CN113470586A - Driving circuit, driving method and debugging method of display panel - Google Patents
Driving circuit, driving method and debugging method of display panel Download PDFInfo
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- CN113470586A CN113470586A CN202110602048.XA CN202110602048A CN113470586A CN 113470586 A CN113470586 A CN 113470586A CN 202110602048 A CN202110602048 A CN 202110602048A CN 113470586 A CN113470586 A CN 113470586A
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
- G09G3/3611—Control of matrices with row and column drivers
- G09G3/3685—Details of drivers for data electrodes
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
- G09G3/3611—Control of matrices with row and column drivers
- G09G3/3696—Generation of voltages supplied to electrode drivers
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G2320/00—Control of display operating conditions
- G09G2320/02—Improving the quality of display appearance
- G09G2320/0271—Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping
- G09G2320/0276—Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
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- Crystallography & Structural Chemistry (AREA)
- Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- General Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- Liquid Crystal Display Device Control (AREA)
- Control Of Indicators Other Than Cathode Ray Tubes (AREA)
Abstract
The application discloses a driving circuit, a driving method and a debugging method of a display panel, wherein the driving circuit comprises a power circuit, a gamma circuit and a data driving circuit, the power circuit provides gamma high-order voltage for the gamma circuit, the driving circuit also comprises a basic voltage generating circuit, and the basic voltage generating circuit provides at least one reference voltage control signal for the data driving circuit; the gamma circuit comprises n output ends, the data driving circuit comprises n receiving ends, and the n receiving ends are connected with the n output ends in a one-to-one correspondence manner; the data driving circuit generates a group of gamma reference voltages according to the reference voltage control signals and the signals received by the n receiving ends; the data driving circuit is also used for receiving an external data source and converting an external data source signal into a gray scale voltage according to a group of gamma reference voltages to drive the panel; the technical scheme of this application can improve gamma correction precision and reduce cost.
Description
Technical Field
The present disclosure relates to the field of display technologies, and in particular, to a driving circuit, a driving method, and a debugging method for a display panel.
Background
The liquid crystal panel is a mainstream display panel in the current market, but due to the photoelectric characteristics of the liquid crystal, generally speaking, if the liquid crystal panel does not perform gamma correction, the transfer function between the light intensity of the liquid crystal display output and the input signal forms an irregular S-line, i.e. a step signal which is 50% lower and 20% higher, while the middle 30% step signal range seriously affects the gray scale and color reproduction effect of the output image for the 90% transmittance range. The purpose of gamma correction is to compensate for this non-linear characteristic, so that the intensity of the liquid crystal display has a power function response characteristic with respect to the input signal.
The current mainstream gamma correction can be divided into two types, one adopts a programmable gamma buffer circuit, but the scheme has the problem of high cost; the other type adopts a resistor string, but has the problem of poor precision. Therefore, the search for a gamma correction method with high precision and low cost has become a problem to be solved in the art.
Disclosure of Invention
An object of the present application is to provide a driving circuit, a driving method, and a debugging method of a display panel to improve gamma correction accuracy and reduce cost.
The application discloses a driving circuit of a display panel, which comprises a power supply circuit, a gamma circuit and a data driving circuit, wherein the power supply circuit provides gamma high-order voltage for the gamma circuit; the gamma circuit comprises n output ends, the data driving circuit comprises n receiving ends, and the n receiving ends are connected with the n output ends in a one-to-one correspondence manner; the data driving circuit generates a group of gamma reference voltages according to the reference voltage control signals and the signals received by the n receiving ends; the data driving circuit is further used for receiving an external data source, converting the external data source signal into a gray scale voltage according to the group of gamma reference voltages and driving the display panel, wherein n is a positive integer.
Optionally, the basic voltage generating circuit provides two reference voltage control signals, namely a first reference voltage control signal and a second reference voltage control signal, for the data driving circuit; the data driving circuit comprises a first resistor string, the first resistor string is formed by connecting n +1 resistors in series and comprises n first output nodes, and the resistors of two adjacent first resistor strings directly correspond to one first output node; the n first output nodes are correspondingly connected with the n receiving ends; one end of the first resistor string receives the first reference voltage control signal, and the other end of the first resistor string receives the second reference voltage control signal.
Optionally, the first reference voltage control signal and the second reference voltage control signal are directly output as the gamma reference voltages; when the first reference voltage control signal is output as the gamma reference voltage, the gray scale of the display panel is 255; when the second reference voltage control signal is output as the gamma reference voltage, the gray scale of the display panel is 0; the data driving circuit generates n +2 gamma reference voltages.
Optionally, the basic voltage generating circuit provides four reference voltage control signals for the data driving circuit, which are a first reference voltage control signal, a second reference voltage control signal, a third reference voltage control signal and a fourth reference voltage control signal, respectively; the data driving circuit comprises a second resistor string and a third resistor string, the second resistor string comprises (n +2)/2 resistors connected in series and n/2 second output nodes, and the resistors of two adjacent second resistor strings directly correspond to one second output node; the third resistor string comprises (n +2)/2 resistors connected in series and n/2 third output nodes, and the resistors of two adjacent third resistor strings directly correspond to one third output node; the n/2 second output nodes and the n/2 third output nodes are correspondingly connected with the n receiving ends respectively; one end of the second resistor string receives the first reference voltage control signal, and the other end of the second resistor string receives the second reference voltage control signal; one end of the third resistor string receives the third reference voltage control signal, and the other end of the third resistor string receives the fourth reference voltage control signal; wherein n is an even number.
Optionally, the first reference voltage control signal, the second reference voltage control signal, the third reference voltage control signal and the fourth reference voltage control signal are directly output as the gamma reference voltages; when the first reference voltage control signal is output as the gamma reference voltage, the gray scale of the display panel is 255; when the second reference voltage control signal is output as the gamma reference voltage, the gray scale of the display panel is 0; when the third reference voltage control signal is output as the gamma reference voltage, the gray scale of the display panel is 0; when the fourth reference voltage control signal is output as the gamma reference voltage, the gray scale of the display panel is-255; the data driving circuit generates n +4 of the gamma reference voltages.
Optionally, the third reference voltage control signal is generated by the second reference voltage control signal; the fourth reference voltage control signal is generated from the first reference voltage control signal.
Optionally, the gamma circuit includes a fourth resistor string, the fourth resistor string includes n +1 resistors connected in series and includes n fourth output nodes, and the resistors of two adjacent fourth resistor strings directly correspond to one fourth output node; the n fourth output nodes are correspondingly connected with the n output ends; one end of the fourth resistor string receives the gamma high-order voltage, and the other end of the fourth resistor string is grounded.
Optionally, the driving circuit further includes that the basic voltage generating circuit is integrated in the power supply circuit.
The application also discloses a driving method of the display panel, which comprises the following steps:
providing gamma high-order voltage, and synchronously providing at least one reference voltage control signal;
the gamma circuit receives the gamma high-order voltage and outputs n intermediate reference voltages to the data driving circuit; the data driving circuit receives the n intermediate reference voltages and the reference voltage control signal, and converts the reference voltage control signal and the n intermediate reference voltages into a set of gamma high-order voltages, wherein the reference voltage control signal is at least one of the set of gamma reference voltages;
the data driving circuit receives an external data source gray scale signal, and converts the external data source gray scale signal into a gray scale voltage according to the group of gamma reference voltages to drive the display panel.
The application also discloses a method for debugging the gamma reference voltage of the display panel, which comprises the following steps:
generating a resistance value of a resistor string of the gamma circuit according to a preset reference voltage control signal;
testing the gamma reference voltage output under the condition of the resistance value of the resistor string, generating a test gamma reference voltage curve, and comparing the test gamma reference voltage curve with a preset gamma reference voltage curve; and
if the comparison is not qualified, the voltage value of the reference voltage control signal is adjusted, so that the test gamma reference voltage curve is matched with a preset gamma reference voltage curve.
In the application, a plurality of gamma reference voltage signals generated inside the data driving circuit are adjusted through the first reference voltage control signal, and the gamma reference voltage signals can be finely adjusted by changing the voltage value of the first reference voltage control signal, so that a group of gamma reference voltage signals formed by the gamma reference voltage signals is more suitable for a gamma 2.2 curve. Compared with the programmable gamma buffer circuit, the programmable gamma buffer circuit needs more ports to control and generate a plurality of gamma reference voltages and has higher cost. Compared with the method that only the gamma high-order voltage is used for controlling the generation of the plurality of gamma reference voltages, the method of the present embodiment trims the plurality of gamma reference voltages generated actually through the first reference voltage control signal, so that the gamma reference voltages are more accurate.
Drawings
The accompanying drawings, which are included to provide a further understanding of the embodiments of the application, are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. It is obvious that the drawings in the following description are only some embodiments of the application, and that for a person skilled in the art, other drawings can be derived from them without inventive effort. In the drawings:
fig. 1 is a schematic diagram of a driving circuit of a display panel of a first embodiment of the present application;
FIG. 2 is a schematic diagram of a gamma circuit and a data driving circuit of a first embodiment of the present application;
FIG. 3 is a schematic diagram of a gamma circuit and a data driving circuit of a first embodiment of the present application;
fig. 4 is a schematic diagram of a driving circuit of a display panel of a second embodiment of the present application;
fig. 5 is a schematic diagram of a driving circuit of a display panel of a third embodiment of the present application;
fig. 6 is a schematic step diagram of a driving method of a display panel according to an embodiment of the present application.
10, a driving circuit; 100. a power supply circuit; 110. a base voltage generating circuit; 200. a gamma circuit; 210. a fourth resistor string; 300. a data driving circuit; 310. a first resistor string; 320. a second resistor string; 330. and a third resistor string.
Detailed Description
It is to be understood that the terminology, the specific structural and functional details disclosed herein are for the purpose of describing particular embodiments only, and are representative, but that the present application may be embodied in many alternate forms and should not be construed as limited to only the embodiments set forth herein.
In the description of the present application, the terms "first", "second" are used for descriptive purposes only and are not to be construed as indicating relative importance or as implicitly indicating the number of technical features indicated. Thus, unless otherwise specified, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; "plurality" means two or more. The terms "comprises" and "comprising," and any variations thereof, are intended to cover a non-exclusive inclusion, such that one or more other features, integers, steps, operations, elements, components, and/or combinations thereof may be present or added.
Further, terms of orientation or positional relationship indicated by "center", "lateral", "upper", "lower", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, are described based on the orientation or relative positional relationship shown in the drawings, are simply for convenience of description of the present application, and do not indicate that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present application.
Furthermore, unless expressly stated or limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly and may include, for example, fixed connections, removable connections, and integral connections; can be mechanically or electrically connected; either directly or indirectly through intervening media, or through both elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.
The present application is described in detail below with reference to the figures and alternative embodiments.
As shown in fig. 1, as a first embodiment of the present application, a driving circuit of a display panel is disclosed, where the driving circuit 10 includes a power circuit 100, a gamma circuit 200 and a data driving circuit 300, the power circuit 100 provides a gamma high-order voltage for the gamma circuit 200, the driving circuit further includes a base voltage generating circuit 110, and the base voltage generating circuit 110 provides at least one reference voltage control signal for the data driving circuit 300; the gamma circuit 200 includes n output terminals out1, out2 … … out n, the data driving circuit 300 includes n receiving terminals in1, in2 … … in n, the n receiving terminals are connected with the n output terminals in a one-to-one correspondence; the data driving circuit 300 generates a set of gamma reference voltages according to the reference voltage control signal and the signals received by the n receiving terminals; the Data driving circuit 300 is further configured to receive an external Data source Data, and convert the external Data source signal into a gray scale voltage Vdata according to the set of gamma reference voltages to drive the panel.
It should be noted that the Power circuit 100, i.e. the Power Management IC (PMIC), includes a plurality of conversion circuits with different circuit functions, and the present application mainly refers to the gamma high voltage AVDD (analog vdd) provided by the Power circuit 100 for the gamma circuit 200, and the conversion circuit generating the AVDD is generally called a Boost circuit (Boost circuit), the gamma circuit 200 outputs a plurality of intermediate reference voltages through an output terminal after receiving the AVDD, and outputs the intermediate reference voltages to the data driving circuit 300, and further generates a plurality of gamma reference voltages, the data driving circuit 300 is a source driving IC, and mainly functions to receive an external data source provided by a front-end timing controller, convert the external data source into a data driving signal in a desired gray scale voltage form by combining with the gamma reference voltages generated by the gamma circuit 200 through digital-to-analog conversion, and output the data driving signal to a corresponding pixel, thereby displaying the corresponding gray scale. The gamma reference voltage signal corresponds to reference voltages of different gray scales, the displayed gray scales correspond to the reference voltages under the reference voltages, and the different gray scales correspond to the transmittance of the liquid crystal one by one, so that the data driving circuit 300 can obtain the transmittance of the liquid crystal required by the corresponding external data source and the brightness required by the corresponding external data source under the condition of input of the external data source.
In this application, the plurality of gamma reference voltage signals generated inside the data driving circuit 300 are adjusted by the first reference voltage control signal, and the plurality of gamma reference voltage signals can be finely adjusted by changing the voltage value of the first reference voltage control signal, so that a set of gamma reference voltage signals formed by the plurality of gamma reference voltage signals more closely fits to the gamma 2.2 curve. Compared with the programmable gamma buffer circuit, the programmable gamma buffer circuit needs more ports to control and generate a plurality of gamma reference voltages and has higher cost. Compared with the method of using only AVDD to control the generation of the plurality of gamma reference voltages, the present embodiment uses the first reference voltage control signal to fine-tune the plurality of gamma reference voltages that are actually generated, so that the gamma reference voltages are more accurate.
Specifically, the base voltage generation circuit 110 of the present embodiment is integrated in the power supply circuit 100. The power supply circuit 100 is used as a total input of the driving circuit of the display panel, and various voltage signals can be generated in the power supply circuit 100, so that the basic voltage generating circuit 110 of the present embodiment may use the circuits in the power supply circuit 100 as they are to generate the required first reference voltage control signal correspondingly. The voltages required for the second reference voltage control signal, the third reference voltage control signal and the fourth reference voltage control signal in the following embodiments can also be implemented by the internal circuit of the power supply circuit 100. Of course, it is also possible to separately provide the base voltage generation circuit 110, and it is not necessary to integrate it in the power supply circuit 100, and separate control is also possible.
As shown in fig. 2, which shows an internal circuit diagram of a specific gamma circuit 200 and a specific data driving circuit 300, the gamma circuit 200 includes a fourth resistor string 210, the fourth resistor string 210 includes 10 resistors connected in series and includes 9 fourth output nodes Out1 and Out2 … … Out9, and the resistors of two adjacent fourth resistor strings 210 directly correspond to one fourth output node; 9 of said fourth output nodes correspond to 9 of said output terminals; one end of the fourth resistor string 210 is connected to the gamma high voltage, and the other end of the fourth resistor string 210 is grounded. The data driving circuit 300 comprises a first resistor string, wherein the first resistor string comprises n +1 resistors connected in series, and comprises n first output nodes corresponding to gamma reference voltages GM1 and GM2 … … GM9 respectively, and the resistors of two adjacent first resistor strings directly correspond to one first output node; 9 first output nodes correspond to 9 receiving terminals In1 and In2 … … In 9; one end of the first resistor string is connected with the first reference voltage control signal, and the other end of the first resistor string is grounded.
In this embodiment, the first reference voltage control signal may also be directly outputted as a gamma reference voltage signal, which may correspond to a gray scale of 255 or 0, where the gray scale of 255 corresponds to a transmittance of 100% and the gray scale of 0 corresponds to a transmittance of 0%. For example, the first reference voltage control signal is corresponding to a gray scale voltage when the gray scale is 255, and the gamma reference voltage output by other receiving terminals can be changed by adjusting the voltage value of the first reference voltage control signalThe pressure value of the pressure signal, in turn, makes the curve more fit to the curved surface of gamma 2.2. As can be seen from fig. 3, where n is 9, the gamma reference voltages outputted from the 9 output nodes corresponding to the first resistor string are 9, and the first reference voltage control signal is directly outputted as one gamma reference voltage to form 10 gamma reference voltages GM1, GM2 … … GM9 and GM 10. Also, the first reference voltage control signal may adjust gamma reference voltages output from the 10 resistor strings. It should be noted that the first resistor string is inside the data driving circuit 300, i.e. the internal resistor in the data driving circuit 300, and the fourth resistor string 210 is disposed inside the gamma circuit 200, i.e. the resistor in the gamma circuit 200, and is called the external resistor. The first resistor string comprises a plurality of external resistors connected in series; the fourth resistor string 210 comprises a plurality of internal resistors connected in series; the external resistor ROuter 1Is connected to the gamma high-order voltage signal, the internal resistor RInner 1Is connected to the first gamma control signal; and the other end of the external resistor is connected with the other end of the internal resistor and outputs a voltage as the gray scale reference.
As a second embodiment of the present application, fig. 4 shows a driving circuit of a display panel, the driving circuit includes a power circuit 100, a gamma circuit 200 and a data driving circuit 300, the power circuit 100 provides a gamma high-order voltage for the gamma circuit 200, and provides two reference voltage control signals, namely a first reference voltage control signal and a second reference voltage control signal, for the data driving circuit 300; the gamma circuit 200 includes a fourth resistor string 210, the fourth resistor string 210 includes 10 resistors connected in series and includes 9 fourth output nodes Out1 and Out2 … … Out9, and the resistors of two adjacent fourth resistor strings 210 directly correspond to one fourth output node; the 9 fourth output nodes are correspondingly connected with the 9 output ends; one end of the fourth resistor string 210 is connected to the gamma high voltage, and the other end of the fourth resistor string 210 is grounded. The data driving circuit 300 includes a first resistor string, the first resistor string includes 10 resistors connected in series and includes 9 first output nodes, and the resistors of two adjacent first resistor strings directly correspond to one first output node; the 9 first output nodes are correspondingly connected with 9 receiving terminals In1 and In2 … … In 9; one end of the first resistor string is connected with the first reference voltage control signal, and the other end of the first resistor string is connected with the second reference voltage control signal.
In this embodiment, the first reference voltage control signal and the second reference voltage control signal are used separately. Compared with the previous embodiment, the other end of the first resistor string is not grounded and is connected to the second reference voltage control signal, so that a gamma reference voltage can be obtained without grounding through a resistor; the second reference voltage control signal is directly adjustable, so that the controlled gamma reference voltage is more accurate, and the accuracy of the output gamma reference voltage is greatly improved compared with the traditional resistor string; compared with a programmable gamma buffer circuit, the display panel has the function of adjusting the gamma reference voltage, is lower in cost, reduces the power consumption of the display panel, reduces the design and manufacturing difficulty of the driving circuit, and further saves the manufacturing cost.
Specifically, the first reference voltage control signal and the second reference voltage control signal are directly output as the gamma reference voltages; when the first reference voltage control signal is output as the gamma reference voltage, the gray scale of the display panel is 255; when the second reference voltage control signal is output as the gamma reference voltage, the gray scale of the display panel is 0; the data driving circuit 300 generates 11 gamma reference voltages. Corresponding to FIG. 4 are 11 gamma reference voltages GM1, GM2 … … GM9, GM10, and GM 11. The gamma voltage adjustment method of the present embodiment may be a symmetric voltage adjustment method, i.e. the amplitude of each gray scale positive and negative frame is equal to the amplitude of the common voltage. This application is direct as gamma reference circuit output with at least one reference voltage control signal, and control is more accurate, when the gamma curve has the deviation, can directly adjust this reference voltage control signal moreover, can make gamma curve more fit gamma 2.2's curve.
As a third embodiment of the present application, a driving circuit of a display panel is shown in fig. 5; the driving circuit comprises a power circuit 100, a gamma circuit 200 and a data driving circuit 300, wherein the power circuit 100 provides gamma high-order voltage for the gamma circuit 200 and four reference voltage control signals, namely a first reference voltage control signal, a second reference voltage control signal, a third reference voltage control signal and a fourth reference voltage control signal, for the data driving circuit 300; the data driving circuit 300 includes a second resistor string 320 and a third resistor string 330, the second resistor string 320 includes 8 resistors connected in series and includes 7 second output nodes, and the resistors of two adjacent second resistor strings 320 directly correspond to one second output node; the third resistor string 330 includes 8 resistors connected in series and includes 7 third output nodes, and the resistors of two adjacent third resistor strings 330 directly correspond to one third output node; the 7 second output nodes and the 7 third output nodes are correspondingly connected with the 14 receiving ends respectively; one end of the second resistor string 320 is connected to the first reference voltage control signal, and the other end of the second resistor string 320 is connected to the second reference voltage control signal; one end of the third resistor string 330 is connected to the third reference voltage control signal, and the other end of the third resistor string 330 is connected to the fourth reference voltage control signal.
Specifically, the first, second, third and fourth reference voltage control signals are directly output as the gamma reference voltages; when the first reference voltage control signal is output as the gamma reference voltage, the gray scale of the display panel is 255; when the second reference voltage control signal is output as the gamma reference voltage, the gray scale of the display panel is 0; when the third reference voltage control signal is output as the gamma reference voltage, the gray scale of the display panel is 0; when the fourth reference voltage control signal is output as the gamma reference voltage, the gray scale of the display panel is-255; the data driving circuit 300 generates 12 gamma reference voltages. Corresponding to FIG. 5 are 11 gamma reference voltages GM1, GM2 … … GM9, GM10, GM11, and GM 12.
Specifically, the third reference voltage control signal is generated from the second reference voltage control signal; the fourth reference voltage control signal is generated from the first reference voltage control signal. In the power supply circuit 100, the first reference voltage control signal, the second reference voltage control signal, the third reference voltage control signal, and the fourth reference voltage control signal may be output independently, and specific voltage values may be adjusted independently, so that gamma reference voltages may be adjusted conveniently.
It should be noted that fig. 5 is a schematic diagram, and in practical use, taking 8-bit 256 gray scale as an example, the corresponding resistor string outputs 14 gamma reference voltages, and the four reference voltage control signals output 4 gamma reference voltages. Totaling 18 gamma reference voltages; the corresponding relations are that GM1 corresponds to 255 gray scale, GM2 corresponds to 254 gray scale, GM3 corresponds to 223 gray scale, GM4 corresponds to 191 gray scale, GM5 corresponds to 127 gray scale, GM6 corresponds to 63 gray scale, GM7 corresponds to 31 gray scale, GM8 corresponds to 1 gray scale, GM9 corresponds to 0 gray scale, GM10 corresponds to reverse 0 gray scale, GM10 corresponds to reverse 0 gray scale, GM11 corresponds to reverse-1 gray scale, GM12 corresponds to-31 gray scale, GM13 corresponds to-63 gray scale, GM14 corresponds to-127 gray scale, GM15 corresponds to-191 gray scale, GM16 corresponds to-223 gray scale, GM17 corresponds to-254 gray scale, and GM18 corresponds to-255 gray scale. The voltages of GAM1-GAM18 are decreased gradually. The gamma voltage adjustment method of the present embodiment may be an asymmetric voltage adjustment method, that is, the amplitude of the positive and negative frames of each gray scale is not equal to the amplitude of the common voltage, that is, the voltage values of the second reference voltage control signal and the third reference voltage control signal are not equal to each other at the gray scale of 0. That is, the voltage of GM9 is not equal to the voltage of GM 10.
Taking 18 gamma reference voltages as an example, the application also discloses a method for debugging the gamma reference voltages of the display panel, which comprises the following steps:
generating a resistance value of a resistor string of the gamma circuit according to a preset reference voltage control signal;
testing the gamma reference voltage output under the condition of the resistance value of the resistor string, generating a test gamma reference voltage curve, and comparing the test gamma reference voltage curve with a preset gamma reference voltage curve;
if the comparison is not qualified, the voltage value of the reference voltage control signal is adjusted, so that the test gamma reference voltage curve is matched with a preset gamma reference voltage curve.
The specific algorithm is as follows: the design development stage of the circuit calculates a group of 18 ideal gamma reference voltages; the first resistor string, the second resistor string and the third resistor string inside the data driving circuit can obtain accurate values through specification or actual measurement of the data driving circuit design. The gamma circuit comprises a resistor string consisting of 16 resistors, and the resistor string is R1-R16 from the AVDD end to the grounding end; given the voltage values of V1-V4, the R16 resistor value is preset as X, and the values of R1-R15 are respectively obtained. Obtaining theoretical resistance values of a plurality of series resistors, manually searching a resistor library to find an actual resistor, welding the actual resistor onto a circuit board, testing whether a test gamma reference voltage curve in the actual circuit board is matched with a preset gamma reference voltage curve, namely judging whether the test gamma reference voltage curve is within an error range and whether the resistor power is within a rated power. If the error of the actual Gamma voltage generated by the resistor string exceeds the specification or the resistor power exceeds the specification, the x value of R16 needs to be determined again until the resistor string resistor meeting the requirement is found.
Corresponding to the driving circuit, as shown in fig. 6, the present application also discloses a driving method of a display panel, comprising the steps of:
s1: providing gamma high-order voltage, and synchronously providing at least one reference voltage control signal;
s2: the gamma circuit receives the gamma high-order voltage and outputs n intermediate reference voltages to the data driving circuit; the data driving circuit receives the n intermediate reference voltages and the reference voltage control signal, and converts the reference voltage control signal and the n intermediate reference voltages into a set of gamma high-order voltages, wherein the reference voltage control signal is at least one of the set of gamma reference voltages;
s3: the data driving circuit receives an external data source gray scale signal and converts the external data source signal into a gray scale voltage according to the group of gamma reference voltages to drive the panel.
This application is direct as gamma reference circuit output with at least one reference voltage control signal, and control is more accurate, when the gamma curve has the deviation, can directly adjust this reference voltage control signal moreover, can make gamma curve more fit gamma 2.2's curve. It should be noted that the intermediate reference voltages, which correspond to the output terminals of the gamma circuits in the above embodiments and are output to the data driving circuit, are a group of intermediate reference voltages output after the gamma high-order voltages enter the resistor strings of the gamma circuits, and because there is an internal resistance in the data driving circuit, the intermediate reference voltages need to be output after being combined with the second resistor string and the third resistor string in the data driving circuit. The data driving circuit receives an external data source gray scale signal processed by the time schedule controller, and the gray scale signal is a specific gray scale value at the moment, and the data driving circuit receives the gray scale value and adjusts a corresponding gray scale voltage to output.
It should be noted that, the limitations of each step in the present disclosure are not considered to limit the order of the steps without affecting the implementation of the specific embodiments, and the steps written in the foregoing may be executed first, or executed later, or even executed simultaneously, and as long as the present disclosure can be implemented, all the steps should be considered as belonging to the protection scope of the present application.
It should be noted that the inventive concept of the present application can form many embodiments, but the present application has a limited space and cannot be listed one by one, so that, on the premise of no conflict, any combination between the above-described embodiments or technical features can form a new embodiment, and after the embodiments or technical features are combined, the original technical effect will be enhanced
The technical solution of the present application can be widely applied to various display panels, such as TN (Twisted Nematic) display panel, IPS (In-Plane Switching) display panel, VA (Vertical Alignment) display panel, MVA (Multi-Domain Vertical Alignment) display panel, and of course, other types of display panels, such as OLED (Organic Light-Emitting Diode) display panel, and the above solution can be applied thereto.
The foregoing is a more detailed description of the present application in connection with specific alternative embodiments, and the specific implementations of the present application are not to be considered limited to these descriptions. For those skilled in the art to which the present application pertains, several simple deductions or substitutions may be made without departing from the concept of the present application, and all should be considered as belonging to the protection scope of the present application.
Claims (10)
1. A drive circuit of a display panel, the drive circuit includes power supply circuit, gamma circuit and data drive circuit, the said power supply circuit provides gamma high-order voltage for the said gamma circuit, characterized by that, the said drive circuit also includes the basic voltage generating circuit, the said basic voltage generating circuit provides at least a reference voltage control signal for the said data drive circuit;
the gamma circuit comprises n output ends, the data driving circuit comprises n receiving ends, and the n receiving ends are connected with the n output ends in a one-to-one correspondence manner;
the data driving circuit generates a group of gamma reference voltages according to the reference voltage control signals and the signals received by the n receiving ends;
the data driving circuit is further used for receiving an external data source, converting the external data source signal into a gray scale voltage according to the group of gamma reference voltages and driving the display panel, wherein n is a positive integer.
2. The driving circuit of the display panel according to claim 1, wherein the basic voltage generating circuit supplies two reference voltage control signals, a first reference voltage control signal and a second reference voltage control signal, to the data driving circuit;
the data driving circuit comprises a first resistor string, the first resistor string comprises n +1 resistors connected in series and n first output nodes, and the resistors of two adjacent first resistor strings directly correspond to one first output node;
the n first output nodes are correspondingly connected with the n receiving ends;
one end of the first resistor string receives the first reference voltage control signal, and the other end of the first resistor string receives the second reference voltage control signal.
3. The driving circuit of the display panel according to claim 2, wherein the first reference voltage control signal and the second reference voltage control signal are directly output as the gamma reference voltages; when the first reference voltage control signal is output as the gamma reference voltage, the gray scale of the display panel is 255; when the second reference voltage control signal is output as the gamma reference voltage, the gray scale of the display panel is 0;
the data driving circuit generates n +2 gamma reference voltages.
4. The driving circuit of the display panel according to claim 1, wherein the basic voltage generating circuit supplies four reference voltage control signals, a first reference voltage control signal, a second reference voltage control signal, a third reference voltage control signal and a fourth reference voltage control signal, to the data driving circuit;
the data driving circuit comprises a second resistor string and a third resistor string, the second resistor string comprises (n +2)/2 resistors connected in series and n/2 second output nodes, and the resistors of two adjacent second resistor strings directly correspond to one second output node;
the third resistor string comprises (n +2)/2 resistors connected in series and n/2 third output nodes, and the resistors of two adjacent third resistor strings directly correspond to one third output node;
the n/2 second output nodes and the n/2 third output nodes are correspondingly connected with the n receiving ends respectively;
one end of the second resistor string receives the first reference voltage control signal, and the other end of the second resistor string receives the second reference voltage control signal; one end of the third resistor string receives the third reference voltage control signal, and the other end of the third resistor string receives the fourth reference voltage control signal;
wherein n is an even number.
5. The driving circuit of the display panel according to claim 4, wherein the first reference voltage control signal, the second reference voltage control signal, the third reference voltage control signal, and the fourth reference voltage control signal are directly output as the gamma reference voltages; when the first reference voltage control signal is output as the gamma reference voltage, the gray scale of the display panel is 255; when the second reference voltage control signal is output as the gamma reference voltage, the gray scale of the display panel is 0; when the third reference voltage control signal is output as the gamma reference voltage, the gray scale of the display panel is 0; when the fourth reference voltage control signal is output as the gamma reference voltage, the gray scale of the display panel is-255;
the data driving circuit generates n +4 of the gamma reference voltages.
6. The driving circuit of the display panel according to claim 4, wherein the third reference voltage control signal is generated from the second reference voltage control signal; the fourth reference voltage control signal is generated from the first reference voltage control signal.
7. The driving circuit of the display panel according to claim 1, wherein the gamma circuit comprises a fourth resistor string, the fourth resistor string comprises n +1 resistors connected in series and n fourth output nodes, and the resistors of two adjacent fourth resistor strings directly correspond to one fourth output node;
the n fourth output nodes are correspondingly connected with the n output ends;
one end of the fourth resistor string receives the gamma high-order voltage, and the other end of the fourth resistor string is grounded.
8. The driving circuit of the display panel according to claim 1, wherein the base voltage generating circuit is integrated in the power supply circuit.
9. A method of driving a display panel, comprising the steps of:
providing gamma high-order voltage, and synchronously providing at least one reference voltage control signal;
the gamma circuit receives the gamma high-order voltage and outputs n intermediate reference voltages to the data driving circuit; the data driving circuit receives the n intermediate reference voltages and the reference voltage control signal, and converts the reference voltage control signal and the n intermediate reference voltages into a set of gamma reference voltages, wherein the reference voltage control signal is at least one of the set of gamma reference voltages; and
the data driving circuit receives an external data source gray scale signal, and converts the external data source gray scale signal into a gray scale voltage according to the group of gamma reference voltages to drive the display panel.
10. A method for debugging a gamma reference voltage, comprising the steps of:
generating a resistance value of a resistor string of the gamma circuit according to a preset reference voltage control signal;
testing the gamma reference voltage output under the condition of the resistance value of the resistor string, generating a test gamma reference voltage curve, and comparing the test gamma reference voltage curve with a preset gamma reference voltage curve; and
if the comparison is not qualified, the voltage value of the reference voltage control signal is adjusted, so that the test gamma reference voltage curve is matched with a preset gamma reference voltage curve.
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| CN113470586B (en) | 2022-03-22 |
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