a schematic diagram of a display driving circuit provided in the third embodiment of the present application;

[0023] Figure 7 This is a timing diagram provided in the third embodiment of the present application;

[0024] Figure 8 is a schematic diagram of a display driving circuit provided in a fourth embodiment of the present application;

[0025] Fig. 9 is a schematic diagram of another display driving circuit provided by the present application;

[0026] Fig.10 It is a schematic diagram of a display device provided by the present application.

[0027] Among them, 10, display device; 20, display driving circuit; 30, display panel; 100, source driving chip; 110, source signal driving module; 120, first short-circuit module; 130, first comparator; 140, second comparator; 150, logic judgment module; 160, second short-circuit module; 170, third comparator; R1, first resistor; T1, first switch; T2, second switch; T3, third switch; T4, fourth switch; T5, fifth switch; T6, sixth switch; m1, first standard voltage; m2, second standard voltage; 200, gamma chip; 210, low voltage difference linear regulator; 220, resistor voltage divider module; 230, fourth comparator; 240, gamma channel; 250, common electrode signal channel; T7, seventh switch; T8, eighth switch; m3, third standard voltage. DETAILED DESCRIPTION

[0028] It should be understood that the terms used herein, the specific structures and functional details disclosed are only for describing specific embodiments and are representative, but the present application can be implemented in many alternative forms and should not be construed as being limited to only the embodiments described herein.

[0029] In addition, unless otherwise clearly specified or limited, "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internally connected between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0030] Figure 1 is a schematic diagram of a source driver chip provided by the present application, such as Figure 1As shown, the source driver chip 100 includes a plurality of source signal driver modules 110, a first short-circuit module 120, a second short-circuit module 160, a comparator and a logic judgment module 150, the source signal driver module 110 includes a first switch T1, the input end of the first switch T1 is connected to the gamma channel 240, and the output end of the first switch T1 is connected to the data line in the display panel 30; the first short-circuit module 120 includes a second switch T2 and a plurality of third switches T3, the input end of the second switch T2 is connected to the common electrode signal channel 250 through a first resistor R1, and the output end of the second switch T2 is connected to the corresponding source signal driver module 110 through the third switch T3; the second short-circuit module 160 includes a fourth switch The first comparator 140 is a first comparator 140, a second comparator 140 and a plurality of fifth switches T5, wherein the input terminal and the output terminal of each fifth switch T5 are respectively connected to two adjacent source signal driving modules 110, and all the fifth switches T5 are grounded through the fourth switch T4; the positive input terminal of the comparator receives the power supply voltage (DVDD), and the negative input terminal of the second comparator 140 receives the first standard voltage m1; the receiving terminal of the logic determination module 150 is connected to the output terminal of the comparator, and the output terminal of the logic determination module 150 is connected to the control terminals of the first switch T1, the second switch T2 and the third switch T3, and the opening and closing of the first switch T1, the second switch T2, the third switch T3, the fourth switch T4 and the fifth switch T5 are controlled according to the output result of the comparator.

[0031] The power supply voltage (DVDD) is a DC voltage (generally 1.8V) supplied to the digital circuit of the source driver chip 100. The source driver chip 100 determines whether it is in a power-on or power-off state by detecting the voltage of DVDD. When DVDD is less than 0.9V, it is determined to be in the initial stage of power-on or power-off. The comparator outputs a low level, and the first switch T1 in the source signal driving module 110 is disconnected, shutting off the voltage output of the output port of the source driver chip 100 to the data line in the display panel 30; at the same time, the second switch T2, the third switch T3, the fourth switch T4 and the fifth switch T5 are opened, and all the output ports of the source driver chip 100 are short-connected together, and then short-connected to the common electrode signal channel 250 and the ground line. The first resistor R1 is a resistor of about 1000Ω, which is used to prevent large current surges.

[0032] It can be understood that, for the convenience of illustration, only two source signal driving modules 110 are shown in the figure, corresponding to the output port Yn and the output port Yn+1 of the source driving chip 100 respectively.

[0033] Combination Figure 1 and Figure 2 As shown, when the display panel 30 is powered on, before DVDD starts to rise from 0V to 0.9V, the first switch T1 of the source driver chip 100 is disconnected, and the second switch T2, the third switch T3, the fourth switch T4 and the fifth switch T5 are turned on, so that the output ports of the source driver chip 100 are all short-connected to the common electrode signal line and the ground line (VSS). Since the common electrode signal line is powered almost at the same time as DVDD, the common electrode signal voltage starts to climb at the same time as DVDD. Since the common electrode signal line and the ground line and the output port of the source driver chip 100 are short-connected together, the output port voltage of the synchronous source driver chip 100 will also be pulled up, and at this time the common electrode signal line will have a relatively large current draw (the current draw will cause the power supply of the common electrode signal line to overheat). Moreover, since the resistance value of the first resistor R1 is relatively large, there will be a difference in the climbing speed of the common electrode signal voltage and the output port voltage of the source driver chip 100, resulting in a voltage drop between the common electrode signal voltage and the output port voltage of the source driver chip 100 during the climbing period, and there will be a relatively short flickering phenomenon at this moment.

[0034] Combination Figure 1 and Figure 3 As shown, when the display panel 30 is powered off, when DVDD is adjusted to below 0.9V, since the common electrode signal line, the ground line, and the output port of the source driver chip 100 are short-circuited together, the common electrode signal line and the output port of the source driver chip 100 all start to lose power. However, since the grounding point is close to the output port of the source driver chip 100, the output port of the source driver chip 100 loses power faster. Therefore, there will be a certain voltage difference between the common electrode signal line and the output port of the source driver chip 100 for a relatively short time at this time, and this voltage difference will cause a relatively fast flickering phenomenon.

[0035] Visible adoption Figure 1 After the driving circuit structure, when the display panel 30 is powered on, the common electrode signal line will have a relatively large current draw, and there will be a voltage drop between the common electrode signal voltage and the output port voltage of the source driver chip 100; when the display panel 30 is powered off, there will be a short voltage difference between the common electrode signal line and the output port of the source driver chip 100, which will cause the display panel 30 to flicker.

[0036] Based on the above problems, the present application provides the following specific embodiments to improve the problems of large current draw and short-term voltage difference between the common electrode signal and the source drive signal during the power-on and power-off processes.

[0037] Embodiment 1:

[0038] like Figure 4As shown, the first embodiment of the present application provides a display driving circuit, the display driving circuit 20 includes a source driving chip 100 and a gamma chip 200, the gamma chip 200 is connected to the source driving chip 100 through multiple gamma channels 240 and a common electrode signal channel 250, the gamma channel 240 is used to output a data driving signal, the data driving signal is output to the data line through the source driving circuit, and finally output to the pixel electrode through the data line; the common electrode signal channel 250 is used to transmit a common voltage signal, and the common voltage signal is used to output to the common electrode; in the display panel 30, an electric field is formed between the pixel electrode and the common electrode to control the deflection of the liquid crystal.

[0039] The source driver chip 100 includes multiple source signal driver modules 110, a first short-circuit module 120, a first comparator 130, a second comparator 140 and a logic determination module 150. The source signal driver module 110 includes a first switch T1, the input end of the first switch T1 is correspondingly connected to the gamma channel 240, the output end of the first switch T1 is correspondingly connected to the data line in the display panel 30, and the output end of the first switch T1 is the output port of the source driver chip 100.

[0040] The first short-circuit module 120 includes a second switch T2 and a plurality of third switches T3, the input end of the second switch T2 is connected to the common electrode signal channel 250, and the output end of the second switch T2 is connected to the corresponding source signal driving module 110 through the third switch T3; the positive input end of the first comparator 130 receives the reference voltage (AVDD), and the negative input end of the first comparator 130 receives the power supply voltage (DVDD); the positive input end of the second comparator 140 receives the power supply voltage, and the negative input end of the second comparator 140 receives the first standard voltage m1; the receiving end of the logic determination module 150 is connected to the output end of the first comparator 130 and the output end of the second comparator 140, and the output end of the logic determination module 150 is connected to the control end of the first switch T1, the second switch T2 and the third switch T3, and the opening and closing of the first switch T1, the second switch T2 and the third switch T3 are controlled according to the output results of the first comparator 130 and the second comparator 140.

[0041] The first standard voltage m1 is the voltage of the display panel 30 in the initial stage of power-on or the voltage of the display panel 30 in the final stage of power-off. The power supply voltage may be 1.8V, and correspondingly, the first standard voltage m1 may be 0.9V.

[0042] In the embodiment of the present application, the display driving circuit 20 has only one short-circuit module, namely, the first short-circuit module 120 ; the display driving circuit 20 also has only two comparators, namely, the first comparator 130 and the second comparator 140 .

[0043] Among them, the number of third switches T3 in the first short-circuit module 120 is the same as the number of output ports in the source driver chip 100, and is also the same as the number of source signal driver modules 110 in the source driver chip 100, and the output end of each third switch T3 is connected to a corresponding source signal driver module 110.

[0044] Each source signal driving module 110 further includes an amplifier, and the input end of the first switch T1 is correspondingly connected to the gamma channel 240 through an amplifier.

[0045] In the embodiment of the present application, when the power supply voltage is less than the first standard voltage m1, the logic determination module 150 controls the second switch T2 and the third switch T3 to be turned on, and controls the first switch T1 to be turned off.

[0046] In the embodiment of the present application, a source signal driving module 110, a first short-circuit module 120, a first comparator 130, a second comparator 140 and a logic determination module 150 are arranged in the source driving chip 100 of the display driving circuit 20. The logic determination module 150 determines whether the current state is power-on or power-off according to the comparison result of the first comparator 130 between the reference voltage and the power supply voltage. At the same time, the logic determination module 150 determines which stage of power-on or power-off is located at this time according to the comparison result of the second comparator 140 between the power supply voltage and the first standard voltage m1. The logic determination module 150 controls the switches in the source signal driving module 110 and the first short-circuit module 120 according to the comprehensive results of the first comparator 130 and the second comparator 140, so that the ports corresponding to the gamma channel 240 and the common electrode signal channel 250 in the source driving chip 100 can be short-circuited in a targeted manner at different stages of power-on or power-off, so as to realize rapid discharge of the common electrode and the pixel electrode, and avoid the problems of large current extraction and short-term voltage difference between the common electrode signal and the source driving signal.

[0047] In the embodiment of the present application, the first short-circuit module 120 further includes a first resistor R1, and the input end of the second switch T2 is connected to the common electrode signal channel 250 through the first resistor R1. The first resistor R1 is 800-1200 ohms and is used to prevent large current surges.

[0048] Second embodiment:

[0049] like Figure 5As shown, as a display driving circuit provided in the second embodiment of the present application, the display driving circuit 20 further includes a second short-circuit module 160 on the basis of the first embodiment, and the second short-circuit module 160 includes a fourth switch T4 and a plurality of fifth switches T5, the input end and the output end of each of the fifth switches T5 are respectively connected to two adjacent source signal driving modules 110, and all the fifth switches T5 are grounded through the fourth switch T4; the output end of the logic determination module 150 is also connected to the control end of the fourth switch T4 and the fifth switch T5, and the opening and closing of the first switch T1, the second switch T2, the third switch T3, the fourth switch T4 and the fifth switch T5 are controlled according to the output results of the first comparator 130 and the second comparator 140.

[0050] In an embodiment of the present application, when the power supply voltage is less than the first standard voltage m1, the logic determination module 150 controls the second switch T2 and the third switch T3 to open, and controls the first switch T1 to open; or, when the power supply voltage is less than the first standard voltage m1, the logic determination module 150 controls the second switch T2, the third switch T3, the fourth switch T4 and the fifth switch T5 to open, and controls the first switch T1 to open.

[0051] When powering on and off, the embodiment of the present application can not only control all output ports of the source driver chip 100 and the common electrode signal channel 250 to be short-circuited together, but can also be further short-circuited to the ground line, so that the discharge effect is better and the problem of flickering of the display panel 30 is further avoided.

[0052] Third embodiment:

[0053] like Figure 6 As shown, as a display driving circuit provided in the third embodiment of the present application, the display driving circuit 20, on the basis of the second embodiment, further includes a third comparator 170, the positive input terminal of the third comparator 170 receives the power supply voltage, the negative input terminal of the third comparator 170 receives the second standard voltage m2, the second standard voltage m2 is the voltage of the display panel 30 in the secondary stage of power-on or the voltage of the display panel 30 in the penultimate stage of power-off; the output terminal of the third comparator 170 is connected to the receiving terminal of the logic determination module 150, and the logic determination module 150 controls the opening and closing of the first switch T1, the second switch T2, the third switch T3, the fourth switch T4 and the fifth switch T5 according to the output results of the first comparator 130, the second comparator 140 and the third comparator 170.

[0054] The first standard voltage m1 may be 0.9V, and the second standard voltage m2 may be 1.1V.

[0055] A1 A2 A3 Turn on the switch 0 0 0 T2, T3 0 0 1 T2, T3, T4, T5 0 1 1 T4, T5 1 0 0 T2, T3 1 0 1 T2, T3, T4, T5 1 1 1 T1

[0056] Table 1

[0057] Combination Figure 6 , Figure 7 As shown in Table 1, when the reference voltage is less than the power supply voltage, and the power supply voltage is less than the first standard voltage m1, the output results of the first comparator 130, the second comparator 140, and the third comparator 170 can be expressed as A1: A2: A3 = 000, which can be understood as the initial time period of power-on or the last time period of power-off, and the power of the pixel electrode and the common electrode on the display panel 30 is relatively small. In this regard, the logic determination module 150 controls the second switch T2 and the third switch T3 to be turned on, and controls the first switch T1, the fourth switch T4, and the fifth switch T5 to be turned off, so as to short-circuit the output port of the source driver chip 100 together, and short-circuit the common electrode, the common electrode signal channel 250, and the common electrode signal line.

[0058] When the reference voltage is less than the power supply voltage, and the power supply voltage is greater than the first standard voltage m1 and less than the second standard voltage m2, the output results of the first comparator 130, the second comparator 140 and the third comparator 170 can be expressed as A1: A2: A3 = 001, which can be understood as the second stage of power-on or the penultimate stage of power-off. At this time, the pixel electrodes and common electrodes on the display panel 30 still have a lot of electricity and need to be released as soon as possible. In this regard, the logic judgment module 150 controls the second switch T2, the third switch T3, the fourth switch T4 and the fifth switch T5 to open, and controls the first switch T1 to open, so as to short-circuit the output ports of the source driver chip 100 together, and short-circuit with the common electrode and ground.

[0059] When the reference voltage is less than the power supply voltage, and the power supply voltage is greater than the second standard voltage m2, the output results of the first comparator 130, the second comparator 140 and the third comparator 170 can be expressed as A1: A2: A3 = 011. At this time, it can be understood that the pixel electrodes need to be discharged quickly, but since the voltage of each pixel electrode is different, the logic judgment module 150 is required to control the fourth switch T4 and the fifth switch T5 to be turned on, and at the same time control the first switch T1, the second switch T2 and the third switch T3 to be turned off, so as to short-circuit all the output ports in the source driver chip 100 (that is, all pixel electrodes are short-circuited), and then short-circuit them to the ground line to quickly discharge the pixel electrodes.

[0060] When the reference voltage is greater than the power supply voltage, and the power supply voltage is less than the first standard voltage m1, the output results of the first comparator 130, the second comparator 140 and the third comparator 170 can be expressed as A1: A2: A3 = 100, which can be understood as the second half of the abnormal power failure of the power supply voltage (DVDD) or the initial stage of voltage recovery after abnormal power failure. In this regard, the logic determination module 150 controls the second switch T2 and the third switch T3 to open, and controls the first switch T1, the fourth switch T4 and the fifth switch T5 to be disconnected, so as to short-circuit all the output ports in the source driver chip 100 and short-circuit with the common electrode, so as to ensure that the pixel electrode voltage and the common electrode voltage drop at the same time.

[0061] When the reference voltage is greater than the power supply voltage, and the power supply voltage is greater than the first standard voltage m1 and less than the second standard voltage m2, the output results of the first comparator 130, the second comparator 140 and the third comparator 170 can be expressed as A1: A2: A3 = 101, which can be understood as the first half of the abnormal power failure of the power supply voltage (DVDD) or the second half of recovery after the abnormal power failure. At this time, the logic judgment module 150 controls the second switch T2, the third switch T3, the fourth switch T4 and the fifth switch T5 to be turned on, and controls the first switch T1 to be turned off, so as to short-circuit all the output ports in the source driver chip 100, and then short-circuit them to the ground line to achieve short-circuit, so as to quickly discharge the pixel electrode and the common electrode.

[0062] When the reference voltage is greater than the power supply voltage, and the power supply voltage is greater than the second standard voltage m2, the output results of the first comparator 130, the second comparator 140 and the third comparator 170 can be expressed as A1:A2:A3=111. At this time, the display panel 30 is in the display time period, and the logic judgment module 150 controls the first switch T1 to open, and controls the second switch T2, the third switch T3, the fourth switch T4 and the fifth switch T5 to be disconnected, and the source driver chip 100 maintains normal voltage output.

[0063] In some embodiments, the display driving circuit 20 may further include more than four comparators, and the connection sequence of more comparators is similar to that of the third embodiment, and will not be elaborated herein.

[0064] Fourth embodiment:

[0065] like Figure 8As shown, as a display driving circuit provided in the fourth embodiment of the present application, the display driving circuit 20 is further provided with a sixth switch T6 in the first short-circuit module 120 on the basis of the third embodiment, the input end of the sixth switch T6 is connected to the input end of the second switch T2, the output end of the sixth switch T6 is grounded, and the control end of the sixth switch T6 is connected to the output end of the logic determination module 150, and the logic determination module 150 controls the opening and closing of the first switch T1, the second switch T2, the third switch T3, the fourth switch T4, the fifth switch T5 and the sixth switch T6 according to the output results of the first comparator 130, the second comparator 140 and the third comparator 170.

[0066] Considering that in the third embodiment, when A1: A2: A3 = 011, the output ports of the source driver chip 100 will first be shorted to the ground line to accelerate the discharge of the pixel electrode, and the common electrode can only discharge slowly; due to the existence of the first resistor R1, when DVDD changes from 0.9V to 1.1V or from 1.1V to 0.9V, there is a voltage difference between the pixel electrode and the common electrode, resulting in a short and slight flicker phenomenon. Based on this, the fourth embodiment of the present application adds a sixth switch T6 in the first short-circuit module 120 to accelerate the discharge of the common electrode and avoid the voltage difference between the pixel electrode and the common electrode.

[0067] A1 A2 A3 Turn on the switch 0 0 0 T2, T3 0 0 1 T2, T3, T4, T5, T6 0 1 1 T4, T5, T6 1 0 0 T2, T3 1 0 1 T2, T3, T4, T5, T6 1 1 1 T1

[0068] Table 2

[0069] As shown in Table 2, in the embodiment of the present application, when the reference voltage is less than the power supply voltage, and the power supply voltage is less than the first standard voltage m1, the output results of the first comparator 130, the second comparator 140 and the third comparator 170 can be expressed as A1: A2: A3 = 000, which can be understood as the initial time period of power-on or the last time period of power-off, and the power of the pixel electrode and the common electrode on the display panel 30 is relatively small. In this regard, the logic determination module 150 controls the second switch T2 and the third switch T3 to open, and controls the first switch T1, the fourth switch T4 and the fifth switch T5 to be disconnected, so as to short-circuit the output port of the source driver chip 100 together, and short-circuit the common electrode, the common electrode signal channel 250, and the common electrode signal line.

[0070] When the reference voltage is less than the power supply voltage, and the power supply voltage is greater than the first standard voltage m1 and less than the second standard voltage m2, the output results of the first comparator 130, the second comparator 140 and the third comparator 170 can be expressed as A1: A2: A3 = 001, which can be understood as the second stage of power-on or the penultimate stage of power-off. At this time, the pixel electrodes and common electrodes on the display panel 30 still have a lot of electricity and need to be released as soon as possible. In this regard, the logic judgment module 150 controls the second switch T2, the third switch T3, the fourth switch T4, the fifth switch T5 and the sixth switch T6 to open, and controls the first switch T1 to be disconnected, short-circuiting the output port of the source driver chip 100 together, short-circuiting with the common electrode and grounding, and then connecting through the first resistor R1, so that the discharge of the pixel electrode and the common electrode can be accelerated at the same time.

[0071] When the reference voltage is less than the power supply voltage, and the power supply voltage is greater than the second standard voltage m2, the output results of the first comparator 130, the second comparator 140 and the third comparator 170 can be expressed as A1: A2: A3 = 011. At this time, it can be understood that the pixel electrodes need to be discharged quickly, but since the voltage of each pixel electrode is different, the logic judgment module 150 is required to control the fourth switch T4, the fifth switch T5 and the sixth switch T6 to be turned on, and at the same time control the first switch T1, the second switch T2 and the third switch T3 to be turned off, so as to short-circuit all the output ports in the source driver chip 100 (that is, all the pixel electrodes are short-circuited), and then short-circuit them to the ground line to quickly discharge the pixel electrodes.

[0072] When the reference voltage is greater than the power supply voltage, and the power supply voltage is less than the first standard voltage m1, the output results of the first comparator 130, the second comparator 140 and the third comparator 170 can be expressed as A1: A2: A3 = 100, which can be understood as the second half of the abnormal power failure of the power supply voltage (DVDD) or the initial stage of voltage recovery after abnormal power failure. In this regard, the logic determination module 150 controls the second switch T2 and the third switch T3 to open, and controls the first switch T1, the fourth switch T4 and the fifth switch T5 to be disconnected, so as to short-circuit all the output ports in the source driver chip 100 and short-circuit with the common electrode, so as to ensure that the pixel electrode voltage and the common electrode voltage drop at the same time.

[0073] When the reference voltage is greater than the power supply voltage, and the power supply voltage is greater than the first standard voltage m1 and less than the second standard voltage m2, the output results of the first comparator 130, the second comparator 140 and the third comparator 170 can be expressed as A1: A2: A3 = 101, which can be understood as the first half of the abnormal power failure of the power supply voltage (DVDD) or the second half of recovery after the abnormal power failure. At this time, the logic judgment module 150 controls the second switch T2, the third switch T3, the fourth switch T4, the fifth switch T5 and the sixth switch T6 to be turned on, and controls the first switch T1 to be turned off, so as to short-circuit all the output ports in the source driver chip 100, and then short-circuit with the common electrode, and short-circuit with the ground line, and then connect through the first resistor R1 to quickly discharge the pixel electrode and the common electrode.

[0074] When the reference voltage is greater than the power supply voltage, and the power supply voltage is greater than the second standard voltage m2, the output results of the first comparator 130, the second comparator 140 and the third comparator 170 can be expressed as A1:A2:A3=111. At this time, the display panel 30 is in the display time period, and the logic judgment module 150 controls the first switch T1 to open, and controls the second switch T2, the third switch T3, the fourth switch T4 and the fifth switch T5 to be disconnected, and the source driver chip 100 maintains normal voltage output.

[0075] like Fig. 9 As shown, in some embodiments, the gamma chip 200 includes a low dropout linear regulator 210 (LowDropout Regulator, LDO), a resistor voltage divider module 220 and a fourth comparator 230. The low dropout linear regulator 210 receives a reference voltage (AVDD) and outputs it to the resistor voltage divider module 220. The resistor voltage divider module 220 outputs a plurality of driving signals, each driving signal passes through a digital-to-analog converter (DAC) and an amplifier (OP) to obtain a gamma voltage and a common voltage. The gamma voltage (gamma) is output to the source driver chip 100 through a gamma channel 240, and the common voltage (CFVCOM) is output to the source driver chip 100 through a common electrode signal channel 250. The gamma chip 200 is connected to the source driver chip 100 through n gamma channels 240 and one common electrode signal channel 250, and the gamma chip 200 includes n digital-to-analog converters and n amplifiers.

[0076] The positive input terminal of the fourth comparator 230 receives the power supply voltage, the negative input terminal of the fourth comparator 230 receives the third standard voltage m3, and the output terminal of the fourth comparator 230 is connected to the receiving terminal of the logic determination module 150; wherein the third standard voltage m3 is 70% of the power supply voltage; the gamma chip 200 further includes n seventh switches T7 and n-1 eighth switches T8, the gamma channel 240 and the common electrode signal channel 250 are connected to the source driver chip 100 through the corresponding seventh switch T7; two adjacent gamma channels 240 are connected through one eighth switch T8, and the common electrode signal channel 250 and the adjacent gamma channel 240 are also connected through one eighth switch T8; the control terminals of the seventh switch T7 and the eighth switch T8 are connected to the output terminal of the logic determination module 150, and the logic determination module 150 controls the opening and closing of the seventh switch T7 and the eighth switch T8 according to the output result of the fourth comparator 230.

[0077] When the fourth comparator 230 detects that DVDD is lower than 70% of the normal DVDD (i.e., the power supply voltage DVDD drops from 1.8V to 1.2V), all seventh switches T7 are disconnected, all eighth switches T8 are opened and short-circuited, and the gamma voltage output by the gamma chip 200 to the source driver chip 100 and the pixel electrodes all output the same voltage. In this way, the voltage output by the source driver chip 100 to the pixel electrodes of the display panel 30 is consistent with the common voltage, so that the pixel electrode voltage and the common electrode voltage can be ensured to be consistent when powering on and off, avoiding flickering problems.

[0078] In some embodiments, there is only one logic determination module 150 in the display driving circuit 20, that is, the source driving chip 100 and the gamma chip 200 share one logic determination module 150. Of course, there may be more than two logic determination modules 150 in the display driving circuit 20, and the source driving chip 100 and the gamma chip 200 respectively use independent logic determination modules 150.

[0079] like Fig.10 As shown, the present application further provides a display device, wherein the display device 10 includes a display panel 30 and the display driving circuit 20 as described above, wherein the display panel 30 is a liquid crystal panel (Liquid Crystal Display, LCD).

[0080] The above content is a further detailed description of the present application in combination with specific optional implementation methods, and it cannot be determined that the specific implementation of the present application is limited to these descriptions. For ordinary technicians in the technical field to which the present application belongs, several simple deductions or substitutions can be made without departing from the concept of the present application, which should be deemed to fall within the scope of protection of the present application.

Claims

1. A display driving circuit, characterized in that: include: Source driver chip: and A gamma chip connected to the source driver chip via a plurality of gamma channels and a common electrode signal channel; The source driver chip comprises: A plurality of source signal driving modules, each of which comprises a first switch, an input end of the first switch being connected to the gamma channel correspondingly, and an output end of the first switch being connected to a data line in the display panel correspondingly; A first short-circuit module, the first short-circuit module includes a second switch and a plurality of third switches, the input end of the second switch is connected to the common electrode signal channel, and the output end of the second switch is connected to the corresponding source signal driving module through the third switch; A first comparator, wherein a positive input terminal of the first comparator receives a reference voltage, and a negative input terminal of the first comparator receives a power supply voltage; a second comparator, wherein a positive input terminal of the second comparator receives a power supply voltage, and a negative input terminal of the second comparator receives a first standard voltage; and a logic determination module, wherein a receiving end of the logic determination module is connected to an output end of the first comparator and an output end of the second comparator, an output end of the logic determination module is connected to control ends of the first switch, the second switch and the third switch, and the opening and closing of the first switch, the second switch and the third switch are controlled according to output results of the first comparator and the second comparator; The first standard voltage is a voltage of the display panel in an initial stage of powering on or a voltage of the display panel in a final stage of powering off.

2. The display driving circuit according to claim 1, characterized in that: When the power supply voltage is lower than the first standard voltage, the logic determination module controls the second switch and the third switch to be turned on, and controls the first switch to be turned off.

3. The display driving circuit according to claim 2, characterized in that: The display driving circuit further includes a second short-circuit module, the second short-circuit module includes a fourth switch and a plurality of fifth switches, the input end and the output end of each of the fifth switches are respectively connected to two adjacent source signal driving modules, and all the fifth switches are grounded through the fourth switch; The output end of the logic judgment module is also connected to the control ends of the fourth switch and the fifth switch, and controls the opening and closing of the first switch, the second switch, the third switch, the fourth switch and the fifth switch according to the output results of the first comparator and the second comparator.

4. The display driving circuit according to claim 3, characterized in that: When the power supply voltage is lower than the first standard voltage, the logic determination module controls the second switch and the third switch to be turned on, and controls the first switch to be turned off; or, when the power supply voltage is lower than the first standard voltage, the logic determination module controls the second switch, the third switch, the fourth switch and the fifth switch to be turned on, and controls the first switch to be turned off.

5. The display driving circuit according to claim 3, characterized in that: The display driving circuit further includes a third comparator, wherein a positive input terminal of the third comparator receives a power supply voltage, and a negative input terminal of the third comparator receives a second standard voltage, wherein the second standard voltage is a voltage of the display panel in a secondary power-on stage or a voltage of the display panel in a penultimate power-off stage; The output end of the third comparator is connected to the receiving end of the logic determination module, and the logic determination module controls the opening and closing of the first switch, the second switch, the third switch, the fourth switch and the fifth switch according to the output results of the first comparator, the second comparator and the third comparator.

6. The display driving circuit according to claim 5, characterized in that: When the reference voltage is lower than the power supply voltage, and the power supply voltage is lower than the first standard voltage, the logic determination module controls the second switch and the third switch to be turned on, and controls the first switch, the fourth switch, and the fifth switch to be turned off; When the reference voltage is lower than the power supply voltage, and the power supply voltage is higher than the first standard voltage and lower than the second standard voltage, the logic determination module controls the second switch, the third switch, the fourth switch, and the fifth switch to be turned on, and controls the first switch to be turned off; When the reference voltage is less than the power supply voltage and the power supply voltage is greater than the second standard voltage, the logic determination module controls the fourth switch and the fifth switch to be turned on, and controls the first switch, the second switch and the third switch to be turned off; When the reference voltage is greater than the power supply voltage and the power supply voltage is less than the first standard voltage, the logic determination module controls the second switch and the third switch to be turned on, and controls the first switch, the fourth switch and the fifth switch to be turned off; When the reference voltage is greater than the power supply voltage, and the power supply voltage is greater than the first standard voltage and less than the second standard voltage, the logic determination module controls the second switch, the third switch, the fourth switch, and the fifth switch to be turned on, and controls the first switch to be turned off; When the reference voltage is greater than the power supply voltage, and the power supply voltage is greater than the second standard voltage, the logic determination module controls the first switch to open, and controls the second switch, the third switch, the fourth switch, and the fifth switch to open.

7. The display driving circuit according to claim 5, characterized in that: The first short-circuit module further includes a sixth switch, an input end of the sixth switch is connected to an input end of the second switch, an output end of the sixth switch is grounded, and a control end of the sixth switch is connected to an output end of the logic determination module, and the logic determination module controls the opening and closing of the first switch, the second switch, the third switch, the fourth switch, the fifth switch and the sixth switch according to the output results of the first comparator, the second comparator and the third comparator; When the reference voltage is lower than the power supply voltage, and the power supply voltage is higher than the first standard voltage and lower than the second standard voltage, the logic determination module controls the second switch, the third switch, the fourth switch, the fifth switch, and the sixth switch to be turned on, and controls the first switch to be turned off; When the reference voltage is less than the power supply voltage and the power supply voltage is greater than the second standard voltage, the logic determination module controls the fourth switch, the fifth switch and the sixth switch to be turned on, and controls the first switch, the second switch and the third switch to be turned off; When the reference voltage is greater than the power supply voltage, and the power supply voltage is greater than the first standard voltage and less than the second standard voltage, the logic determination module controls the second switch, the third switch, the fourth switch, the fifth switch, and the sixth switch to be turned on, and controls the first switch to be turned off.

8. The display driving circuit according to any one of claims 1 to 7, characterized in that: The first short-circuit module further includes a first resistor, and the input end of the second switch is connected to the common electrode signal channel through the first resistor.

9. The display driving circuit according to any one of claims 1 to 8, characterized in that: The gamma chip is connected to the source driver chip via n gamma channels and a common electrode signal channel; The gamma chip includes a fourth comparator, a positive input terminal of the fourth comparator receives a power supply voltage, a negative input terminal of the fourth comparator receives a third standard voltage, and an output terminal of the fourth comparator is connected to a receiving terminal of the logic determination module; wherein the third standard voltage is 70% of the power supply voltage; The gamma chip further includes n seventh switches and n-1 eighth switches, the gamma channel and the common electrode signal channel are connected to the source driver chip through the corresponding seventh switches; two adjacent gamma channels are connected through one eighth switch, and the common electrode signal channel and the adjacent gamma channel are also connected through one eighth switch; The control ends of the seventh switch and the eighth switch are connected to the output end of the logic determination module, and the logic determination module controls the opening and closing of the seventh switch and the eighth switch according to the output result of the fourth comparator.

10. A display device, characterized in that: It comprises a display panel and a display driving circuit as claimed in any one of claims 1 to 9, wherein the display driving circuit is used to drive the display panel.

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