A compensation circuit and a compensation method for improving the coupling of an LED display screen

Abstract

The present application discloses a compensation circuit for improving the coupling of an LED display screen, which includes a main control circuit and a row transistor follower circuit. The main control circuit controls the row transistor follower circuit to obtain the target boosting voltage of the turned-on row transistors, so that after the row transistor follower circuit obtains the target boosting voltage, it controls the voltage of the unturned-on row transistors to boost the target boosting voltage accordingly, canceling the influence of the coupling effect of various parasitic parameters on the PCB board of the LED display screen, thereby improving the color unevenness phenomenon when a brighter gray scale is superimposed beside a lower gray scale in the display picture and enhancing the user experience.

Description

Technical Field

[0001] This application relates to the field of integrated circuit technology, and particularly to a compensation circuit and a compensation method for improving the coupling of an LED display screen. Background Art

[0002] A light-emitting diode (LED) display screen uses the cumulative lighting time of each sub-frame display data to display different gray levels. The interval available for lighting the LED lamps in each sub-frame is called the display area. On the premise of a fixed display frequency, the display time of the display area will change according to different line scan numbers. Figure 1 FIG. 1 is a schematic diagram of the principle of an LED display screen provided by the prior art. As Figure 1 shown, each line scan will be sequentially turned on during data display. To avoid the coupling effect of the current in the R / G / B display channels on the line transistors when they are turned off or on, the line transistors will be locked at a certain voltage when they are not turned on, so that the LED lamps are in a reverse bias and not lit state. During the display process, on the one hand, the size limitation of the transistors in the internal circuit of the LED chip makes its on-resistance have a limit value, resulting in different accumulated currents when each line scan is turned on, and causing differences in the voltage values of each line transistor. When the voltage of the turned-on line scan terminal changes, in order to reach the forward bias conduction voltage of the LED lamp, the output voltage of the channel control terminal will also rise accordingly. At the same time, the channel control terminal will also be affected by the parasitic effects of the other unturned-on line scans and unlit LED lamps, resulting in the phenomenon that when a brighter image is superimposed beside a lower gray level in the display screen, the same gray level has inconsistent brightness. On the other hand, outside the LED chip, when the channel control terminal is turned off, due to various parasitic parameters on the PCB board, such as the PCB board traces and the influence of the characteristic parameters of different lamp beads, the charge remaining in the parasitic capacitance value will also cause inconsistent display brightness of the image, resulting in a high-contrast coupling phenomenon in the LED display screen.

[0003] To solve the above-mentioned LED display screen coupling phenomenon, the existing method is to stagger the turn-on times of the R / G / B display channels in the display area to reduce the instantaneous load effect of the power supply and the coupling effect on the lamp board when the channel control terminal outputs, thereby improving the uneven color display phenomenon when a lower gray level in the display screen is superimposed with a brighter gray level. However, this method has some problems: at a high line scan number, the display time will surely decrease, and staggering the turn-on start times of the R / G / B display channels within a limited time will affect the presentation of the display contrast. In addition, even if the turn-on start times of the R / G / B display channels are staggered, due to the different turn-off times of different channels, it will still be affected by the coupling effect of various parasitic parameters on the PCB board. Therefore, the prior art can only reduce the coupling phenomenon of the LED display screen and cannot effectively solve the problem. Summary of the Invention

[0004] The objective of this application is to provide a compensation circuit and a compensation method for improving the coupling of an LED display screen, which improves the color rendering unevenness phenomenon when a brighter gray level is superimposed beside a lower gray level in the display screen, and enhances the user experience.

[0005] To solve the above technical problems, this application provides a compensation circuit for improving the coupling of an LED display screen, including a main control circuit and a row transistor follower circuit. The row transistor follower circuit is connected to each row transistor, and the main control circuit is connected to the row transistor follower circuit to control the row transistor follower circuit to obtain the target boosting voltage of the turned-on row transistor, and control the first switch of the turned-on row transistor to disconnect and the first switch of the unturned-on row transistor to close. After obtaining the target boosting voltage, the row transistor follower circuit controls the voltage of the unturned-on row transistor to be boosted by the target boosting voltage.

[0006] Preferably, the row transistor follower circuit specifically includes a first multiplexer, a capacitor, a first bias voltage generation circuit, and a first operational amplifier;

[0007] The input end of the first multiplexer is connected to the turned-on row transistor, the output end of the first multiplexer is connected to the first end of the capacitor, the output end of the first bias voltage generation circuit is connected to the input end of the first operational amplifier, the output end of the first operational amplifier is connected to the second end of the capacitor, and the common end of the first operational amplifier and the capacitor is connected to the unturned-on row transistor.

[0008] Preferably, the first bias voltage generation circuit specifically includes a first bandgap reference voltage source and a multiplication circuit. The first bandgap reference voltage source is connected to the multiplication circuit, and the multiplication circuit is connected to the input end of the first operational amplifier.

[0009] Preferably, the row transistor follower circuit specifically includes a second multiplexer, a second bias voltage generation circuit, and a second operational amplifier;

[0010] The input end of the second multiplexer is connected to the turned-on row transistor, the output end of the second multiplexer is connected to the input end of the second bias voltage generation circuit, the output end of the second bias voltage generation circuit is connected to the input end of the second operational amplifier, and the output end of the second operational amplifier is connected to the unturned-on row transistor.

[0011] Preferably, the second bias voltage generation circuit specifically includes a second bandgap reference voltage source and an addition circuit. The input end of the second bandgap reference voltage source is connected to the output end of the second multiplexer, the output end of the second bandgap reference voltage source is connected to the input end of the addition circuit, and the output end of the addition circuit is connected to the input end of the second operational amplifier.

[0012] To solve the above technical problems, the present application also provides a compensation method for improving the coupling of an LED display screen. Based on the compensation circuit for improving the coupling of the LED display screen, it includes:

[0013] Control the first switch of the turned-on row transistor to disconnect, and the first switch of the unturned-on row transistor to close;

[0014] Control the row transistor follower circuit to obtain the target boost voltage of the turned-on row transistor, so that after the row transistor follower circuit obtains the target boost voltage, it controls the voltage of the unturned-on row transistor to boost by the target boost voltage.

[0015] To solve the above technical problems, the present application also provides an LED display screen system, which includes an LED display screen and also includes the compensation circuit for improving the coupling of the LED display screen as described above.

[0016] The compensation circuit for improving the coupling of the LED display screen provided by the present application includes a main control circuit and a row transistor follower circuit. The main control circuit controls the row transistor follower circuit to obtain the target boost voltage of the turned-on row transistor, so that after the row transistor follower circuit obtains the target boost voltage, it controls the voltage of the unturned-on row transistor to boost by the target boost voltage accordingly, canceling the influence of the coupling effect of various parasitic parameters on the LED display screen PCB board, and thus improving the color display unevenness phenomenon when a brighter gray scale is superimposed beside a lower gray scale in the display picture, and improving the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] To more clearly illustrate the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 A schematic diagram of the principle of an LED display screen provided by the prior art;

[0019] Figure 2 A structural diagram of a compensation circuit for improving the coupling of an LED display screen provided by an embodiment of the present application;

[0020] Figure 3 Another structural diagram of a compensation circuit for improving the coupling of an LED display screen provided by an embodiment of the present application;

[0021] Figure 4 A waveform diagram of the voltage of a row transistor provided by an embodiment of the present application;

[0022] Figure 5 A structural diagram of a row transistor follower circuit provided by an embodiment of the present application;

[0023] Figure 6 Schematic diagram of another line tube following circuit provided by an embodiment of the present application;

[0024] Figure 7 Flowchart of a compensation method for improving the coupling of an LED display screen provided by an embodiment of the present application. Detailed implementation manners

[0025] Next, the technical solutions in the embodiments of the present application will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0026] The core of the present application is to provide a compensation circuit and a compensation method for improving the coupling of an LED display screen, which improve the color unevenness phenomenon when a brighter gray scale is superimposed beside a lower gray scale of the display screen, and improve the user experience.

[0027] In order to enable those skilled in the art to better understand the solution of the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific implementation manners.

[0028] Figure 2 Structural diagram of a compensation circuit for improving the coupling of an LED display screen provided by an embodiment of the present application. As Figure 2 shown, the compensation circuit includes a main control circuit 1 and a line tube following circuit 2. The line tube following circuit 2 is connected to each line tube 3, and the main control circuit 1 is connected to the line tube following circuit 2 to control the line tube following circuit 2 to obtain the target boost voltage of the turned-on line tube, and control the first switch of the turned-on line tube to be disconnected, and the first switch of the unturned-on line tube to be closed. After obtaining the target boost voltage, the line tube following circuit 2 controls the voltage of the unturned-on line tube to be boosted to the target boost voltage.

[0029] In specific implementation, the line tube following circuit 2 is connected to each line tube 3. When the line tube control end of the line tube following circuit 2 controls a certain line tube to access a low level, the line tube is turned on. At this time, the voltage of the turned-on line tube will be boosted, and the main control circuit 1 controls the line tube following circuit 2 to obtain the target boost voltage of the turned-on line tube. Figure 3 Structural diagram of another compensation circuit for improving the coupling of an LED display screen provided by an embodiment of the present application. As Figure 3 shown, the output end VOUT of the line tube following circuit 2 is connected to each line tube 3, and the main control circuit 1 controls the first switch of the turned-on line tube to be disconnected, Figure 3 Taking line 2 as the turned-on line tube for illustration, the first switch of line 2 is disconnected, and the first switches of the remaining unturned-on line tubes are closed. After obtaining the target boost voltage, the line tube following circuit 2 controls the voltage of the unturned-on line tube to be boosted to the target boost voltage.Figure 4 A waveform schematic diagram of the line tube voltage provided by the embodiment of the present application. As Figure 4 shown, 1 is the voltage before the first row is not lifted, 2 is the voltage after lifting, and the voltage of the first row of the non-activated line tube increases with the target lifting voltage of the second row of the activated line tube.

[0030] It should be noted that the embodiment of the present application does not limit the specific structure of the main control circuit 1. According to the actual situation, it can be any circuit structure that can implement the relevant functions of the present application. The main control circuit 1 can be a separate controller, or integrated with the line tube control end and the channel control end, or can also be an MCU in other devices. This embodiment does not make a limit.

[0031] The compensation circuit for improving the coupling of the LED display screen provided by the present application includes a main control circuit and a line tube following circuit. The main control circuit controls the line tube following circuit to obtain the target lifting voltage of the activated line tube, so that after the line tube following circuit obtains the target lifting voltage, it controls the voltage of the non-activated line tube to increase by the target lifting voltage, canceling the influence of the coupling effect of various parasitic parameters on the LED display screen PCB board, and then improving the color unevenness phenomenon when a brighter gray scale is superimposed beside a lower gray scale in the display screen, and improving the user experience.

[0032] Figure 5 A structural schematic diagram of a line tube following circuit provided by the embodiment of the present application. As Figure 5 shown, on the basis of the above embodiment, as a preferred embodiment, the line tube following circuit 2 specifically includes a first multiplexer 10, a capacitor C, a first bias voltage generation circuit 11, and a first operational amplifier 12;

[0033] The input end of the first multiplexer 10 is connected to the activated line tube, the output end of the first multiplexer 10 is connected to the first end of the capacitor C, the output end of the first bias voltage generation circuit 11 is connected to the input end of the first operational amplifier 12, the output end of the first operational amplifier 12 is connected to the second end of the capacitor C, and the common end of the first operational amplifier 12 and the capacitor C is connected to the non-activated line tube.

[0034] Specifically, the first bias voltage generation circuit 11 specifically includes a first bandgap reference voltage source and a multiplication circuit. The first bandgap reference voltage source is connected to the multiplication circuit, and the multiplication circuit is connected to the input end of the first operational amplifier 12.

[0035] In a specific implementation, an input voltage is provided to the first bias generation circuit 11. After passing through the first bias generation circuit 11 and the first operational amplifier 12, the output is the initial voltage of the unactivated row transistor, which is generally a high level. Here, taking 2V as an example. When row 2 is the activated row transistor, the second switch of row 2 is closed, that is, the left side of the capacitor C is initially 2V and the right side is 0V. At this time, the voltage difference across the capacitor is 2V. Suppose the voltage of row 2 rises by 0.2V, then the first multiplexer 10 outputs 0.2V, and the right side of the capacitor C instantaneously rises to 0.2V. According to the principle that the instantaneous voltage difference across the capacitor remains unchanged, the left side will simultaneously rise to 2.2V, so that the voltage difference across the capacitor C remains 2V. In addition, although the first operational amplifier 12 continues to output 2V to the left side of the capacitor C, in this design, the capacitance value of the capacitor C is very large, and even with the first operational amplifier 12, the left side of the capacitor cannot be stably maintained at 2V in a short period of time. Instead, it will be affected by the instantaneous rise of the voltage on the right side of the capacitor C and become 2.2V.

[0036] Figure 6 FIG. is a schematic structural diagram of a row transistor following circuit provided by an embodiment of the present application. As Figure 6 shown, on the basis of the above embodiment, as a preferred embodiment, the row transistor following circuit 2 specifically includes a second multiplexer 20, a second bias generation circuit 21, and a second operational amplifier 22;

[0037] The input end of the second multiplexer 20 is connected to the activated row transistor, the output end of the second multiplexer 20 is connected to the input end of the second bias generation circuit 21, the output end of the second bias generation circuit 21 is connected to the input end of the second operational amplifier 22, and the output end of the second operational amplifier 22 is connected to the unactivated row transistor.

[0038] Specifically, the second bias generation circuit 21 specifically includes a second bandgap reference voltage source and an adder circuit. The input end of the second bandgap reference voltage source is connected to the output end of the second multiplexer 20, the output end of the second bandgap reference voltage source is connected to the input end of the adder circuit, and the output end of the adder circuit is connected to the input end of the second operational amplifier 22.

[0039] In a specific implementation, when row 2 is the activated row transistor, the second switch of row 2 is closed. Suppose the voltage of row 2 rises by 0.2V, then the second multiplexer 20 outputs 0.2V to the second bias generation circuit 21. The second bias generation circuit 21 includes a second bandgap reference voltage source and an adder circuit, which can add the initial voltage of the unactivated row transistor and the rising voltage (i.e., 0.2V) and output it to the unactivated row transistor via the second operational amplifier 22. The voltage of the unactivated row transistor rises by 0.2V as the activated row transistor rises.

[0040] The compensation circuit for improving the coupling of the LED display provided by the present application provides two implementation manners of the row transistor following circuit. After the row transistor following circuit obtains the target boosting voltage, it controls the voltage of the unactivated row transistors to boost by the target boosting voltage, canceling the influence of the coupling effect of various parasitic parameters on the PCB board of the LED display, thereby improving the color unevenness phenomenon when a brighter gray scale is superimposed beside a lower gray scale in the display picture and enhancing the user experience.

[0041] In the above implementation, the compensation circuit for improving the coupling of the LED display is described in detail in terms of the hardware circuit structure and connection relationship. On this basis, the present application also provides a compensation method for improving the coupling of the LED display applied to the compensation circuit. Figure 7 It is a flowchart of a compensation method for improving the coupling of the LED display provided by an embodiment of the present application. As Figure 7 shown, the method includes:

[0042] S10: Control the first switch of the activated row transistors to disconnect, and the first switch of the unactivated row transistors to close.

[0043] S11: Control the row transistor following circuit 2 to obtain the target boosting voltage of the activated row transistors, so that after the row transistor following circuit 2 obtains the target boosting voltage, it controls the voltage of the unactivated row transistors to boost by the target boosting voltage.

[0044] It can be understood that the above method can be implemented by the main control circuit 1, which is the same as the main control circuit 1 mentioned above, or can be implemented by other MCUs, which is not limited in this embodiment.

[0045] The compensation method for improving the coupling of the LED display provided by this embodiment is implemented based on the compensation circuit for improving the coupling of the LED display. The compensation circuit includes a main control circuit and a row transistor following circuit. The main control circuit controls the row transistor following circuit to obtain the target boosting voltage of the activated row transistors, so that after the row transistor following circuit obtains the target boosting voltage, it controls the voltage of the unactivated row transistors to boost by the target boosting voltage, canceling the influence of the coupling effect of various parasitic parameters on the PCB board of the LED display, thereby improving the color unevenness phenomenon when a brighter gray scale is superimposed beside a lower gray scale in the display picture and enhancing the user experience.

[0046] In addition, the present application also provides an LED display system, including an LED display and also including the compensation circuit for improving the coupling of the LED display mentioned in the above embodiments.

[0047] Since the compensation circuit for improving the coupling of the LED display has been described in detail above, it will not be elaborated in this embodiment.

[0048] The LED display screen system provided by this embodiment includes a compensation circuit for improving the coupling of the LED display screen. The compensation circuit includes a main control circuit and a line tube follower circuit. The main control circuit controls the line tube follower circuit to obtain the target boost voltage of the turned-on line tube, so that after the line tube follower circuit obtains the target boost voltage, it controls the voltage of the unturned-on line tube to boost the target boost voltage accordingly, canceling the influence of the coupling effect of various parasitic parameters on the LED display screen PCB board, thereby improving the color rendering unevenness phenomenon when a brighter gray scale is superimposed beside a lower gray scale in the display picture and enhancing the user experience.

[0049] The above has introduced in detail a compensation circuit and a compensation method for improving the coupling of an LED display screen provided by this application. The various embodiments in the specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same and similar parts among the various embodiments, reference can be made to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple. For the relevant parts, reference can be made to the description in the method part. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principle of this application, several improvements and modifications can still be made to this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

[0050] It should also be noted that in this specification, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of another identical element in the process, method, article or device including the said element.

Claims

1. A compensation circuit for improving the coupling of an LED display screen, characterized in that, it includes a main control circuit and a row transistor follower circuit. The row transistor follower circuit is connected to each row transistor. The main control circuit is connected to the row transistor follower circuit, controls the row transistor follower circuit to obtain the target boost voltage of the turned-on row transistor, and controls the first switch of the turned-on row transistor to be turned off and the first switch of the unturned-on row transistor to be turned on. After obtaining the target boost voltage, the row transistor follower circuit controls the voltage of the unturned-on row transistor to be boosted by the target boost voltage.

2. The compensation circuit for improving the coupling of an LED display screen according to claim 1, characterized in that, the row transistor follower circuit specifically includes a first multiplexer, a capacitor, a first bias voltage generation circuit, and a first operational amplifier; the input end of the first multiplexer is connected to the turned-on row transistor, the output end of the first multiplexer is connected to the first end of the capacitor, the output end of the first bias voltage generation circuit is connected to the input end of the first operational amplifier, the output end of the first operational amplifier is connected to the second end of the capacitor, and the common end of the first operational amplifier and the capacitor is connected to the unturned-on row transistor.

3. The compensation circuit for improving the coupling of an LED display screen according to claim 2, characterized in that, the first bias voltage generation circuit specifically includes a first bandgap reference voltage source and a multiplication circuit. The first bandgap reference voltage source is connected to the multiplication circuit, and the multiplication circuit is connected to the input end of the first operational amplifier.

4. The compensation circuit for improving the coupling of an LED display screen according to claim 1, characterized in that, the row transistor follower circuit specifically includes a second multiplexer, a second bias voltage generation circuit, and a second operational amplifier; the input end of the second multiplexer is connected to the turned-on row transistor, the output end of the second multiplexer is connected to the input end of the second bias voltage generation circuit, the output end of the second bias voltage generation circuit is connected to the input end of the second operational amplifier, and the output end of the second operational amplifier is connected to the unturned-on row transistor.

5. The compensation circuit for improving the coupling of an LED display screen according to claim 4, characterized in that, the second bias voltage generation circuit specifically includes a second bandgap reference voltage source and an addition circuit. The input end of the second bandgap reference voltage source is connected to the output end of the second multiplexer, the output end of the second bandgap reference voltage source is connected to the input end of the addition circuit, and the output end of the addition circuit is connected to the input end of the second operational amplifier.

6. A compensation method for improving the coupling of an LED display screen, characterized in that, based on the compensation circuit for improving the coupling of an LED display screen according to any one of claims 1 to 5, it includes: controlling the first switch of the turned-on row transistor to be turned off and the first switch of the unturned-on row transistor to be turned on; controlling the row transistor follower circuit to obtain the target boost voltage of the turned-on row transistor, so that after obtaining the target boost voltage, the row transistor follower circuit controls the voltage of the unturned-on row transistor to be boosted by the target boost voltage.

7. An LED display screen system, including an LED display screen, characterized in that, It further includes a compensation circuit for improving the coupling of the LED display screen as described in any one of claims 1 to 5.

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