Voltage regulating circuit, system and display device

Abstract

The invention discloses a voltage regulating circuit and system and a display device, the voltage regulating circuit comprises a voltage comparator, a switch module and a voltage regulating module, the output end of the voltage regulating module is connected with the positive electrode input end of the voltage comparator and the input end of a display device, and the negative electrode input end of the voltage comparator is grounded; the output end of the voltage comparator is connected with the input end of the switch module, and the output end of the switch module is connected with the input end of the voltage regulating module; the voltage comparator is used for transmitting a first signal to the switch module when the voltage of the positive electrode input end is greater than the voltage of the negative electrode input end; the switch module is used for transmitting a second signal to the voltage regulating module according to the first signal; and the voltage regulating module is used for regulating the input voltage to obtain an output voltage according to the received voltage regulating control signal and the second signal, and outputting the output voltage through the output end of the voltage regulating module. The negative electrode input end of the voltage comparator is grounded, so that the voltage regulating process is not influenced by the rising speed of the output voltage.

Description

Technical Field

[0001] The present application relates to the field of electronic technology, and in particular to a voltage regulating circuit, system and display device. Background Art

[0002] Usually, for wearable or mobile phone organic light-emitting diode (OLED) products, the output voltage AVDD of the light-emitting diode included in it is usually controlled by the power management integrated circuit (Power Management IC, PMIC), but the specific value of the voltage adjustment needs to be controlled by an external controller. PMIC usually uses a single bus (1-swire) or dual bus (2-swire) communication protocol to communicate with the external controller, and the voltage regulation is completed by the external controller by issuing instructions to the swire signal to control the PMIC.

[0003] Currently, the signal for starting the voltage regulation process is usually determined based on whether the voltage value of the voltage to be adjusted (AVDD) reaches a reference voltage. When the voltage value of AVDD reaches the reference voltage, the external controller sends an instruction to the PMIC to adjust the voltage value of AVDD.

[0004] However, during the voltage adjustment process, the voltage output rate is affected by many factors such as the charging and discharging conditions of the product's output capacitor, the back-end load conditions, and the switching rate. Therefore, during each voltage adjustment process, the voltage load will be different, resulting in different voltage rise rates, resulting in different times to reach the reference voltage, which in turn affects the accuracy of the voltage adjustment. Summary of the invention

[0005] In view of this, the present application provides a voltage regulation circuit, system and display device to solve the problem of unstable voltage regulation accuracy in traditional solutions.

[0006] The first aspect of the present application provides a voltage regulating circuit, comprising: a voltage comparator, a switch module and a voltage regulating module, wherein the output end of the voltage regulating module is connected to the positive input end of the voltage comparator and the input end of a display device, the negative input end of the voltage comparator is grounded, the output end of the voltage comparator is connected to the input end of the switch module, and the output end of the switch module is connected to the input end of the voltage regulating module; the voltage comparator is used to transmit a first signal to the switch module when the voltage at the positive input end is greater than the voltage at the negative input end; the switch module is used to transmit a second signal to the voltage regulating module according to the first signal; the voltage regulating module is used to regulate the input voltage according to the received voltage regulation control signal and the second signal to obtain an output voltage, and output the output voltage through the output end of the voltage regulating module.

[0007] Optionally, the switch module includes: an anti-shake module and a transistor, the input end of the anti-shake module is connected to the output end of the voltage comparator, the output end of the anti-shake module is connected to the transistor, and the output end of the transistor is connected to the input end of the voltage regulation module; the anti-shake module is used to filter the noise in the first signal, obtain the second signal, and output the second signal to the transistor; the transistor is used to turn on according to the second signal.

[0008] Optionally, the transistor is an NMOS transistor.

[0009] Optionally, the voltage regulating module is used to output a voltage to the positive input terminal of the voltage comparator when the voltage value of the input voltage rises to an undervoltage protection value, and after receiving the second signal, regulate the input voltage according to the received voltage regulation control signal to obtain the output voltage.

[0010] Optionally, when the voltage value of the input voltage rises to the under-voltage protection value and after a delay of a first time value, the voltage regulation control signal changes from a low level to a high level, and after a delay of a second time value, switches between a high level and a low level; the voltage regulation module is used to regulate the input voltage to obtain an output voltage according to the number of times the voltage regulation control signal switches between a high level and a low level after receiving the second signal.

[0011] Optionally, the voltage regulation module includes: a voltage regulator and a counter; the counter is used to count the number of times the voltage regulation control signal continuously switches between a high level and a low level after receiving the second signal; the voltage regulator is used to regulate the input voltage according to the count value obtained by the counter to obtain the output voltage.

[0012] Optionally, the voltage regulator regulates the input voltage according to different count values ​​to obtain different output voltages.

[0013] The second aspect of the present application provides a voltage regulation system, comprising: a voltage regulation circuit, a control device and a power supply device as in the first aspect of the embodiment; the power supply device is used to input voltage to the voltage regulation circuit and the control device; the control device is used to send a voltage regulation control signal to the input end of the voltage regulation circuit.

[0014] Optionally, the control device is used to change the voltage regulation control signal from a low level to a high level after the voltage value of the input voltage of the power supply device rises to an undervoltage protection value and after a delay of a first time value, and control the voltage regulation control signal to switch between a high level and a low level according to a preset number of times after a delay of a second time value;

[0015] Preferably, the voltage regulating circuit is used to output a voltage according to a preset voltage value when receiving an input voltage from the power supply device and a low-level voltage regulating control signal.

[0016] A third aspect of the present application provides a display device, comprising a display device and a voltage regulation system as described in any one of the second aspects of the present application, wherein a voltage regulation circuit of the voltage regulation system outputs a voltage to drive the display device.

[0017] By setting the voltage comparator to ground, the voltage regulation module can start voltage regulation after outputting the voltage according to the input voltage. Compared with setting the output voltage value to reach the reference voltage before starting voltage regulation, the voltage regulation process is not affected by the rising rate of the output voltage, thereby improving the accuracy of voltage regulation. In addition, since no reference voltage is required, the circuit structure can be simplified. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of the present application. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0019] Figure 1 is a schematic diagram of a voltage regulating circuit according to an embodiment of the present application;

[0020] Figure 2 is a signal timing diagram applicable to the embodiments of the present application;

[0021] Figure 3 It is a signal timing diagram of the voltage regulation process in the prior art;

[0022] Figure 4 is a schematic diagram of a voltage regulating circuit according to another embodiment of the present application;

[0023] Figure 5 is a schematic diagram of a voltage regulating circuit according to another embodiment of the present application;

[0024] Figure 6 is a schematic diagram of a voltage regulating system according to an embodiment of the present application;

[0025] Figure 7 is a schematic diagram of a display device according to an embodiment of the present application. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the embodiments of the present application should fall within the scope of protection of the embodiments of the present application.

[0027] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The singular forms of "a", "said" and "the" used in this application and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0028] It should be understood that although the terms first, second, third, etc. may be used in the present application to describe various information, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0029] The technical solutions in the embodiments of the present application are clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application. In the absence of conflict, the following embodiments and their technical features can be combined with each other.

[0030] Figure 1 is a schematic diagram of a voltage regulating circuit according to an embodiment of the present application. Figure 1 As shown, the voltage regulating circuit 100 includes:

[0031] A voltage comparator 101, a switch module 102 and a voltage regulating module 103, wherein the output end of the voltage regulating module 103 is connected to the positive input end of the voltage comparator 101 and the input end of the display device 200, the negative input end of the voltage comparator 101 is grounded, the output end of the voltage comparator 101 is connected to the input end of the switch module 102, and the output end of the switch module 102 is connected to the input end of the voltage regulating module 103. The voltage comparator 101 is used to transmit a first signal to the switch module 102 when the voltage at the positive input end is greater than the voltage at the negative input end. The switch module 102 is used to transmit a second signal to the voltage regulating module 103 according to the first signal. The voltage regulating module 103 is used to regulate the input voltage according to the received voltage regulation control signal and the second signal to obtain an output voltage, and output the output voltage through the output end of the voltage regulating module 103.

[0032] Electronic devices such as mobile phones and computers usually include display devices for image display. The display devices can be, for example, liquid crystal displays (LCD) or organic light emitting diodes (OLED) and other types of display screens. The display device 200 is usually operated by a power management integrated circuit (PMIC) that is a power chip in the electronic device. In different display scenarios or requirements, the display device 200 usually requires different voltage values ​​to operate. The display device 200 may include a display panel. The power supply voltage provides an input voltage for the PMIC. The PMIC provides a driving voltage for the display panel after voltage regulation. Therefore, for the voltage regulation circuit 100 (PMIC) of the present application, it first receives an input voltage provided by a power supply device such as a power supply. After receiving the input voltage and receiving the driving voltage, the voltage regulation circuit 100 (PMIC) of the present application first receives an input voltage provided by a power supply device such as a power supply. When the received voltage regulation control signal is at a high level, the voltage regulation module 103 will start and generate voltage AVDD, and input AVDD to the positive input terminal of the voltage comparator 101. Since the negative input terminal of the voltage comparator 101 is grounded, the voltage comparator 101 will output a high-level first signal to the switch module 102 after receiving AVDD. The switch module 102 transmits a second signal to the voltage regulation module 103 according to the first signal. At this time, the voltage regulation module 103 regulates the received input voltage according to the received second signal and the voltage regulation control signal to obtain an output voltage that matches the requirements of the display device 200.

[0033] It should be noted that the voltage regulation control signal includes a signal for indicating the target voltage for voltage regulation by the voltage regulation module 103 .

[0034] Specifically, the voltage regulating module 103 is used to output a voltage to the positive input terminal of the voltage comparator 101 when the voltage value of the input voltage rises to the undervoltage protection value, and after receiving the second signal, regulate the input voltage according to the received voltage regulating control signal to obtain the output voltage.

[0035] The power supply module that provides the input voltage usually starts when there is a demand from the voltage regulating circuit 100, and gradually increases the input voltage provided. In order to avoid damage to the device, an undervoltage protection value is set. When the input voltage is greater than the undervoltage protection value, the voltage regulating module 103 starts normally according to the voltage regulating control signal, outputs AVDD, and after receiving the second signal, regulates the input voltage according to the received voltage regulating control signal to obtain the output voltage. By setting the voltage regulating module 103 to output the voltage AVDD to the positive input terminal of the voltage comparator 101 when the voltage value of the input voltage rises to the undervoltage protection value, each device in the circuit can be protected from undervoltage. At the same time, compared with the voltage regulation process in the prior art, the voltage regulating circuit 100 can directly adjust the output voltage AVDD to the voltage value required by the display device 200, which has higher efficiency.

[0036] Specifically, when the voltage value of the input voltage rises to the undervoltage protection value and after a delay of a first time value, the voltage regulation control signal changes from a low level to a high level, and after a delay of a second time value, switches between a high level and a low level. The voltage regulation module 103 is used to regulate the input voltage to obtain an output voltage according to the number of times the voltage regulation control signal switches between a high level and a low level after receiving the second signal.

[0037] according to Figure 2 It can be seen from the signal timing diagram shown that the voltage regulation control signal ACTRL rises to a high level after the voltage value of the input voltage VIN rises to the undervoltage protection value and after a delay of the first time value T1. The reason for setting T1 is to ensure that ACTRL can work stably and eliminate the glitch interference of some signals. After ACTRL rises to a high level, the voltage regulation module 103 starts normally according to the voltage regulation control signal and outputs AVDD. After a delay of the second time value T2, the voltage regulation module 103 works stably and further eliminates the glitch interference of some signals. At this time, ACTRL will switch between a high level and a low level. At the same time, the voltage regulation module 103 will regulate the input voltage according to the number of times the voltage regulation control signal switches between a high level and a low level after receiving the second signal to obtain the output voltage.

[0038] It should be noted that the number of times ACTRL switches between the high level and the low level is related to the target voltage for instructing the voltage regulation module 103 to regulate the voltage. Figure 3It can be seen from the signal timing diagram of the prior art voltage regulation process that since the voltage regulation module 103 needs to wait for AVDD to reach the reference voltage before starting voltage regulation, at least part of the number of times ACTRL switches between high level and low level may be missed, resulting in a deviation between the voltage regulation result and the required voltage regulation result.

[0039] In the embodiment of the present application, by setting the voltage comparator 101 to be grounded, the voltage regulating module 103 can start regulating the voltage after outputting the voltage according to the input voltage. Compared with setting the output voltage value to reach the reference voltage before starting the voltage regulation, the voltage regulation process can be unaffected by the rising rate of the output voltage, thereby improving the accuracy of the voltage regulation. In addition, since no reference voltage is required, the circuit structure can be simplified.

[0040] Figure 4 is a schematic diagram of a voltage regulating circuit according to another embodiment of the present application. Figure 4 As shown, the switch module 102 includes: an anti-shake module 1021 and a transistor 1022, the input end of the anti-shake module 1021 is connected to the output end of the voltage comparator 101, the output end of the anti-shake module 1021 is connected to the transistor 1022, and the output end of the transistor 1022 is connected to the input end of the voltage regulation module 103. The anti-shake module 1021 is used to filter the noise in the first signal, obtain the second signal, and output the second signal to the transistor 1022. The transistor 1022 is used to be turned on according to the second signal.

[0041] Since the negative input terminal of the voltage comparator 101 is grounded, the reference voltage provided by the grounding is relatively "dirty" relative to the stable voltage supply terminal, so the voltage comparator 101 is subject to more interference. Therefore, an anti-shake module 1021 is set in the switch module 102. After receiving the first signal output from the output terminal of the voltage comparator 101, the anti-shake module 1021 filters the noise in the first signal. Noise refers to the signal interference generated by some external energy during the transmission process of the signal. These energies are noise. Noise usually causes signal distortion. After being processed by the anti-shake module 1021, a "clean" second signal is obtained. The transistor 1022 will be turned on after receiving the second signal. At this time, the second signal of the switch module 102 will be transmitted to the input terminal of the voltage regulating module 103. The voltage regulating module 103 can regulate the received input voltage according to the received second signal and the voltage regulating control signal.

[0042] Specifically, the transistor 1022 may be an NMOS transistor, and when receiving the second signal of a high level, the NMOS transistor is turned on.

[0043] In the embodiment of the present application, by providing an anti-shake module 1021 in the switch module 102, noise in the first signal can be filtered, thereby reducing interference caused by the grounding of the negative input terminal of the voltage comparator 101, so as to improve the accuracy of voltage regulation.

[0044] Figure 5 is a schematic diagram of a voltage regulating circuit according to another embodiment of the present application. Figure 5 As shown, the voltage regulating module 103 includes: a voltage regulator 1031 and a counter 1032. The counter 1032 is used to count the number of times the voltage regulating control signal continuously switches between a high level and a low level after receiving the second signal. The voltage regulator 1031 is used to regulate the input voltage according to the count value obtained by the counter 1032 to obtain the output voltage.

[0045] During the voltage regulation process, since the number of times ACTRL switches between a high level and a low level is related to the target voltage for indicating the voltage regulation of the voltage regulation module 103, a counter 1032 is provided in the voltage regulation module 103. After the voltage regulation module 103 receives the second signal, the counter 1032 counts the number of times the voltage regulation control signal switches continuously between a high level and a low level. The count value obtained indicates the target voltage required by the display device 200. The voltage regulator 1031 adjusts the input voltage according to the count value obtained by counting the counter 1032 to obtain an output voltage AVDD that matches the voltage value of the target voltage.

[0046] Specifically, the voltage regulator 1031 regulates the input voltage according to different count values ​​to obtain different output voltages. For example, when the number of times the voltage regulation control signal continuously switches between the high level and the low level is pulse=1, the target voltage is 7.9V, when pulse=2, the target voltage is 8.2V, and when pulse=3, the target voltage is 8.5V.

[0047] In the embodiment of the present application, by setting the counter 1032 , the voltage value of the output voltage can be accurately controlled by the voltage regulator 1031 .

[0048] Figure 6 is a schematic diagram of a voltage regulating system according to an embodiment of the present application. Figure 6 As shown, the voltage regulation system 300 includes: the voltage regulation circuit 100 as in the above embodiment, a control device 301 and a power supply device 302. The power supply device 302 is used to input voltage to the voltage regulation circuit 100 and the control device 301. The control device 301 is used to send a voltage regulation control signal to the input end of the voltage regulation circuit 100.

[0049] The control device 301 may be a display driver IC (DDIC). After the control device 301 receives the input voltage provided by the power supply device 302, it will generate a high-level voltage regulation control signal, and send the voltage regulation control signal to the input end of the voltage regulation circuit through a control bit single-wire (1-Swire) interface or a control bit double-wire (2-Swire) interface. The voltage regulation circuit 100 first receives the input voltage provided by the power supply device 302. After receiving the input voltage and the received voltage regulation control signal is at a high level, the voltage regulation module in the voltage regulation circuit 100 will start and generate the voltage AVDD, and input the AVDD into the voltage regulation circuit 100. 0, since the negative input terminal of the voltage comparator in the voltage regulating circuit 100 is grounded, the voltage comparator in the voltage regulating circuit 100 will output a high-level first signal to the switch module in the voltage regulating circuit 100 after receiving AVDD, and the switch module in the voltage regulating circuit 100 transmits a second signal to the voltage regulating module in the voltage regulating circuit 100 according to the first signal. At this time, the voltage regulating module in the voltage regulating circuit 100 regulates the received input voltage according to the received second signal and the voltage regulation control signal to obtain an output voltage that matches the requirement of the display device 200.

[0050] Specifically, the control device 301 is used to change the voltage regulation control signal from a low level to a high level when the voltage value of the input voltage of the power supply device 302 rises to the undervoltage protection value and after a delay of a first time value, and after a delay of a second time value, control the voltage regulation control signal to switch between a high level and a low level according to a preset number of times.

[0051] The control device 301 generates a high-level voltage regulation control signal ACTRL after the voltage value of the input voltage VIN provided by the power supply device 302 rises to the undervoltage protection value and after a delay of the first time value T1. The reason for setting T1 is to generate ACTRL so that it can work stably and eliminate the burr interference of some signals. After the voltage regulation control signal ACTRL rises to a high level, the voltage regulation circuit 100 starts normally according to the voltage regulation control signal and outputs AVDD. After a delay of the second time value T2, the voltage regulation circuit 100 works stably and further eliminates the burr interference of some signals. At this time, the control device 301 controls the voltage regulation control signal ACTRL to switch between high level and low level in order to indicate the voltage value of the target voltage that the voltage regulation circuit 100 needs to adjust. The number of times ACTRL switches between high level and low level is related to the target voltage that indicates the voltage regulation module 103 to regulate the voltage. For example, when the number of times the voltage regulation control signal continuously switches between high level and low level is pulse=1, the target voltage is 7.9V, when pulse=2, the target voltage is 8.2V, and when pulse=3, the target voltage is 8.5V. At the same time, the voltage regulation circuit 100 will regulate the input voltage to obtain the output voltage according to the number of times the voltage regulation control signal switches between high level and low level after receiving the second signal. By setting the first time value and the second time value, the control device 301 and the voltage regulation circuit 100 can operate in a stable state during the voltage regulation process, thereby improving the accuracy of the voltage regulation.

[0052] Specifically, the voltage regulating circuit 100 is used to output a voltage according to a preset voltage value when receiving an input voltage from the power supply device 302 and a low-level voltage regulating control signal.

[0053] The voltage regulating circuit 100 starts to output AVDD normally after receiving the input voltage from the power supply device 302. At this time, voltage regulation may not be required. At this time, the voltage regulation control signal output by the control device 301 is at a low level. At this time, the switch module in the voltage regulating circuit 100 will not be turned on, and the voltage comparator in the voltage regulating circuit 100 will not operate. The voltage regulating module in the voltage regulating circuit 100 does not perform the voltage regulation function, and outputs the voltage AVDD according to the preset voltage value, thereby ensuring the normal use of the voltage regulating circuit 100.

[0054] In the embodiment of the present application, by setting the voltage comparator in the voltage regulating circuit 100 to be grounded, the voltage regulating module can start regulating the voltage after outputting the voltage according to the input voltage. Compared with setting the output voltage value to reach the reference voltage before starting the voltage regulation, the voltage regulation process can be unaffected by the rising rate of the output voltage, thereby improving the accuracy of the voltage regulation. In addition, since no reference voltage is required, the circuit structure can be simplified.

[0055] Figure 7 is a schematic diagram of a display device according to an embodiment of the present application. Figure 7 As shown, the display device 400 includes a display device 200 and a voltage regulating system 300 as in the above embodiment, and the voltage regulating circuit 100 of the voltage regulating system 300 outputs a voltage to drive the display device 200 .

[0056] The specific implementation of the voltage regulation system 300, the voltage regulation circuit 100 and the display device 200 in the display apparatus 400 can refer to the corresponding descriptions of the corresponding units in the aforementioned voltage regulation system embodiment and the corresponding descriptions of the corresponding units in the aforementioned voltage regulation circuit embodiment, which will not be repeated here.

[0057] Although the present application has been shown and described with respect to one or more implementations, equivalent variations and modifications will occur to those skilled in the art based on reading and understanding of this specification and the accompanying drawings. The present application includes all such modifications and variations and is limited only by the scope of the appended claims. In particular, with respect to the various functions performed by the above-mentioned components, the terms used to describe such components are intended to correspond to any component (unless otherwise indicated) that performs the specified function of the component (e.g., it is functionally equivalent), even if it is not structurally equivalent to the disclosed structure that performs the functions in the exemplary implementation of the present specification shown herein.

[0058] That is, the above description is only an embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the specification and drawings of the present application, such as the mutual combination of technical features between the embodiments, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

[0059] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0060] In order to enable any technician in the field to implement and use the application, the application provides the above description. In the above description, various details are listed for the purpose of explanation. It should be understood that those of ordinary skill in the art can recognize that the application can also be implemented without using these specific details. In other embodiments, the well-known process will not be elaborated in detail to avoid unnecessary details that make the description of the application obscure. Therefore, the application is not intended to be limited to the embodiments shown, but is consistent with the widest range of principles and features disclosed in the application.

[0061] It should be noted that, under the premise of no conflict, the various embodiments and / or the technical features in the various embodiments described in this application can be arbitrarily combined with each other, and the technical solution obtained after the combination should also fall within the protection scope of this application.

[0062] It should be understood that the specific examples in the embodiments of the present application are only to help those skilled in the art better understand the embodiments of the present application, rather than to limit the scope of the embodiments of the present application. Those skilled in the art can make various improvements and modifications based on the above embodiments, and these improvements or modifications all fall within the scope of protection of the present application. The above is only a specific implementation method of the present application, but the scope of protection of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be based on the scope of protection of the claims.

Claims

1. A voltage regulating circuit, characterized in that: include: A voltage comparator, a switch module and a voltage regulating module, wherein the output end of the voltage regulating module is connected to the positive input end of the voltage comparator and the input end of the display device, the negative input end of the voltage comparator is grounded, the output end of the voltage comparator is connected to the input end of the switch module, and the output end of the switch module is connected to the input end of the voltage regulating module; The voltage comparator is used to transmit a first signal to the switch module when the voltage at the positive input terminal is greater than the voltage at the negative input terminal; The switch module is used to transmit a second signal to the voltage regulating module according to the first signal; The voltage regulating module is used to regulate the input voltage to obtain the output voltage according to the received voltage regulating control signal and the second signal, and output the output voltage through the output end of the voltage regulating module.

2. The voltage regulating circuit according to claim 1, characterized in that: The switch module includes: an anti-shake module and a transistor, the input end of the anti-shake module is connected to the output end of the voltage comparator, the output end of the anti-shake module is connected to the transistor, and the output end of the transistor is connected to the input end of the voltage regulation module; The anti-shake module is used to filter the noise in the first signal, obtain the second signal, and output the second signal to the transistor; The transistor is configured to be turned on according to the second signal.

3. The voltage regulating circuit according to claim 2, characterized in that: The transistor is an NMOS transistor.

4. The voltage regulating circuit according to claim 1, characterized in that: The voltage regulating module is used to output a voltage to the positive input terminal of the voltage comparator when the voltage value of the input voltage rises to the under-voltage protection value, and after receiving the second signal, regulate the input voltage according to the received voltage regulation control signal to obtain the output voltage.

5. The voltage regulating circuit according to claim 4, characterized in that: The voltage regulation control signal changes from a low level to a high level after a delay of a first time value when the voltage value of the input voltage rises to the undervoltage protection value, and switches between a high level and a low level after a delay of a second time value; The voltage regulating module is used to regulate the input voltage to obtain the output voltage according to the number of times the voltage regulating control signal switches between the high level and the low level after receiving the second signal.

6. The voltage regulating circuit according to claim 5, characterized in that: The voltage regulation module comprises: a voltage regulator and a counter; The counter is used to count the number of times the voltage regulation control signal switches continuously between a high level and a low level after receiving the second signal; The voltage regulator is used to regulate the input voltage according to the count value obtained by counting by the counter to obtain the output voltage.

7. The voltage regulating circuit according to claim 6, characterized in that: The voltage regulator regulates the input voltage according to different count values ​​to obtain different output voltages.

8. A voltage regulating system, characterized in that: include: The voltage regulating circuit, control device and power supply device as described in any one of claims 1 to 7; The power supply device is used to input voltage to the voltage regulating circuit and the control device; The control device is used to send a voltage regulation control signal to the input end of the voltage regulation circuit.

9. The system according to claim 8, characterized in that The control device is used to change the voltage regulation control signal from a low level to a high level after a delay of a first time value when the voltage value of the input voltage of the power supply device rises to an undervoltage protection value, and after a delay of a second time value, control the voltage regulation control signal to switch between a high level and a low level according to a preset number of times; Preferably, The voltage regulating circuit is used to output a voltage according to a preset voltage value when receiving an input voltage from the power supply device and a low-level voltage regulating control signal.

10. A display device, comprising a display device and the voltage regulating system according to claim 8 or 9, wherein the voltage regulating circuit of the voltage regulating system outputs a voltage to drive the display device.

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