Display device

Abstract

A display device comprises a display panel, a power management integrated circuit, a source electrode driving circuit and a common voltage module located outside the display panel and the power management integrated circuit. The source electrode driving circuit is electrically connected with the display panel and the power management integrated circuit respectively; the common voltage module is used for providing a common voltage signal for a common electrode of the display panel, and the common voltage signal and a shell of the display device are equipotential; the power management integrated circuit is used for providing a positive voltage source and a negative voltage source for the source electrode driving circuit; the source electrode driving circuit is used for generating a positive-polarity or negative-polarity analog data signal of the display panel, a power supply used by the positive-polarity analog data signal is the positive voltage source, and a power supply used by the negative-polarity analog data signal is the negative voltage source.

Description

Technical Field

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

[0002] Liquid crystal display products are mainly composed of liquid crystal display panel, timing controller (TCON), source driver circuit (Source Driver), power management integrated circuit (Power Management IC, PMIC) and backlight source.

[0003] At present, the source drive circuits used in large-size LCD products are basically full positive voltage (AVDD) or full positive half voltage (HAVDD). A characteristic of LCD panels is that when the bright and dark images are continuously alternating, the human eye will feel flickering. This is because the LCD panel controls the liquid crystal deflection with voltage, and the liquid crystal is driven in an alternating manner. If the reference voltage (VCOM) of the liquid crystal deflection is not debugged well, the voltages of the two frames before and after will be different, and the displayed image will appear to be alternating between bright and dark, and flickering.

[0004] In the prior art, the Flicker value is generally minimized by adjusting the liquid crystal deflection reference voltage (usually recorded as VCOM voltage), wherein the VCOM voltage is generally output by the PMIC. However, in large-size display products, the VCOM electrode is generally located on the color film substrate side of the liquid crystal display panel. Since the source drive circuit generally adopts the HAVDD architecture, the VCOM voltage is generally set at around 7 to 8V. When doing reliability high and low temperature tests or other tests that generate water vapor, water vapor usually enters between the VCOM electrode (Vcom≒7V) and the GND (0V) of the liquid crystal display product, and the connection circuit (Return circuit) is formed by the water vapor, causing electrochemical corrosion. Summary of the invention

[0005] The embodiments of the present disclosure provide a display device to solve the above problems existing in the prior art.

[0006] In a first aspect, in order to solve the above technical problems, the present disclosure provides a display device, including:

[0007] A display panel, a power management integrated circuit and a source driving circuit, and a common voltage module located outside the display panel and the power management integrated circuit; the source driving circuit is electrically connected to the display panel and the power management integrated circuit respectively; the common voltage module is used to provide a common voltage signal to the common electrode of the display panel, and the common voltage signal has the same potential as the housing of the display device;

[0008] The power management integrated circuit is used to provide a positive voltage source and a negative voltage source to the source driving circuit; the source driving circuit is used to generate an analog data signal of positive polarity or negative polarity for the display panel, the power source used by the analog data signal of positive polarity is the positive voltage source, and the power source used by the analog data signal of negative polarity is the negative voltage source.

[0009] In a possible implementation manner, the source driving circuit includes:

[0010] A plurality of gamma voltage generating circuits correspond to a plurality of gamma voltages; the gamma voltage generating circuits are used to buffer the corresponding original gamma voltages to obtain corresponding gamma voltages, and the gamma voltages are used to generate analog data signals required by the display panel; the reference voltage of the gamma voltage generating circuit includes the positive voltage source and the negative voltage source.

[0011] In a possible implementation manner, the gamma voltage generating circuit includes:

[0012] a first operational amplifier, wherein an inverting input terminal of the first operational amplifier is connected to an output terminal of the first operational amplifier, and the output terminal of the first operational amplifier serves as an output terminal of the gamma voltage generating circuit; and two power supply terminals of the first operational amplifier are respectively connected to the positive voltage source and the negative voltage source;

[0013] A protection circuit, wherein the input end of the protection circuit serves as the input end of the gamma voltage generating circuit, the output end of the protection circuit is connected to the non-inverting input end of the first operational amplifier, the two reference voltages of the protection circuit are the positive voltage source and the negative voltage source, and the protection circuit is used to prevent static electricity and leakage of the first operational amplifier.

[0014] In a possible implementation manner, the protection circuit includes:

[0015] a second operational amplifier, wherein a non-inverting input terminal of the second operational amplifier is used to receive the original gamma voltage, an output terminal of the second operational amplifier is connected to an inverting input terminal of the second operational amplifier and a non-inverting input terminal of the first operational amplifier, and the second operational amplifier is used to prevent leakage of the non-inverting input terminal of the first operational amplifier;

[0016] a first diode, electrically connected between the inverting input terminal of the second operational amplifier and the positive voltage source, the first diode being used to guide the leakage current generated when the original gamma voltage is greater than 0 to the positive voltage source;

[0017] The second diode is connected between the inverting input terminal of the second operational amplifier and the negative voltage source, and the second diode is used to guide the leakage current generated when the original gamma voltage is less than 0 to the negative voltage source.

[0018] In a possible implementation manner, the protection circuit further includes:

[0019] A third diode and a fourth diode connected in parallel, with the anode of the third diode connected between the cathode of the fourth diode and the cathode of the first diode, and the cathode of the third diode connected to the anode of the fourth diode and the non-inverting input terminal of the second operational amplifier;

[0020] The third diode is used to prevent positive static electricity from damaging the non-inverting input terminal of the second operational amplifier;

[0021] The fourth diode is used to prevent negative static electricity from damaging the non-inverting input terminal of the second operational amplifier.

[0022] In a possible implementation manner, the protection circuit further includes:

[0023] a first resistor connected between the inverting input terminal of the second operational amplifier and the cathode of the first diode;

[0024] Or / and a second resistor, connected between the signal input terminal and the non-inverting input terminal of the second operational amplifier; the second resistor is configured to limit the current of the non-inverting input terminal of the second operational amplifier.

[0025] In a possible implementation manner, the common voltage module is grounded, and the housing is grounded.

[0026] In a possible implementation manner, the source driving circuit includes the common voltage generating module.

[0027] A possible implementation manner, a power management integrated circuit, includes:

[0028] A first power supply generating circuit, used for generating the positive voltage source;

[0029] The second power supply generating circuit is used to generate the negative voltage source.

[0030] In a possible implementation manner, the display panel includes:

[0031] An array substrate and a counter substrate;

[0032] The array substrate comprises scan lines and data lines, wherein the scan lines and the data lines intersect to define a pixel area, and the pixel area comprises a pixel electrode;

[0033] The counter substrate includes the common electrode, and the common electrode is electrically connected to the common voltage module.

[0034] A possible implementation further includes:

[0035] A timing control circuit, electrically connected to the display panel and the source driving circuit;

[0036] The timing control circuit is used to generate a control signal according to an input synchronization signal, and provide the control signal to the display panel to control the source driving circuit to generate a corresponding analog data signal according to the digital data signal provided by the timing control circuit and load it onto the corresponding data line. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A schematic diagram showing the structure of a product;

[0038] Figure 2 Schematic diagram showing corrosion of products due to water vapor intrusion;

[0039] Figure 3 A schematic diagram of the structure of a display device provided in an embodiment of the present disclosure;

[0040] Figure 4 A schematic diagram of the structure of another display device provided by an embodiment of the present disclosure;

[0041] Figure 5 A schematic diagram of the structure of a voltage management integrated circuit provided by an embodiment of the present disclosure;

[0042] Figure 6 A schematic diagram of the structure of another display device provided by an embodiment of the present disclosure;

[0043] Figure 7 The schematic diagram of a gamma generation circuit in the related art in which the reference voltage is a positive voltage source;

[0044] Figure 8 The schematic diagram of a gamma generation circuit in which the reference voltage is a negative voltage source in the related art;

[0045] Fig. 9 A schematic diagram of the structure of another display device provided by an embodiment of the present disclosure;

[0046] Fig.10 A schematic diagram of the structure of a gamma generation circuit provided by an embodiment of the present disclosure;

[0047] Fig.11 A schematic diagram of another protection circuit provided in an embodiment of the present disclosure;

[0048] Fig.12A schematic diagram of another protection circuit provided in an embodiment of the present disclosure;

[0049] Figure 13-Figure 15 A schematic diagram of another protection circuit provided in an embodiment of the present disclosure.

[0050] Reference numerals:

[0051] Liquid crystal display panel 100, source driving circuit 200, PMIC 300, TCON 400, housing 500, backlight source 600, array substrate 100a, color film substrate 100b, frame sealant 700, UV glue 800, front frame 500a, bottom frame 500b;

[0052] Display panel 1, power management integrated circuit 2, source driving circuit 3, common voltage module VCOM, gamma voltage generating circuit 31, first power generating circuit 21, second power generating circuit 22, main control circuit 23, first buck circuit 24, boost circuit 25, second buck circuit 26, positive voltage source PAVDD, negative voltage source NAVDD, first operational amplifier OP1, protection circuit DS, first diode D1, second diode D2, second operational amplifier OP2, third diode D3, fourth diode D4, first resistor R1, second resistor R2, array substrate 11, opposing substrate 12, common electrode 121, timing control circuit 4. DETAILED DESCRIPTION

[0053] The embodiments of the present disclosure provide a display device to solve the problem that the common electrode of a display product is easily corroded due to water vapor intrusion.

[0054] In order to make the above-mentioned purposes, features and advantages of the present disclosure more obvious and easy to understand, the present disclosure will be further described below with reference to the accompanying drawings and examples. However, the example embodiments can be implemented in various forms and should not be understood as being limited to the embodiments described herein; on the contrary, these embodiments are provided to make the present disclosure more comprehensive and complete, and to fully convey the concepts of the example embodiments to those skilled in the art. The same figure marks in the figures represent the same or similar structures, and thus their repeated descriptions will be omitted. The words expressing position and direction described in the present disclosure are all explained using the accompanying drawings as examples, but changes can be made as needed, and the changes made are all included in the scope of protection of the present disclosure. The drawings of the present disclosure are only used to illustrate the relative position relationship and do not represent the true proportion.

[0055] It should be noted that specific details are described in the following description to facilitate a full understanding of the present disclosure. However, the present disclosure can be implemented in a variety of other ways different from those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present disclosure. Therefore, the present disclosure is not limited to the specific implementation methods disclosed below. The subsequent description of the specification is a preferred implementation method for implementing the present disclosure, but the description is for the purpose of illustrating the general principles of the present disclosure and is not intended to limit the scope of the present disclosure. The scope of protection of the present disclosure shall be determined by the definition of the attached claims.

[0056] See also Figure 1 Schematic diagram of a display product, which generally includes a liquid crystal display panel 100, a source driving circuit 200, a PMIC 300, and a TCON 400.

[0057] The liquid crystal display panel 100 includes an array substrate 100a, a color film substrate 100b and liquid crystals. Data lines and gate lines are formed on the array substrate 100a. Thin film transistors (TFTs) arranged at the intersections of the data lines and the gate lines are used to transmit data signals to pixel electrodes of the array substrate 100a. TCON400 is used to generate a control signal (such as STV / CLK / VDD) for controlling the source driving circuit 200 according to the input synchronization signal. The source driving circuit 200 is used to generate a data signal required to drive the liquid crystal display panel 100 according to the data signal required by the source driving circuit 200 generated by TCON400, and input the data signal into the pixel electrode of the liquid crystal display panel 100. PMIC300 provides the voltage required by each module, such as PMIC300 provides a VCOM voltage for the liquid crystal TV panel and provides a full positive voltage (AVDD) or a full half positive voltage (HAVDD) for the source driving circuit 200.

[0058] See also Figure 2 Schematic diagram of corrosion caused by water vapor intrusion into a display product. The large-size display product includes a housing 500 (including a front frame 500a and a bottom frame 500b), a backlight source 600, an array substrate 100a and a color filter substrate 100b arranged opposite to each other, a frame sealant 700 is arranged around the display area of ​​the array substrate 100a, and a UV glue 800 is arranged on the outer edges of the array substrate 100a and the color filter substrate 100b. Since the common electrode of the large-size display product is arranged on the side of the color filter substrate 100b, and the source drive circuit 200 adopts a full half positive voltage (HAVDD) architecture, the VCOM voltage is generally set at about 7 to 8V.

[0059] When doing reliability high and low temperature tests or other tests that generate water vapor, water vapor will enter the gap between the color film substrate 100b and the array substrate 100a in the corner of the display panel where there is no UV glue 800 protection. The water vapor is in direct contact with the common electrode. When power is applied, a connection circuit is formed between the common electrode (the voltage of the common motor Vcom≒7V) and the shell 500 (usually grounded, which is 0V) through the water vapor, causing electrochemical corrosion of the common electrode, which in turn leads to abnormal display of the display product.

[0060] In order to solve the above problems, an embodiment of the present disclosure provides a display device, which will be described in detail below with reference to the accompanying drawings.

[0061] See also Figure 3 A schematic diagram of a display device provided in an embodiment of the present disclosure, the display device comprising:

[0062] Display panel 1, power management integrated circuit 2 and source driving circuit 3, common voltage module VCOM located outside display panel 1 and power management integrated circuit 2; source driving circuit 3 is electrically connected to display panel 1 and power management integrated circuit 2 respectively; common voltage module VCOM is used to provide common voltage signal to common electrode 121 of display panel 1, and common voltage signal has the same potential as housing 500 (not shown) of display device;

[0063] The power management integrated circuit 2 is used to provide a positive voltage source PAVDD and a negative voltage source NAVDD to the source driving circuit 3; the source driving circuit 3 is used to generate a positive polarity or negative polarity analog data signal for the display panel 1, the power supply used by the positive polarity analog data signal is the positive voltage source PAVDD, and the power supply used by the negative polarity analog data signal is the negative voltage source NAVDD.

[0064] The positive voltage source PAVDD and the negative voltage source NAVDD have the same absolute value.

[0065] Since a common voltage module VCOM is provided in the display device, the common voltage module VCOM makes the common voltage signal provided to the common electrode 121 equal to the housing 500 of the display device, so that even if water vapor invades the display panel 1, since the common electrode 121 and the housing 500 of the display panel 1 are equal in potential, no electric field will be formed between the common electrode 121 and the display panel 1, and no electrochemical corrosion will occur on the common electrode 121; and since the common voltage module VCOM that provides the common voltage to the common electrode 121 is provided outside the power management integrated circuit 2, it is no longer necessary to provide the common voltage module VCOM inside the power management integrated circuit 2 as in the prior art, thereby effectively reducing the cost of the power management integrated circuit 2. At the same time, since the power management integrated circuit 2 provides the positive voltage source PAVDD and the negative voltage source NAVDD for the source driving circuit 3, the driving voltage inside the source driving circuit 3 can adopt a positive and negative voltage architecture, which is convenient for adjusting the flicker phenomenon (Flicker) through the gamma circuit inside the source driving circuit 3 to maintain a good display effect.

[0066] In some embodiments, the common voltage module VCOM is grounded, and the housing 500 of the display device is also grounded. In this way, the common electrode 121 and the housing 500 can have the same potential without adding additional circuits.

[0067] See also Figure 4 This is a schematic diagram of the structure of another display device provided in an embodiment of the present disclosure. The display panel 1 in the display device includes:

[0068] An array substrate 11 and an opposing substrate 12;

[0069] The array substrate 11 includes scan lines (not shown) and data lines (not shown). The scan lines and the data lines intersect to define a pixel region. The pixel region includes a pixel electrode ( Figure 4 not shown);

[0070] The counter substrate 12 includes a common electrode 121, and the common electrode 121 is connected to a common voltage module VCOM ( Fig.14 not shown) electrical connections.

[0071] like Figure 4 As shown, since the common electrode 121 is electrically connected to the common voltage module VCOM, and the common voltage module VCOM and the shell 500 of the display device are at the same potential, such as 0V, no electric field will be generated between the shell 500 and the common electrode 121. When performing reliability high and low temperature tests or other tests that generate water vapor, even if water vapor invades the display panel 1, a connection circuit between the shell 500 and the common electrode 121 will not be formed through the water vapor, thereby preventing the common electrode 121 from electrochemical corrosion.

[0072] See also Figure 5 A schematic diagram of the structure of a voltage management integrated circuit provided by an embodiment of the present disclosure. The power management integrated circuit 2 includes:

[0073] A first power supply generating circuit 21, used for generating a positive voltage source PAVDD;

[0074] The second power supply generating circuit 22 is used to generate a negative voltage source NAVDD.

[0075] like Figure 5 As shown, the power management integrated circuit 2 also includes:

[0076] A main control circuit 23, used to control the power management integrated circuit 2 according to the external signal received by VIN;

[0077] A first step-down circuit 24 is used to generate a core voltage required by the source driving circuit 3, which is usually 1.1V, and is provided to the source driving circuit 3 through VIO;

[0078] A boost circuit 25, used to generate a high level signal for turning on pixels in the display panel 1, provided by VGH;

[0079] The second step-down circuit 26 is used to generate a low-level signal for turning off pixels in the display panel 1 and is provided through VGL.

[0080] Since the power management integrated circuit 2 in the embodiment provided by the present disclosure is provided with a first power generation circuit 21 providing a positive voltage source PAVDD and a second power generation circuit 22 providing a negative voltage source NAVDD, the source driving circuit 3 can obtain the positive voltage source PAVDD and the negative voltage source NAVDD from the power management integrated circuit 2, thereby adopting a positive and negative voltage architecture and adjusting the flicker phenomenon by adjusting the gamma voltage. At the same time, since the power management integrated circuit 2 no longer needs to be provided with a voltage generation circuit providing a common voltage signal, the cost of the power management integrated circuit 2 can be effectively saved.

[0081] See also Figure 6 A schematic structural diagram of another display device provided in an embodiment of the present disclosure.

[0082] like Figure 6 As shown, the source driving circuit 3 includes a common voltage generating module. In other embodiments, the common voltage generating module may also be arranged in other driving circuits outside the display panel 1, such as in a gate driving circuit or in a timing control circuit 4, without any specific limitation.

[0083] Please continue to see Figure 6 , the source driving circuit 3 further includes:

[0084] Multiple gamma voltage generating circuits 31 correspond to multiple gamma voltages; the gamma voltage generating circuit 31 is used to buffer the corresponding original gamma voltage to obtain the corresponding gamma voltage, and the gamma voltage is used to generate the analog data signal required by the display panel 1; the driving voltage of the gamma voltage generating circuit 31 includes a positive voltage source PAVDD and a negative voltage source NAVDD.

[0085] For example, the display panel 1 includes 18 gamma voltages (denoted as GMA1 to GMA18), each of which corresponds to a gamma voltage generating circuit 31. The gamma generating circuit 31 can convert the digital data signal sent by the timing control board into an analog data signal that can be recognized by the display panel 1.

[0086] In the related art, the reference voltage of GMA1-9 is the positive voltage source PAVDD, and the reference voltage of GMA10-18 is the negative voltage source NAVDD. Figure 7 and Figure 8 As shown, Figure 7 is a schematic diagram of a gamma generation circuit in which the reference voltage is a positive voltage source in the related art, Figure 8 FIG. 1 is a schematic diagram of a gamma generation circuit in which the reference voltage is a negative voltage source in the related art. Figure 7 and Figure 8 It can be seen that the gamma generation circuits in the related art all include an operational amplifier circuit (OP) and two diodes (D1', D2'), and the difference is that their reference voltages are different. This circuit structure makes it impossible for any gamma generation circuit to cross 0V. For example, the gamma generation circuit corresponding to GMA10 cannot cross 0V from a negative voltage to a positive voltage, so it is impossible to adjust the flicker phenomenon through gamma adjustment.

[0087] For example, when adjusting GMA10, when the input voltage Vin' corresponding to GMA10 is adjusted, diodes D1' and D2' are connected in series, and the two ends are connected to GND (i.e. 0V) and NAVDD respectively. The non-inverting input of the operational amplifier OP is connected to Vin' after being protected from static electricity by diodes D1' and D2', and the power supply of the operational amplifier OP is connected to GND and NAVDD respectively. When the input voltage Vin' corresponding to GMA10 is a negative voltage, the circuit is powered normally. However, when the input voltage Vin' corresponding to GMA10 is a positive voltage, the voltage will leak through diode D1', and the leakage will cause poor display and damage to diode D1'. This limits GMA9>0V and GMA10<0V, which brings inconvenience to adjusting the flicker phenomenon by adjusting the gamma voltage. Therefore, the gamma generation circuit in the prior art cannot adjust the flicker phenomenon by adjusting the gamma voltage.

[0088] In the present disclosure, the positive voltage source PAVDD and the negative voltage source NAVDD are used as reference voltages of the gamma generation circuit, so that the gamma voltage can be freely adjusted within the voltage range between the positive voltage source PAVDD and the negative voltage source NAVDD, thereby adjusting the flicker phenomenon by adjusting the gamma voltage.

[0089] See also Fig. 9 A schematic structural diagram of another display device provided in an embodiment of the present disclosure.

[0090] The display device also includes:

[0091] The timing control circuit 4 is electrically connected to the display panel 1 and the source driving circuit 3;

[0092] The timing control circuit 4 is used to generate a control signal according to the input synchronization signal, and provide the control signal to the display panel 1 to control the source driving circuit 3 to generate a corresponding analog data signal according to the digital data signal provided by the timing control circuit 4 and load it onto the corresponding data line.

[0093] See also Fig.10 A schematic diagram of the structure of a gamma generation circuit provided in an embodiment of the present disclosure.

[0094] The gamma voltage generating circuit 31 comprises:

[0095] The first operational amplifier OP1, the inverting input terminal (-) of the first operational amplifier OP1 is connected to the output terminal of the first operational amplifier OP1, and the output terminal of the first operational amplifier OP1 serves as the output terminal Vout of the gamma voltage generating circuit 31; the two power supply terminals of the first operational amplifier OP1 are respectively connected to the positive voltage source PAVDD and the negative voltage source NAVDD.

[0096] Protection circuit DS, the input end of the protection circuit DS serves as the input end Vin of the gamma voltage generating circuit 31, the output end of the protection circuit DS is connected to the non-inverting input end of the first operational amplifier OP1, the two reference voltages of the protection circuit DS are respectively the positive voltage source PAVDD and the negative voltage source NAVDD, and the protection circuit DS is used to prevent static electricity and leakage of the first operational amplifier OP1.

[0097] The protection circuit DS can be as follows Fig.10 As shown in the figure, it is composed of a first diode D1 and a second diode D2, one end of the first diode D1 and the second diode D2 are connected to the non-inverting input terminal of the first operational amplifier OP1, and the other end are connected to the positive voltage source PAVDD and the negative voltage source NAVDD respectively.

[0098] Taking the adjustment of GMA10 as an example, when adjusting the voltage received at the input terminal Vin of GMA10 during power-on, the first diode D1 and the second diode D2 are connected in series, with both ends connected to PAVDD and NAVDD respectively. The non-inverting input terminal of the first operational amplifier OP1 is connected to the voltage after anti-static protection through the first diode D1 and the second diode D2. The power supply of the first operational amplifier OP1 is connected to PAVDD and NAVDD respectively. When the voltage received at the corresponding input terminal of GMA10 is a negative voltage, the circuit is normally powered. When the voltage Vin received at the corresponding input terminal Vin of GMA10 is a positive voltage, if Vin < PAVDD, the first diode D1 is cut off and no leakage current will be generated. If Vin > PAVDD, it means that Vin is static electricity, and the first diode D1 conducts to discharge the static electricity, playing a role in anti-static protection. Therefore, when the voltage received at the corresponding input terminal of GMA10 is a positive voltage, the circuit can still work normally. This enables the gamma voltage generation circuit 31 to work normally regardless of whether the original gamma voltage received at the input terminal Vin corresponding to GMA10 is positive or negative, so that the flashing phenomenon can be adjusted by adjusting the original gamma voltage.

[0099] Please refer to Fig.11 for another schematic diagram of the protection circuit provided by the embodiments of the present disclosure. The protection circuit DS includes:

[0100] A second operational amplifier OP2. The non-inverting input terminal of the second operational amplifier OP2 is used to receive the original gamma voltage. The output terminal of the second operational amplifier OP2 is connected to the inverting input terminal of the second operational amplifier OP2 and the non-inverting input terminal of the first operational amplifier OP1. The second operational amplifier OP2 is used to prevent the non-inverting input terminal of the first operational amplifier OP1 from leaking electricity. The two power supply terminals of the second operational amplifier OP2 are respectively connected to the positive voltage source PAVDD and the negative voltage source NAVDD.

[0101] A first diode D1, electrically connected between the inverting input terminal of the second operational amplifier OP2 and the positive voltage source PAVDD. The first diode D1 is used to divert the leakage current generated when the original gamma voltage is greater than 0 to the positive voltage source PAVDD. The positive electrode of the first diode D1 is connected to the positive voltage source PAVDD, and the negative electrode of the first diode D1 is connected to the inverting input terminal of the second operational amplifier OP2.

[0102] A second diode D2, connected between the inverting input terminal of the second operational amplifier OP2 and the negative voltage source NAVDD. The second diode D2 is used to divert the leakage current generated when the original gamma voltage is less than 0 to the negative voltage source NAVDD. The positive electrode of the second diode D2 is connected to the inverting input terminal of the second operational amplifier OP2, and the negative electrode of the second diode D2 is connected to the negative voltage source NAVDD.

[0103] The second operational amplifier OP2 generates an anti-leakage original gamma voltage based on the original gamma voltage, and then sends it to the first operational amplifier OP1 for buffering into a gamma voltage, so as to convert the received digital data signal into an analog data signal required by the display panel 1.

[0104] Please refer to Fig.12 the schematic diagram of another protection circuit provided by the embodiment of the present disclosure.

[0105] The protection circuit DS further includes:

[0106] A third diode D3 and a fourth diode D4 connected in parallel, the positive electrode of the third diode D3 is between the negative electrode of the fourth diode D4 and the negative electrode of the first diode D1, and the negative electrode of the third diode D3 is connected to the positive electrode of the fourth diode D4 and the non-inverting input terminal of the second operational amplifier OP2;

[0107] The third diode D3 is used to prevent positive-polarity static electricity from damaging the non-inverting input terminal of the second operational amplifier OP2;

[0108] The fourth diode D4 is used to prevent negative-polarity static electricity from damaging the non-inverting input terminal of the second operational amplifier OP2.

[0109] As Fig.12 shown, if the signal input terminal Vin of the gamma voltage generation circuit 31 receives positive-polarity static electricity, Vin > PAVDD, the first diode D1 and the third diode D3 conduct, and the positive-polarity static electricity is discharged through the path formed by the third diode D3 and the first diode D1; if the signal input terminal Vin of the gamma voltage generation circuit 31 receives negative-polarity static electricity, Vin < NAVDD, the second diode D2 and the fourth diode D4 conduct, and the negative-polarity static electricity is discharged through the path formed by the fourth diode D4 and the second diode D2, thereby preventing static electricity from damaging the second operational amplifier OP2. If the signal input terminal Vin of the gamma voltage generation circuit 31 receives positive and negative original gamma voltages, then 0 < Vin < PAVDD, the third diode D3 conducts, and the first diode D1 and the second diode D2 are cut off, and no leakage current will occur; if the signal input terminal Vin of the gamma voltage generation circuit 31 receives negative-polarity original gamma voltage, then NAVDD < Vin < 0, the fourth diode D4 conducts, and the first diode D1 and the second diode D2 are cut off, and no leakage current will occur either, so leakage current can be prevented.

[0110] In the embodiment provided in the present disclosure, by setting a third diode D3 and a fourth diode D4 in parallel at the non-inverting input terminal of the second operational amplifier OP2, and connecting the anode of the third diode D3 with the cathode of the fourth diode D4 and the cathode of the first diode D1, and connecting the cathode of the third diode D3 with the anode of the fourth diode D4 and the non-inverting input terminal of the second operational amplifier OP2, static electricity can be prevented from damaging the non-inverting input terminal of the second operational amplifier OP2, and leakage current can be effectively prevented when the original gamma voltage is positive or negative.

[0111] See also Figures 13-15 A schematic diagram of another protection circuit provided in an embodiment of the present disclosure.

[0112] The protection circuit DS also includes:

[0113] A first resistor R1 is connected between the inverting input terminal of the second operational amplifier OP2 and the cathode of the first diode D1;

[0114] Or / and a second resistor R2, connected between the signal input terminal and the non-inverting input terminal of the second operational amplifier OP2; the second resistor R2 is configured to limit the leakage current of the non-inverting input terminal of the second operational amplifier OP2.

[0115] like Fig.13 As shown, a first resistor R1 can be set between the inverting input terminal of the second operational amplifier OP2 and the cathode of the first diode D1 to limit the current flowing into the positive voltage source PAVDD and the negative voltage source NAVDD, thereby protecting the second operational amplifier OP2 and the first operational amplifier OP1; or Fig.14 As shown in FIG. 1 , a second resistor R2 is provided between the non-inverting input terminal of the second operational amplifier OP2 and the signal input terminal Vin to limit the current flowing into the non-inverting input terminal of the second operational amplifier OP2, thereby protecting the second operational amplifier OP2. The first resistor R1 and the second resistor R2 may be as follows: Fig.15 As shown, they are also arranged in the anti-static protection circuit DS, thereby strengthening the protection of the first operational amplifier OP1 and the second operational amplifier OP2.

[0116] The display device may be a display device such as a liquid crystal display, a liquid crystal display screen, a liquid crystal television, or may be a mobile device such as a mobile phone, a tablet computer, a notebook, or the like.

[0117] Although the preferred embodiments of the present disclosure have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present disclosure.

[0118] Obviously, those skilled in the art can make various changes and modifications to the present disclosure without departing from the spirit and scope of the present disclosure. Thus, if these modifications and variations of the present disclosure fall within the scope of the claims of the present disclosure and their equivalents, the present disclosure is also intended to include these modifications and variations.

Claims

1. A display device, comprising: A display panel, a power management integrated circuit and a source driving circuit, and a common voltage module located outside the display panel and the power management integrated circuit; The source driving circuit is electrically connected to the display panel and the power management integrated circuit respectively; the common voltage module is used to provide a common voltage signal to the common electrode of the display panel, and the common voltage signal has the same potential as the housing of the display device; The power management integrated circuit is used to provide a positive voltage source and a negative voltage source to the source driving circuit; the source driving circuit is used to generate an analog data signal of positive polarity or negative polarity for the display panel, the power source used by the analog data signal of positive polarity is the positive voltage source, and the power source used by the analog data signal of negative polarity is the negative voltage source.

2. The display device according to claim 1, wherein the source driving circuit comprises: A plurality of gamma voltage generating circuits correspond to a plurality of gamma voltages; the gamma voltage generating circuits are used to buffer the corresponding original gamma voltages to obtain corresponding gamma voltages, and the gamma voltages are used to generate analog data signals required by the display panel; the reference voltage of the gamma voltage generating circuit includes the positive voltage source and the negative voltage source.

3. The display device according to claim 2, wherein the gamma voltage generating circuit comprises: a first operational amplifier, wherein an inverting input terminal of the first operational amplifier is connected to an output terminal of the first operational amplifier, and the output terminal of the first operational amplifier serves as an output terminal of the gamma voltage generating circuit; and two power supply terminals of the first operational amplifier are respectively connected to the positive voltage source and the negative voltage source; A protection circuit, wherein the input end of the protection circuit serves as the input end of the gamma voltage generating circuit, the output end of the protection circuit is connected to the non-inverting input end of the first operational amplifier, the two reference voltages of the protection circuit are the positive voltage source and the negative voltage source, and the protection circuit is used to prevent static electricity and leakage of the first operational amplifier.

4. The display device according to claim 3, wherein the protection circuit comprises: a second operational amplifier, wherein a non-inverting input terminal of the second operational amplifier is used to receive the original gamma voltage, an output terminal of the second operational amplifier is connected to an inverting input terminal of the second operational amplifier and a non-inverting input terminal of the first operational amplifier, and the second operational amplifier is used to prevent leakage of the non-inverting input terminal of the first operational amplifier; a first diode, electrically connected between the inverting input terminal of the second operational amplifier and the positive voltage source, the first diode being used to guide the leakage current generated when the original gamma voltage is greater than 0 to the positive voltage source; The second diode is connected between the inverting input terminal of the second operational amplifier and the negative voltage source, and the second diode is used to guide the leakage current generated when the original gamma voltage is less than 0 to the negative voltage source.

5. The display device according to claim 4, wherein the protection circuit further comprises: A third diode and a fourth diode connected in parallel, with the anode of the third diode connected between the cathode of the fourth diode and the cathode of the first diode, and the cathode of the third diode connected to the anode of the fourth diode and the non-inverting input terminal of the second operational amplifier; The third diode is used to prevent positive static electricity from damaging the non-inverting input terminal of the second operational amplifier; The fourth diode is used to prevent negative static electricity from damaging the non-inverting input terminal of the second operational amplifier.

6. The display device according to claim 5, wherein the protection circuit further comprises: a first resistor connected between the inverting input terminal of the second operational amplifier and the cathode of the first diode; Or / and a second resistor, connected between the signal input terminal and the non-inverting input terminal of the second operational amplifier; the second resistor is configured to limit the current of the non-inverting input terminal of the second operational amplifier. 7 . The display device according to claim 1 , wherein the common voltage module is grounded, and the housing is grounded. 8 . The display device according to claim 7 , wherein the source driving circuit comprises the common voltage generating module.

9. The display device as claimed in claim 7, wherein the power management integrated circuit comprises: A first power supply generating circuit, used for generating the positive voltage source; The second power supply generating circuit is used to generate the negative voltage source.

10. The display device according to claim 7, wherein the display panel comprises: An array substrate and a counter substrate; The array substrate comprises scan lines and data lines, wherein the scan lines and the data lines intersect to define a pixel area, and the pixel area comprises a pixel electrode; The counter substrate includes the common electrode, and the common electrode is electrically connected to the common voltage module.

11. The display device according to claim 10, further comprising: A timing control circuit, electrically connected to the display panel and the source driving circuit; The timing control circuit is used to generate a control signal according to an input synchronization signal, and provide the control signal to the display panel to control the source drive circuit to generate a corresponding analog data signal according to the digital data signal provided by the timing control circuit and load it onto the corresponding data line.

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