Screen driving circuit and control method thereof

Abstract

The application relates to a screen driving circuit and a control method. The screen driving circuit comprises a sampling circuit configured to sample based on a low-voltage gamma voltage and a low-voltage reference voltage; an operational amplifier connected to a high-voltage reference voltage, and the operational amplifier is configured to output a target voltage based on the high-voltage reference voltage and the voltage sampled by the sampling circuit, so as to drive a screen by the target voltage; wherein the low-voltage gamma voltage is matched with the low-voltage reference voltage, and the low-voltage reference voltage is a reference voltage smaller than the high-voltage reference voltage. The screen driving circuit can reduce the size of a chip where the screen driving circuit is located.

Description

Technical Field

[0001] This application relates to the field of screen driving, and in particular to a screen driving circuit and its control method. Background Technology

[0002] Display screens are widely used in all aspects of life. They work by controlling the flipping of liquid crystal molecules with voltage, which in turn controls the amount of light passing through the liquid crystal molecules. Combined with three-primary-color filtering technology, this allows for the display of images with different colors and brightness levels. The voltage signal controlling the flipping of the liquid crystal molecules comes from the corresponding driving circuit.

[0003] The driving circuit requires a reference voltage generation circuit to drive the screen for display. To make the colors appear more linear to the human eye, gamma calibration is needed for the reference voltage, but the circuit used for gamma calibration is too large. Summary of the Invention

[0004] Therefore, it is necessary to provide a screen driving circuit and its control method, which can reduce the size of the chip in which the screen driving circuit is located.

[0005] This application provides a screen driving circuit, including:

[0006] A sampling circuit configured to sample based on a low-voltage gamma voltage and a low-voltage reference voltage;

[0007] An operational amplifier is connected to a high-voltage reference voltage, and the operational amplifier is configured to output a target voltage based on the high-voltage reference voltage and the voltage sampled by the sampling circuit, so as to drive the screen through the target voltage;

[0008] The low-voltage gamma voltage is adapted to the low-voltage reference voltage, and the low-voltage reference voltage is a reference voltage that is lower than the high-voltage reference voltage.

[0009] In one embodiment, the sampling circuit includes a sampling capacitor, a switch S1, and a switch S2; the first terminal of the sampling capacitor is connected to the input terminal of the low-voltage gamma voltage via the switch S1, and the second terminal of the sampling capacitor is connected to the input terminal of the low-voltage reference voltage via the switch S2.

[0010] In one embodiment, the first input terminal of the operational amplifier is connected to the high-voltage reference voltage during both the sampling and output phases;

[0011] During the sampling phase, the second input terminal of the operational amplifier is disconnected from the output terminal of the sampling circuit, and the sampling circuit is connected to the low-voltage gamma voltage and the low-voltage reference voltage to perform sampling.

[0012] During the output phase, the second input terminal of the operational amplifier is connected to the output terminal of the sampling circuit, and the sampling circuit is not connected to the low-voltage gamma voltage and the low-voltage reference voltage, so as to output the target voltage through the operational amplifier.

[0013] In one embodiment, the sampling capacitor in the sampling circuit is used to store the sampled charge, and the second input terminal of the operational amplifier is connected to the second terminal of the sampling capacitor through switch S3; the output terminal of the operational amplifier is connected to the first terminal of the sampling capacitor through switch S4.

[0014] In one embodiment, the output of the operational amplifier is connected to the second input of the operational amplifier via switch S5.

[0015] In one embodiment, the first input terminal of the operational amplifier is a non-inverting input terminal, and the second input terminal of the operational amplifier is an inverting input terminal.

[0016] In one embodiment, the input terminal of the low-voltage gamma voltage is connected to the sampling circuit via a first buffer, and the input terminal of the low-voltage reference voltage is connected to the sampling circuit via a second buffer.

[0017] In one embodiment, the voltage sampled by the sampling circuit is matched to a first voltage difference, and the voltage sampled by the sampling circuit is matched to a second voltage difference; the first voltage difference is the voltage difference between the low-voltage gamma voltage and the low-voltage reference voltage; the second voltage difference is the voltage difference between the target voltage and the high-voltage reference voltage.

[0018] In one embodiment, the target voltage is matched to the cumulative value of the low-voltage gamma voltage and a third voltage difference, the third voltage difference being the voltage difference between the low-voltage reference voltage and the high-voltage reference voltage.

[0019] This application also provides a control method applied to a screen driving circuit, the screen driving circuit including a sampling circuit and an operational amplifier, the method comprising:

[0020] The sampling circuit is controlled to sample the low-voltage gamma voltage and the low-voltage reference voltage.

[0021] When the sampling circuit completes sampling, the operational amplifier is controlled to output a target voltage based on the high-voltage reference voltage and the voltage sampled by the sampling circuit; the low-voltage reference voltage is less than the high-voltage reference voltage.

[0022] The screen is driven by the target voltage;

[0023] The low-voltage gamma voltage is adapted to the low-voltage reference voltage, and the low-voltage reference voltage is a reference voltage that is lower than the high-voltage reference voltage.

[0024] The aforementioned screen driving circuit directly connects to the low-voltage gamma voltage and the low-voltage reference voltage, eliminating the need for a gamma voltage generation circuit in the high-voltage domain and reducing circuit size. The sampling circuit is configured to sample based on the low-voltage gamma voltage and the low-voltage reference voltage, resulting in less charge collected and higher charge collection efficiency. Furthermore, since the reference voltage has already been calibrated in the low-voltage domain, adjustments can be made to factors such as hue to make the colors perceived by the human eye more linear. Simultaneously, the operational amplifier processes the voltage based on the high-voltage reference voltage and the voltage sampled by the sampling circuit, allowing the sampled voltage to be adjusted according to the high-voltage reference voltage. This ensures that the target voltage is also within the high-voltage domain, thereby generating richer colors through a wider range of voltages. Moreover, because the operational amplifier is connected to the high-voltage reference voltage, the reference voltage received by the operational amplifier is stable, preventing voltage domain switching of the reference voltage from affecting the time it takes for the operational amplifier to generate the target voltage. Therefore, the operational amplifier can quickly establish and output the target voltage to support high refresh rate screens. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the voltage drive circuit architecture;

[0027] Figure 2 This is a schematic diagram of the original gamma voltage curve;

[0028] Figure 3 This is a schematic diagram of the screen driving circuit structure for the reference voltage input in one embodiment;

[0029] Figure 4 This is a schematic diagram of the gamma voltage curve of a specific embodiment;

[0030] Figure 5 This is a schematic diagram of a sampling circuit in one embodiment;

[0031] Figure 6 This is a circuit diagram of the output stage in one embodiment;

[0032] Figure 7This is a circuit diagram of the output stage in another embodiment;

[0033] Figure 8 This is a schematic diagram of the screen driving circuit structure in a specific embodiment;

[0034] Figure 9 This is a flowchart of the control method for the screen driver circuit.

[0035] Figure labeling: 310 - sampling circuit; 320 - operational amplifier. Detailed Implementation

[0036] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0038] It is understood that the terms "first," "second," etc., used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of this application, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0039] It is understood that the term "connection" in the following embodiments should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have electrical signal or data transmission with each other.

[0040] It is understandable that "at least one" refers to one or more, and "multiple" refers to two or more. "At least a part of an element" refers to part or all of an element.

[0041] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0042] like Figure 1 As shown, existing display driving circuits include a reference voltage generation circuit, a reference voltage selection circuit, and a buffer. During display, not all generated reference voltages are sent to the buffer; only one level is selected by the selection circuit to control the liquid crystal molecules. Therefore, gamma correction is also performed on this single level. The gamma correction curve shows the X-axis representing different voltage points and the Y-axis representing the ratio of the voltage to the highest voltage, as shown... Figure 2 As shown.

[0043] It's important to understand that to prevent polarization of LCD liquid crystal molecules, positive and negative voltage driving circuits are typically used. This means the driving unit is divided into positive and negative voltage sections, usually in equal numbers. Therefore, at any given time, half of the driving voltage is positive, and the other half is negative. The same liquid crystal molecule is driven by positive voltage half the time and negative voltage half the time. This alternating positive and negative voltage drive prevents liquid crystal molecule polarization. Consequently, the gamma curve is divided into positive voltage gamma curves and negative voltage gamma curves, which may lead to excessively large chip sizes.

[0044] In one embodiment, such as Figure 3 As shown, the screen driving circuit includes: a sampling circuit 310, which is configured to sample based on a low-voltage gamma voltage and a low-voltage reference voltage; an operational amplifier 320 connected to a high-voltage reference voltage, and the operational amplifier 320 is configured to output a target voltage based on the high-voltage reference voltage and the voltage sampled by the sampling circuit 310, so as to drive the screen through the target voltage; wherein, the low-voltage gamma voltage is matched with the low-voltage reference voltage, and the low-voltage reference voltage is a reference voltage that is lower than the high-voltage reference voltage.

[0045] Low-voltage gamma voltage is the calibration voltage in the low-voltage domain. Low-voltage gamma voltage is... Figure 2The original gamma curve was split into multiple segments, and the voltage value of each segment was reduced to the low-voltage domain of its respective screen driver circuit. The gamma voltage variation pattern within each segment matches the variation pattern of the original gamma, and the gamma voltage within each segment is within the low-voltage domain. When the gamma voltage within each segment is at its minimum value, the ratio of the gamma voltage within each segment to the maximum voltage is 0; when the gamma voltage within each segment is at its maximum value, the ratio of the gamma voltage within each segment to the maximum voltage is the maximum value set within the low-voltage domain.

[0046] Optionally, such as Figure 4 As shown in (a), the curve of the original gamma voltage is divided into four segments, and the change pattern of the gamma voltage in each segment matches the change pattern of the original gamma voltage; the magnitude, relative relationship, and change pattern of the gamma voltage in each segment are as follows: Figure 4 As shown in (b).

[0047] The matching of low-voltage gamma voltage and low-voltage reference voltage means that both the low-voltage gamma voltage and the low-voltage reference voltage are in the low-voltage domain of the screen driving circuit, so that the sampling efficiency of the low-voltage gamma voltage and the low-voltage reference voltage is relatively high.

[0048] Both low-voltage and high-voltage reference voltages can be used to drive screens for display, but they differ in their voltage domains, connected components, and applications.

[0049] From a voltage domain perspective, the low-voltage reference voltage is a reference voltage within the low-voltage domain, which can be used to drive the screen for display. The high-voltage reference voltage is a reference voltage within the high-voltage domain, which can be used to drive the screen for display, ensuring that the low-voltage reference voltage is lower than the high-voltage reference voltage. In terms of connected components and their applications, the low-voltage reference voltage is connected to the sampling circuit 310 for sampling; while the high-voltage reference voltage is directly connected to the operational amplifier 320 to generate the target voltage.

[0050] Optionally, the low-voltage domain of the screen driver circuit includes various voltages lower than a certain low-voltage domain threshold. In some applications, the low-voltage domain threshold may be 1.8V or 2.5V, and in other applications, it may be 3.3V or 5V. The high-voltage domain of the screen driver circuit includes various voltages within a high-voltage domain range, where the minimum value of the high-voltage domain range is greater than the low-voltage domain threshold. Optionally, the high-voltage domain range can be from 12V to 30V.

[0051] The target voltage is the output voltage of operational amplifier 320. Since the target voltage is generated based on the high-voltage reference voltage and the voltage sampled by sampling circuit 310, and the voltage sampled by sampling circuit 310 is generated based on low-voltage gamma voltage and low-voltage reference voltage, the target voltage can also be a voltage related to low-voltage gamma voltage, low-voltage reference voltage, and high-voltage reference voltage.

[0052] The sampling circuit 310 is a circuit that samples the voltage input to the sampling circuit 310. The sampling circuit 310 includes at least a capacitor and a switch to sample the input voltage through the capacitor and to control whether the sampling phase ends through the corresponding switch; when the sampling ends, the voltage sampled by the sampling circuit 310 is held.

[0053] The sampling circuit 310 has a sampling phase and an output phase. During the sampling phase, the output terminals of the low-voltage gamma voltage and the low-voltage reference voltage are connected to the power supply path of the sampling circuit 310, so that the sampling circuit 310 samples based on the low-voltage gamma voltage and the low-voltage reference voltage. During the output phase, the output terminals of the low-voltage gamma voltage and the low-voltage reference voltage are disconnected from the sampling circuit 310, so that the voltage sampled by the sampling circuit 310 is input to the operational amplifier 320.

[0054] Operational amplifier 320 performs voltage signal processing based on a high-voltage reference voltage and the voltage output from sampling circuit 310. The input terminal of operational amplifier 320 is connected to the high-voltage reference voltage, ensuring a stable reference voltage received by operational amplifier 320. This avoids the voltage domain switching of the reference voltage affecting the time it takes for operational amplifier 320 to generate the target voltage, thus enabling operational amplifier 320 to establish and output the target voltage more quickly. During the sampling phase, the power supply path between operational amplifier 320 and sampling circuit 310 is disconnected; during the output phase, the power supply path between operational amplifier 320 and sampling circuit 310 is connected, allowing operational amplifier 320 to output the target voltage.

[0055] In this embodiment, the screen driving circuit connects to a low-voltage gamma voltage and a low-voltage reference voltage, eliminating the need for a gamma voltage generation circuit in the high-voltage domain and reducing circuit size. The sampling circuit 310 is configured to sample based on the low-voltage gamma voltage and the low-voltage reference voltage, resulting in less charge collected and higher efficiency. Furthermore, since the reference voltage has already been calibrated in the low-voltage domain, adjustments can be made to factors such as hue to achieve a more linear color perception. Simultaneously, the operational amplifier 320 processes the voltage sampled by the sampling circuit 310 based on the high-voltage reference voltage, allowing the sampled voltage to be adjusted according to the high-voltage reference voltage. This ensures the target voltage is also within the high-voltage domain, resulting in richer colors through a wider range of voltages. Moreover, the high-voltage reference voltage connected to the operational amplifier 320 ensures a stable reference voltage, preventing voltage domain switching from affecting the target voltage generation time. This allows the operational amplifier 320 to quickly establish and output the target voltage, supporting high refresh rate screens.

[0056] In an optional embodiment, the circuit structure for sampling circuit 310 is described. For example... Figure 5 As shown, the sampling circuit 310 includes a sampling capacitor, a switch S1, and a switch S2; the first terminal of the sampling capacitor is connected to the input terminal of the low-voltage gamma voltage via switch S1, and the second terminal of the sampling capacitor is connected to the input terminal of the low-voltage reference voltage via switch S2.

[0057] A sampling capacitor is a capacitor used to store the sampled charge. The first and second terminals of the sampling capacitor are two different terminals. The voltages applied to the first and second terminals respectively ensure that the charge stored in the sampling capacitor is the potential difference between the low-voltage gamma voltage and the low-voltage reference voltage. Switches S1 and S2 are different switches and can be used to control the sampling process of the sampling capacitor.

[0058] In this embodiment, different switches are connected to the two ends of the sampling capacitor. When both switches S1 and S2 are closed, the sampling capacitor collects and stores charge. When both switches S1 and S2 are open, the charge in the sampling capacitor is released to form the voltage sampled by the sampling circuit 310 itself.

[0059] In one embodiment, the circuit structure of the screen driving circuit at different stages is illustrated. During the sampling and output stages, the first input terminal of the operational amplifier 320 is connected to a high-voltage reference voltage. During the sampling stage, the second input terminal of the operational amplifier 320 is disconnected from the output terminal of the sampling circuit 310, and the sampling circuit 310 is connected to a low-voltage gamma voltage and a low-voltage reference voltage for sampling. During the output stage, the second input terminal of the operational amplifier 320 is connected to the output terminal of the sampling circuit 310, and the sampling circuit 310 is not connected to the low-voltage gamma voltage and the low-voltage reference voltage for outputting the target voltage through the operational amplifier 320.

[0060] The sampling phase is the stage where the sampling capacitor collects and stores charge. During the sampling phase, the sampling circuit 310 is connected to a low-voltage gamma voltage and a low-voltage reference voltage, and the sampling circuit 310 and the operational amplifier 320 are not turned on, so that the sampling circuit 310 can perform sampling without affecting the signal processing of the operational amplifier 320.

[0061] In the output stage, the sampling capacitor releases its stored charge to release the voltage sampled by the sampling circuit 310. The operational amplifier 320 then generates the target voltage based on the high-voltage reference voltage and the voltage released by the sampling circuit 310. During the output stage, the sampling circuit 310 is not connected to the low-voltage gamma voltage or the low-voltage reference voltage, and its output terminal is connected to the operational amplifier 320, allowing the voltage sampled by the sampling circuit 310 to be transmitted to the operational amplifier 320.

[0062] The first input terminal and the second input terminal of the operational amplifier 320 are different input terminals.

[0063] In this embodiment, regardless of whether the screen driving circuit is in the sampling stage or the output stage, the first input terminal of the operational amplifier 320 is continuously connected to a high-voltage reference voltage. Therefore, the first input terminal of the operational amplifier 320 will not be affected by the changes in the sampling circuit 310, which makes the reference voltage received by the operational amplifier 320 more stable. This avoids the signal of the sampling circuit 310 from affecting the signal stability of the operational amplifier 320, thereby enabling the operational amplifier 320 to establish and output the target voltage more quickly to support high refresh rate screens.

[0064] In one feasible embodiment, such as Figure 6 The diagram illustrates the required circuit connection for the output voltage of the sampling circuit 310. The sampling capacitor in the sampling circuit 310 stores the sampled charge. The second input terminal of the operational amplifier 320 is connected to the second terminal of the sampling capacitor via switch S3; the output terminal of the operational amplifier 320 is connected to the first terminal of the sampling capacitor via switch S4.

[0065] Operational amplifier 320 has two input terminals connected to a reference voltage and the second terminal of a sampling capacitor, respectively. When switches S3 and S4 are closed, operational amplifier 320 adjusts its output voltage to make the voltages at the two input terminals equal. Since the first terminal of the sampling capacitor is connected to the output terminal of operational amplifier 320 via switch S4, and the second terminal is connected to the second input terminal of operational amplifier 320 via switch S3, the voltage difference across the capacitor is gradually adjusted to zero by operational amplifier 320. Therefore, the charge on the capacitor is released through operational amplifier 320. Then, since the output terminal of operational amplifier 320 and the two terminals of the sampling capacitor form a closed loop, the charge on the sampling capacitor flows through operational amplifier 320 until the voltage across the capacitor reaches a balanced state, at which point operational amplifier 320 outputs the target voltage. In the balanced state, the voltages at the two input terminals of operational amplifier 320 are equal.

[0066] In this embodiment, the charge flow between the sampling circuit 310 and the operational amplifier 320 is controlled by switches S3 and S4 to construct a feedback circuit between the sampling circuit 310 and the operational amplifier 320. This feedback circuit can be turned on in the output stage to output the target voltage.

[0067] In an optional embodiment, such as Figure 7 As shown, another feedback circuit of operational amplifier 320 is described. The output terminal of operational amplifier 320 is connected to the second input terminal of operational amplifier 320 via switch S5.

[0068] When switch S5 is on, the voltage output by operational amplifier 320 directly acts on the second input terminal of operational amplifier 320, forming a feedback mechanism of operational amplifier 320 itself; when switch S5 is off, the voltage output by operational amplifier 320 does not act on the second input terminal of operational amplifier 320 through switch S5.

[0069] Optionally, switch S5 is turned on during the sampling phase to control operational amplifier 320 to be in a closed-loop state during the sampling phase; switch S5 is turned off during the output phase to control operational amplifier 320 to output target voltage based on high voltage reference voltage and voltage sampled by sampling circuit 310.

[0070] Optionally, the first input terminal is an inverting input terminal, and the second input terminal of the operational amplifier 320 is a non-inverting input terminal. Therefore, when the output voltage of the operational amplifier 320 is applied to the input terminal and superimposed, a positive feedback voltage is formed, further enhancing the signal amplitude.

[0071] In this embodiment, the output terminal of the operational amplifier 320 is connected to the second input terminal through switch S5, thereby forming a feedback mechanism for the operational amplifier 320. This feedback circuit can be turned on during the output stage to regulate the voltage of the operational amplifier 320.

[0072] In one feasible embodiment, the first input terminal of the operational amplifier 320 is a non-inverting input terminal, and the second input terminal of the operational amplifier 320 is an inverting input terminal.

[0073] In this embodiment, the voltage output by the operational amplifier 320 is subtracted from the voltage released by the capacitor, which reduces the fluctuation of the output signal and helps to improve the stability of the circuit, thereby reducing the possibility of screen distortion.

[0074] In an optional embodiment, the input terminal of the low-voltage gamma voltage is connected to the sampling circuit 310 via a first buffer, and the input terminal of the low-voltage reference voltage is connected to the sampling circuit 310 via a second buffer.

[0075] The first buffer is a voltage buffer used to buffer low-voltage gamma voltage, and the second buffer is a voltage buffer used to buffer low-voltage reference voltage.

[0076] The first and second buffers are buffers on different circuits. The buffers are used to stabilize the low-voltage gamma voltage and the low-voltage reference voltage, so as to drive the screen load with a smooth low-voltage gamma voltage and low-voltage reference voltage. The low-voltage gamma voltage and low-voltage reference voltage input to the buffers both apply to the sampling circuit 310.

[0077] Optionally, switch S1 is disposed between the first buffer and the sampling circuit 310 to control the voltage input to the corresponding sampling circuit 310 more quickly; alternatively, switch S2 is disposed between the second buffer and the sampling circuit 310 to control the voltage input to the corresponding sampling circuit 310 more quickly.

[0078] In an optional embodiment, the voltage relationship acting on the sampling circuit 310 is described. The voltage sampled by the sampling circuit 310 is matched to a first voltage difference, and the voltage sampled by the sampling circuit 310 is matched to a second voltage difference; the first voltage difference is the voltage difference between the low-voltage gamma voltage and the low-voltage reference voltage; the second voltage difference is the voltage difference between the target voltage and the high-voltage reference voltage.

[0079] The product of the first voltage and the capacity of the sampling circuit 310 is the amount of charge in the sampling circuit 310 during the sampling process. Matching the voltage sampled by the sampling circuit 310 to the first voltage difference means that the voltage sampled by the sampling circuit 310 is equal to the first voltage difference, or the difference or ratio between the voltage sampled by the sampling circuit 310 and the first voltage difference is less than a preset value.

[0080] The product of the second voltage difference and the capacity of the sampling circuit 310 is the amount of charge released by the sampling circuit 310 during the output stage. Matching the voltage sampled by the sampling circuit 310 to the second voltage difference means that the voltage sampled by the sampling circuit 310 is equal to the second voltage difference, or the difference or ratio between the voltage sampled by the sampling circuit 310 and the second voltage difference is less than a preset value.

[0081] For example, both the first voltage difference and the second voltage difference are equal to the voltage sampled by the sampling circuit 310. The voltage relationship at this time can be represented by the following expression:

[0082] ;

[0083] in, It is a low-voltage gamma voltage. It is the low-voltage reference voltage. This refers to the capacity of the sampling circuit 310. It is the target voltage. It is the high-voltage reference voltage; It is the first voltage difference; It is the second voltage difference; It is the amount of charge accumulated by the sampling circuit 310 during the sampling phase; It is the amount of charge released by the sampling circuit 310 during the output stage.

[0084] In this embodiment, the voltage sampled by the sampling circuit 310 is based on the first voltage difference and can be used to form the second voltage difference. This follows the principle of charge conservation and forms the voltage change characteristics of the sampling stage and the output stage, thus laying the foundation for screen driving.

[0085] In another alternative embodiment, the voltage relationship acting on the sampling circuit 310 is described. The target voltage is matched to the cumulative value of the low-voltage gamma voltage and the third voltage difference, which is the voltage difference between the low-voltage reference voltage and the high-voltage reference voltage.

[0086] The third voltage difference is the voltage variation between different reference voltages. This third voltage difference may not actually exist in the circuit, but it serves as a voltage characteristic of the screen driving circuit, reflecting the corresponding voltage relationship. The third voltage difference may be the difference or ratio between the low-voltage and high-voltage reference voltages, or a mapping result obtained through a mapping table.

[0087] The cumulative value of the low-voltage gamma voltage and the third voltage difference can be the sum of the low-voltage gamma voltage and the third voltage difference, or it can be the result obtained based on the mapping table.

[0088] For example,

[0089]

[0090] in, It is a low-voltage gamma voltage. It is the low-voltage reference voltage. It is the high-voltage reference voltage. It is the third voltage difference.

[0091] In this embodiment, the target voltage and the difference between the low-voltage gamma voltage and the third voltage have numerical characteristics. The target voltage can be predicted through the corresponding numerical characteristics, thus laying the design foundation for the screen driving circuit.

[0092] In one embodiment, Figure 8 As shown, the screen driving circuit includes a first buffer buf1, a second buffer buf1, a sampling circuit 310 and an operational amplifier 320. The sampling circuit 310 includes a sampling capacitor C, a switch S1 and a switch S2.

[0093] The input terminal of the low-voltage gamma voltage is connected to the input terminal of the first buffer buf1, and the output terminal of the first buffer buf1 is connected to the first terminal of the sampling capacitor C via switch S1; the input terminal of the low-voltage reference voltage is connected to the input terminal of the second buffer buf2, and the output terminal of the second buffer buf2 is connected to the second terminal of the sampling capacitor C via switch S2.

[0094] The non-inverting input of operational amplifier 320 is connected to a high-voltage reference voltage. The second terminal of sampling capacitor C is connected to the inverting input of operational amplifier 320 via switch S3. The output of operational amplifier 320 is connected to the first terminal of sampling capacitor via switch S4. The output of operational amplifier 320 is also connected to the inverting input of operational amplifier 320 via switch S5.

[0095] A switch S2 is connected between the second terminal of the sampling capacitor C and the second buffer; the inverting input terminal of the operational amplifier 320 is connected to the second terminal of the sampling capacitor C via a switch S3; and the output terminal of the operational amplifier 320 is connected to the first terminal of the sampling capacitor via a switch S4.

[0096] In one embodiment, this application also provides a control method, such as Figure 9 As shown, this method is applied to a screen driving circuit, which includes a sampling circuit 310 and an operational amplifier 320. The method includes:

[0097] Step 902: Control sampling circuit 310 to connect low-voltage gamma voltage and low-voltage reference voltage for sampling.

[0098] Step 904: After the sampling circuit 310 has completed sampling, the operational amplifier 320 is controlled to output a target voltage based on the high voltage reference voltage and the voltage sampled by the sampling circuit 310; the low voltage reference voltage is less than the high voltage reference voltage.

[0099] The completion of sampling by the sampling circuit 310 can be determined by a clock signal or by whether the charge contained in the sampling circuit 310 has reached a preset value.

[0100] In an optional embodiment, the first input terminal of the operational amplifier 320 is connected to a high-voltage reference voltage; the control sampling circuit 310 to sample by connecting a low-voltage gamma voltage and a low-voltage reference voltage includes: controlling the second input terminal of the operational amplifier 320 to disconnect from the output terminal of the sampling circuit 310, and controlling the sampling circuit 310 to sample by connecting a low-voltage gamma voltage and a low-voltage reference voltage.

[0101] Correspondingly, the operational amplifier 320 outputs a target voltage based on the high-voltage reference voltage and the voltage sampled by the sampling circuit 310, including: controlling the second input terminal of the operational amplifier 320 to be connected to the output terminal of the sampling circuit 310, and controlling the sampling circuit 310 to stop connecting the low-voltage gamma voltage and the low-voltage reference voltage, so that the operational amplifier 320 outputs the target voltage.

[0102] Step 906: Drive the screen with the target voltage; wherein the low-voltage gamma voltage is matched with the low-voltage reference voltage, and the low-voltage reference voltage is a reference voltage that is lower than the high-voltage reference voltage.

[0103] Optionally, the screen driving circuit can be connected to the screen via a metal wire to drive the screen with a target voltage.

[0104] Optionally, the liquid crystal molecules in the screen can be driven to move by a target voltage for display.

[0105] In one specific embodiment, the control method is applied to Figure 8 In the circuit, during the sampling phase, switches S1 and S2 are closed to allow the sampling capacitor C to sample. Simultaneously, switch S5 is closed for negative feedback, aligning the voltages at the non-inverting and inverting inputs of operational amplifier 320, and switches S3 and S4 are opened. During the output phase, switches S1, S2, and S5 provide negative feedback, and switches S3 and S4 are closed to release the charge collected by capacitor C.

[0106] In the description of this specification, references to terms such as "some embodiments," "other embodiments," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiments or examples.

[0107] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0108] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A screen driving circuit, characterized in that, include: A sampling circuit configured to sample based on the voltage difference between a low-voltage gamma voltage and a low-voltage reference voltage; An operational amplifier is connected to a high-voltage reference voltage, and the operational amplifier is configured to output a target voltage based on the high-voltage reference voltage and the voltage difference sampled by the sampling circuit, so as to drive the screen through the target voltage; Wherein, the low-voltage gamma voltage is adapted to the low-voltage reference voltage, and the low-voltage reference voltage is a reference voltage that is lower than the high-voltage reference voltage; During both the sampling and output phases, the first input terminal of the operational amplifier is connected to the high-voltage reference voltage; During the sampling phase, the second input terminal of the operational amplifier is disconnected from the output terminal of the sampling circuit, and the sampling circuit is connected to the low-voltage gamma voltage and the low-voltage reference voltage to perform sampling. During the output phase, the second input terminal of the operational amplifier is connected to the output terminal of the sampling circuit, and the sampling circuit is not connected to the low-voltage gamma voltage and the low-voltage reference voltage, so as to output the target voltage through the operational amplifier.

2. The screen driving circuit according to claim 1, characterized in that, The sampling circuit includes a sampling capacitor, a switch S1, and a switch S2; the first end of the sampling capacitor is connected to the input terminal of the low-voltage gamma voltage via the switch S1, and the second end of the sampling capacitor is connected to the input terminal of the low-voltage reference voltage via the switch S2.

3. The screen driving circuit according to claim 1, characterized in that, The sampling capacitor in the sampling circuit is used to store the sampled charge. The second input terminal of the operational amplifier is connected to the second terminal of the sampling capacitor through switch S3. The output terminal of the operational amplifier is connected to the first terminal of the sampling capacitor through switch S4.

4. The screen driving circuit according to claim 1, characterized in that, The output terminal of the operational amplifier is connected to the second input terminal of the operational amplifier via switch S5.

5. The screen driving circuit according to claim 3 or 4, characterized in that, The first input terminal of the operational amplifier is a non-inverting input terminal, and the second input terminal of the operational amplifier is an inverting input terminal.

6. The screen driving circuit according to claim 3 or 4, characterized in that, The first input terminal of the operational amplifier is an inverting input terminal, and the second input terminal of the operational amplifier is a non-inverting input terminal.

7. The screen driving circuit according to claim 1, characterized in that, The input terminal of the low-voltage gamma voltage is connected to the sampling circuit via a first buffer, and the input terminal of the low-voltage reference voltage is connected to the sampling circuit via a second buffer.

8. The screen driving circuit according to claim 1, characterized in that, The voltage sampled by the sampling circuit is matched to a first voltage difference, and the voltage sampled by the sampling circuit is matched to a second voltage difference; the first voltage difference is the voltage difference between the low-voltage gamma voltage and the low-voltage reference voltage; The second voltage difference is the voltage difference between the target voltage and the high-voltage reference voltage.

9. The screen driving circuit according to claim 1, characterized in that, The target voltage is matched to the cumulative value of the low-voltage gamma voltage and the third voltage difference, which is the voltage difference between the low-voltage reference voltage and the high-voltage reference voltage.

10. A control method, characterized in that, Applied to the screen driving circuit according to any one of claims 1 to 9, the screen driving circuit including a sampling circuit and an operational amplifier, the method includes: The sampling circuit is controlled to sample a low-voltage gamma voltage and a low-voltage reference voltage to obtain the voltage difference. When the sampling circuit completes sampling, the operational amplifier is controlled to output a target voltage based on the voltage difference between the high-voltage reference voltage and the voltage sampled by the sampling circuit; the low-voltage reference voltage is less than the high-voltage reference voltage. The screen is driven by the target voltage; The low-voltage gamma voltage is adapted to the low-voltage reference voltage, and the low-voltage reference voltage is a reference voltage that is lower than the high-voltage reference voltage.

Images