An overvoltage protection circuit, device and apparatus

Abstract

The present disclosure relates to an overvoltage protection circuit, device and equipment, the overvoltage protection circuit comprising: an overvoltage detection module, a pull-up module and a protection switch module.The overvoltage detection module comprises a reference source and a first voltage dividing unit; the input end of the first voltage dividing unit is connected with a voltage terminal to be detected, and the output end of the first voltage dividing unit is connected with the voltage acquisition end of the reference source; the low-voltage side of the protection switch module is connected between the second end of the pull-up module and the ground end, and the high-voltage side of the protection switch module is connected between the second power supply signal end and the electrical equipment; the reference source is used to conduct in the case that the first voltage dividing voltage output by the first voltage dividing unit is greater than the preset reference voltage, so as to pull down the voltage of the low-voltage side of the protection switch module; the protection switch module is used to disconnect the high-voltage side in the case that the voltage of the low-voltage side is lower than the conduction threshold value.The present disclosure can improve the reference voltage stability of the reference source, and make the overvoltage protection circuit compatible with any type of reference source.

Description

Technical Field

[0001] This disclosure relates to the field of circuit protection technology, and in particular to an overvoltage protection circuit, device, and equipment. Background Technology

[0002] The TL431 is a three-terminal adjustable parallel voltage regulator, a precision adjustable reference source that meets specified thermal stability requirements within automotive, commercial, and military temperature ranges. The TL431 is commonly used in overvoltage protection circuits. However, in conventional techniques, adjusting the TL431 reference voltage is difficult, and replacing the TL431 in an overvoltage protection circuit with any 431 precision reference source requires adjusting the hardware parameters of the overvoltage protection circuit, resulting in poor compatibility between the overvoltage protection circuit and the reference source. Therefore, improving the stability of the reference voltage and ensuring compatibility of the overvoltage protection circuit with any type of reference source are technical problems that urgently need to be solved by those skilled in the art. Utility Model Content

[0003] To solve the above-mentioned technical problems, or at least partially solve them, this disclosure provides an overvoltage protection circuit, device, and equipment that can improve the reference voltage stability of a reference source and make the overvoltage protection circuit compatible with any type of reference source.

[0004] This disclosure provides an overvoltage protection circuit, including: an overvoltage detection module, a pull-up module, and a protection switch module. The overvoltage detection module includes a reference source and a first voltage divider unit; the input terminal of the first voltage divider unit is connected to the voltage to be measured, and the output terminal of the first voltage divider unit is connected to the voltage acquisition terminal of the reference source; the first terminal of the pull-up module is connected to a first power signal terminal, and the second terminal of the pull-up module is connected to a ground terminal through the reference source; the low-voltage side of the protection switch module is connected between the second terminal of the pull-up module and the ground terminal, and the high-voltage side of the protection switch module is connected between a second power signal terminal and the electrical equipment; wherein, the voltage division ratio of the first voltage divider unit is adjustable, and the reference source is used to conduct when the first voltage divided by the first voltage divider unit is greater than a preset reference voltage, so as to pull down the voltage on the low-voltage side of the protection switch module; the protection switch module is used to disconnect the high-voltage side when the voltage on the low-voltage side is lower than the conduction threshold.

[0005] Optionally, the first voltage divider unit includes a first voltage divider resistor and a second voltage divider resistor; the first end of the first voltage divider resistor is connected to the voltage to be measured, the second end of the first voltage divider resistor is connected to the first end of the second voltage divider resistor and the voltage acquisition terminal of the reference source, and the second end of the second voltage divider resistor is grounded; wherein, the reference source is used to acquire the voltage divided by the second voltage divider resistor.

[0006] Optionally, both the first and second voltage divider resistors are adjustable resistors.

[0007] Optionally, the protection switch module includes: a first terminal of the first protection unit connected to a second terminal of the pull-up module; a first terminal of the first switch unit connected to a second terminal of the first protection unit, and the second and fourth terminals of the first switch unit grounded; the first switch unit is used to disconnect the third and fourth terminals when the voltage at both terminals is less than the first switch threshold voltage; a first terminal of the second switch unit connected to a second power signal terminal, and a second terminal of the second switch unit connected to the third terminal of the first switch unit; wherein, the second switch unit is used to cut off the power supply to the electrical equipment when the first switch unit is disconnected.

[0008] Optionally, the first protection unit includes a protection resistor; the first end of the protection resistor is connected to the second end of the pull-up module, and the second end of the protection resistor is connected to the first end of the first switching unit.

[0009] Optionally, the first protection unit also includes at least one diode; the positive terminal of the diode is electrically connected to the second terminal of the pull-up module, and the negative terminal of the diode is electrically connected to the first terminal of the protection resistor.

[0010] Optionally, the first switching unit includes an optocoupler; the first end of the optocoupler is connected to the second end of the first protection unit, the second end and the fourth end of the optocoupler are grounded, and the third end of the optocoupler is connected to the second end of the second switching unit.

[0011] Optionally, the second switching unit includes a relay; the first terminal of the relay is connected to the ground terminal, the second terminal of the relay is connected to the third terminal of the first switching unit, and the third terminal and the fourth terminal of the relay are respectively connected to the power supply terminal and the ground terminal of the electrical equipment; the relay is used to cut off the power supply to the electrical equipment when the first switching unit is open.

[0012] This disclosure also provides an overvoltage protection device, including any of the overvoltage protection circuits described above.

[0013] This disclosure also provides an overvoltage protection device, including electrical equipment and the overvoltage protection device as described above.

[0014] This disclosure provides an overvoltage protection circuit, device, and equipment. The overvoltage protection circuit includes an overvoltage detection module, a pull-up module, and a protection switch module. The overvoltage detection module includes a reference source and a first voltage divider unit. Under normal operating conditions, the resistance value of the first voltage divider unit is adjusted to change its voltage division ratio, ensuring that the voltage acquired by the reference source is less than or equal to its reference voltage value. In this state, the reference source remains in normal operation. When the equipment experiences overvoltage, the hardware parameters of the first voltage divider unit remain unchanged, but the first voltage division voltage acquired by the reference source from the first voltage divider unit is greater than the reference voltage value. At this time, the reference source conducts, changing its internal resistance and altering the voltage division between the pull-up module and the reference source. This, in turn, changes the voltage division of the protection switch module on the low-voltage side. When the voltage on the low-voltage side of the protection switch module falls below the conduction threshold, the protection switch module disconnects the high-voltage side, thereby cutting off the connection between the second power signal terminal and the equipment, achieving overvoltage protection. This disclosure allows adjustment of the voltage division ratio of the first voltage divider unit by adjusting its resistance value, ensuring that the voltage acquired by the reference source is less than or equal to the reference voltage. Furthermore, the resistance value of the first voltage divider unit remains fixed after adjustment, thus maintaining its voltage division even when the operating voltage of the electrical equipment remains unchanged. This fixes and stabilizes the reference voltage of the reference source, allowing it to be directly replaced with other reference sources of the same voltage without further adjustment. For reference sources with different reference voltages, the internal resistance value of the first voltage divider unit can be adjusted directly. Therefore, the overvoltage protection circuit provided by this disclosure is compatible with any type of reference source. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application 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.

[0016] Figure 1 A circuit diagram of an overvoltage protection circuit provided for the prior art.

[0017] Figure 2 This is a schematic diagram of an overvoltage protection circuit provided in an embodiment of the present disclosure.

[0018] Figure 3 This is a schematic diagram of another overvoltage protection circuit provided in an embodiment of the present disclosure.

[0019] Figure 4This is a schematic diagram of another overvoltage protection circuit provided in an embodiment of the present disclosure.

[0020] Figure 5 This is a schematic diagram of a preferred overvoltage protection circuit provided in an embodiment of the present disclosure. Detailed Implementation

[0021] The features and exemplary embodiments of various aspects of this application will now be described in detail. Numerous specific details are set forth in the following detailed description in order to provide a comprehensive understanding of this application. However, it will be apparent to those skilled in the art that this application can be implemented without some of these specific details. The following description of embodiments is merely intended to provide a better understanding of this application by illustrating examples thereof.

[0022] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The embodiments will now be described in detail with reference to the accompanying drawings.

[0023] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0024] It should be understood that when describing the structure of a component, when referring to a layer or region as being "above" or "on top of" another layer or region, it can mean that it is directly above the other layer or region, or that it contains other layers or regions between it and the other layer or region. Furthermore, if the component is flipped over, that layer or region will be located "below" or "under" the other layer or region.

[0025] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0026] In the embodiments of this application, the term "electrical connection" can refer to a direct electrical connection between two components, or it can refer to an electrical connection between two components via one or more other components.

[0027] In the embodiments of this application, the first node, the second node, and the third node are defined only for the convenience of describing the circuit structure, and the first node, the second node, and the third node are not actual circuit units.

[0028] Various modifications and variations can be made to this application without departing from its spirit or scope, which will be apparent to those skilled in the art. Therefore, this application is intended to cover modifications and variations falling within the scope of the corresponding claims (the claimed technical solutions) and their equivalents. It should be noted that the implementation methods provided in the embodiments of this application can be combined with each other without contradiction.

[0029] The TL431 is a three-terminal adjustable parallel voltage regulator, a precision adjustable reference source that meets specified thermal stability requirements within automotive, commercial, and military temperature ranges. The TL431 is commonly used in overvoltage protection circuits. Figure 1 A circuit diagram of an overvoltage protection circuit provided for the prior art, such as... Figure 1 As shown, in conventional techniques, adjusting the voltage value acquired by the TL431 reference source requires simultaneously adjusting the resistance values ​​of the first resistor R01, the second resistor R02, and the third resistor R03, as well as the capacitance value of the first capacitor C01. Therefore, conventional techniques necessitate adjusting the hardware parameters of multiple electrical components to ensure that the voltage acquired by the TL431 reference source is less than or equal to the reference voltage value. This adjustment process makes it difficult to control the TL431's reference voltage. Furthermore, replacing the TL431 with a different model of reference source also requires readjusting the hardware parameters of multiple electrical components, making it difficult to ensure that the overvoltage protection circuit is compatible with any model of reference source.

[0030] To solve the above-mentioned technical problems, this disclosure provides an overvoltage protection circuit. Figure 2 This is a schematic diagram of an overvoltage protection circuit provided in an embodiment of the present disclosure, as shown below. Figure 2 As shown, the overvoltage protection circuit includes: an overvoltage detection module, a pull-up module 200, and a protection switch module 300.

[0031] The overvoltage detection module includes a reference source 110 and a first voltage divider unit 120; the input terminal of the first voltage divider unit 120 is connected to the voltage to be measured terminal 410, and the output terminal of the first voltage divider unit 120 is connected to the voltage acquisition terminal of the reference source 110.

[0032] The first end of the pull-up module 200 is connected to the first power signal terminal 510, and the second end of the pull-up module 200 is connected to the ground terminal through the reference source 110; The low-voltage side of the protection switch module 300 is connected between the second terminal of the pull-up module 200 and the ground terminal, and the high-voltage side of the protection switch module 300 is connected between the second power signal terminal 520 and the electrical equipment 400.

[0033] The voltage division ratio of the first voltage divider unit 120 is adjustable. The reference source 110 is used to turn on when the first voltage divider voltage output by the first voltage divider unit 120 is greater than a preset reference voltage, so as to pull down the voltage on the low-voltage side of the protection switch module 300. The protection switch module 300 is used to disconnect the high-voltage side when the voltage on the low-voltage side is lower than the conduction threshold. The voltage provided by the first power signal terminal is less than the voltage provided by the second power signal terminal.

[0034] Specifically, when the electrical equipment 400 is operating normally, the resistance value within the first voltage divider unit 120 is adjusted based on the reference voltage value of the reference source 110, thereby adjusting the voltage division ratio of the first voltage divider unit 120. This ensures that when the first voltage divider unit 120 receives the voltage provided by the electrical equipment 400 from the voltage under test terminal 410, it provides the reference source 110 with a first voltage divided by the voltage division ratio. This first voltage divided by the voltage division ratio is less than or equal to the reference voltage value of the reference source 110, and the reference source 110 remains in normal operating condition. However, when the electrical equipment 400 experiences overvoltage operation, the hardware parameters of the first voltage divider unit 120 do not change, so the voltage division ratio remains unchanged. However, because the voltage received by the voltage under test terminal 410 from the electrical equipment 400 increases, the first voltage divided by the voltage received by the reference source 110 increases and becomes greater than the reference voltage value of the reference source 110. At this time, the reference source 110 is turned on, and its internal resistance changes. This alters the voltage division between the pull-up module 200 and the reference source 110 based on the voltage provided by the first power signal terminal 510. Furthermore, the reference source 110 is connected in parallel with the low-voltage side of the protection switch module 300, thus changing the voltage on the low-voltage side of the protection switch module 300. When the voltage on the low-voltage side of the protection switch module 300 falls below the turn-on threshold, the protection switch module 300 disconnects the high-voltage side, thereby cutting off the connection between the second power signal terminal 520 and the electrical equipment 400, achieving overvoltage protection.

[0035] This disclosure allows adjustment of the voltage division ratio of the first voltage divider unit 120 by adjusting its resistance value. This ensures that the first voltage division voltage acquired by the voltage acquisition terminal of the reference source 110 is less than or equal to the reference voltage. Furthermore, since the resistance value of the first voltage divider unit 120 is fixed after adjustment, the voltage division ratio of the first voltage divider unit 120 will not change. Therefore, the first voltage division voltage acquired by the voltage acquisition terminal of the reference source 110 will not change if the operating voltage of the electrical equipment 400 remains unchanged. This achieves a fixed reference voltage for the reference source 110, stabilizing the reference voltage of the reference source 110. Consequently, other reference sources with the same reference voltage can be directly replaced without further adjustment of the reference voltage. For reference sources with different reference voltages, the internal resistance of the first voltage divider unit 120 can be adjusted directly during normal operation of the electrical equipment 400. This ensures that different reference sources, after being connected to the overvoltage protection circuit provided in this disclosure, can all meet the requirement that the voltage collected by the voltage acquisition terminal is lower than the reference voltage value under normal conditions. Therefore, the overvoltage protection circuit provided in this disclosure can be compatible with any type of reference source.

[0036] In some embodiments, Figure 3 A schematic diagram of another overvoltage protection circuit provided in this disclosure embodiment is shown below. Figure 3 As shown, the first voltage divider unit 120 includes a first voltage divider resistor R1 and a second voltage divider resistor R2.

[0037] The first end of the first voltage divider resistor R1 is connected to the voltage to be measured terminal 410. The second end of the first voltage divider resistor R1 is connected to the first end of the second voltage divider resistor R2 and the voltage acquisition terminal of the reference source 110. The second end of the second voltage divider resistor R2 is grounded. The reference source 110 is used to acquire the voltage divided by the second voltage divider resistor R2.

[0038] Specifically, when the electrical equipment 400 is operating normally, the resistance values ​​of the first voltage divider resistor R1 and the second voltage divider resistor R2 are adjusted according to the reference voltage value of the reference source 110. This adjusts the voltage division ratio between the first voltage divider resistor R1 and the second voltage divider resistor R2, so that when the voltage provided by the electrical equipment 400 is collected at the voltage terminal 410 to be measured, the voltage acquisition terminal of the reference source 110 collects the voltage divided by the second voltage divider resistor R2 according to the voltage division ratio. At this time, the voltage divided by the second voltage divider resistor R2 is less than or equal to the reference voltage value of the reference source 110, and the reference source 110 remains in normal operating condition. When the electrical equipment 400 operates under overvoltage conditions, since the resistance values ​​of the first voltage divider resistor R1 and the second voltage divider resistor R2 do not change, the voltage division ratio between the first voltage divider resistor R1 and the second voltage divider resistor R2 remains unchanged. However, because the voltage supplied by the electrical equipment 400 is increased at the voltage terminal 410 to be measured, the voltage division of both the first voltage divider resistor R1 and the second voltage divider resistor R2 increases. That is, the voltage division of the second voltage divider resistor R2 acquired by the voltage acquisition terminal of the reference source 110 increases and is greater than the reference voltage value of the reference source 110, causing the reference source 110 to conduct.

[0039] This disclosure allows adjustment of the voltage division ratio between the first voltage divider resistor R1 and the second voltage divider resistor R2 by adjusting their resistance values. This ensures that the first voltage division voltage acquired by the voltage acquisition terminal of the reference source 110 is less than or equal to the reference voltage. Furthermore, after adjustment, the resistance values ​​of the first and second voltage divider resistors R1 and R2 remain fixed, thus the voltage division ratio between them does not change. Consequently, the voltage division acquired by the voltage acquisition terminal of the reference source 110 remains unchanged unless the operating voltage of the electrical equipment 400 changes. This achieves a fixed reference voltage for the reference source 110, stabilizing its reference voltage. Consequently, other reference sources with the same reference voltage can be directly replaced without further adjustment of the reference voltage. For reference sources with different reference voltages, the resistance values ​​of the first voltage divider resistor R1 and the second voltage divider resistor R2 can be adjusted directly during the normal operation of the electrical equipment 400 to change the voltage division ratio between the first voltage divider resistor R1 and the second voltage divider resistor R2. Therefore, after different reference sources are connected to the overvoltage protection circuit provided in this disclosure, they can all meet the requirement that the voltage collected by the voltage acquisition terminal is lower than the reference voltage value under normal conditions. Thus, the overvoltage protection circuit provided in this disclosure can be compatible with any type of reference source.

[0040] In some embodiments, both the first voltage divider resistor and the second voltage divider resistor are precision resistors.

[0041] Specifically, both the first and second voltage divider resistors are precision resistors, which improves the accuracy of adjusting the resistance. This makes the voltage division ratio between the first and second voltage divider resistors more precise, and the voltage acquired by the reference source based on the voltage division ratio is also more accurate. This avoids the problem that the voltage acquired by the reference source exceeds the reference voltage value and conducts when the electrical equipment is operating normally due to errors in the voltage division ratio of the first and second voltage divider resistors, thus incorrectly cutting off the power supply to the electrical equipment.

[0042] In some embodiments, both the first voltage divider resistor and the second voltage divider resistor are adjustable resistors.

[0043] Specifically, both the first and second voltage divider resistors are adjustable resistors, allowing the overvoltage protection circuit to directly adjust the resistance values ​​of the first and second voltage divider resistors after replacing any type of reference source, without having to re-solder new voltage divider resistors, thereby further reducing the difficulty of adjusting the reference voltage.

[0044] In some embodiments, Figure 4 A schematic diagram of another overvoltage protection circuit provided in this disclosure embodiment is shown below. Figure 4 As shown, the protection switch module includes: a first protection unit 310, a first switch unit 320, and a second switch unit 330. The first terminal of the first protection unit 310 is connected to the second terminal of the pull-up module 200; the first terminal of the first switch unit 320 is connected to the second terminal of the first protection unit 310, and the second and fourth terminals of the first switch unit 320 are grounded; the first switch unit 320 is used to disconnect the third and fourth terminals when the voltage across its terminals is less than the first switch threshold voltage; the first terminal of the second switch unit 330 is connected to the second power signal terminal 520, and the second terminal of the second switch unit 330 is connected to the third terminal of the first switch unit 320; wherein, the second switch unit 330 is used to cut off the power supply to the electrical equipment 400 when the first switch unit 320 is disconnected.

[0045] Specifically, when the electrical equipment 400 experiences overvoltage operation, the hardware parameters of the first voltage divider unit 120 remain unchanged, therefore the voltage division ratio of the first voltage divider unit 120 remains constant. However, because the voltage supplied by the electrical equipment 400 is increased at the voltage measurement terminal 410, the first voltage division voltage measured by the voltage acquisition terminal of the reference source 110 increases and exceeds the reference voltage value of the reference source 110. At this time, the reference source 110 is turned on, and its internal resistance decreases, causing the voltage division ratio between the pull-up module 200 and the reference source 110 to change, resulting in a decrease in the voltage division of the reference source 110. Furthermore, the reference source 110 is connected in parallel with the first protection unit 310 and the first switch unit 320, which are connected in series. Therefore, the voltage across the first switch unit 320 will also decrease. When the voltage across the first switch unit 320 is less than the first switch threshold voltage, the first switch unit 320 will disconnect the third and fourth terminals, thereby cutting off the connection between the second terminal of the second switch unit 330 and the ground terminal, thus disconnecting the path within the second switch unit 330. This, in turn, causes the second switch unit 330 to disconnect the connection between the second power signal terminal 520 and the electrical equipment 400, thereby achieving overvoltage protection. Furthermore, when the internal resistance of the reference source 110 decreases and the voltage provided by the first power signal terminal 510 remains unchanged, the current flowing to the first switching unit 320 increases, posing a risk of overcurrent damage to the first switching unit 320. The first protection unit 310 can reduce the current flowing to the first switching unit 320, and by adjusting the voltage division ratio between the first switching unit 320 and the first protection unit 310, overcurrent protection for the first switching unit 320 can be achieved, while also ensuring that the first switching unit 320 can disconnect normally when an overvoltage fault occurs in the electrical equipment.

[0046] In some embodiments, see continue to see Figure 4 The first protection unit 310 includes a protection resistor R3; The first end of the protection resistor R3 is connected to the second end of the pull-up module 200, and the second end of the protection resistor R3 is connected to the first end of the first switching unit 320.

[0047] Specifically, when the electrical equipment 400 experiences overvoltage operation, the internal resistance of the reference source 110 decreases, while the voltage provided by the first power signal terminal 510 remains unchanged, causing the current flowing to the first switching unit 320 to increase. This disclosure sets a protection resistor R3 to adjust the current in the branch where the protection resistor R3 and the first switching unit 320 are located. Furthermore, by adjusting the resistance values ​​of the protection resistor R3 and the first switching unit 320, the voltage division ratio between the protection resistor R3 and the first switching unit 320 can be adjusted. This achieves overcurrent protection for the first switching unit 320 while also ensuring that the voltage division across the first switching unit 320 meets the disconnection condition when the electrical equipment experiences an overvoltage fault.

[0048] The aforementioned protective resistor R3 can be a single resistor or a combination of multiple resistors connected in series and parallel; there are no restrictions on this.

[0049] In some embodiments, the first protection unit further includes at least one diode; the positive terminal of the diode is electrically connected to the second terminal of the pull-up module, and the negative terminal of the diode is electrically connected to the first terminal of the protection resistor.

[0050] For example, taking a first protection unit comprising a first diode and a second diode, the positive terminal of the first diode is electrically connected to the second terminal of the pull-up module, the negative terminal of the first diode is connected to the positive terminal of the second diode, and the negative terminal of the second diode is electrically connected to the first terminal of the protection resistor. The voltage drop across the first and second diodes can be used to divide the voltage with the first switching unit. Furthermore, when an overcurrent fault occurs in the branch containing the first switching unit, if the branch current exceeds the maximum withstand current of the first and second diodes, the first and second diodes will disconnect, thereby preventing excessive branch current from damaging the first switching unit and achieving protection for the first switching unit.

[0051] In some embodiments, the first switching unit includes an optocoupler; a first end of the optocoupler is connected to a second end of the first protection unit, the second end and a fourth end of the optocoupler are grounded, and a third end of the optocoupler is connected to a second end of the second switching unit.

[0052] Specifically, under normal operating conditions, the voltage detected by the voltage detection terminal of the reference source is less than or equal to the reference voltage value. Therefore, the reference source is in normal operating condition, ensuring that the voltage division between the first and second terminals of the optocoupler meets the emission condition of the LED within the optocoupler. The third and fourth terminals of the optocoupler are conductive, and the second switching unit is also in a conductive state. When the electrical equipment experiences overvoltage operation, the voltage detected by the voltage detection terminal of the reference source exceeds the reference voltage value. At this time, the reference source conducts, and its internal resistance decreases, causing the voltage division between the first and second terminals of the optocoupler to decrease. This no longer meets the emission condition of the LED, causing the third and fourth terminals of the optocoupler to disconnect. This disconnects the connection between the second terminal of the second switching unit and the ground terminal, breaking the conductive path within the second switching unit. This, in turn, cuts off the connection between the second power signal terminal and the electrical equipment, achieving overvoltage protection.

[0053] In some embodiments, the second switching unit includes a relay; a first terminal of the relay is connected to a ground terminal, a second terminal of the relay is connected to a third terminal of the first switching unit, and the third terminal and a fourth terminal of the relay are respectively connected to the power supply terminal and the ground terminal of the electrical equipment; the relay is used to cut off the power supply to the electrical equipment when the first switching unit is disconnected.

[0054] Specifically, under normal operating conditions, the voltage detected by the voltage detection terminal of the reference source is less than or equal to the reference voltage value. Therefore, the reference source is in normal operating condition, and the third and fourth terminals of the first switching unit are conducting, as is the relay. When the electrical equipment experiences overvoltage, the voltage detected by the voltage detection terminal of the reference source exceeds the reference voltage value. At this time, the reference source conducts, and its internal resistance decreases, causing the voltage drop between the first and second terminals of the first switching unit to decrease. This does not meet the conduction condition of the first switching unit, causing the third and fourth terminals of the first switching unit to disconnect. This disconnects the connection between the second terminal of the relay and the ground terminal, breaking the conductive path within the relay and thus cutting off the connection between the second power signal terminal and the electrical equipment, achieving overvoltage protection.

[0055] In some embodiments, Figure 5 A schematic diagram of a preferred overvoltage protection circuit provided in this disclosure embodiment is shown below. Figure 5 As shown, the overvoltage protection circuit includes a reference source 110, a first voltage divider resistor R1, a second voltage divider resistor R2, a pull-up resistor R4, a first diode D1, a second diode D2, a protection resistor R3, an optocoupler U1, and a relay U2.

[0056] The first end of the first voltage divider resistor R1 is connected to the voltage to be measured terminal 410. The second end of the first voltage divider resistor R1 is connected to the first end of the second voltage divider resistor R2 and the voltage acquisition terminal of the reference source 110. The second end of the second voltage divider resistor R2 is grounded. The first end of the reference source 110 is connected to the first power signal terminal 510 through the pull-up resistor R4. The second end of the reference source 110 is grounded. The first end of the reference source 110 is connected to the positive terminal of the first diode D1. The negative terminal of the first diode D1 is connected to the positive terminal of the second diode D2. The negative terminal of the second diode is connected to the first end of the optocoupler U1 through the protection resistor R3. The second and fourth ends of the optocoupler U1 are grounded. The third end of the optocoupler U1 is connected to the second end of the relay U2. The first end of the relay U2 is connected to the second power signal terminal 520. The third and fourth ends of the relay U2 are respectively connected to the power supply terminal and the ground terminal of the electrical equipment 400.

[0057] For example, the reference source 110 can be, for instance, a TL431, with a reference voltage of 2.5V. Taking a first voltage divider resistor R1 with a resistance of 1KΩ, a second voltage divider resistor R2 with a resistance of 5KΩ, a first power signal terminal 510 providing 5V, and a pull-up resistor R4 with a resistance of 510Ω as an example, the voltage acquired by the voltage acquisition terminal of the reference source 110 is [5K / (1K+5K)]×Vin, where Vin is the voltage input to the voltage under test terminal 410. When the voltage acquired by the voltage acquisition terminal of the reference source 110 is greater than the reference voltage value, the cathode to anode of the reference source 110 is conductive, and the voltage division across the reference source 110 is 1.8V. When the voltage acquired by the voltage acquisition terminal of the reference source 110 is equal to the reference voltage value, the cathode to anode of the reference source 110 is not conductive, and the voltage division across the reference source 110 is 3.6V.

[0058] Under normal operating conditions of electrical equipment 400, the voltage acquired by the voltage acquisition terminal of the reference source 110 is equal to the reference voltage value. At this time, the voltage across the reference source 110 is 3.6V. Therefore, the voltage across the first diode D1, the second diode D2, the protective resistor R3, and the optocoupler U1 connected in series is also 3.6V. The voltage across the optocoupler U1 is 3.6V minus the voltage drop across the first diode D1 and the second diode D2, and then minus the voltage drop across the protective resistor R3. At this time, the voltage across the light-emitting diode of the optocoupler U1 meets the light-emitting condition, and the third and fourth terminals of the optocoupler U1 are conducting, and the relay U2 is in the conducting state.

[0059] When the electrical equipment 400 is operating under overvoltage conditions, the voltage acquired by the voltage acquisition terminal of the reference source 110 is greater than the reference voltage value. At this time, the voltage across the reference source 110 is 1.8V. Therefore, the voltage across the first diode D1, the second diode D2, the protective resistor R3, and the optocoupler U1 connected in series is also 1.8V. The voltage across the optocoupler U1 is 1.8V minus the voltage drop across the first diode D1 and the second diode D2, and then minus the voltage drop across the protective resistor R3. At this time, the voltage across the light-emitting diode of the optocoupler U1 does not meet the light-emitting condition. The third and fourth terminals of the optocoupler U1 are disconnected, which breaks the conductive path in the relay U2, thereby cutting off the connection between the second power signal terminal 520 and the electrical equipment 400, and realizing overvoltage protection.

[0060] This disclosure allows adjustment of the voltage division ratio between the first voltage divider resistor R1 and the second voltage divider resistor R2 by adjusting their resistance values. This ensures that the first voltage division voltage acquired by the voltage acquisition terminal of the reference source 110 is less than or equal to the reference voltage. Furthermore, after adjustment, the resistance values ​​of the first and second voltage divider resistors R1 and R2 remain fixed, thus the voltage division ratio between them does not change. Consequently, the voltage division acquired by the voltage acquisition terminal of the reference source 110 remains unchanged unless the operating voltage of the electrical equipment 400 changes. This achieves a fixed reference voltage for the reference source 110, stabilizing its reference voltage. Consequently, other reference sources with the same reference voltage can be directly replaced without further adjustment of the reference voltage. For reference sources with different reference voltages, the resistance values ​​of the first voltage divider resistor R1 and the second voltage divider resistor R2 can be adjusted directly during the normal operation of the electrical equipment 400 to change the voltage division ratio between the first voltage divider resistor R1 and the second voltage divider resistor R2. Therefore, after different reference sources are connected to the overvoltage protection circuit provided in this disclosure, they can all meet the requirement that the voltage collected by the voltage acquisition terminal is lower than the reference voltage value under normal conditions. Thus, the overvoltage protection circuit provided in this disclosure can be compatible with any type of reference source.

[0061] It should be noted that the reference source 110 can also be, for example, FW431, HJ431, XCA431, LN8402, etc., without specific limitations here.

[0062] This disclosure also provides an overvoltage protection device, including an overvoltage protection circuit as described in any of the above embodiments.

[0063] It is understood that the overvoltage protection device provided in this application embodiment can achieve the corresponding beneficial effects of the overvoltage protection circuit provided in the above embodiments, which will not be elaborated here.

[0064] This disclosure also provides an overvoltage protection device, including electrical equipment and an overvoltage protection device as described in the above embodiments.

[0065] It is understood that the overvoltage protection device provided in this application embodiment can achieve the corresponding beneficial effects of the overvoltage protection device provided in the above embodiments, which will not be elaborated here.

[0066] The above are merely specific embodiments of this disclosure, enabling those skilled in the art to understand or implement this disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not to be limited to these embodiments, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An overvoltage protection circuit, characterized in that, include: An overvoltage detection module includes a reference source and a first voltage divider unit; the input terminal of the first voltage divider unit is connected to the voltage to be measured, and the output terminal of the first voltage divider unit is connected to the voltage acquisition terminal of the reference source. A pull-up module, wherein a first end of the pull-up module is connected to a first power signal terminal, and a second end of the pull-up module is connected to a ground terminal through the reference source; A protection switch module, wherein the low-voltage side of the protection switch module is connected between the second terminal of the pull-up module and the ground terminal, and the high-voltage side of the protection switch module is connected between the second power signal terminal and the electrical equipment; The voltage division ratio of the first voltage divider unit is adjustable. The reference source is used to turn on when the first voltage division voltage output by the first voltage divider unit is greater than a preset reference voltage, so as to pull down the voltage on the low-voltage side of the protection switch module. The protection switch module is used to disconnect the high-voltage side when the voltage on the low-voltage side is lower than the conduction threshold.

2. The overvoltage protection circuit according to claim 1, characterized in that, The first voltage divider unit includes a first voltage divider resistor and a second voltage divider resistor; The first end of the first voltage divider resistor is connected to the voltage to be measured, the second end of the first voltage divider resistor is connected to the first end of the second voltage divider resistor and the voltage acquisition terminal of the reference source, and the second end of the second voltage divider resistor is grounded. The reference source is used to acquire the voltage division of the second voltage divider resistor.

3. The overvoltage protection circuit according to claim 2, characterized in that, Both the first voltage divider resistor and the second voltage divider resistor are adjustable resistors.

4. The overvoltage protection circuit according to claim 1, characterized in that, The protection switch module includes: The first protection unit, the first end of which is connected to the second end of the pull-up module; The first switching unit has a first terminal connected to the second terminal of the first protection unit, and the second and fourth terminals of the first switching unit are grounded; the first switching unit is used to disconnect the third and fourth terminals when the voltage at both terminals is less than the first switching threshold voltage. The second switching unit has a first end connected to a second power signal terminal and a second end connected to a third end of the first switching unit; wherein the second switching unit is used to cut off the power supply to the electrical equipment when the first switching unit is open.

5. The overvoltage protection circuit according to claim 4, characterized in that, The first protection unit includes a protection resistor; The first end of the protection resistor is connected to the second end of the pull-up module, and the second end of the protection resistor is connected to the first end of the first switching unit.

6. The overvoltage protection circuit according to claim 5, characterized in that, The first protection unit also includes at least one diode; The positive terminal of the diode is electrically connected to the second terminal of the pull-up module, and the negative terminal of the diode is electrically connected to the first terminal of the protection resistor.

7. The overvoltage protection circuit according to claim 4, characterized in that, The first switching unit includes an optocoupler; The first end of the optocoupler is connected to the second end of the first protection unit, the second end and the fourth end of the optocoupler are grounded, and the third end of the optocoupler is connected to the second end of the second switching unit.

8. The overvoltage protection circuit according to claim 4, characterized in that, The second switching unit includes a relay; The first terminal of the relay is connected to the ground terminal, the second terminal of the relay is connected to the third terminal of the first switching unit, and the third terminal and the fourth terminal of the relay are respectively connected to the power supply terminal and the ground terminal of the electrical equipment. The relay is used to cut off the power supply to the electrical equipment when the first switching unit is disconnected.

9. An overvoltage protection device, characterized in that, Includes the overvoltage protection circuit as described in any one of claims 1-8.

10. An overvoltage protection device, characterized in that, This includes electrical equipment and the overvoltage protection device as described in claim 9.

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