Overvoltage protection circuit and electronic device

Abstract

The application is suitable for the field of power electronics, and provides an overvoltage protection circuit and an electronic device. The overvoltage protection circuit comprises a charging and discharging unit, a discharging switch unit, a first switch unit, a first switch control unit, an overvoltage protection unit, a voltage dividing unit and a second switch unit. The charging and discharging unit is electrically connected with the discharging switch unit, the voltage dividing unit, a power supply and a load switch unit respectively. The discharging switch unit is electrically connected with the voltage dividing unit, the first switch unit and the power supply respectively. The first switch unit is electrically connected with the first switch control unit, the second switch unit and the power supply respectively. The overvoltage protection unit is electrically connected with the first switch control unit and the power supply respectively. The voltage dividing unit is used for being electrically connected with the power supply and grounded through the second switch unit. The overvoltage protection circuit provided by the application saves the cost and improves the response speed when protecting the electronic device from overvoltage.

Description

Technical Field

[0001] This application belongs to the field of power electronics, and in particular relates to an overvoltage protection circuit and electronic device. Background Technology

[0002] Excessive voltage can easily occur during the startup or operation of electronic devices, posing safety hazards and potentially damaging the equipment. Therefore, an overvoltage protection circuit is typically added to the power supply circuit to improve safety. Existing overvoltage protection methods usually include undervoltage shutdown protection, overvoltage current limiting protection, and instantaneous overvoltage protection. However, these methods all rely on monitoring the voltage signal in the circuit and immediately cutting off the circuit via a controller or switching element when the voltage exceeds a set value. Because the calculation speed of the controller and the response speed of the switching element are often not fast enough, they cannot process the overvoltage signal and cut off the circuit in time, leaving the equipment vulnerable to damage. Therefore, existing overvoltage protection circuits suffer from slow response speed and poor overvoltage protection effectiveness. Summary of the Invention

[0003] This application provides an overvoltage protection circuit and electronic device that can solve the problem of poor overvoltage protection effect caused by the slow response speed of existing overvoltage protection circuits.

[0004] In a first aspect, embodiments of this application provide an overvoltage protection circuit, including a charging and discharging unit, a discharging switch unit, a first switch unit, a first switch control unit, an overvoltage protection unit, a voltage divider unit, and a second switch unit;

[0005] The charging and discharging unit is electrically connected to the discharge switch unit, the voltage divider unit, the power supply, and the load switch unit, respectively. The discharge switch unit is electrically connected to the voltage divider unit, the first switch unit, and the power supply, respectively. The first switch unit is electrically connected to the first switch control unit, the second switch unit, and the power supply, respectively. The overvoltage protection unit is electrically connected to the first switch control unit and the power supply, respectively. The voltage divider unit is used to be electrically connected to the power supply and is grounded through the second switch unit.

[0006] When the second switching unit is turned on, the voltage divider unit is used to divide the voltage output by the power supply and output a first voltage signal to the load switching unit. The charging and discharging unit is used to charge according to the first voltage signal, so that the load switching unit is turned on.

[0007] When the voltage output by the power supply is greater than the preset voltage, the overvoltage protection unit outputs an overvoltage protection signal to the first switch control unit; the first switch control unit is used to output a first switch signal to the first switch unit and the second switch unit according to the overvoltage protection signal, and the second switch unit is used to disconnect according to the first switch signal, so that the voltage divider unit stops outputting the first voltage signal; the first switch unit is used to disconnect according to the first switch signal, the discharge switch unit is turned on, the charge and discharge unit discharges through the discharge switch unit, so that the load switch unit is disconnected.

[0008] In one possible implementation of the first aspect, the charging and discharging unit includes a first capacitor, a first terminal of which is electrically connected to the first terminal of the discharge switch unit, the first terminal of the voltage divider unit, the power supply and the first terminal of the load switch unit, respectively, and a second terminal of which is electrically connected to the second terminal of the voltage divider unit and the second terminal of the load switch unit, respectively.

[0009] In one possible implementation of the first aspect, the discharge switch unit includes a first switch transistor and a first resistor. The gate of the first switch transistor is electrically connected to the first switch unit and the power supply, respectively. The drain of the first switch transistor is electrically connected to a first terminal of the first resistor. The source of the first switch transistor is electrically connected to the voltage divider unit. The second terminal of the first resistor is electrically connected to a first terminal of the first capacitor and a first terminal of the voltage divider unit, respectively.

[0010] In one possible implementation of the first aspect, the first switching unit includes a second switching transistor, the gate of the second switching transistor being electrically connected to the first switching control unit and the second switching unit respectively, the drain of the second switching transistor being electrically connected to the discharge switching unit and the power supply respectively, and the source of the second switching transistor being grounded.

[0011] In one possible implementation of the first aspect, the first switch control unit includes a second resistor and a second capacitor, the first end of the second resistor is electrically connected to the overvoltage protection unit, the second end of the second resistor is electrically connected to the first end of the second capacitor, the second switch unit and the first switch unit respectively, and the second end of the second capacitor is grounded.

[0012] In one possible implementation of the first aspect, the overvoltage protection unit includes a first transistor and a first Zener diode, the base of the first transistor is electrically connected to the anode of the first Zener diode, the collector of the first transistor is electrically connected to the first switch control unit, the emitter of the first transistor is grounded, and the cathode of the first Zener diode is used to be electrically connected to the power supply.

[0013] In one possible implementation of the first aspect, the overvoltage protection unit further includes a third capacitor and a third resistor, wherein the first terminal of the third capacitor is electrically connected to the cathode of the first Zener diode and the first terminal of the third resistor, and the second terminal of the third capacitor is electrically connected to the second terminal of the third resistor and the power supply.

[0014] In one possible implementation of the first aspect, the voltage divider unit includes a fourth resistor and a fifth resistor. The first end of the fourth resistor serves as the first end of the voltage divider unit and is electrically connected to the power supply and the first end of the charging / discharging unit, respectively. The second end of the fourth resistor serves as the second end of the voltage divider unit and is electrically connected to the first end of the fifth resistor, the discharge switch unit, and the second end of the charging / discharging unit, respectively. The second end of the fifth resistor is electrically connected to the second switch unit.

[0015] In one possible implementation of the first aspect, the second switching unit includes a third switching transistor, the drain of which is electrically connected to the voltage divider unit, the gate of which is electrically connected to the first switching control unit and the first switching unit, and the source of which is grounded.

[0016] In a second aspect, embodiments of this application provide an electronic device including the overvoltage protection circuit described in any one of the first aspects.

[0017] The beneficial effects of the embodiments of this application compared with the prior art are:

[0018] The overvoltage protection circuit provided in this application includes a charging / discharging unit, a discharging switch unit, a first switch unit, a first switch control unit, an overvoltage protection unit, a voltage divider unit, and a second switch unit. In practical applications, both the first switch unit and the first switch control unit need to be electrically connected to the control unit. At the instant the electronic device is turned on, the second switch unit conducts. The voltage divider unit divides the voltage output from the power supply and outputs a first voltage signal to the load switch unit. The charging / discharging unit charges according to the first voltage signal, causing the load switch unit to conduct. Therefore, during the charging process, the charging / discharging unit can control the load switch unit to delay conduction. Simultaneously, the charging / discharging unit can absorb the inrush current generated at the instant the electronic device is turned on, preventing excessive inrush current from damaging the electronic device and extending its service life.

[0019] When the voltage output by the power supply exceeds a preset voltage, the overvoltage protection unit outputs an overvoltage protection signal to the first switch control unit. The first switch control unit outputs a first switch signal to the first switch unit and the second switch unit based on the overvoltage protection signal. The second switch unit disconnects based on the first switch signal, causing the voltage divider unit to stop outputting the first voltage signal. At this time, the charging and discharging unit cannot receive the first voltage signal and cannot charge based on it. The first switch unit disconnects based on the first switch signal, the discharge switch unit turns on, and the charging and discharging unit rapidly discharges through the discharge switch unit, causing the load switch unit to quickly switch from a conducting state to a disconnected state. This achieves overvoltage protection for the electronic equipment, preventing damage from excessive voltage. Therefore, the overvoltage protection circuit provided in this application embodiment saves costs and improves response speed when providing overvoltage protection for electronic equipment. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic block diagram of an overvoltage protection circuit provided in one embodiment of this application;

[0022] Figure 2 This is a circuit connection diagram of an overvoltage protection circuit provided in an embodiment of this application;

[0023] Figure 3 This is a circuit connection diagram of an overvoltage protection circuit provided in another embodiment of this application;

[0024] Figure 4 This is a waveform diagram of various parameters of an existing overvoltage protection circuit when the input voltage is 24V;

[0025] Figure 5 This is a waveform diagram of various parameters of the overvoltage protection circuit provided in this application embodiment when the output voltage of the power supply is 24V;

[0026] Figure 6 This is a waveform diagram of various parameters of an existing overvoltage protection circuit during an input voltage range of 8-48V;

[0027] Figure 7 This is a waveform diagram of various parameters of the overvoltage protection circuit provided in this application embodiment when the output voltage of the power supply is 8-48V.

[0028] In the diagram: 10. Overvoltage protection circuit; 101. Charging and discharging unit; 102. Discharge switch unit; 103. First switch unit; 104. First switch control unit; 105. Overvoltage protection unit; 106. Voltage divider unit; 107. Second switch unit; 108. Overvoltage detection unit; 109. Voltage stabilizing unit; 20. Load switch unit; 30. Power supply; 40. Control unit; 50. Load. Detailed Implementation

[0029] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0030] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0031] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if [the described condition or event] is detected" may be interpreted, depending on the context, as "once determined," "in response to determination," "once [the described condition or event] is detected," or "in response to detection of [the described condition or event]."

[0032] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0033] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0034] Existing overvoltage protection methods typically include undervoltage shutdown protection, overvoltage current limiting protection, and instantaneous overvoltage protection. However, all of these methods rely on monitoring the voltage signal in the circuit. When the voltage exceeds a set value, a controller or switching element immediately cuts off the circuit to protect it. Because the calculation speed of the controller and the response speed of the switching element are often too slow to process the overvoltage signal and cut off the circuit in time, the equipment is easily damaged. Therefore, existing overvoltage protection circuits suffer from slow response speed and poor overvoltage protection effectiveness.

[0035] Based on the above problems, the overvoltage protection circuit provided in this application includes a charging / discharging unit, a discharging switch unit, a first switch unit, a first switch control unit, an overvoltage protection unit, a voltage divider unit, and a second switch unit. In practical applications, both the first switch unit and the first switch control unit need to be electrically connected to the control unit. At the instant the electronic device is turned on, the second switch unit is turned on, the voltage divider unit is used to divide the voltage output by the power supply and output a first voltage signal to the load switch unit, and the charging / discharging unit is used to charge according to the first voltage signal, causing the load switch unit to turn on. Therefore, during the charging process, the charging / discharging unit can control the load switch unit to delay its turn-on. Simultaneously, the charging / discharging unit can absorb the inrush current generated at the instant the electronic device is turned on, preventing excessive inrush current from damaging the electronic device and extending its service life.

[0036] When the voltage output by the power supply exceeds a preset voltage, the overvoltage protection unit outputs an overvoltage protection signal to the first switch control unit. The first switch control unit outputs a first switch signal to the first switch unit and the second switch unit based on the overvoltage protection signal. The second switch unit disconnects based on the first switch signal, causing the voltage divider unit to stop outputting the first voltage signal. At this time, the charging and discharging unit cannot receive the first voltage signal and cannot charge based on it. The first switch unit disconnects based on the first switch signal, the discharge switch unit turns on, and the charging and discharging unit rapidly discharges through the discharge switch unit, causing the load switch unit to quickly switch from a conducting state to a disconnected state. This achieves overvoltage protection for the electronic equipment, preventing damage from excessive voltage. Therefore, the overvoltage protection circuit provided in this application embodiment saves costs and improves response speed when providing overvoltage protection for electronic equipment.

[0037] To illustrate the technical solution described in this application, specific embodiments are provided below.

[0038] Figure 1 A schematic block diagram of an overvoltage protection circuit 10 according to an embodiment of this application is shown. See also... Figure 1As shown, the overvoltage protection circuit 10 includes a charging and discharging unit 101, a discharging switch unit 102, a first switch unit 103, a first switch control unit 104, an overvoltage protection unit 105, a voltage divider unit 106, and a second switch unit 107.

[0039] The charging and discharging unit 101 is electrically connected to the discharge switch unit 102, the voltage divider unit 106, the power supply 30, and the load switch unit 20, respectively. The discharge switch unit 102 is electrically connected to the voltage divider unit 106, the first switch unit 103, and the power supply 30, respectively. The first switch unit 103 is electrically connected to the first switch control unit 104, the second switch unit 107, and the power supply 30, respectively. The overvoltage protection unit 105 is electrically connected to the first switch control unit 104 and the power supply 30, respectively. The voltage divider unit 106 is used to be electrically connected to the power supply 30 and is grounded through the second switch unit 107.

[0040] Specifically, in practical applications, both the first switching unit 103 and the first switching control unit 104 need to be electrically connected to the control unit 40. At the instant the electronic device is turned on, the second switching unit 107 is turned on, the voltage divider unit 106 divides the voltage output from the power supply 30 and outputs a first voltage signal to the load switching unit 20, and the charging / discharging unit 101 charges according to the first voltage signal, causing the load switching unit 20 to turn on. Therefore, during the charging process, the charging / discharging unit 101 can control the load switching unit 20 to delay its turn-on. Simultaneously, the charging / discharging unit 101 can absorb the inrush current generated at the instant the electronic device is turned on, preventing excessive inrush current from damaging the electronic device and extending its service life.

[0041] When the voltage output by the power supply 30 exceeds a preset voltage, the overvoltage protection unit 105 outputs an overvoltage protection signal to the first switch control unit 104. The first switch control unit 104 outputs a first switch signal to the first switch unit 103 and the second switch unit 107 based on the overvoltage protection signal. The second switch unit 107 disconnects based on the first switch signal, causing the voltage divider unit 106 to stop outputting the first voltage signal. At this time, the charging / discharging unit 101 cannot receive the first voltage signal and charge according to it. The first switch unit 103 disconnects based on the first switch signal, the discharge switch unit 102 is turned on, and the charging / discharging unit 101 rapidly discharges through the discharge switch unit 102, causing the load switch unit 20 to quickly change from a conducting state to a disconnected state. This achieves overvoltage protection for the electronic device, preventing damage from excessive voltage. Therefore, the overvoltage protection circuit 10 provided in this embodiment saves costs and improves response speed when providing overvoltage protection for electronic devices.

[0042] It should be noted that the power supply 30 can be a DC power supply for powering electronic equipment. When the voltage output by the power supply 30 is less than or equal to a preset voltage, the overvoltage protection unit 105 will not output an overvoltage protection signal to the first switch control unit 104, and the first switch control unit 104 will not output a first switch signal to the first switch unit 103. At this time, the first switch unit 103 is in the on state, the discharge switch unit 102 is in the off state, and the load switch unit 20 is in the on state. The overvoltage protection circuit 10 does not need to provide overvoltage protection for the electronic equipment.

[0043] For example, designers can select a preset voltage value according to actual conditions, such as selecting a preset voltage of 24V. When the voltage output by the power supply 30 is greater than 24V, the overvoltage protection circuit 10 can provide overvoltage protection for the electronic equipment.

[0044] It should be noted that the load switch unit 20 determines its state based on the first voltage signal. When the difference between the voltage output by the power supply 30 and the voltage value of the first voltage signal is greater than or equal to the conduction threshold of the load switch unit 20, the load switch unit 20 is in the conducting state; when the difference between the voltage output by the power supply 30 and the voltage value of the first voltage signal is less than the conduction threshold of the load switch unit 20, the load switch unit 20 is in the disconnected state.

[0045] It should be noted that the control unit 40 is used to detect the first switch signal output by the first switch control unit 104, and determine whether the overvoltage protection circuit 10 is in an overvoltage protection state based on the first switch signal. When the control unit 40 detects that the first switch signal is a high-level signal, it determines that the overvoltage protection circuit 10 is in a normal working state and there is no need to perform overvoltage protection on the electronic equipment; when the control unit 40 detects that the first switch signal is a low-level signal, it determines that the overvoltage protection circuit 10 is in an overvoltage protection state, and at this time, overvoltage protection on the electronic equipment is required.

[0046] In one embodiment of this application, such as Figure 2 As shown, the charging and discharging unit 101 includes a first capacitor C1. The first end of the first capacitor C1 is electrically connected to the first end of the discharge switch unit 102, the first end of the voltage divider unit 106, the power supply 30, and the first end of the load switch unit 20, respectively. The second end of the first capacitor C1 is electrically connected to the second end of the voltage divider unit 106 and the second end of the load switch unit 20, respectively.

[0047] Specifically, at the instant the electronic device is turned on, the first capacitor C1 is in a charging state, where it stores energy. As the voltage across the first capacitor C1 gradually increases, when the voltage across the first capacitor C1 exceeds the conduction voltage of the load switch unit 20, the load switch unit 20 changes from an off state to a conducting state. Since the charging of the first capacitor C1 takes a certain amount of time, this achieves a soft start for the load switch unit 20. Simultaneously, during the charging process, the first capacitor C1 can absorb the inrush current generated at the instant the electronic device is turned on, preventing excessive inrush current from damaging the electronic device and extending its service life. When the voltage output by the power supply 30 exceeds a preset voltage, the first capacitor C1 is in a discharging state. At this time, the first capacitor C1 releases energy through the discharge switch unit 102, thereby changing the load switch unit 20 from a conducting state to an off state, preventing damage to the electronic device due to excessive voltage. The overvoltage protection circuit 10 provided in this embodiment saves costs and improves response speed when protecting electronic devices from overvoltage.

[0048] It should be noted that by adding a first capacitor C1 and discharging it, the turn-off time of the load switching unit 20 can be accelerated by several hundred milliseconds, which greatly improves the response speed and reliability of the overvoltage protection circuit 10.

[0049] For example, the designer can select the capacitance and rated voltage of the first capacitor C1 according to the actual situation. For example, the capacitance of the first capacitor C1 can be selected as 0.47μF and the rated voltage as 50V.

[0050] In one embodiment of this application, such as Figure 2 As shown, the discharge switch unit 102 includes a first switch transistor Q1 and a first resistor R1. The gate of the first switch transistor Q1 is electrically connected to the first switch unit 103 and the power supply 30, respectively. The drain of the first switch transistor Q1 is electrically connected to the first end of the first resistor R1. The source of the first switch transistor Q1 is electrically connected to the second end of the voltage divider unit 106. The second end of the first resistor R1 is electrically connected to the first end of the first capacitor C1 and the first end of the voltage divider unit 106, respectively.

[0051] Specifically, when the first switching unit 103 is in the off state, the gate of the first switching transistor Q1 receives the voltage output from the power supply 30. At this time, the voltage difference between the gate and source of the first switching transistor Q1 is greater than or equal to the turn-on voltage of the first switching transistor Q1, and the first switching transistor Q1 is in the on state. The first capacitor C1 discharges through the first switching transistor Q1 and the first resistor R1. When the first capacitor C1 has finished discharging, the load switching unit 20 is disconnected, realizing overvoltage protection for the electronic equipment and preventing damage to the electronic equipment due to excessive voltage. Setting the first resistor R1 can prevent the first capacitor C1 from short-circuiting when the first switching transistor Q1 is in the on state (i.e., during the discharge of the first capacitor C1). If the first resistor R1 is not set, when the first switching transistor Q1 is in the on state, the first terminal and the second terminal of the first capacitor C1 are equivalent to being connected in series, which will cause the first capacitor C1 to short-circuit, forming a large current, and even causing danger. At the same time, setting the first resistor R1 can limit the current, thereby making the discharge speed of the first capacitor C1 faster and speeding up the disconnection of the load switching unit 20.

[0052] For example, designers can select the type and model of the first switching transistor Q1 according to the actual situation, that is, a fully controllable power device such as a metal-oxide-semiconductor field-effect transistor or an insulated-gate bipolar transistor can be used. For example, the first switching transistor Q1 can be selected as an NMOS transistor, and the model of the first switching transistor Q1 can be selected as 2N7002K-7. Designers can also select the resistance value and accuracy of the first resistor R1 according to the actual situation. For example, the resistance value of the first resistor R1 can be selected as 100Ω, and the accuracy is ±5%.

[0053] In one embodiment of this application, such as Figure 2 As shown, the first switching unit 103 includes a second switching transistor Q2. The gate of the second switching transistor Q2 is electrically connected to the first switching control unit 104 and the second switching unit 107, respectively. The drain of the second switching transistor Q2 is electrically connected to the discharge switching unit 102 and the power supply 30, respectively. The source of the second switching transistor Q2 is grounded.

[0054] Specifically, the second switch Q2 receives the first switch signal output by the first switch unit 103 and disconnects according to the first switch signal. When the second switch Q2 is in the off state, the first switch Q1 is in the on state, and the first capacitor C1 can discharge through the first switch Q1 and the first resistor R1. When the second switch Q2 is in the on state, the first switch Q1 is in the off state and cannot provide a discharge path for the first capacitor C1, therefore, there is no need for overvoltage protection of the electronic equipment.

[0055] For example, designers can select the type and model of the second switch Q2 according to the actual situation, that is, they can use fully controllable power devices such as metal-oxide-semiconductor field-effect transistors or insulated-gate bipolar transistors. For example, the second switch Q2 can be selected as an NMOS transistor, and the model of the second switch Q2 can be selected as 2N7002K-7.

[0056] In one embodiment of this application, such as Figure 2 As shown, the first switch control unit 104 includes a second resistor R2 and a second capacitor C2. The first end of the second resistor R2 is electrically connected to the overvoltage protection unit 105, and the second end of the second resistor R2 is electrically connected to the first end of the second capacitor C2, the second switch unit 107 and the first switch unit 103 respectively. The second end of the second capacitor C2 is grounded.

[0057] Specifically, at the instant the electronic device is turned on, the second capacitor C2 is in a charging state, where it stores energy, and points A and B are both at a high level. When the voltage output by the power supply 30 exceeds the preset voltage, the overvoltage protection unit 105 outputs an overvoltage protection signal to the first switch control unit 104, causing the voltage at point A to drop. The second capacitor C2 then discharges, releasing energy, which in turn pulls the voltage at point B down. The second resistor R2 limits the current and provides a discharge path for the second capacitor C2.

[0058] For example, the designer can select the capacitance and rated voltage of the second capacitor C2 according to the actual situation. For instance, the capacitance of the second capacitor C2 can be selected as 100pF and the rated voltage as 50V. The designer can also select the resistance and accuracy of the second resistor R2 according to the actual situation. For instance, the resistance of the second resistor R2 can be selected as 10Ω and the accuracy as ±5%.

[0059] In one embodiment of this application, such as Figure 2 As shown, the overvoltage protection unit 105 includes a first transistor VT1 and a first Zener diode ZD1. The base of the first transistor VT1 is electrically connected to the anode of the first Zener diode ZD1, the collector of the first transistor VT1 is electrically connected to the first switch control unit 104, the emitter of the first transistor VT1 is grounded, and the cathode of the first Zener diode ZD1 is used to be electrically connected to the power supply 30.

[0060] Specifically, the first Zener diode ZD1 can achieve a stable voltage output during reverse breakdown. When the first Zener diode ZD1 is turned on, i.e., in reverse breakdown state, it generates a stable voltage output; however, in normal state, because it is a reverse-biased diode, it is in the cutoff state and has only a very small reverse leakage current. That is, when the voltage output by the power supply 30 is less than or equal to the preset voltage, the first Zener diode ZD1 is in the cutoff state. At this time, the voltage difference between the base and emitter of the first transistor VT1 is less than the turn-on voltage of the first transistor VT1, the first transistor VT1 is in the cutoff state, and point A is at a high level. When the voltage output by the power supply 30 is greater than the preset voltage, the first Zener diode ZD1 is turned on, i.e., the first Zener diode ZD1 is reverse-broken down. At this time, the voltage difference between the base and emitter of the first transistor VT1 is greater than or equal to the turn-on voltage of the first transistor VT1, the first transistor VT1 is in the turn-on state, and point A is pulled low.

[0061] For example, the designer can select the type and model of the first transistor VT1 according to the actual situation. For instance, an NPN type first transistor VT1 can be selected, and the model of the first transistor VT1 can be PMBT2222. The designer can also select the voltage regulation value of the first Zener diode ZD1 according to the actual situation. For instance, the voltage regulation value of the first Zener diode ZD1 can be selected as 27V.

[0062] In one embodiment of this application, such as Figure 2 As shown, the overvoltage protection unit 105 also includes a third capacitor C3 and a third resistor R3. The first end of the third capacitor C3 is electrically connected to the cathode of the first Zener diode ZD1 and the first end of the third resistor R3, respectively. The second end of the third capacitor C3 is electrically connected to the second end of the third resistor R3 and the power supply 30, respectively.

[0063] Specifically, the third resistor R3 is used for current limiting. Due to the instability of the voltage output by the power supply 30, when the voltage output by the power supply 30 is AC voltage, the third capacitor C3 can speed up the transmission of the voltage signal, so that the voltage output by the power supply 30 can quickly break down the first Zener diode ZD1, thereby improving the overvoltage protection efficiency of the overvoltage protection circuit 10.

[0064] For example, designers can select the capacitance and rated voltage of the third capacitor C3 according to the actual situation. For instance, the capacitance of the third capacitor C3 can be selected as 0.1μF and the rated voltage as 50V. Designers can also select the resistance and accuracy of the third resistor R3 according to the actual situation. For instance, the resistance of the third resistor R3 can be selected as 3.3KΩ and the accuracy as ±5%.

[0065] In one embodiment of this application, such as Figure 2As shown, the overvoltage protection unit 105 also includes a sixth resistor R6, a seventh resistor R7, and a fourth capacitor C4. The first end of the sixth resistor R6 is electrically connected to the base of the first transistor VT1 and the first end of the fourth capacitor C4, respectively. The second end of the sixth resistor R6 is electrically connected to the first end of the seventh resistor R7 and the anode of the first Zener diode ZD1, respectively. The second end of the seventh resistor R7 is electrically connected to the second end of the fourth capacitor C4 and the emitter of the first transistor VT1 and grounded.

[0066] Specifically, the sixth resistor R6 and the seventh resistor R7 are both used for voltage division and current limiting to prevent excessive current in the circuit from damaging the components. The fourth capacitor C4 is used for filtering to remove high-frequency noise signals from the voltage output by the power supply 30, preventing high-frequency signals from interfering with the circuit and improving the reliability of the overvoltage protection circuit 10.

[0067] It should be noted that designers can select the parameters of the fourth capacitor C4 according to the actual situation. For example, when selecting the fourth capacitor C4, parameters such as the ripple frequency to be filtered, voltage capacity, and rated power should be considered to ensure that it works normally and filters correctly.

[0068] For example, designers can select the resistance values ​​and accuracy of the sixth resistor R6 and the seventh resistor R7 according to the actual situation. For instance, the resistance value of the sixth resistor R6 can be selected as 3.3KΩ with an accuracy of ±5%, and the resistance value of the seventh resistor R7 can be selected as 10KΩ with an accuracy of ±1%. Designers can also select the capacitance and rated voltage of the fourth capacitor C4 according to the actual situation. For instance, the capacitance of the fourth capacitor C4 can be selected as 100pF with a rated voltage of 50V.

[0069] In one embodiment of this application, such as Figure 2 As shown, the voltage divider unit 106 includes a fourth resistor R4 and a fifth resistor R5. The first end of the fourth resistor R4 serves as the first end of the voltage divider unit 106 and is electrically connected to the first end of the power supply 30 and the charging / discharging unit 101, respectively. The second end of the fourth resistor R4 serves as the second end of the voltage divider unit 106 and is electrically connected to the first end of the fifth resistor R5, the second end of the discharge switch unit 102 and the second end of the charging / discharging unit 101, respectively. The second end of the fifth resistor R5 is electrically connected to the second switch unit 107.

[0070] Specifically, the fourth resistor R4 and the fifth resistor R5 are both used to divide the voltage output by the power supply 30 and output a first voltage signal to the load switching unit 20, and the first capacitor C1 is charged according to the first voltage signal. At the same time, the fourth resistor R4 and the fifth resistor R5 are also used to provide a power supply circuit for the power supply 30 after the first capacitor C1 is fully charged.

[0071] For example, designers can select the resistance values ​​and accuracy of the fourth resistor R4 and the fifth resistor R5 according to the actual situation. For example, the resistance value of the fourth resistor R4 can be selected as 51KΩ with an accuracy of ±1%, and the resistance value of the fifth resistor R5 can be selected as 51KΩ with an accuracy of ±1%.

[0072] In one embodiment of this application, such as Figure 2 As shown, the second switching unit 107 includes a third switching transistor Q3. The drain of the third switching transistor Q3 is electrically connected to the voltage divider unit, the gate of the third switching transistor Q3 is electrically connected to the first switching control unit 104 and the first switching unit 103 respectively, and the source of the third switching transistor Q3 is grounded.

[0073] Specifically, the third switch Q3 provides a voltage divider circuit for the fourth resistor R4 and the fifth resistor R5, and also provides a charging circuit for the first capacitor C1. When the third switch Q3 is in the on state, current flows out from the power supply 30, through the fourth resistor R4, the fifth resistor R5 and the third switch Q3, and to ground, providing a voltage divider circuit for the fourth resistor R4 and the fifth resistor R5; at the same time, at the moment the electronic device is turned on, current can also flow out from the power supply 30, through the first capacitor C1 and the third switch Q3, and to ground, providing a charging circuit for the first capacitor C1.

[0074] For example, designers can select the type and model of the third switch Q3 according to the actual situation, that is, they can use fully controllable power devices such as metal-oxide-semiconductor field-effect transistors or insulated-gate bipolar transistors. For example, the third switch Q3 can be an NMOS transistor, and the model of the third switch Q3 selected is 2N7002K-7.

[0075] It should be noted that, as Figure 2 As shown, the load switching unit 20 includes a fourth switch Q4, a fifth switch Q5, and a sixth switch Q6. The source of the fourth switch Q4, the source of the fifth switch Q5, and the source of the sixth switch Q6 are all electrically connected to the first terminal of the first capacitor C1. The gate of the fourth switch Q4, the gate of the fifth switch Q5, and the gate of the sixth switch Q6 are all electrically connected to the second terminal of the first capacitor C1. The drain of the fourth switch Q4, the drain of the fifth switch Q5, and the drain of the sixth switch Q6 are all electrically connected to the load 50.

[0076] Specifically, the purpose of setting three switching transistors (Q4, Q5, and Q6) is to improve current throughput and transmission efficiency, provide a larger current input to the load 50, make the electronic equipment more stable, and extend the service life of the electronic equipment.

[0077] For example, designers can select the type and model of the fourth switch Q4, the fifth switch Q5, and the sixth switch Q6 according to the actual situation; that is, they can use fully controllable power devices such as metal-oxide-semiconductor field-effect transistors or insulated-gate bipolar transistors. For instance, the fourth switch Q4, the fifth switch Q5, and the sixth switch Q6 can all be PMOS transistors, and the model of the fourth switch Q4, the fifth switch Q5, and the sixth switch Q6 can all be HYG210P06L.

[0078] The following is combined with Figure 2 The specific working principle of this application will be explained in detail.

[0079] When the voltage output by the power supply 30 is less than or equal to the preset voltage, the first Zener diode ZD1 is in the off state, the first transistor VT1 is in the off state, point A is at a high level, the second capacitor C2 does not discharge, and point B is at a high level. Therefore, the second switch Q2 is in the on state, the first switch Q1 is in the off state, and there is no need for overvoltage protection for the electronic equipment.

[0080] When the output voltage of the power supply 30 exceeds the preset voltage, the first Zener diode ZD1 and the first transistor VT1 are both turned on, pulling point A low. The second capacitor C2 discharges, pulling point B low. Therefore, the second switch Q2 is turned off, the first switch Q1 is turned on, and the second capacitor C2 discharges rapidly through the first switch Q1 and the first resistor R1. The fourth switch Q4 quickly switches from the on state to the off state, thus achieving overvoltage protection for the electronic equipment and preventing damage from excessive voltage.

[0081] At the same time, at the instant the electronic device is turned on, the first capacitor C1 is in a charging state. When the voltage across the first capacitor C1 reaches the turn-on voltage of the fourth switch Q4 (the fifth switch Q5 and the sixth switch Q6), the fourth switch Q4 (the fifth switch Q5 and the sixth switch Q6) is turned on, thereby realizing the soft start of the fourth switch Q4 (the fifth switch Q5 and the sixth switch Q6). This can avoid generating a large inrush current at the instant the electronic device is turned on, thereby damaging the electronic device and extending the service life of the electronic device.

[0082] In one embodiment of this application, such as Figure 3 As shown, the second switching unit 107 also includes an eighth resistor R8. The first end of the eighth resistor R8 is electrically connected to the second end of the fifth resistor R5 and the drain of the third switching transistor Q3, respectively. The second end of the eighth resistor R8 is electrically connected to the source of the third switching transistor Q3 and grounded.

[0083] Specifically, the eighth resistor, R8, is used to adjust the circuit between the drain and source of the third switching transistor, Q3. By adjusting the resistance value of the eighth resistor, the signal can be attenuated or amplified to achieve the desired signal level. Simultaneously, the eighth resistor, R8, also changes the operating point of the third switching transistor Q3, thereby affecting the circuit's gain, bandwidth, and other characteristics. By appropriately selecting suitable resistor values ​​and adjusting them according to different circuit requirements, the circuit's performance can be optimized to the maximum extent.

[0084] In one embodiment of this application, such as Figure 3 As shown, the overvoltage protection circuit 10 also includes an overvoltage detection unit 108, which is electrically connected to the control unit 40 and the first switch control unit 104 respectively.

[0085] Specifically, the overvoltage detection unit 108 is used to detect the state of the overvoltage protection circuit 10, and when the overvoltage protection circuit 10 is in the overvoltage protection state, it outputs an overvoltage detection signal to the control unit 40.

[0086] In one embodiment of this application, such as Figure 3 As shown, the overvoltage detection unit 108 includes a ninth resistor R9 and a tenth resistor R10. The first end of the ninth resistor R9 is used to be electrically connected to the control unit 40. The second end of the ninth resistor R9 is electrically connected to the first end of the tenth resistor R10, the overvoltage protection unit 105 and the first switch control unit 104, respectively. The second end of the tenth resistor R10 is grounded.

[0087] Specifically, the ninth resistor R9 and the tenth resistor R10 are both used for voltage division and current limiting to prevent excessive current in the circuit from damaging the devices. At the same time, the ninth resistor R9 is also used to isolate the control unit 40 and the first switch control unit 104 to prevent the control unit 40 from malfunctioning when receiving the overvoltage protection signal output by the overvoltage protection unit 105, thus affecting the overvoltage protection effect of the overvoltage protection circuit 10.

[0088] For example, designers can select the resistance value and accuracy of the ninth resistor R9 and the tenth resistor R10 according to the actual situation. For example, the resistance value of the ninth resistor R9 can be selected as 1KΩ with an accuracy of ±1%, and the resistance value of the tenth resistor R10 can be selected as 10KΩ with an accuracy of ±1%.

[0089] In one embodiment of this application, such as Figure 3 As shown, the overvoltage protection circuit 10 also includes an eleventh resistor R11. The first end of the eleventh resistor R11 is used to be electrically connected to the power supply 30, and the second end of the eleventh resistor R11 is electrically connected to the first switching unit 103 and the discharge switching unit 102 respectively.

[0090] Specifically, the eleventh resistor R11 is placed between the gate of the first switching transistor Q1 and the power supply 30 to limit overvoltage and overcurrent in the circuit. The eleventh resistor R11 is commonly referred to as the gate current limiting resistor; it controls the gate drive current of the first switching transistor Q1 while preventing excessive current from flowing into the power supply or load 50. When the first switching transistor Q1 is in the on-state, the voltage provided by the power supply 30 creates a certain bias voltage between its gate and source, resulting in an increase in the gate drive current. Without proper limiting, these currents may exceed the maximum design value of the first switching transistor Q1, causing it to fail or be damaged. By adding the eleventh resistor R11 between the gate and the power supply, the gate drive current can be controlled, thereby protecting the switching transistor and extending its effective lifespan. Simultaneously, the eleventh resistor R11 can also be used to adjust the off-time and on-time of the first switching transistor Q1 to improve circuit performance and reduce noise and harmonics.

[0091] For example, designers can select the resistance value and accuracy of the eleventh resistor R11 according to the actual situation. For instance, the resistance value of the eleventh resistor R11 can be selected as 10KΩ and the accuracy as ±1%.

[0092] In one embodiment of this application, such as Figure 3 As shown, the overvoltage protection circuit 10 also includes a voltage regulator unit 109, which is electrically connected to the first switching unit 103 and the discharge switching unit 102.

[0093] Specifically, the voltage regulator unit 109 is used to provide a stable voltage to prevent damage to the first switch transistor Q1 in the first switching unit 103 after the charging and discharging unit 101 has finished charging.

[0094] In one embodiment of this application, such as Figure 3 As shown, the voltage regulator unit 109 includes a second Zener diode ZD2. The anode of the second Zener diode ZD2 is electrically connected to the drain of the second switch Q2, and the cathode of the second Zener diode ZD2 is electrically connected to the gate of the first switch Q1.

[0095] Specifically, the second Zener diode ZD2 provides a stable voltage to prevent damage to the first switching transistor Q1 due to a voltage difference between its gate and source exceeding its withstand voltage. At the moment the electronic device is turned on, the second and third switching transistors Q2 and Q3 are in the ON state, the first capacitor C1 is charging, and the fourth and fifth resistors R4 and R5 divide the 24V output voltage from the power supply 30. After the first capacitor C1 has finished charging, the voltage divided by the fourth and fifth resistors R4 and R5 is 12V. When the second switching transistor Q2 is ON, the gate-to-ground voltage of the first switching transistor Q1 is 0V, which is -24V relative to its source. Since the gate-to-source withstand voltage range of most existing semiconductor transistors is ±20V, the first switching transistor Q1 will be damaged if the voltage difference between its gate and source exceeds its withstand voltage. Therefore, if a 12V second Zener diode ZD2 is placed between the gate of the first switching transistor Q1 and the drain of the second switching transistor Q2, when the second switching transistor Q2 is in the on state, the voltage difference between the gate and source of the first switching transistor Q1 is less than the withstand voltage of the first switching transistor Q1. This avoids the first switching transistor Q1 from being damaged due to the voltage difference between the gate and source being greater than the withstand voltage of the first switching transistor Q1, thereby improving the stability of the first switching transistor Q1 and the reliability of the overvoltage protection circuit 10.

[0096] For example, the designer can select the model and voltage regulation value of the second Zener diode ZD2 according to the actual situation. For example, the model of the second Zener diode ZD2 can be selected as MMSZ5242BT1, and the voltage regulation value of the second Zener diode ZD2 can be selected as 12V.

[0097] It should be noted that, as Figure 3 As shown, the load switching unit 20 also includes a twelfth resistor R12 and a fifth capacitor C5. The first end of the twelfth resistor R12 is electrically connected to the source of the fourth switch Q4, the source of the fifth switch Q5, and the source of the sixth switch Q6, respectively. The second end of the twelfth resistor R12 is electrically connected to the first end of the fifth capacitor C5. The second end of the fifth capacitor C5 is electrically connected to the drain of the fourth switch Q4, the drain of the fifth switch Q5, and the drain of the sixth switch Q6, respectively.

[0098] Specifically, the twelfth resistor R12 and the fifth capacitor C5 are connected in series, primarily for suppressing and filtering the voltage in the circuit. The twelfth resistor R12 limits current flow, controlling the speed and magnitude of current flow through the circuit. During circuit switching, the twelfth resistor R12 restricts the charging and discharging of the fifth capacitor C5 to avoid noise and interference caused by voltage surges. Simultaneously, after the circuit is turned off, the fifth capacitor C5 discharges through the twelfth resistor R12, thus preventing voltage reversal or instantaneous power supply bounce. The fifth capacitor C5 suppresses high-frequency noise and waveform distortion, making the signal in the circuit smoother and more stable. During circuit switching, the energy storage function of the fifth capacitor C5 allows for a faster instantaneous response, reducing turn-on delay or breakdown, and improving the performance and reliability of the overvoltage protection circuit 10.

[0099] For example, a waveform diagram of various parameters of an existing overvoltage protection circuit when the input voltage is 24V is shown below. Figure 4 As shown; the waveform diagram of each parameter of the overvoltage protection circuit 10 provided in this embodiment of the application when the output voltage of the power supply 30 is 24V is shown in the figure. Figure 5 As shown.

[0100] It should be noted that, Figure 4 The waveform diagrams shown in the image, from top to bottom, are the output voltage waveform, the input current waveform, and the input voltage waveform. Figure 5 The waveform diagrams shown, from top to bottom, are the output voltage waveform, the input current waveform, and the input voltage waveform. It can be seen that existing overvoltage protection circuits generate an inrush current of 160A when the input voltage is 24V, while the overvoltage protection circuit 10 provided in this embodiment generates an inrush current of approximately 21A when the output voltage of the power supply 30 is 24V. Therefore, when both input voltages are 24V, compared to existing overvoltage protection circuits, the overvoltage protection circuit provided in this application can reduce the inrush current at the moment the electronic device is turned on, thereby improving the service life of the electronic device.

[0101] For example, the waveform diagrams of various parameters of an existing overvoltage protection circuit during an input voltage range of 8-48V are shown below. Figure 6 As shown; the waveform diagrams of various parameters of the overvoltage protection circuit 10 provided in this embodiment of the application during the process where the voltage output by the power supply 30 is 8-48V are shown in the figure. Figure 7 As shown.

[0102] It should be noted that, Figure 6 The waveform diagrams in the image, from top to bottom, are the waveform diagrams of the protection voltage. Figure 3The waveform diagrams are as follows: waveform diagram of point A, waveform diagram of input current, waveform diagram of output voltage, and waveform diagram of input voltage. Figure 7 The waveform diagrams in the image, from top to bottom, are the waveform diagrams of the protection voltage. Figure 3 The waveform diagrams at point A, the input current, the output voltage, and the input voltage are shown. It can be seen that existing overvoltage protection circuits, when the input voltage exceeds 27V (abnormal) during an input voltage range of 8-48V, initiate overvoltage protection for approximately 10ms. Protection occurs immediately after the output voltage reaches 27V, but the output voltage v(out) remains above 27V for more than 10ms. The overvoltage protection circuit 10 provided in this embodiment, when the output voltage of the power supply 30 is between 8-48V, initiates overvoltage protection when the input voltage exceeds 27V (abnormal), with a protection time of approximately 600µs. Protection occurs immediately after the output voltage reaches 30V, and the output voltage drops. Therefore, during an input voltage range of 8-48V, compared to existing overvoltage protection circuits, the overvoltage protection circuit provided in this application can accelerate the turn-off time of the load switching unit 20, significantly improving the response speed and reliability of the overvoltage protection circuit 10.

[0103] It should be noted that this can be achieved through adjustment. Figure 3 The resistance value of the first resistor R1 in the circuit adjusts the protection time of the overvoltage protection circuit. The smaller the resistance value of the first resistor R1, the faster the protection time.

[0104] This application also discloses an electronic device including the overvoltage protection circuit 10 described above. By using the overvoltage protection circuit 10, the electronic device can achieve overvoltage protection, avoiding damage to the electronic device caused by excessively high voltage output by the power supply 30. At the same time, it saves costs and improves response speed when protecting the electronic device from overvoltage.

[0105] Since the processing and functions implemented by the electronic device in this embodiment are basically the same as the embodiments, principles and examples of the overvoltage protection circuit described above, any parts not detailed in this embodiment can be referred to the relevant descriptions in the foregoing embodiments, and will not be repeated here.

[0106] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. An overvoltage protection circuit, characterized in that, It includes a charging / discharging unit, a discharging switch unit, a first switch unit, a first switch control unit, an overvoltage protection unit, a voltage divider unit, and a second switch unit; The charging and discharging unit is electrically connected to the discharge switch unit, the voltage divider unit, the power supply, and the load switch unit, respectively. The discharge switch unit is electrically connected to the voltage divider unit, the first switch unit, and the power supply, respectively. The first switch unit is electrically connected to the first switch control unit, the second switch unit, and the power supply, respectively. The overvoltage protection unit is electrically connected to the first switch control unit and the power supply, respectively. The voltage divider unit is used to be electrically connected to the power supply and is grounded through the second switch unit. When the second switching unit is turned on, the voltage divider unit is used to divide the voltage output by the power supply and output a first voltage signal to the load switching unit. The charging and discharging unit is used to charge according to the first voltage signal, so that the load switching unit is turned on. When the voltage output by the power supply is greater than the preset voltage, the overvoltage protection unit outputs an overvoltage protection signal to the first switch control unit; the first switch control unit is used to output a first switch signal to the first switch unit and the second switch unit according to the overvoltage protection signal, and the second switch unit is used to disconnect according to the first switch signal, so that the voltage divider unit stops outputting the first voltage signal; the first switch unit is used to disconnect according to the first switch signal, the discharge switch unit is turned on, the charge and discharge unit discharges through the discharge switch unit, so that the load switch unit is disconnected.

2. The overvoltage protection circuit according to claim 1, characterized in that, The charging and discharging unit includes a first capacitor. The first end of the first capacitor is electrically connected to the first end of the discharge switch unit, the first end of the voltage divider unit, the power supply, and the first end of the load switch unit. The second end of the first capacitor is electrically connected to the second end of the voltage divider unit and the second end of the load switch unit.

3. The overvoltage protection circuit according to claim 2, characterized in that, The discharge switch unit includes a first switch transistor and a first resistor. The gate of the first switch transistor is electrically connected to the first switch unit and the power supply, respectively. The drain of the first switch transistor is electrically connected to the first end of the first resistor. The source of the first switch transistor is electrically connected to the voltage divider unit. The second end of the first resistor is electrically connected to the first end of the first capacitor and the first end of the voltage divider unit, respectively.

4. The overvoltage protection circuit according to claim 1, characterized in that, The first switching unit includes a second switching transistor. The gate of the second switching transistor is electrically connected to the first switching control unit and the second switching unit, respectively. The drain of the second switching transistor is electrically connected to the discharge switching unit and the power supply, respectively. The source of the second switching transistor is grounded.

5. The overvoltage protection circuit according to claim 1, characterized in that, The first switch control unit includes a second resistor and a second capacitor. The first end of the second resistor is electrically connected to the overvoltage protection unit. The second end of the second resistor is electrically connected to the first end of the second capacitor, the second switch unit, and the first switch unit, respectively. The second end of the second capacitor is grounded.

6. The overvoltage protection circuit according to claim 1, characterized in that, The overvoltage protection unit includes a first transistor and a first Zener diode. The base of the first transistor is electrically connected to the anode of the first Zener diode, the collector of the first transistor is electrically connected to the first switch control unit, the emitter of the first transistor is grounded, and the cathode of the first Zener diode is used to be electrically connected to the power supply.

7. The overvoltage protection circuit according to claim 6, characterized in that, The overvoltage protection unit further includes a third capacitor and a third resistor. The first end of the third capacitor is electrically connected to the cathode of the first Zener diode and the first end of the third resistor, respectively. The second end of the third capacitor is electrically connected to the second end of the third resistor and the power supply.

8. The overvoltage protection circuit according to claim 1, characterized in that, The voltage divider unit includes a fourth resistor and a fifth resistor. The first end of the fourth resistor serves as the first end of the voltage divider unit and is electrically connected to the power supply and the first end of the charging / discharging unit, respectively. The second end of the fourth resistor serves as the second end of the voltage divider unit and is electrically connected to the first end of the fifth resistor, the discharge switch unit, and the second end of the charging / discharging unit, respectively. The second end of the fifth resistor is electrically connected to the second switch unit.

9. The overvoltage protection circuit according to claim 1, characterized in that, The second switching unit includes a third switching transistor, the drain of which is electrically connected to the voltage divider unit, the gate of which is electrically connected to the first switching control unit and the first switching unit, and the source of which is grounded.

10. An electronic device, characterized in that, Includes the overvoltage protection circuit as described in any one of claims 1-9.

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