Control circuit, control method and display device

Abstract

The present application provides a control circuit, a control method and a display device. The control circuit includes: a sampling module for collecting a level signal corresponding to a pulse width modulation signal; a switching module, one end of which is connected to the sampling module and the other end of which is connected to at least one set of signal feedback terminals; and an operating power source connected to the sampling module and the switching module, for supplying power to the sampling module and the switching module, the signal feedback terminal includes at least two feedback points, the feedback points are for connecting to a light-emitting unit, and the switching module can switch between a first mode and a second mode according to a relationship between the level signal and a preset threshold value, in the first mode, the switching module can control each feedback point in the signal feedback terminal to be independent of each other, and in the second mode, the switching module can control each feedback point in the signal feedback terminal to be associated with each other.

Description

[Technical Field]

[0001] This application claims priority from a Chinese patent application filed with the China Patent Office on May 9, 2022, bearing application number CN202210498041.2 and entitled "Control Circuit, Control Method and Display Device," the entire contents of which are incorporated herein by reference.

[0002] The present application relates to the technical field of display driving, and in particular to a control circuit, a control method, and a display device. [Background technology]

[0003] In the backlight of a display panel, the lighting of light-emitting diodes is controlled by pulse width modulation (PWM). However, a low-level signal appears in the current PWM signal. When a low-level PWM signal is converted into a current signal, the current value is low. The low current causes a large fluctuation in the voltage at the feedback terminal of the light-emitting diode. Large fluctuations in voltage cause the brightness of the light-emitting diode to fluctuate up and down, resulting in the light-emitting diode continuously flashing.

[0004] The above information disclosed in the background art above is merely intended to enhance understanding of the background of the present invention and may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] This application provides a technical solution to reduce the continuous blinking of a light-emitting diode when a PWM signal is a low-level signal.

[0006] According to a first aspect of the present application, there is provided a control circuit including a sampling module for collecting a level signal corresponding to a pulse width modulated signal, said control circuit comprising: a switching module, one end of which is connected to the sampling module and the other end of which is connected to at least one set of signal feedback terminals; an operating power supply connected to the sampling module and the switching module to supply power to the sampling module and the switching module; The signal feedback end includes at least two feedback points, the feedback points are for connection to light-emitting units, and the switching module can switch between a first mode and a second mode based on the relationship between the level signal and a preset threshold, and in the first mode, the switching module can control each feedback point in the signal feedback end to be independent of each other, and in the second mode, the switching module can control each feedback point in the signal feedback end to be associated with each other.

[0007] According to a second aspect of the present application, the present application further provides a control method, the control method comprising: controlling a sampling module to collect a level signal corresponding to the pulse width modulation signal and transmit the level signal to a switching module; controlling the switching module to receive the level signal, and controlling the switching module to switch between a first mode and a second mode based on a relationship between the level signal and a preset threshold; wherein one end of the switching module is connected to the sampling module, and the other end is connected to at least one set of signal feedback terminals, the signal feedback terminals include at least two feedback points, and the feedback points are for connecting to light-emitting units, and the switching module and the sampling module are both connected to an operating power source; In the first mode, the switching module can control each feedback point in the signal feedback end to be independent of each other, and in the second mode, the switching module can control each feedback point in the signal feedback end to be related to each other.

[0008] According to a third aspect of the present application, the present application further provides a display device including a plurality of light emitting units and the above control circuit, wherein the feedback points are connected to the light emitting units in one-to-one correspondence.

[0009] In the technical solution of the present application, an operating power supply supplies power to the sampling module and the switching module, and the sampling module sends a collected level signal to the switching module, where the level signal corresponds to a pulse-width modulation signal. The switching module can switch between a first mode and a second mode based on the driving level signal. In the first mode, each feedback point is independent of the other, and the current connected to each feedback point is also independent. In the second mode, the two feedback points are related to each other, and the two feedback points are connected to the same path. When a low-level signal is received, the switching module switches to the second mode, which corresponds to merging two low-current paths, thereby increasing the current flow through these paths. The increase in current reduces the relative fluctuation of the voltage, stabilizing the brightness of the LED and preventing it from fluctuating. This solution can effectively reduce the flickering of the LED's brightness.

[0010] It is to be understood that both the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present application. [Brief explanation of the drawings]

[0011] The following drawings are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application, and together with the description, serve to explain the principles of the present application.

[0012] In order to make the contents of the present invention more clearly understandable, the present invention will be described in more detail below based on specific embodiments of the present invention with reference to the accompanying drawings. [Figure 1] FIG. 1 is a connection schematic diagram of a first embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram of a connection to the light-emitting unit in FIG. 1 of the present application. [Figure 3] FIG. 1 is a circuit diagram of a first embodiment of the present invention. [Figure 4] FIG. 4 is a flow diagram of a control method according to a second embodiment of the present invention. [Figure 5] FIG. 10 is a specific flow diagram of step S20 in the second embodiment of the present invention. [Figure 6] FIG. 10 is a connection schematic diagram of a third embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] While the present application may readily be expressed in different forms of embodiment, it is only a few specific embodiments thereof that are shown in the accompanying drawings and described in detail herein, and at the same time, it can be understood that the present application should be considered as an illustrative illustration of the principles of the present application and is not intended to limit the present application to the so described herein.

[0014] Therefore, a feature pointed out in this specification is a feature for describing one embodiment of the present application, and does not necessarily imply that each embodiment of the present application necessarily includes the described feature. Also, please note that many features are described in this specification. Some features may be combined to illustrate possible system designs, but these features may also be used in other combinations not explicitly described. Therefore, unless specifically described, the described combinations are not intended to be limiting.

[0015] In the embodiments illustrated in the drawings, directional designations (e.g., up, down, left, right, front, and back) are used to interpret the structure and movement of each element herein as relative, not absolute. These descriptions are appropriate when these elements are in the positions shown in the drawings. If the descriptions of the positions of these elements change, these directional designations will change accordingly.

[0016] Exemplary embodiments will be described more fully below with reference to the drawings. However, the exemplary embodiments may be implemented in a variety of forms and should not be understood as being limited to the examples set forth herein. On the contrary, the provision of these embodiments fully conveys the full scope of the present application and the concept of the exemplary embodiments to those skilled in the art. The drawings are merely schematic illustrations of the present application and are not necessarily drawn to scale. Note that the same reference numerals in the drawings represent the same or similar parts, and redundant description will be omitted.

[0017] Preferred embodiments of the present invention will be described in more detail below with reference to the drawings of this specification.

[0018] Example 1 Referring to FIGS. 1 and 2, the present application provides a control circuit, which includes a sampling module 1, a switching module 2, and an operating power supply 3. The operating power supply 3 is connected to the sampling module 1 and the switching module 2 and supplies power to the sampling module 1 and the switching module 2. The operating power supply 3 is a DC power supply VCC, and power supplied from the operating power supply 3 ensures that various electronic components in the sampling module 1 and the switching module 2 can operate normally. The voltage of the operating power supply 3 may be 5 volts or 12 volts. The sampling module 1 is used to collect a level signal corresponding to a pulse-width modulation signal, which is also simply referred to as a PWM signal. One end of the switching module 2 is connected to the sampling module 1, and the other end is connected to at least one set of signal feedback terminals 4, which include at least two feedback points.

[0019] The signal feedback terminal 4 may have a plurality of terminals, but is not limited to one, and may be, for example, two or three. The number of feedback points in each set of signal feedback terminals 4 is also not limited to two, and may be three or more. The feedback points are connected to the light-emitting units 5. Generally, one end of the light-emitting units 5 is connected to the feedback point, and the other end is connected to the negative pole 6 of the backlight connector. The light-emitting units 5 can be turned on or off by turning on the switching module 2. The light-emitting units 5 may be LEDs (light-emitting diodes), OLEDs (organic light-emitting diodes), AMOLEDs (active-matrix organic light-emitting diodes), etc.

[0020] In this embodiment, the number of light-emitting units 5 connected to the feedback point is not limited to one, and may be a lamp string consisting of multiple light-emitting units 5. The switching module 2 can switch between the first mode and the second mode based on the relationship between the level signal and the preset threshold. In the first mode, the switching module 2 can control each feedback point in the signal feedback terminal 4 to be independent of each other. The independence of each feedback point means that the current or voltage between them is separated and each has an independent distribution path. In the second mode, the switching module 2 can control each feedback point in the signal feedback terminal 4 to be associated with each other. The association can be understood as connecting each feedback point to share a single distribution path. The preset threshold can be understood as a basis for determining whether the level signal is high or low. The magnitude of the preset threshold can be adjusted, and typically, the range of the preset threshold is 0.1% to 10%. The preset threshold can be a specific value within the range or a range. For example, if the preset threshold is 5%, the switching module 2 determines whether to switch to the first mode or the second mode based on 5% as the limit. Alternatively, the preset threshold may be 0.1%, 0.3%, 0.5%, 1%, 2%, 3%, 4%, 6%, 7%, 8%, 9%, 10%, etc.

[0021] In this technical solution, the operating power supply 3 supplies power to the sampling module 1 and the switching module 2. The sampling module 1 sends a collected level signal to the switching module 2, where the level signal corresponds to a pulse-width modulation signal. The switching module 2 can switch between a first mode and a second mode based on the driving level signal. In the first mode, each feedback point is independent of the other, and the current connected to each feedback point is also supplied independently through different paths. In the second mode, the two feedback points are related to each other, and the two feedback points are connected to the same path. When a low-level signal is received, the switching module 2 switches to the second mode, which corresponds to merging two low-current paths, thereby increasing the current flow through these paths. The increase in current reduces the relative fluctuation of the voltage, stabilizing the brightness of the LED and preventing it from fluctuating. This solution can effectively reduce the flickering of the LED brightness.

[0022] 3, in order to effectively complete the switching operation of the switching module 2, the switching module 2 includes at least one constant current source sub-module 21 and at least one control switch sub-module 22, and the constant current source sub-module 21, the control switch sub-module 22 and the signal feedback terminal 4 are arranged in one-to-one correspondence. Here, the control switch sub-module 22 includes a first switch K1 and a second switch K2.

[0023] The constant current source submodule 21 includes at least two constant current sources. Each constant current source has a power supply terminal, an input terminal, and an output terminal. The input terminal of the constant current source is connected to the sampling module 1 via an input path. The power supply terminal of the constant current source is connected to the operating power supply 3 via a power supply path. The output terminal of the constant current source is connected to a feedback point of the signal feedback terminal 4 via a feedback path. The constant current sources provide a stable DC current, which allows the light-emitting unit 5 to remain lit without the cycle of turning off, on, and then off and on again. This eliminates flickering stripes on the display screen, improving the display quality. The power supply terminal of the constant current source includes a positive power supply pole and a negative power supply pole. The positive power supply pole is connected to the operating power supply 3, and the negative power supply pole is grounded.

[0024] Among the multiple power supply paths, one power supply path does not have a first switch K1, but the remaining power supply paths do. At the signal feedback terminal 4, each feedback path connected to a respective feedback point is connected via a second switch. One or more second switches K2 may be provided. When multiple second switches K2 are provided, the multiple second switches K2 are connected to each feedback path. In the constant current source connected to the power supply path not provided with the first switch K1, the operating power supply 3 remains connected thereto at all times. In this way, when the first switch K1 in the remaining power supply path is turned off, the second switch K2 is turned on, so that all constant current sources in the constant current source submodule 21 are connected to the operating power supply via a single path.

[0025] Specifically, in the operation process of the switching module 2, in a first mode, the first switch K1 is turned on and the second switch K2 is turned off. If a plurality of first switches K1 and a plurality of second switches K2 are provided, the first switches K1 are all turned on and the second switches K2 are all turned off. In a second mode, the first switch K1 is turned off and the second switch K2 is turned on. Similarly, if a plurality of first switches K1 and a plurality of second switches K2 are provided, the first switches K1 are all turned off and the second switches K2 are all turned on.

[0026] According to one embodiment, a plurality of constant current source sub-modules 21 are provided, and the plurality of constant current source sub-modules 21 are provided in parallel, and each constant current source sub-module 21 is connected to one set of signal feedback terminals 4. As can be seen from this, a plurality of signal feedback terminals 4 are provided. In addition, a plurality of control switch sub-modules 22 are also provided, and each set of constant current sources is connected to one set of control switch sub-modules 22. The control switch sub-modules 22 of each set control the connection state between the signal feedback terminals 4 of each set and the constant current source sub-modules 21. As shown in FIG. 3, two constant current source sub-modules 21 may be provided, but this is not limited thereto, and more may be provided.

[0027] According to one embodiment, the switching module 2 further includes a control unit 23, which is connected to the control switch submodule 22 and controls the on / off of the first switch K1 and the on / off of the second switch K2. The control unit 23 can be understood as an MCU (Microcontroller Unit), which may be provided with a memory, and preset thresholds may be stored in the memory. The MCU further includes a processor. When the switching module 2 operates, the processor retrieves the preset thresholds stored in the memory, compares the duty ratio of the received PWM signal with the preset thresholds stored in the memory, and performs subsequent control operations based on the comparison result. The duty ratio of this PWM signal corresponds to the level signal collected by the sampling module 1. Here, the duty ratio is the ratio of the conduction time to the total time within one pulse signal period. It can be seen that the lower the duty ratio, the shorter the conduction time. The level signal collected by the sampling module 1 is a converted version of the duty ratio. When the duty ratio is low, the level signal is at a low level, and when the duty ratio is high, the level signal is at a high level.

[0028] According to one embodiment, the constant current source includes a first operational amplifier U1, a first field effect transistor Q1, and a first resistor R1, wherein the positive terminal of the power supply of the first operational amplifier U1 is connected to the operating power supply 3, the negative terminal of the power supply of the first operational amplifier U1 is grounded, the positive signal input terminal of the first operational amplifier U1 is connected to the sampling module 1, the negative signal input terminal of the first operational amplifier U1 is connected to the first resistor R1, the other end of the first resistor R1 is grounded, the signal output terminal of the first operational amplifier U1 is connected to the first field effect transistor Q1, one end of the first field effect transistor Q1 is connected to the first resistor R1, and the other end of the first field effect transistor Q1 is connected to a feedback point.

[0029] For example, two constant current source submodules 21 are provided. One of the constant current source submodules 21 includes two constant current sources. One constant current source includes a first operational amplifier U1 and a first field effect transistor Q1, with one end of the first operational amplifier U1 and the first field effect transistor Q1 both connected to a first resistor R1. The other constant current source includes a third operational amplifier U3 and a third field effect transistor Q3, with one end of the third operational amplifier U3 and the third field effect transistor Q3 both connected to a fourth resistor R4. When the first switch K1 is turned on and the second switch K2 is turned off, these two constant current sources are connected in parallel. The other constant current source submodule 21 also includes two constant current sources. One constant current source includes a fourth operational amplifier U4 and a fourth field effect transistor Q4, with one end of the fourth operational amplifier U4 and the fourth field effect transistor Q4 both connected to a fifth resistor R5. The other constant current source includes a fifth operational amplifier U5 and a fifth field-effect transistor Q5, each connected to a sixth resistor R6. The resistances of the first resistor R1, the fourth resistor R4, the fifth resistor R5, and the sixth resistor R6 are typically equal. A seventh resistor R7 is also connected in parallel to the constant current source submodule 21, and its resistance may be equal to that of the first resistor R1. The field-effect transistor can be understood as a metal-oxide-semiconductor field-effect transistor (MOSFET). A metal-oxide-semiconductor field-effect transistor (MOSF) is simply called a MOS transistor (MOSFET). It is commonly referred to as a metal-oxide-semiconductor field-effect transistor or a metal-insulator-semiconductor. G: gate; S: source; D: drain. The source and drain of a MOS tube are interchangeable.

[0030] According to one embodiment, the sampling module 1 includes a second operational amplifier U2, a first sampling point A, and a second sampling point B. The first sampling point A is connected to the positive signal input of the second operational amplifier U2, and the second sampling point B is connected to the negative signal input of the second operational amplifier U2. A second field-effect transistor Q2 is disposed between the negative signal input of the second operational amplifier U2 and the second sampling point B. In this embodiment, the field-effect transistor functions as a switch. At a low level, the second field-effect transistor Q2 is turned off, and at a high level, the second field-effect transistor Q2 is conductive. As can be seen, at a low level, the second field-effect transistor Q2 is turned off. Furthermore, the sampling module 1 further includes a second resistor R2 and a third resistor R3. One end of the second field-effect transistor Q2 is connected to the second resistor R2, and the other end of the second resistor R2 is grounded. One end of the third resistor R3 is connected to the negative signal input of the second operational amplifier U2, and the other end of the third resistor R3 is grounded. The path consisting of the second field-effect transistor Q2 and the second resistor R2 is connected in parallel to the third resistor R3. At a low level, the second field-effect transistor Q2 is off, and current flows through the second and third resistors R2 and R3. The second and third resistors R2 and R3 are connected in series, increasing their resistance, and the current flowing through the second operational amplifier U2 is reduced. At a high level, the second field-effect transistor Q2 is on, and current flows through the second field-effect transistor Q2. The second and third resistors R2 and R3 are connected in parallel, decreasing their resistance, and the current flowing through the second operational amplifier U2 is reduced. Here, the positive signal input of the operational amplifier can be understood as the positive-phase input terminal, and the negative signal input of the operational amplifier can be understood as the inverting-phase input terminal.

[0031] Furthermore, to ensure that the current through the path consisting of the second field-effect transistor Q2 and the second resistor R2 is the same as that through the path consisting of the third resistor R3, the resistance values ​​of the second resistor R2 and the third resistor R3 may be equal, and the resistance value of the second resistor R2 and the third resistor R3 is 60.4 kΩ. The sampling module 1 also includes a sixth field-effect transistor Q6 and a seventh field-effect transistor Q7, both connected to the operating power supply 3, with the sixth field-effect transistor Q6 connected in parallel to the seventh field-effect transistor Q7. The other ends of the sixth field-effect transistor Q6 and the seventh field-effect transistor Q7 are connected to an eighth field-effect transistor Q8, which is connected to the output terminal of the second operational amplifier U2. The first sampling point A and the second sampling point B are the same sampling point and are two paths extending from the same point.

[0032] Example 2 The present application further provides a control method, which includes the following steps:

[0033] In step S10, the sampling module collects a level signal corresponding to the pulse width modulation signal and controls the level signal to be transmitted to the switching module, where one end of the switching module is connected to the sampling module and the other end is connected to at least one set of signal feedback terminals, the signal feedback terminals including at least two feedback points, the feedback points are for connecting to the light emitting units, and the switching module and the sampling module are both connected to an operating power supply. The operating power supply is a DC power supply, and power supplied from the operating power supply ensures that the various electronic components in the sampling module and the switching module can operate normally. The voltage of the operating power supply may be 5V or 12V. The sampling module collects a level signal corresponding to the pulse width modulation signal, which is also simply referred to as a PWM signal.

[0034] In step S20, the switching module is controlled to receive a level signal and to switch between a first mode and a second mode based on the relationship between the level signal and a preset threshold. In the first mode, the switching module controls the feedback points in the signal feedback terminal to be independent of each other. In the second mode, the switching module controls the feedback points in the signal feedback terminal to be associated with each other. The association can be understood as connecting the feedback points to share a single distribution path. The preset threshold can be understood as a basis for determining whether the level signal is high or low. The magnitude of the preset threshold can be adjusted. Typically, the range of the preset threshold is 0.1% to 10%. The preset threshold can be a specific value within the range or a range. For example, if the preset threshold is 5%, the switching module 2 determines whether to switch to the first mode or the second mode based on 5%. Alternatively, the preset threshold may be 0.1%, 0.3%, 0.5%, 1%, 2%, 3%, 4%, 6%, 7%, 8%, 9%, 10%, etc.

[0035] Specifically, according to one embodiment, the step of controlling the switching module to switch between the first mode and the second mode based on the relationship between the level signal and the preset threshold includes the following steps.

[0036] In step S210, a duty ratio representing a level signal is obtained from the pulse width modulation signal. The duty ratio is the ratio of the energization time to the total time within one pulse signal period. It can be seen that the lower the duty ratio, the shorter the energization time. The level signal collected by the sampling module is a conversion of the duty ratio. If the duty ratio is low, the level signal is low level, and if the duty ratio is high, the level signal is high level.

[0037] In step S220, the duty ratio is compared with a preset threshold value, and a switching command is output based on the comparison result.

[0038] In step S230, if the duty ratio is smaller than the preset threshold, a first switching command is output, and the switching module is controlled to switch to a first mode according to the first switching command. In the first mode, the switching module can control each feedback point in the signal feedback terminal to be independent from each other. The independence of each feedback point means that the current or voltage between them is separated and each has an independent flow path.

[0039] In step S240, if the duty ratio is greater than or equal to the preset threshold, a second switching command is output, and the switching module is controlled to switch to a second mode according to the second switching command. In the second mode, the switching module can control the feedback points in the signal feedback terminal to be associated with each other. Being associated with each other can be understood as connecting the feedback points to share a single distribution path.

[0040] In the first mode, the feedback points are independent of each other, and the currents connected to each feedback point are also independent. In the second mode, the two feedback points are related to each other, and the two feedback points are connected to the same path. When a low-level signal is received, the switching module switches to the second mode, which corresponds to merging two low-current paths, thereby increasing the current flow through these paths. The increase in current reduces the relative fluctuation of the voltage, stabilizing the brightness of the LED and preventing it from fluctuating. This solution can effectively reduce the flickering of the LED brightness.

[0041] Example 3 6, the present application further provides a display device, which includes a plurality of light emitting units 5 and a control circuit, and the feedback points 41 are connected to the light emitting units 5 in a one-to-one correspondence, and the lighting of the light emitting units 5 is controlled by controlling the switching modules 2 in the circuit.

[0042] In this embodiment, the display device includes, but is not limited to, a liquid crystal display panel, an organic light emitting diode display panel, a field emission display panel, a plasma display panel, and a curved panel, and the liquid crystal panel includes a thin film transistor liquid crystal display panel, a TN panel (TN, i.e., Twisted Nematic), a VA type panel (VA, i.e., Wide Viewing Angle type), an IPS panel (IPS, i.e., In-Plane Switching), etc.

[0043] The display device embodiments of the present application include the technical solutions of all the control circuit embodiments described above, and the technical effects obtained are exactly the same, so detailed descriptions are omitted here.

[0044] Although the present application has been described with reference to several exemplary embodiments, the terms used are illustrative and exemplary, not limiting. Since the present application can be specifically embodied in various forms without departing from the spirit or scope of the present application, the above-described embodiments should not be limited to any of the above details, but should be broadly construed in the spirit and scope defined by the appended claims. Accordingly, all changes and modifications that come within the scope of the claims or their equivalents should be embraced within the scope of the claims.

Claims

1. A control circuit including a sampling module for acquiring a level signal corresponding to a pulse width modulated signal, the control circuit comprising: a switching module, one end of which is connected to the sampling module and the other end of which is connected to at least one set of signal feedback terminals; an operating power supply connected to the sampling module and the switching module to supply power to the sampling module and the switching module; the signal feedback end includes at least two feedback points, the feedback points are for connection to light emitting units; the switching module can switch between a first mode and a second mode according to the relationship between the level signal and a preset threshold; in the first mode, the switching module can control the feedback points in the signal feedback end to be independent of each other; in the second mode, the switching module can control the feedback points in the signal feedback end to be associated with each other; the feedback points being independent of each other means that the feedback points have independent distribution paths; and the feedback points being associated with each other means that the feedback points share a single distribution path; The switching module includes at least one constant current source sub-module and at least one control switch sub-module, and the constant current source sub-module, the control switch sub-module and the signal feedback terminal are arranged in one-to-one correspondence; the control switch sub-module includes a first switch and a second switch; The constant current source sub-module includes at least two constant current sources, each of which has a power supply terminal, an input terminal and an output terminal, the input terminal of the constant current source being connected to the sampling module through an input path, the power supply terminal of the constant current source being connected to the operating power supply through a power supply path, and the output terminal of the constant current source being connected to a feedback point of the signal feedback terminal through a feedback path; one of the plurality of power supply paths is not provided with the first switch, but the remaining power supply paths are provided with the first switch; At the signal feedback terminal, each feedback path connected to each feedback point is connected via the second switch; In the first mode, the first switch is turned on and the second switch is turned off; In the second mode, the first switch is turned off and the second switch is turned on.

2. 2. The control circuit according to claim 1, wherein a plurality of the constant current source sub-modules are provided, the plurality of constant current source sub-modules are provided in parallel with each other, and each of the constant current source sub-modules is connected to one set of the signal feedback terminals.

3. the switching module further includes a control unit; the control unit is connected to the control switch sub-module; 2. The control circuit according to claim 1, wherein the control unit is for controlling the on or off of the first switch and the on or off of the second switch.

4. the constant current source includes a first operational amplifier, a first field effect transistor, and a first resistor; 2. The control circuit of claim 1, wherein a positive terminal of a power supply of the first operational amplifier is connected to the operating power supply, a negative terminal of the power supply of the first operational amplifier is grounded, a positive terminal of a signal input of the first operational amplifier is connected to the sampling module, a negative terminal of a signal input of the first operational amplifier is connected to the first resistor, the other end of the first resistor is grounded, a signal output terminal of the first operational amplifier is connected to the first field effect transistor, one end of the first field effect transistor is connected to the first resistor, and the other end of the first field effect transistor is connected to one of the feedback points.

5. the sampling module includes a second operational amplifier, a second field effect transistor, a first sampling point and a second sampling point; The first sampling point is connected to the signal input positive terminal of the second operational amplifier, and the second sampling point is connected to the control end of the second field effect transistor; the sampling module further includes a second resistor; 2. The control circuit according to claim 1, wherein one end of the second field-effect transistor is connected to the second resistor, the other end of the second resistor is grounded, and the other end of the second field-effect transistor is connected to a signal input negative electrode of the second operational amplifier.

6. the sampling module further includes a third resistor; 6. The control circuit according to claim 5, wherein one end of the third resistor is connected to a signal input negative terminal of the second operational amplifier, the other end of the third resistor is grounded, and a path consisting of the second field effect transistor and the second resistor is connected in parallel to the third resistor.

7. controlling a sampling module to collect a level signal corresponding to the pulse width modulation signal and transmit the level signal to a switching module; controlling the switching module to receive the level signal, and controlling the switching module to switch between a first mode and a second mode based on a relationship between the level signal and a preset threshold; One end of the switching module is connected to the sampling module, and the other end is connected to at least one set of signal feedback terminals, the signal feedback terminals include at least two feedback points, and the feedback points are for connecting to light-emitting units, and the switching module and the sampling module are both connected to an operating power source; In the first mode, the switching module can control the feedback points in the signal feedback end to be independent of each other; in the second mode, the switching module can control the feedback points in the signal feedback end to be associated with each other, where the feedback points being independent of each other means that the feedback points have independent distribution paths, and the feedback points being associated with each other means that the feedback points share one distribution path; The switching module includes at least one constant current source sub-module and at least one control switch sub-module, and the constant current source sub-module, the control switch sub-module and the signal feedback terminal are arranged in one-to-one correspondence; the control switch sub-module includes a first switch and a second switch; The constant current source sub-module includes at least two constant current sources, each of which has a power supply terminal, an input terminal and an output terminal, the input terminal of the constant current source being connected to the sampling module through an input path, the power supply terminal of the constant current source being connected to the operating power supply through a power supply path, and the output terminal of the constant current source being connected to a feedback point of the signal feedback terminal through a feedback path; one of the plurality of power supply paths is not provided with the first switch, but the remaining power supply paths are provided with the first switch; At the signal feedback terminal, each feedback path connected to each feedback point is connected via the second switch; In the first mode, the first switch is turned on and the second switch is turned off; In the second mode, the first switch is turned off and the second switch is turned on.

8. The step of controlling the switching module to switch between a first mode and a second mode based on the relationship between the level signal and a preset threshold value includes: obtaining a duty ratio indicative of the level signal from a pulse width modulated signal; comparing the duty ratio with a preset threshold; When the duty ratio is smaller than the preset threshold, outputting a first switching command, and controlling the switching module to switch to the first mode according to the first switching command; 8. The control method according to claim 7, further comprising: when the duty ratio is equal to or greater than the preset threshold, outputting a second switching command; and controlling the switching module to switch to the second mode based on the second switching command.

9. 9. The control method of claim 8, wherein the preset threshold ranges from 0.1% to 10%.

10. 8. The control method according to claim 7, wherein a plurality of the constant current source sub-modules are provided, the plurality of constant current source sub-modules are provided in parallel with each other, and each of the constant current source sub-modules is connected to one set of the signal feedback terminals.

11. the constant current source includes a first operational amplifier, a first field effect transistor, and a first resistor; 8. The control method of claim 7, wherein a positive terminal of a power supply of the first operational amplifier is connected to the operating power supply, a negative terminal of the power supply of the first operational amplifier is grounded, a positive terminal of a signal input of the first operational amplifier is connected to the sampling module, a negative terminal of a signal input of the first operational amplifier is connected to the first resistor, the other end of the first resistor is grounded, a signal output terminal of the first operational amplifier is connected to the first field effect transistor, one end of the first field effect transistor is connected to the first resistor, and the other end of the first field effect transistor is connected to one of the feedback points.

12. A display device including a plurality of light-emitting units and a control circuit, the control circuit comprising: a sampling module for collecting a level signal corresponding to the pulse width modulated signal; a switching module, one end of which is connected to the sampling module and the other end of which is connected to at least one set of signal feedback terminals; an operating power supply connected to the sampling module and the switching module to supply power to the sampling module and the switching module; the signal feedback end includes at least two feedback points, the feedback points are for connection to light emitting units; the switching module can switch between a first mode and a second mode according to the relationship between the level signal and a preset threshold; in the first mode, the switching module can control the feedback points in the signal feedback end to be independent of each other; in the second mode, the switching module can control the feedback points in the signal feedback end to be associated with each other; the feedback points being independent of each other means that the feedback points have independent distribution paths; and the feedback points being associated with each other means that the feedback points share a single distribution path; The feedback points are connected to the light emitting units in one-to-one correspondence; The switching module includes at least one constant current source sub-module and at least one control switch sub-module, and the constant current source sub-module, the control switch sub-module and the signal feedback terminal are arranged in one-to-one correspondence; the control switch sub-module includes a first switch and a second switch; The constant current source sub-module includes at least two constant current sources, each of which has a power supply terminal, an input terminal and an output terminal, the input terminal of the constant current source being connected to the sampling module through an input path, the power supply terminal of the constant current source being connected to the operating power supply through a power supply path, and the output terminal of the constant current source being connected to a feedback point of the signal feedback terminal through a feedback path; one of the plurality of power supply paths is not provided with the first switch, but the remaining power supply paths are provided with the first switch; At the signal feedback terminal, each feedback path connected to each feedback point is connected via the second switch; In the first mode, the first switch is turned on and the second switch is turned off; In the second mode, the first switch is turned off and the second switch is turned on.

13. 13. The display device according to claim 12, wherein a plurality of the constant current source sub-modules are provided, the plurality of constant current source sub-modules are provided in parallel with each other, and each of the constant current source sub-modules is connected to one set of the signal feedback terminals.

14. the switching module further includes a control unit; the control unit is connected to the control switch sub-module; 13. The display device according to claim 12, wherein the control unit controls the on / off of the first switch and the on / off of the second switch.

15. the constant current source includes a first operational amplifier, a first field effect transistor, and a first resistor; 13. The display device of claim 12, wherein a positive terminal of a power supply of the first operational amplifier is connected to the operating power supply, a negative terminal of the power supply of the first operational amplifier is grounded, a positive terminal of a signal input of the first operational amplifier is connected to the sampling module, a negative terminal of a signal input of the first operational amplifier is connected to the first resistor, the other end of the first resistor is grounded, a signal output terminal of the first operational amplifier is connected to the first field effect transistor, one end of the first field effect transistor is connected to the first resistor, and the other end of the first field effect transistor is connected to one of the feedback points.

16. the sampling module includes a second operational amplifier, a second field effect transistor, a first sampling point and a second sampling point; The first sampling point is connected to the signal input positive terminal of the second operational amplifier, and the second sampling point is connected to the control end of the second field effect transistor; the sampling module further includes a second resistor; 13. The display device according to claim 12, wherein one end of the second field-effect transistor is connected to the second resistor, the other end of the second resistor is grounded, and the other end of the second field-effect transistor is connected to a signal input negative electrode of the second operational amplifier.

17. the sampling module further includes a third resistor; 17. The display device of claim 16, wherein one end of the third resistor is connected to a negative signal input terminal of the second operational amplifier, the other end of the third resistor is grounded, and a path consisting of the second field effect transistor and the second resistor is connected in parallel to the third resistor.

Images