Display driving device, control method thereof and display device
By controlling the power supply voltage through the display driver module, a gamma voltage is generated to stabilize the gate-source cross voltage of the driving transistor, thus solving the problem of brightness decay in the display device and achieving brightness compensation and effect improvement.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHENGDU VISTAR OPTEOLECTRONICS CO LTD
- Filing Date
- 2024-10-29
- Publication Date
- 2026-05-01
Smart Images
Figure CN121963635A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of display technology, and in particular to a display driving device and its control method, and a display device. Background Technology
[0002] With the development of display technology, people are increasingly demanding higher performance from display devices. Currently, when the brightness of a display device is too high or the external load is too large, there is a problem that it cannot fully compensate for the voltage drop on the power line ELVDD, resulting in a decrease in the brightness of the display device and affecting its display effect. Summary of the Invention
[0003] This invention provides a display driving device and its control method, as well as a display device, to perform display brightness compensation on the display device and improve the display effect of the display device.
[0004] In a first aspect, the present invention provides a display driving device, comprising: a power supply module and a display driving module; the power supply module includes a power supply terminal, which outputs a power supply voltage; the display driving module is connected to the power supply terminal and is used to generate a gamma voltage based on a reference voltage, wherein the reference voltage follows the change of the power supply voltage; the display driving module is also used to compare the value of the power supply voltage with the value of a first set voltage, and control the magnitude of the power supply voltage output by the power supply module based on the comparison result.
[0005] Optionally, the display driving module includes a control module and a gamma voltage generation module; the reference voltage includes a first reference voltage and a second reference voltage; the control module includes a first reference voltage output terminal, a second reference voltage output terminal, and an indicator signal output terminal; the first reference voltage output terminal is used to output the first reference voltage, and the second reference voltage output terminal is used to output the second reference voltage; the indicator signal output terminal is used to output an indicator signal, and the power supply module is used to control the magnitude of the power supply voltage according to the indicator signal; the first input terminal of the control module is connected to the output terminal of the power supply module, and the second input terminal of the control module is connected to a first set voltage, used to output the first reference voltage and the second reference voltage; it is also used to compare the value of the power supply voltage with the value of the first set voltage, and to determine whether to output an indicator signal according to the comparison result, so as to control the magnitude of the power supply voltage; the gamma voltage generation module is connected to the first reference voltage output terminal and the second reference voltage output terminal, used to generate a gamma voltage according to the first reference voltage and the second reference voltage.
[0006] Optionally, the value of the first reference voltage is equal to the value of the power supply voltage minus the value of the first set voltage, and the value of the second reference voltage is equal to the value of the power supply voltage plus the value of the second set voltage.
[0007] Optionally, the control module includes a voltage comparator, a selector, and a pulse count adjustment module. The non-inverting input of the voltage comparator serves as the first input of the control module, and the inverting input serves as the second input. The voltage comparator outputs a first-level signal when the power supply voltage is greater than or equal to a first set voltage, and outputs a second-level signal when the power supply voltage is less than the first set voltage. The input of the selector is connected to the output of the voltage comparator. The first output of the selector serves as a first reference voltage output, and the second output serves as a second reference voltage output. The selector outputs a first reference voltage and a second reference voltage when the voltage comparator outputs a first-level signal, and outputs a second-level signal, a first reference voltage, and a second reference voltage when the voltage comparator outputs a second-level signal. The input of the pulse count adjustment module is connected to the third output of the selector. The output of the pulse count adjustment module serves as an indicator signal output of the control module, and adjusts the number of pulses of the indicator signal output to the power supply module according to the second-level signal to control the magnitude of the power supply voltage.
[0008] Optionally, the first level signal is a high level signal and the second level signal is a low level signal.
[0009] Optionally, the selector includes a first transistor, a second transistor, and a third transistor; the gate of the first transistor serves as the input terminal of the selector, the first terminal of the first transistor is connected to a first reference voltage, and the second terminal of the first transistor serves as the first output terminal of the selector; the gate of the second transistor is connected to the gate of the first transistor, the first terminal of the second transistor is connected to the first terminal of the first transistor, and the second terminal of the second transistor is connected to the second terminal of the first transistor; the gate of the third transistor is connected to the gate of the second transistor, the first terminal of the third transistor is connected to a second reference voltage, and the second terminal of the third transistor serves as the second output terminal of the selector.
[0010] Optionally, both the power supply module and the pulse count adjustment module store a first relationship, which is the correspondence between the number of pulses of the indicator signal and the target voltage; the power supply module includes a signal conditioning module, which is used to receive the indicator signal and increase the value of the power supply voltage to the target voltage according to the first relationship.
[0011] Optionally, the more pulses the indicator signal has, the greater the corresponding target voltage value.
[0012] Optionally, the fewer the number of pulses in the indicator signal, the larger the corresponding target voltage value.
[0013] Optionally, the signal conditioning module includes a pulse counter, which includes an indicator signal input terminal for receiving an indicator signal and counting the number of pulses of the indicator signal.
[0014] Optionally, the gamma voltage generation module further includes a plurality of voltage divider resistors connected in series between the first reference voltage output terminal and the second reference voltage output terminal.
[0015] Secondly, embodiments of the present invention also provide a control method for a display driving device, applicable to any display driving device provided in any embodiment of the present invention. The control method includes: acquiring a power supply voltage; generating a gamma voltage based on a reference voltage, wherein the reference voltage follows changes in the power supply voltage; comparing the value of the power supply voltage with the value of a first set voltage, and controlling the magnitude of the power supply voltage based on the comparison result, thereby making the reference voltage greater than or equal to 0.
[0016] Optionally, the display driving module includes a voltage comparator, a selector, and a pulse count adjustment module; the reference voltage includes a first reference voltage and a second reference voltage; the step of comparing the power supply voltage value with the first set voltage value and controlling the magnitude of the power supply voltage according to the comparison result, thereby making the reference voltage greater than or equal to 0, includes: the voltage comparator comparing the power supply voltage value with the first set voltage value, and outputting a first level signal when the power supply voltage value is greater than or equal to the first set voltage value, and outputting a second level signal when the power supply voltage value is less than the first set voltage value; when the voltage comparator outputs the first level signal, the selector outputs the first reference voltage and the second reference voltage; when the voltage comparator outputs the second level signal, the selector outputs the first reference voltage, the second reference voltage, and the second level signal, and the pulse count adjustment module adjusts the number of pulses of the indication signal output to the power supply module according to the second level signal to control the power supply voltage to increase to the target voltage; when the power supply voltage increases to the target voltage, the step of comparing the power supply voltage value with the first set voltage value by the voltage comparator is returned to continue until the value of the first reference voltage is greater than or equal to 0.
[0017] Optionally, when the voltage comparator outputs a second-level signal, the value of the first reference voltage is equal to 0.
[0018] Thirdly, embodiments of the present invention also provide a display device, including the display driving device provided in any embodiment of the present invention.
[0019] The display driving device provided in this embodiment of the invention includes a power supply module and a display driving module. The display driving module compares the value of the power supply voltage with the value of a first set voltage. Through this comparison, the display driving module can control the magnitude of the power supply voltage output by the power supply module according to the comparison result, so that the value of the power supply voltage is greater than or equal to the value of the first set voltage. When the value of the power supply voltage is greater than or equal to the value of the first set voltage, this makes the value of the reference voltage greater than or equal to 0. The change of the reference voltage affects the generation of the gamma voltage (i.e., the data voltage). That is, by controlling the value of the power supply voltage to be greater than or equal to the value of the first set voltage through the display driving module, the attenuation of the power supply voltage can be the same as the attenuation of the data voltage, thereby keeping the gate-source voltage of the driving transistor constant. The stability of the gate-source voltage of the driving transistor is crucial for the control of display brightness. When the gate-source voltage is stable, it can be ensured that the pixels in the display device can emit light in a relatively stable state, thereby realizing display brightness compensation and improving the display effect.
[0020] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description
[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0022] Figure 1 This is a simplified circuit diagram of a pixel circuit driving a light-emitting device to emit light.
[0023] Figure 2 This is a schematic diagram of the structure of a display device provided by related technologies;
[0024] Figure 3 This is a schematic diagram of the structure of a gamma circuit in a display driver chip provided by related technologies;
[0025] Figure 4 This is a schematic diagram of the structure of a display driving device provided in an embodiment of the present invention;
[0026] Figure 5 This is a schematic diagram of another display driver module provided in an embodiment of the present invention;
[0027] Figure 6 This is a schematic diagram of another display driver module provided in an embodiment of the present invention;
[0028] Figure 7 This is a schematic diagram of another display driver module provided in an embodiment of the present invention;
[0029] Figure 8 This is a schematic diagram of another display driver module provided in an embodiment of the present invention;
[0030] Figure 9 This is a schematic diagram of another display driver module provided in an embodiment of the present invention;
[0031] Figure 10 This is a flowchart illustrating a control method for a display driving device provided in an embodiment of the present invention;
[0032] Figure 11 This is a schematic diagram of the structure of a display device provided in an embodiment of the present invention. Detailed Implementation
[0033] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.
[0034] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.
[0035] Before describing the technical solutions provided by the embodiments of the present invention, in order to facilitate understanding of the embodiments of the present invention, the present invention first specifically explains the problems existing in the related art:
[0036] The inventors discovered that in a display device, the light-emitting device D1 is driven to emit light by a pixel circuit. The light-emitting device D1 can be an organic light-emitting diode (OLED) or a micro-light-emitting diode (Micro-LED). Figure 1 This is a simplified circuit diagram illustrating how a pixel circuit drives a light-emitting device to emit light. (Reference) Figure 1 During display, the brightness of the pixels in the display device is determined by the current I flowing through the light-emitting device D1. The magnitude of the current I mainly depends on the gate-source voltage VGS of the driving transistor TFT. The smaller VGS is, the larger the current I flowing through the driving transistor TFT, and the brighter the pixel. Wherein, VGS = Vdata - VDD, Vdata represents the voltage value on the data line Data, and VDD represents the voltage value on the power line ELVDD. Figure 1 In this context, ELVSS represents the second power line connected to the cathode of the light-emitting device D1.
[0037] Figure 2 This is a structural schematic diagram of a display device provided by related technologies. (Reference) Figure 2 The display device includes a display panel 01 and a display driver 02. The display panel 01 is provided with a matrix of pixels, multiple data lines (Data) and multiple power lines (ELVDD), and each pixel includes a light-emitting device and pixel circuitry.
[0038] The display driver device 02 includes a display driver integrated circuit (DDIC) 021 and a power management integrated circuit (PMIC) 022. The display driver chip 021 provides a data voltage Vdata to the data line Data, and the power management integrated circuit 022 provides a power voltage VDD to the power line ELVDD. However, because the power management integrated circuit 022 is relatively far from the display panel 01, and the power line ELVDD between the power management integrated circuit 022 and the display panel 01 is relatively long, the voltage drop (IR Drop) on the power line ELVDD causes the power voltage VDD reaching the display panel 01 to be lower than the voltage output by the power management integrated circuit 022, resulting in a dimmer overall screen brightness.
[0039] The display driver chip 021 in current display devices all have added dynamic ELVDD function. The so-called dynamic ELVDD function refers to the design of the reference voltage that can change with the power supply voltage VDD, which is originally the minimum gamma voltage and the maximum gamma voltage across the gamma resistor string in the gamma circuit. The main purpose is to compensate for the voltage drop on the power supply line ELVDD and prevent the screen brightness from decreasing. Figure 3 This is a schematic diagram of the gamma circuit in a display driver chip provided by related technologies. (Combined with...) Figures 1 to 3 The gamma circuit can generate a gamma voltage based on a first reference voltage and a second reference voltage, where the first reference voltage is equal to VDD-A and the second reference voltage is equal to VDD+B, where VDD is the power supply voltage, A is the first set voltage, and B is the second set voltage. The gamma voltage is the data voltage Vdata.
[0040] Assuming the power supply voltage VDD is 4.6V, the first setting voltage A is set to 4V, and the second setting voltage B is set to 2.4V, meaning the first reference voltage is 0.6V and the second reference voltage is 7V, then the gamma voltage at the intermediate node W (assuming a grayscale of 255, and assuming it's exactly at the intermediate node W in the gamma resistor series is (7+0.6) / 2 = 3.8V) will decrease if the power supply voltage VDD drops, for example, by 0.2V. This results in a 0.4V decrease in the voltage at the first output terminal S (i.e., the first reference voltage), a 0.4V decrease in the voltage at the second output terminal M (i.e., the second reference voltage), a 6.8V decrease in the voltage at the second output terminal M, and a 3.6V decrease in the gamma voltage at the intermediate node W. The 0.2V decrease in power supply voltage VDD causes a brightness reduction, and the gamma voltage also decreases by 0.2V, meaning the data voltage Vdata also decreases by 0.2V. Since the gate-source voltage VGS of the driving transistor DTFT remains unchanged, the screen will brighten, thus offsetting the effect of the power supply voltage VDD drop.
[0041] However, a problem exists: as screens become brighter, the current draw also increases, leading to a larger voltage drop in the power supply voltage VDD. Assuming a power supply voltage VDD of 4.6V, a first voltage A of 4.2V, and a second voltage B of 2.4V, the first output terminal S voltage is 0.4V, and the second output terminal M voltage is 7V. If the data voltage Vdata corresponding to 255 grayscale levels is 1V, and if the power supply voltage VDD drops by 0.6V, then the first output terminal S voltage becomes 0V (the internal circuitry of the display driver chip prevents negative voltage; theoretically, when the calculated value is negative, the corresponding output voltage remains unchanged, always at the minimum value of 0V), and the second output terminal M voltage becomes 6.4V. In this case, the data voltage corresponding to 255 grayscale levels would be 0.528V. While the power supply voltage VDD drops by 0.6V, the data voltage Vdata only drops by about 0.42V. This means that the change in the gate-source voltage VGS of the driving transistor DTFT caused by the power supply voltage drop in VDD can only partially compensate for the difference, ultimately resulting in a significant decrease in the brightness of the display device.
[0042] In view of the inventors' above-mentioned research findings, and in order to solve the problems of the prior art, embodiments of the present invention provide a display driving device and its control method, as well as a display device. The display driving device provided by the embodiments of the present invention will be described first below.
[0043] Figure 4 This is a schematic diagram of the structure of a display driving device provided in an embodiment of the present invention. Figure 4 As shown, the display driving device includes a power supply module 11 and a display driving module 12.
[0044] The power supply module 11 includes a power supply terminal that outputs a power supply voltage VDD. The display driver module 12 is connected to the power supply terminal of the power supply module 11 and is used to generate a gamma voltage based on a reference voltage, which follows the changes in the power supply voltage VDD. The display driver module 12 is also used to compare the value of the power supply voltage VDD with the value of a first set voltage A, and control the magnitude of the power supply voltage VDD output by the power supply module 11 based on the comparison result.
[0045] Specifically, the fact that the reference voltage follows the power supply voltage VDD means that when the power supply voltage VDD changes, the reference voltage will also change accordingly, thereby affecting the generation of gamma voltage and adjusting the display effect of the screen.
[0046] In some embodiments, the reference voltage includes a first reference voltage VREF1 and a second reference voltage VREF2. The display driver module 12 generates a gamma voltage based on the first reference voltage VREF1 and the second reference voltage VREF2, which is the data voltage Vdata. Optionally, the value of the first reference voltage VREF1 is equal to the value of the power supply voltage VDD minus the value of the first set voltage A, and the value of the second reference voltage VREF2 is equal to the value of the power supply voltage VDD plus the value of the second set voltage B. That is, VREF1 = VDD - A, VREF2 = VDD + B.
[0047] In some embodiments, if the display driving module 12 determines that the value of the power supply voltage VDD is greater than or equal to the value of the first set voltage A, it does not control the power supply voltage VDD output by the power supply module 11 to change. If the display driving module 12 determines that the value of the power supply voltage VDD is less than the value of the first set voltage A, it controls the power supply voltage VDD output by the power supply module 11 to increase. The display driving module 12 then determines whether the value of the power supply voltage VDD is still less than the value of the first set voltage A. If the value of the power supply voltage VDD is still less than the value of the first set voltage A, it continues to control the power supply voltage VDD to increase until the value of the power supply voltage VDD is greater than or equal to the value of the first set voltage A. At this time, the first reference voltage VREF1 and the second reference voltage VREF2 are both greater than or equal to 0, thereby ensuring that the degree of decrease in the data voltage Vdata matches the degree of decrease in the power supply voltage VDD, for example, the two change at the same rate, so that the gate-source voltage VGS of the driving transistor DTFT remains unchanged, thereby offsetting the effect caused by the voltage drop of the power supply voltage VDD and improving the display effect. It is understood that when the power supply voltage VDD increases to the maximum output voltage of the power supply module 11, it is also necessary to stop increasing the value of the power supply voltage VDD.
[0048] Explanation of principle: When the display driver module 12 determines that the value of the power supply voltage VDD is greater than or equal to the value of the first set voltage A, that is, VDD-A is greater than or equal to 0, it means that the first reference voltage VREF1 is positive. After the voltage drop on the power line ELVDD, it will not be less than 0. It can be ensured that the voltage drop on the power line ELVDD is compensated by reducing the same data voltage Vdata.
[0049] When the display driver module 12 determines that the power supply voltage VDD is less than the first set voltage A (i.e., VDD-A is less than 0), it means that the first reference voltage is 0 (as mentioned above, the circuit is limited to a minimum of 0V and cannot produce negative values). At this time, compensation by the data voltage Vdata can only partially compensate, so the value of the power supply voltage VDD needs to be increased to make the first reference voltage VREF1 positive. The purpose is to ensure that the first reference voltage VREF1 and the second reference voltage VREF2 can both have a margin for attenuation, ensuring that the degree of reduction in data voltage Vdata is the same as the degree of reduction in power supply voltage VDD. For example, if the brightness decreases due to a 0.2V decrease in power supply voltage VDD, the gamma voltage also decreases by 0.2V, meaning the data voltage Vdata also decreases by 0.2V. The gate-source voltage VGS of the driving transistor DTFT remains unchanged, causing the screen to brighten, thereby offsetting the effect caused by the voltage drop in power supply voltage VDD.
[0050] The display driving device provided in this embodiment of the invention includes a power supply module and a display driving module. The display driving module compares the value of the power supply voltage with the value of a first set voltage. Through this comparison, the display driving module can control the magnitude of the power supply voltage output by the power supply module according to the comparison result, so that the value of the power supply voltage is greater than or equal to the value of the first set voltage. When the value of the power supply voltage is greater than or equal to the value of the first set voltage, this makes the value of the reference voltage greater than or equal to 0. The change of the reference voltage affects the generation of the gamma voltage (i.e., the data voltage). That is, by controlling the value of the power supply voltage to be greater than or equal to the value of the first set voltage through the display driving module, the attenuation of the power supply voltage can be the same as the attenuation of the data voltage, thereby keeping the gate-source voltage of the driving transistor constant. The stability of the gate-source voltage of the driving transistor is crucial for the control of display brightness. When the gate-source voltage is stable, it can be ensured that the pixels in the display device can emit light in a relatively stable state, thereby realizing display brightness compensation and improving the display effect.
[0051] Figure 5 This is a schematic diagram of another display driver module provided in an embodiment of the present invention. For example... Figure 5 As shown, optionally, the display driving module 12 includes a control module 121 and a gamma voltage generation module 122.
[0052] The reference voltages include a first reference voltage VREF1 and a second reference voltage VREF2. The control module 121 includes a first reference voltage output terminal OUT1, a second reference voltage output terminal OUT2, and an indication signal output terminal OUT3; the first reference voltage output terminal OUT1 is used to output the first reference voltage VREF1, and the second reference voltage output terminal OUT2 is used to output the second reference voltage VREF2; the indication signal output terminal OUT3 is used to output an indication signal swire, and the power supply module 11 is used to control the magnitude of the power supply voltage VDD according to the indication signal swire.
[0053] The first input terminal of the control module 121 is connected to the output terminal of the power module 11. The second input terminal of the control module 121 is connected to the first set voltage A, which is used to output the first reference voltage VREF1 and the second reference voltage VREF2. It is also used to compare the value of the power supply voltage VDD with the value of the first set voltage A, and to determine whether to output the indication signal swire according to the comparison result, so as to control the magnitude of the power supply voltage VDD.
[0054] The gamma voltage generation module 122 is connected to the first reference voltage output terminal OUT1 and the second reference voltage output terminal OUT2, and is used to generate gamma voltage based on the first reference voltage VREF1 and the second reference voltage VREF2.
[0055] Specifically, the control module 121 compares the value of the power supply voltage VDD with the value of the first set voltage A. Through this comparison, the control module 121 can determine whether the value of the power supply voltage VDD is greater than or equal to the value of the first set voltage A. If the value of the power supply voltage VDD is less than the value of the first set voltage A, the control module 121 outputs an indication signal swire based on the comparison result. This indication signal swire is sent to the power supply module 11, which adjusts the magnitude of the power supply voltage VDD according to the indication signal swire, increasing the power supply voltage VDD until its value is greater than or equal to the value of the first set voltage A. It can be understood that the maximum value of the power supply voltage VDD is less than or equal to the maximum output voltage of the power supply module 11. The maximum output voltage of the power supply module 11 refers to the highest voltage value that the power supply module 11 can output under specific operating conditions.
[0056] If the value of the power supply voltage VDD is greater than or equal to the value of the first set voltage A, that is, the first reference voltage VREF1 is greater than or equal to 0, then the control module 121 does not need to output the indication signal swire, keeps the first reference voltage VREF1 and the second reference voltage VREF2 unchanged, and generates a gamma voltage based on the first reference voltage VREF1 and the second reference voltage VREF2.
[0057] The target voltage information carried in the indication signal swire is used to characterize the target voltage. The target voltage is the power supply voltage VDD that the power supply module 11 needs to provide again when the control module 121 determines that the initial power supply voltage VDD is less than the first set voltage A. The target voltage is greater than the initial power supply voltage VDD. The target voltage information can be characterized by the number of pulses in the indication signal swire sent by the control module 121 to the power supply module 11.
[0058] Optionally, continue to refer to Figure 5 The gamma voltage generation module 122 also includes a plurality of voltage divider resistors R1 connected in series between the first reference voltage output terminal OUT1 and the second reference voltage output terminal OUT2.
[0059] As a preferred embodiment of the present invention, Figure 6 This is a schematic diagram of another display driver module provided in an embodiment of the present invention, such as... Figure 6 As shown, the control module 121 includes a voltage comparator U1, a selector 1211, and a pulse count adjustment module 1212.
[0060] Optionally, the non-inverting input of voltage comparator U1 serves as the first input of control module 121, and the inverting input of voltage comparator U1 serves as the second input of control module 121. Voltage comparator U1 is used to output a first level signal when the value of power supply voltage VDD is greater than or equal to the value of the first set voltage A, and to output a second level signal when the value of power supply voltage VDD is less than the value of the first set voltage A.
[0061] Selector 1211 includes an input terminal, a first output terminal, a second output terminal, and a third output terminal. The input terminal of selector 1211 is connected to the output terminal of voltage comparator U1. The first output terminal of selector 1211 serves as the first reference voltage output terminal OUT1, and the second output terminal of selector 1211 serves as the second reference voltage output terminal OUT2. It is used to output the first reference voltage VREF1 and the second reference voltage VREF2 when voltage comparator U1 outputs a first-level signal. When voltage comparator U1 outputs a second-level signal, it outputs the second-level signal, the first reference voltage VREF1, and the second reference voltage VREF2.
[0062] The input terminal of the pulse count adjustment module 1212 is connected to the third output terminal of the selector 1211. The output terminal of the pulse count adjustment module 1212 serves as the indicator signal output terminal OUT3 of the control module 121, used to adjust the number of pulses of the indicator signal swire output to the power supply module 11 according to the second level signal, thereby controlling the magnitude of the power supply voltage VDD. Optionally, the first level signal is a high level signal, and the second level signal is a low level signal.
[0063] Specifically, when a second-level signal is received from selector 1211, pulse count adjustment module 1212 parses the input second-level signal. The second-level signal may contain specific encoded information to indicate the comparison result between the power supply voltage VDD and the first set voltage A, as well as the direction and degree of adjustment. For example, some bits of the second-level signal may indicate the degree to which the power supply voltage VDD is less than the first set voltage A, while other bits may indicate the magnitude of the adjustment. For instance, the second-level signal is an 8-bit binary number, where the high 4 bits indicate the degree to which the power supply voltage is less than the first set voltage, and the low 4 bits indicate the magnitude of the adjustment. If the second-level signal is "01010001", the high 4 bits "0101" indicate the degree to which the power supply voltage is less than the first set voltage, and the low 4 bits "0001" indicate that one more pulse is needed. Pulse count adjustment module 1212 increases or decreases the pulse count of the indicator signal by one based on the second-level signal. For example, if the initial indicator signal has 83 pulses and the corresponding power supply voltage is 4.6V, then the current indicator signal has 84 or 82 pulses and the corresponding power supply voltage is 4.7V.
[0064] Figure 7 This is a schematic diagram of another display driver module provided in an embodiment of the present invention, such as... Figure 7 As shown, selector 1211 includes a first transistor T1, a second transistor T2, and a third transistor T3.
[0065] The gate of the first transistor T1 serves as the input terminal of the selector 1211, the first terminal of the first transistor T1 is connected to the first reference voltage VREF1, and the second terminal of the first transistor T1 serves as the first output terminal of the selector 1211.
[0066] The gate of the second transistor T2 is connected to the gate of the first transistor T1, the first terminal of the second transistor T2 is connected to the first terminal of the first transistor T1, and the second terminal of the second transistor T2 is connected to the second terminal of the first transistor T1.
[0067] The gate of the third transistor T3 is connected to the gate of the second transistor T2. The first terminal of the third transistor T3 is connected to the second reference voltage VREF2. The second terminal of the third transistor T3 serves as the second output terminal of the selector 1211.
[0068] Optionally, the first transistor T1 is an N-channel transistor, and the second transistor T2 and the third transistor are P-channel transistors. When the voltage comparator U1 outputs a first-level signal (i.e., a high-level signal), the first transistor T1 and the third transistor T3 are turned on, the second transistor T2 is turned off, the first reference voltage VREF1 is output to the first reference voltage output terminal OUT1 through the first transistor T1, and the second reference voltage VREF2 is output to the second reference voltage output terminal OUT2 through the third transistor T3.
[0069] When voltage comparator U1 outputs a second-level signal (i.e., a low-level signal), the second transistor T2 and the third transistor T3 are turned on, while the first transistor T3 is turned off. The first reference voltage VREF1 is output to the first reference voltage output terminal OUT1 via the second transistor T2, and the second reference voltage VREF2 is output to the second reference voltage output terminal OUT2 via the third transistor T3. The second-level signal is then input to the input terminal of the pulse count adjustment module 1212 via the third output terminal of the selector 1211. In other words, regardless of whether voltage comparator U1 outputs a first-level signal or a second-level signal, both the first reference voltage output terminal OUT1 and the second reference voltage output terminal OUT2 will have outputs. This is to ensure normal display on the display panel. However, when voltage comparator U1 outputs a second-level signal, the power supply voltage VDD can be dynamically adjusted until its value is greater than or equal to the value of the first set voltage A, compensating for the reduced brightness.
[0070] Figure 8 This is a schematic diagram of another display driver module provided in an embodiment of the present invention, such as... Figure 8 As shown, optionally, both the power supply module 11 and the pulse count adjustment module 1212 store a first relationship, which is the correspondence between the number of pulses of the indicator signal and the target voltage.
[0071] The power module 11 includes a signal conditioning module 111, which receives an indication signal and increases the value of the power supply voltage VDD to the target voltage according to a first relationship.
[0072] Optionally, the more pulses in the indication signal, the larger the corresponding target voltage value. For example, when the indication signal contains 83 pulses, the signal conditioning module 111 adjusts the power supply voltage VDD to 4.6V, which is the target voltage; when the indication signal contains 84 pulses, the signal conditioning module 111 adjusts the power supply voltage VDD to 4.7V; when the indication signal contains 85 pulses, the signal conditioning module 111 adjusts the power supply voltage VDD to 4.8V; when the indication signal contains 86 pulses, the signal conditioning module 111 adjusts the power supply voltage VDD to 4.9V; and when the indication signal contains 87 pulses, the signal conditioning module 111 adjusts the power supply voltage VDD to 5.0V.
[0073] Optionally, the fewer the number of pulses in the indication signal, the larger the corresponding target voltage value. For example, when the indication signal contains 42 pulses, the signal conditioning module 111 adjusts the power supply voltage VDD to 7.9V; when the indication signal contains 43 pulses, the signal conditioning module 111 adjusts the power supply voltage VDD to 7.6V; when the indication signal contains 44 pulses, the signal conditioning module 111 adjusts the power supply voltage VDD to 7.3V; when the indication signal contains 45 pulses, the signal conditioning module 111 adjusts the power supply voltage VDD to 7.0V; and when the indication signal contains 46 pulses, the signal conditioning module 111 adjusts the power supply voltage VDD to 6.7V.
[0074] Optionally, continue to refer to Figure 8 The signal conditioning module 111 includes a pulse counter 1111, which includes an indicator signal input terminal for receiving an indicator signal swire and counting the number of pulses of the indicator signal swire.
[0075] Specifically, in order to enable the signal conditioning module 111 to adjust the voltage value of the power supply voltage VDD based on the indicator signal swire and the first relationship, the technical solution adopted in this invention includes a pulse counter 1111, which is provided with an indicator signal input terminal for receiving the indicator signal swire and counting the number of pulses of the indicator signal swire. This allows the signal conditioning module 111 to adjust the voltage value of the power supply voltage VDD according to the first relationship, i.e., the correspondence between the number of pulses of the indicator signal swire and the voltage value of the power supply voltage VDD (i.e., the target voltage).
[0076] Figure 9 This is a schematic diagram of another display driver module provided in an embodiment of the present invention, such as... Figure 9 As shown, the display driving device includes a power supply module 11 and a display driving module 12. Optionally, the display driving module 12 includes a control module 121 and a gamma voltage generation module 122.
[0077] The control module 121 includes a voltage comparator U1, a selector 1211, and a pulse count adjustment module 1212. The selector 1211 includes a first transistor T1, a second transistor T2, and a third transistor T3. The power supply module 11 includes a signal conditioning module 111, which includes a pulse counter 1111.
[0078] Continue to refer to Figure 9 The working process of this display driver is as follows:
[0079] The voltage comparator U1 compares the value of the power supply voltage VDD with the value of the first set voltage A, and outputs a first level signal when the value of the power supply voltage VDD is greater than or equal to the value of the first set voltage A, and outputs a second level signal when the value of the power supply voltage VDD is less than the value of the first set voltage A.
[0080] When voltage comparator U1 outputs the first level signal (i.e., high level signal), the first transistor T1 and the third transistor T3 are turned on, the second transistor T2 is turned off, the first reference voltage VREF1 is output to the first reference voltage output terminal OUT1 through the first transistor T1, and the second reference voltage VREF2 is output to the second reference voltage output terminal OUT2 through the third transistor T3.
[0081] When voltage comparator U1 outputs a second-level signal (i.e., a low-level signal), the second transistor T2 and the third transistor T3 are turned on, and the first transistor T3 is turned off. The first reference voltage VREF1 is output to the first reference voltage output terminal OUT1 through the second transistor T2, and the second reference voltage VREF2 is output to the second reference voltage output terminal OUT2 through the third transistor T3. The second-level signal is input to the input terminal of the pulse count adjustment module 1212 through the third output terminal of selector 1211. The pulse count adjustment module 1212 adjusts the number of pulses of the indication signal swire output to the power supply module 11 according to the second-level signal. The signal conditioning module 111 receives the indication signal swire and increases the value of the power supply voltage VDD to the target voltage according to the first relationship. When the power supply voltage VDD increases to the target voltage, voltage comparator U1 compares the value of the power supply voltage VDD with the value of the first set voltage A again until the value of the first reference voltage VREF1 is greater than or equal to 0, then stops increasing the power supply voltage.
[0082] It should be noted that when the power supply voltage VDD increases to the maximum output voltage of the power module 11, even if the power supply voltage VDD is still less than the first set voltage A, the power supply voltage VDD must be kept at the maximum output voltage.
[0083] In summary, the display driving device provided in this embodiment of the invention changes the value of the power supply voltage so that both the first reference voltage VREF1 and the second reference voltage VREF2 are greater than or equal to 0, thereby ensuring that the decrease in data voltage Vdata is the same as the decrease in power supply voltage VDD. This keeps the gate-source voltage VGS of the driving transistor DTFT constant, thus offsetting the effect caused by the voltage drop of power supply voltage VDD and improving the display effect.
[0084] Based on the same inventive concept, the present invention also provides a control method for a display driving device, which can be applied to the display driving device provided in any of the above embodiments of the present invention. Figure 10 This is a flowchart illustrating a control method for a display driving device provided in an embodiment of the present invention.
[0085] Combination Figure 4 and Figure 10 The control method for the display driving device includes:
[0086] S110, Obtain the power supply voltage.
[0087] Specifically, the display driver module first needs to obtain the power supply voltage output by the power supply module. This can be achieved through a connection to the power supply module or a specific voltage detection circuit.
[0088] S120: Generate gamma voltage based on reference voltage.
[0089] Specifically, the reference voltage follows the power supply voltage. The display driver module can generate a gamma voltage based on the current reference voltage using specific circuitry or algorithms.
[0090] S130. The value of the power supply voltage is compared with the value of the first set voltage, and the magnitude of the power supply voltage is controlled according to the comparison result, so that the reference voltage is greater than or equal to 0.
[0091] Specifically, the display driver module compares the acquired power supply voltage value with the value of a first set voltage. This comparison can be implemented using a voltage comparator or similar circuitry within the display driver module. The first set voltage is typically a specific value determined based on the design requirements and performance specifications of the display driver device. If the power supply voltage value is less than the first set voltage value, the power supply voltage needs to be increased. This can be achieved by controlling the output of the power supply module. By adjusting the power supply voltage, ensuring that the reference voltage is greater than or equal to 0, the degree of data voltage drop is matched by the degree of power supply voltage drop. This keeps the gate-source voltage across the driving transistor constant, thus offsetting the effects of the power supply voltage drop and improving the display effect.
[0092] In some embodiments, in order to reasonably achieve control of the display driving device in the foregoing embodiments, the display driving module may optionally include a voltage comparator, a selector, and a pulse count adjustment module; the reference voltage includes a first reference voltage and a second reference voltage.
[0093] The steps of comparing the power supply voltage with the first set voltage and controlling the power supply voltage based on the comparison result to make the reference voltage greater than or equal to 0 include:
[0094] The voltage comparator compares the power supply voltage with the value of a first set voltage, and outputs a first level signal when the power supply voltage is greater than or equal to the first set voltage, and outputs a second level signal when the power supply voltage is less than the first set voltage.
[0095] When the voltage comparator outputs a first-level signal, the selector outputs a first reference voltage and a second reference voltage. When the voltage comparator outputs a second-level signal, the selector outputs a first reference voltage, a second reference voltage, and a second-level signal. The pulse count adjustment module adjusts the number of pulses in the indication signal output to the power supply module according to the second-level signal to control the power supply voltage to increase to the target voltage.
[0096] When the power supply voltage increases to the target voltage, the process returns to the step of comparing the power supply voltage value with the first set voltage value using the voltage comparator, continuing until the value of the first reference voltage is greater than or equal to 0, at which point the increase in power supply voltage stops. Optionally, when the voltage comparator outputs a second-level signal, the value of the first reference voltage is equal to 0.
[0097] Based on the display driving device provided in the above embodiments, the present invention also provides a display device, including the display driving device provided in any embodiment of the present invention. Figure 11 This is a schematic diagram of the structure of a display device provided in an embodiment of the present invention. Figure 11 The provided display device 100 includes the display driving device 200 provided in any embodiment of the present invention.
[0098] Optionally, the display device 100 further includes a display panel 300, on which pixels arranged in a matrix, multiple data lines, and multiple power lines are disposed. Each pixel includes an organic light-emitting element and pixel circuitry. The display driving device 100 is used to provide data voltage to the data lines and also to provide power voltage to the power lines.
[0099] Figure 11The embodiments use a mobile phone as an example to describe the display device 100. It is understood that the display device provided in this embodiment can be other display devices with display functions, such as wearable products, computers, televisions, and in-vehicle display devices; this invention does not impose specific limitations on these. The display device provided in this embodiment has the beneficial effects of the display driving device 200 provided in this embodiment. For details, please refer to the specific descriptions of the display driving device 200 in the above embodiments; these will not be repeated here.
[0100] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.
Claims
1. A display driving device, characterized in that, include: Power supply module and display driver module; The power module includes a power terminal, which outputs a power voltage. The display driver module is connected to the power supply terminal and is used to generate a gamma voltage based on a reference voltage, wherein the reference voltage follows the change of the power supply voltage. The display driver module is also used to compare the value of the power supply voltage with the value of the first set voltage, and control the magnitude of the power supply voltage output by the power supply module according to the comparison result.
2. The display driving device according to claim 1, characterized in that, The display driver module includes a control module and a gamma voltage generation module; The reference voltage includes a first reference voltage and a second reference voltage; the control module includes a first reference voltage output terminal, a second reference voltage output terminal, and an indication signal output terminal. The first reference voltage output terminal is used to output the first reference voltage, and the second reference voltage output terminal is used to output the second reference voltage; the indicator signal output terminal is used to output an indicator signal, and the power module is used to control the magnitude of the power supply voltage according to the indicator signal. The first input terminal of the control module is connected to the output terminal of the power supply module, and the second input terminal of the control module is connected to the first set voltage, for outputting the first reference voltage and the second reference voltage; it is also used to compare the value of the power supply voltage with the value of the first set voltage, and to determine whether to output the indication signal based on the comparison result, so as to control the magnitude of the power supply voltage; The gamma voltage generation module is connected to the first reference voltage output terminal and the second reference voltage output terminal, and is used to generate gamma voltage based on the first reference voltage and the second reference voltage. Preferably, the value of the first reference voltage is equal to the value of the power supply voltage minus the value of the first set voltage, and the value of the second reference voltage is equal to the value of the power supply voltage plus the value of the second set voltage.
3. The display driving device according to claim 2, characterized in that, The control module includes a voltage comparator, a selector, and a pulse count adjustment module; The non-inverting input of the voltage comparator serves as the first input of the control module, and the inverting input of the voltage comparator serves as the second input of the control module. The voltage comparator is used to output a first level signal when the value of the power supply voltage is greater than or equal to the value of the first set voltage, and to output a second level signal when the value of the power supply voltage is less than the value of the first set voltage. The selector includes an input terminal, a first output terminal, a second output terminal, and a third output terminal. The input terminal of the selector is connected to the output terminal of the voltage comparator. The first output terminal of the selector serves as the first reference voltage output terminal, and the second output terminal of the selector serves as the second reference voltage output terminal. It is used to output the first reference voltage and the second reference voltage when the voltage comparator outputs the first level signal. When the voltage comparator outputs the second level signal, it outputs the second level signal, the first reference voltage, and the second reference voltage. The input terminal of the pulse count adjustment module is connected to the third output terminal of the selector. The output terminal of the pulse count adjustment module serves as the indicator signal output terminal of the control module, and is used to adjust the number of pulses of the indicator signal output to the power supply module according to the second level signal, so as to control the magnitude of the power supply voltage. Preferably, the first level signal is a high level signal, and the second level signal is a low level signal.
4. The display driving device according to claim 3, characterized in that, The selector includes a first transistor, a second transistor, and a third transistor; The gate of the first transistor serves as the input terminal of the selector, the first terminal of the first transistor is connected to the first reference voltage, and the second terminal of the first transistor serves as the first output terminal of the selector. The gate of the second transistor is connected to the gate of the first transistor, the first terminal of the second transistor is connected to the first terminal of the first transistor, and the second terminal of the second transistor is connected to the second terminal of the first transistor. The gate of the third transistor is connected to the gate of the second transistor, the first terminal of the third transistor is connected to the second reference voltage, and the second terminal of the third transistor serves as the second output terminal of the selector.
5. The display driving device according to claim 3, characterized in that, Both the power supply module and the pulse count adjustment module store a first relationship, which is the correspondence between the pulse count of the indicator signal and the target voltage. The power module includes a signal conditioning module, which is used to receive the indication signal and increase the value of the power supply voltage to the target voltage according to the first relationship; Preferably, the more pulses the indication signal has, the greater the corresponding target voltage value; Preferably, the fewer the number of pulses in the indication signal, the larger the corresponding target voltage value.
6. The display driving device according to claim 5, characterized in that, The signal conditioning module includes a pulse counter, which includes an indicator signal input terminal for receiving the indicator signal and counting the number of pulses of the indicator signal.
7. The display driving device according to claim 2, characterized in that, The gamma voltage generation module further includes multiple voltage divider resistors connected in series between the first reference voltage output terminal and the second reference voltage output terminal.
8. A control method for a display driving device, characterized in that, The control method, applied to the display driving device according to any one of claims 1-8, comprises: Obtain the power supply voltage; A gamma voltage is generated based on a reference voltage; the reference voltage follows the changes in the power supply voltage. The value of the power supply voltage is compared with the value of the first set voltage, and the magnitude of the power supply voltage is controlled according to the comparison result, so that the reference voltage is greater than or equal to 0.
9. The control method for the display driving device according to claim 9, characterized in that, The display driving module includes a voltage comparator, a selector, and a pulse count adjustment module; the reference voltage includes a first reference voltage and a second reference voltage. The step of comparing the value of the power supply voltage with the value of the first set voltage, and controlling the magnitude of the power supply voltage according to the comparison result, so that the reference voltage is greater than or equal to 0, includes: The voltage comparator compares the value of the power supply voltage with the value of a first set voltage, and outputs a first level signal when the value of the power supply voltage is greater than or equal to the value of the first set voltage, and outputs a second level signal when the value of the power supply voltage is less than the value of the first set voltage; When the voltage comparator outputs the first level signal, the selector outputs the first reference voltage and the second reference voltage; When the voltage comparator outputs the second level signal, the selector outputs the first reference voltage, the second reference voltage, and the second level signal. The pulse count adjustment module adjusts the number of pulses of the indication signal output to the power module according to the second level signal, so as to control the power supply voltage to increase to the target voltage. When the power supply voltage increases to the target voltage, the process returns to the step of the voltage comparator comparing the value of the power supply voltage with the value of the first set voltage, until the value of the first reference voltage is greater than or equal to 0, at which point the increase of the power supply voltage stops. Preferably, when the voltage comparator outputs the second level signal, the value of the first reference voltage is equal to 0.
10. A display device, characterized in that, Includes the display driving device as described in any one of claims 1-7.