An overvoltage protection circuit for a high voltage circuit
By combining a voltage detection module, a reference voltage acquisition module, and a shunt module, the overvoltage protection problem of high-voltage and ultra-high-voltage circuits is solved, achieving reliable protection for high-voltage circuits and avoiding damage and insufficient accuracy of traditional devices.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- CETC XIAN NAVIGATION TECH CO LTD
- Filing Date
- 2025-09-17
- Publication Date
- 2026-08-04
AI Technical Summary
In the existing technology, overvoltage protection devices for high-voltage and ultra-high-voltage circuits are difficult to adapt to high-voltage environments. They suffer from problems such as difficulty in finding the upper limit of the withstand voltage, high cost, easy damage, and low clamping accuracy, and cannot effectively protect downstream circuits.
The system employs a combination of a detection voltage acquisition module, a reference voltage acquisition module, an overvoltage detection module, and a current shunt module. Overvoltage protection is achieved through voltage division and comparison, while current shunt is performed using components such as operational amplifiers and transistors.
It achieves reliable overvoltage protection in high-voltage and ultra-high-voltage scenarios, avoids damage to traditional devices, improves clamping accuracy and protection effect, and adapts to long-term stable operation in high-voltage environments.
Smart Images
Figure CN224596153U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of overvoltage protection technology, and in particular to an overvoltage protection circuit for a high-voltage circuit. Background Technology
[0002] The output voltage of high-voltage and ultra-high-voltage circuits is highly susceptible to abnormal overvoltage phenomena due to various factors. For example, voltage fluctuations on the mains side and surge voltages caused by lightning strikes can cause the output voltage to spike instantaneously. Once this happens, precision components in downstream circuits (such as chips, sensors, and power modules) will be at risk of breakdown and damage, which may not only cause equipment shutdowns and production interruptions, but could even lead to serious safety accidents.
[0003] In existing technologies, overvoltage protection is typically achieved by connecting TVS diodes, varistors, and other protective devices in parallel on the busbar. When an overvoltage occurs in the circuit, these devices can quickly conduct, dissipating the overvoltage energy, thereby clamping the voltage and protecting downstream circuits.
[0004] However, these traditional protection devices are inadequate in high-voltage and ultra-high-voltage applications. Firstly, TVS diodes and varistors have upper limits on their withstand voltage. For ultra-high-voltage environments, it's difficult to find devices with suitable parameters, and even if they are found, their manufacturing processes are complex, significantly increasing costs. Secondly, under high-voltage and high-current conditions, these devices are subjected to enormous energy surges when turned on. Their limited current-carrying capacity makes them prone to burnout and unable to be reused multiple times, failing to meet the protection requirements for long-term stable operation of high-voltage and ultra-high-voltage circuits. Furthermore, their clamping voltage accuracy is relatively low; in high-voltage scenarios, they may not be able to accurately limit the voltage within a safe range, potentially posing a threat to downstream circuits.
[0005] Therefore, for high-voltage and ultra-high-voltage applications, there is an urgent need for a new overvoltage protection circuit that can adapt to the characteristics of high-voltage environments and has reliable protection performance. Utility Model Content
[0006] This application provides an overvoltage protection circuit for high-voltage circuits, which solves the technical problem that traditional overvoltage protection devices are difficult to apply in high-voltage and ultra-high-voltage scenarios, and realizes overvoltage protection for high-voltage circuits.
[0007] In a first aspect, embodiments of this application provide an overvoltage protection circuit for a high-voltage circuit, comprising: Voltage acquisition module, reference voltage acquisition module, overvoltage detection module, shunt module; The input terminals of the voltage detection module are electrically connected to the high-voltage bus and one end of the shunt module, respectively. The output terminal of the voltage detection module is electrically connected to one input terminal of the overvoltage detection module. The output terminal of the reference voltage acquisition module is electrically connected to the other input terminal of the overvoltage detection module. The output terminal of the overvoltage detection module is electrically connected to the other end of the shunt module. The voltage acquisition module is used to divide the input high-voltage bus voltage and output the detection voltage; The reference voltage acquisition module is used to output a reference voltage; The overvoltage detection module is used to compare the detected voltage with the reference voltage and output either a no-overvoltage signal or an overvoltage signal. The shunt module is used to shunt the current of the high-voltage bus according to the overvoltage signal to achieve overvoltage protection.
[0008] Furthermore, the detection voltage acquisition module includes: First resistor R1, third resistor R3; One end of the first resistor R1 is connected to the first high-voltage bus node Vo1, the second high-voltage bus node Vo2, and one end of the shunt module, respectively. The other end of the first resistor R1 is connected to one end of the third resistor R3 and one input terminal of the overvoltage detection module, respectively. The other end of the third resistor R3 is grounded.
[0009] Furthermore, the voltage detection acquisition module also includes: The third capacitor C3 is connected in parallel with the third resistor R3.
[0010] Furthermore, the reference voltage acquisition module includes: 12V regulated power supply, fifth resistor R5, eighth resistor R8; One end of the fifth resistor R5 is connected to a 12V regulated power source, and the other end of the fifth resistor R5 is connected to one end of the eighth resistor R8 and the other input terminal of the overvoltage detection module. The other end of the eighth resistor R8 is grounded.
[0011] Furthermore, the reference voltage acquisition module also includes: The fourth capacitor C4 is connected in parallel with the eighth resistor R8.
[0012] Furthermore, the overvoltage detection module includes: Ninth resistor R9, operational amplifier IC1, seventh resistor R7; One end of the ninth resistor R9 is connected to the output terminal of the detection voltage acquisition module, and the other end of the ninth resistor R9 is connected to the negative inverting input terminal of the operational amplifier IC1. The non-inverting input terminal of operational amplifier IC1 is connected to the reference voltage acquisition module, the output terminal of operational amplifier IC1 is connected to one end of the seventh resistor R7, and the other end of the seventh resistor R7 is connected to the other end of the shunt module.
[0013] Furthermore, the overvoltage detection module also includes: The tenth resistor is R10, the fifth capacitor is C5, and the sixth capacitor is C6; One end of the tenth resistor R10 is connected to the other end of the ninth resistor R9, the negative inverting input terminal of the operational amplifier IC1, and one end of the fifth capacitor C5. The other end of the tenth resistor R10 is connected to one end of the sixth capacitor C6. The other end of the sixth capacitor C6 is connected to the other end of the fifth capacitor C5, the output terminal of the operational amplifier IC1, and one end of the seventh resistor R7.
[0014] Furthermore, the traffic splitting module includes: First diode D1, fourth resistor R4, first transistor VT1, second resistor R2; One end of the second resistor R2 is connected to the first high-voltage bus node Vo1, the second high-voltage bus node Vo2, and the input terminal of the voltage detection module, respectively. One end of the fourth resistor R4 is connected to a 12V regulated power source, and the other end of the fourth resistor R4 is connected to the positive terminal of the first diode D1. The negative terminal of the first diode D1 is connected to the base of the first transistor VT1. The collector of the first transistor VT1 is connected to the other end of the second resistor R2. The emitter of the first transistor VT1 is connected to the output terminal of the overvoltage detection module.
[0015] Furthermore, the traffic splitting module also includes: The sixth resistor R6 and the second diode D2; One end of the sixth resistor R6 is connected to the negative terminal of the first diode D1 and the base of the first transistor VT1, respectively. The other end of the sixth resistor R6 is connected to the positive terminal of the second diode D2. The negative terminal of the second diode D2 is connected to the other end of the second resistor R2 and the collector of the first transistor VT1, respectively.
[0016] Furthermore, the overvoltage protection circuit of the high-voltage circuit also includes: First bus filter capacitor C1, second bus filter capacitor C2; One end of the first bus filter capacitor C1 is connected to the high-voltage bus, the input terminal of the voltage detection module, one end of the shunt module, and one end of the second bus filter capacitor C2. The other end of the first bus filter capacitor C1 is grounded, and the other end of the second bus filter capacitor C2 is grounded.
[0017] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages: This embodiment uses a voltage detection module to divide the input high-voltage bus voltage and output a detection voltage. A reference voltage acquisition module is used to output a reference voltage. An overvoltage detection module compares the detection voltage with the reference voltage and outputs either a no-overvoltage signal or an overvoltage signal. When a high-voltage bus overvoltage occurs, the shunt module shunts the current of the high-voltage bus according to the overvoltage signal. This solves the technical problem that traditional overvoltage protection devices are difficult to apply in high-voltage and ultra-high-voltage scenarios, and achieves overvoltage protection for high-voltage circuits. Attached Figure Description
[0018] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0019] Figure 1 A system block diagram of an overvoltage protection circuit for a high-voltage circuit provided in an embodiment of this application; Figure 2 This is a circuit diagram of an overvoltage protection circuit for a high-voltage circuit provided in an embodiment of this application; Figure 3 This is another circuit diagram of the overvoltage protection circuit of the high-voltage circuit provided in the embodiments of this application. Detailed Implementation
[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of the present utility model. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present utility model.
[0021] In the description of the embodiments of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing the embodiments of this utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. In addition, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this utility model can be understood according to the specific circumstances.
[0022] The output voltage of high-voltage and ultra-high-voltage circuits is highly susceptible to abnormal overvoltage phenomena due to various factors. For example, voltage fluctuations on the mains side and surge voltages caused by lightning strikes can cause the output voltage to spike instantaneously. Once this happens, precision components in downstream circuits (such as chips, sensors, and power modules) will be at risk of breakdown and damage, which may not only cause equipment shutdowns and production interruptions, but could even lead to serious safety accidents.
[0023] In existing technologies, overvoltage protection is typically achieved by connecting TVS diodes, varistors, and other protective devices in parallel on the busbar. When an overvoltage occurs in the circuit, these devices can quickly conduct, dissipating the overvoltage energy, thereby clamping the voltage and protecting downstream circuits.
[0024] However, these traditional protection devices are inadequate in high-voltage and ultra-high-voltage applications. Firstly, TVS diodes and varistors have upper limits on their withstand voltage. For ultra-high-voltage environments, it's difficult to find devices with suitable parameters, and even if they are found, their manufacturing processes are complex, significantly increasing costs. Secondly, under high-voltage and high-current conditions, these devices are subjected to enormous energy surges when turned on. Their limited current-carrying capacity makes them prone to burnout and unable to be reused multiple times, failing to meet the protection requirements for long-term stable operation of high-voltage and ultra-high-voltage circuits. Furthermore, their clamping voltage accuracy is relatively low; in high-voltage scenarios, they may not be able to accurately limit the voltage within a safe range, potentially posing a threat to downstream circuits.
[0025] Therefore, for high-voltage and ultra-high-voltage applications, there is an urgent need for a new overvoltage protection circuit that can adapt to the characteristics of high-voltage environments and has reliable protection performance.
[0026] Against this background, this disclosure provides an overvoltage protection circuit for high-voltage circuits, which can realize overvoltage protection for high-voltage circuits.
[0027] The overvoltage protection circuit of this high-voltage circuit will be described below with reference to the accompanying drawings.
[0028] Figure 1 This is a system block diagram of an overvoltage protection circuit for a high-voltage circuit provided in an embodiment of this application. (See diagram below.) Figure 1 As shown, the overvoltage protection circuit of this high-voltage circuit may include: Voltage acquisition module 110, reference voltage acquisition module 120, overvoltage detection module 130, and shunt module 140; The input terminal of the voltage detection module 110 is electrically connected to one end of the high voltage bus 100 and the shunt module 140, respectively. The output terminal of the voltage detection module 110 is electrically connected to one input terminal of the overvoltage detection module 130. The output terminal of the reference voltage acquisition module 120 is electrically connected to the other input terminal of the overvoltage detection module 130. The output terminal of the overvoltage detection module 130 is electrically connected to the other end of the shunt module 140. The voltage detection module 110 is used to divide the input high-voltage bus 110 voltage and output the detection voltage; The reference voltage acquisition module 120 is used to output a reference voltage; The overvoltage detection module 130 is used to compare the detected voltage with the reference voltage and output a no-overvoltage signal or an overvoltage signal. The shunt module 140 is used to shunt the current of the high-voltage bus 100 according to the overvoltage signal to achieve overvoltage protection.
[0029] It is understandable that when the detected voltage is greater than the reference voltage, the overvoltage detection module outputs an overvoltage signal; when the detected voltage is less than the reference voltage, the overvoltage detection module outputs a no-overvoltage signal.
[0030] This embodiment uses a voltage detection module to divide the input high-voltage bus voltage and output a detection voltage. A reference voltage acquisition module is used to output a reference voltage. An overvoltage detection module compares the detection voltage with the reference voltage and outputs either a no-overvoltage signal or an overvoltage signal. When a high-voltage bus overvoltage occurs, the shunt module shunts the current of the high-voltage bus according to the overvoltage signal. This solves the technical problem that traditional overvoltage protection devices are difficult to apply in high-voltage and ultra-high-voltage scenarios, and achieves overvoltage protection for high-voltage circuits.
[0031] Figure 2 This is a circuit diagram of an overvoltage protection circuit for a high-voltage circuit provided in an embodiment of this application. (Reference) Figure 2 Specifically, the voltage detection acquisition module includes: First resistor R1, third resistor R3; One end of the first resistor R1 is connected to the first high-voltage bus node Vo1, the second high-voltage bus node Vo2, and one end of the shunt module, respectively. The other end of the first resistor R1 is connected to one end of the third resistor R3 and one input terminal of the overvoltage detection module, respectively. The other end of the third resistor R3 is grounded.
[0032] Figure 3 This is another circuit diagram of the overvoltage protection circuit for the high-voltage circuit provided in the embodiments of this application. (Reference) Figure 3 In some possible embodiments, the detection voltage acquisition module further includes: The third capacitor C3 is connected in parallel with the third resistor R3.
[0033] In this embodiment, the voltage after voltage division by the first resistor R1 and the third resistor R3 is filtered by the third capacitor C3, so that the voltage at one input terminal of the overvoltage detection module is more stable, thereby improving the accuracy of the overvoltage detection module.
[0034] refer to Figure 2 Specifically, the reference voltage acquisition module includes: 12V regulated power supply, fifth resistor R5, eighth resistor R8; One end of the fifth resistor R5 is connected to a 12V regulated power source, and the other end of the fifth resistor R5 is connected to one end of the eighth resistor R8 and the other input terminal of the overvoltage detection module. The other end of the eighth resistor R8 is grounded.
[0035] refer to Figure 3 In some possible embodiments, the reference voltage acquisition module further includes: The fourth capacitor C4 is connected in parallel with the eighth resistor R8.
[0036] In this embodiment, the reference voltage obtained by voltage division of the fifth resistor R5 and the eighth resistor R8 is filtered by the fourth capacitor C4, so that the voltage at the other input terminal of the overvoltage detection module is more stable, thereby improving the judgment accuracy of the overvoltage detection module.
[0037] refer to Figure 2 Specifically, the overvoltage detection module includes: Ninth resistor R9, operational amplifier IC1, seventh resistor R7; One end of the ninth resistor R9 is connected to the output terminal of the detection voltage acquisition module, and the other end of the ninth resistor R9 is connected to the negative inverting input terminal of the operational amplifier IC1. The non-inverting input terminal of operational amplifier IC1 is connected to the reference voltage acquisition module, the output terminal of operational amplifier IC1 is connected to one end of the seventh resistor R7, and the other end of the seventh resistor R7 is connected to the other end of the shunt module.
[0038] refer to Figure 3 In some possible embodiments, the overvoltage detection module further includes: The tenth resistor is R10, the fifth capacitor is C5, and the sixth capacitor is C6; One end of the tenth resistor R10 is connected to the other end of the ninth resistor R9, the negative inverting input terminal of the operational amplifier IC1, and one end of the fifth capacitor C5. The other end of the tenth resistor R10 is connected to one end of the sixth capacitor C6. The other end of the sixth capacitor C6 is connected to the other end of the fifth capacitor C5, the output terminal of the operational amplifier IC1, and one end of the seventh resistor R7.
[0039] In this embodiment, the rise / fall rate of the operational amplifier IC1 is adjusted by the tenth resistor R10, the fifth capacitor C5, and the sixth capacitor C6 to avoid oscillation or excessively fast / slow response, thereby optimizing the dynamic response characteristics of the operational amplifier IC1.
[0040] refer to Figure 2 Specifically, the traffic splitting module includes: First diode D1, fourth resistor R4, first transistor VT1, second resistor R2; One end of the second resistor R2 is connected to the first high-voltage bus node Vo1, the second high-voltage bus node Vo2, and the input terminal of the voltage detection module, respectively. One end of the fourth resistor R4 is connected to a 12V regulated power source, and the other end of the fourth resistor R4 is connected to the positive terminal of the first diode D1. The negative terminal of the first diode D1 is connected to the base of the first transistor VT1. The collector of the first transistor VT1 is connected to the other end of the second resistor R2. The emitter of the first transistor VT1 is connected to the output terminal of the overvoltage detection module.
[0041] refer to Figure 3 In some possible embodiments, the traffic splitting module further includes: The sixth resistor R6 and the second diode D2; One end of the sixth resistor R6 is connected to the negative terminal of the first diode D1 and the base of the first transistor VT1, respectively. The other end of the sixth resistor R6 is connected to the positive terminal of the second diode D2. The negative terminal of the second diode D2 is connected to the other end of the second resistor R2 and the collector of the first transistor VT1, respectively.
[0042] In this embodiment, the sixth resistor R6 and the second diode D2 are used as auxiliary voltage regulator circuits to further stabilize the base voltage of the first transistor VT1, ensuring that the conduction state of the first transistor VT1 is only controlled by the output signal of the operational amplifier IC1, and avoiding abnormal rise in the base voltage of the first transistor VT1 (such as fluctuation of the 12V voltage regulator or external interference) which would cause reverse breakdown between the base and emitter of the first transistor VT1.
[0043] refer to Figure 3 In some possible embodiments, the overvoltage protection circuit of the high-voltage circuit further includes: First bus filter capacitor C1, second bus filter capacitor C2; One end of the first bus filter capacitor C1 is connected to the high-voltage bus, the input terminal of the voltage detection module, one end of the shunt module, and one end of the second bus filter capacitor C2. The other end of the first bus filter capacitor C1 is grounded, and the other end of the second bus filter capacitor C2 is grounded.
[0044] In this embodiment, the first bus filter capacitor C1 and the second bus filter capacitor C2 are used as filter capacitors for the high-voltage bus, which can filter out the ripple in the voltage of the high-voltage bus, making the bus voltage more stable and avoiding interference from the bus ripple with the subsequent operation of the overvoltage protection circuit.
[0045] The overvoltage protection circuit of the high-voltage circuit in this application is illustrated below with a complete example. (Reference) Figure 3 The overall circuit of the overvoltage protection circuit of this high-voltage circuit is as follows: One end of the first bus filter capacitor C1 is connected to the first high-voltage bus node Vo1, one end of the first resistor R1, one end of the second resistor R2, one end of the second bus filter capacitor C2, and the second high-voltage bus node Vo2. The other end of the first bus filter capacitor C1 is grounded, and the other end of the second bus filter capacitor C2 is grounded. The other end of the first resistor R1 is connected to one end of the third resistor R3, one end of the third capacitor C3, and one end of the ninth resistor R9. The other ends of the third resistor R3 and the third capacitor C3 are both grounded. The other end of the ninth resistor R9 is connected to one end of the tenth resistor R10, one end of the fifth capacitor C5, and the inverting input of the operational amplifier IC1. The other end of the tenth resistor R10 is connected to one end of the sixth capacitor C6. The non-inverting input of operational amplifier IC1 is connected to one end of the fifth resistor R5, one end of the fourth capacitor C4, and one end of the eighth resistor R8. The other end of the fifth resistor R5 is connected to a 12V regulated power supply. The other ends of the fourth capacitor C4 and the eighth resistor R8 are both grounded. The positive power supply of operational amplifier IC1 is connected to a 12V regulated power supply, and the negative power supply of operational amplifier IC1 is grounded. The output of operational amplifier IC1 is connected to one end of the seventh resistor R7, the other end of the fifth capacitor C5, and the other end of the sixth capacitor C6. The other end of the seventh resistor R7 is connected to the emitter of the first transistor VT1; the base of the first transistor VT1 is connected to one end of the sixth resistor R6 and the cathode of the first diode D1, the anode of the first diode D1 is connected to one end of the fourth resistor R4, and the other end of the fourth resistor R4 is connected to a 12V regulated power supply; the other end of the sixth resistor R6 is connected to the anode of the second diode D2, and the cathode of the second diode D2 is connected to the collector of the first transistor VT1 and the other end of the second resistor R2.
[0046] In this embodiment, when a high-voltage bus overvoltage occurs, the voltage at the voltage divider node of the first resistor R1 and the third resistor R3 will increase. This causes the input voltage at the inverting input of operational amplifier IC1 to be greater than the voltage divided by the fifth resistor R5 and the eighth resistor R8 at the non-inverting input of the 12V regulated power supply. This results in a decrease in the output voltage of operational amplifier IC1, which in turn lowers the emitter voltage of the first transistor VT1. Meanwhile, the base voltage of the first transistor VT1 remains stable under the 12V regulated power supply, the fourth resistor R4, and the first diode D1. Therefore, the voltage difference between the base and emitter voltages of the first transistor VT1 will increase, thereby enhancing the conduction of the first transistor VT1 and increasing the base and emitter currents. At this time, the second resistor R2 diverts the current from the high-voltage bus, reducing the current flowing to the purely resistive load. For a purely resistive load, V = I × R. The decrease in load current will cause the voltage across the load to drop, thus achieving overvoltage protection for the high-voltage bus.
[0047] It can be understood that the first high-voltage bus node Vo1 and the second high-voltage bus node Vo2 represent different locations on the same high-voltage bus; the positive power supply terminal of the operational amplifier IC1 is connected to a 12V regulated power source, and the negative power supply terminal of the operational amplifier IC1 is grounded.
[0048] The first resistor R1 and the third resistor R3 form a voltage divider circuit, which is used to reduce the voltage of the high-voltage bus proportionally and transmit it as the detection voltage to the negative input terminal of the operational amplifier IC1.
[0049] The fifth resistor R5 and the eighth resistor R8 are used to divide the voltage from the 12V regulated source to obtain a stable reference voltage, which is then input to the non-inverting input of the operational amplifier IC1 as a comparison standard for "overvoltage".
[0050] Operational amplifier IC1 acts as a voltage comparator, used to reduce the output voltage and trigger subsequent protection actions when the negative terminal voltage (detection voltage) is higher than the positive terminal voltage (reference voltage).
[0051] The first transistor VT1 is used to increase the conduction degree of the first transistor VT1 when the output of the first transistor VT1 decreases, thereby shunting the high-voltage bus current.
[0052] The second resistor R2 is used to shunt the high-voltage bus current through the second resistor R2 and the first transistor VT1 when the first transistor VT1 is turned on, thereby reducing the load current.
[0053] The fourth resistor R4 and the first diode D1 are used to ensure the stability of the base voltage of the first transistor VT1, so that the conduction degree of the first transistor VT1 can be adjusted according to the change of the emitter voltage.
[0054] The ninth resistor R9 is used to transmit the "overvoltage detection signal" after the voltage divider of the first resistor R1 and the third resistor R3 to the negative input terminal of the operational amplifier IC1. At the same time, it limits the current flowing into the operational amplifier IC1, protects the input pins of the operational amplifier IC1, and prevents the current of the voltage divider circuit from being too large and damaging the operational amplifier IC1.
[0055] The seventh resistor, R7, is used to transmit the output of operational amplifier IC1 to the emitter of the first transistor VT1, adjusting the emitter voltage of VT1 and limiting the current flowing from the output of operational amplifier IC1 to the emitter of VT1. This prevents damage to the operational amplifier due to overcurrent (the operational amplifier's output current capability is limited, typically only in the mA range, while the emitter current of VT1 may be large. If the seventh resistor, R7, is removed, the output of operational amplifier IC1 will be directly connected to the emitter of VT1; in this case, the emitter current of VT1 will be directly provided by the operational amplifier's output, far exceeding the operational amplifier's maximum output current capability, inevitably leading to the burnout of operational amplifier IC1). It also reduces the interference of VT1 emitter current fluctuations on the output of operational amplifier IC1, ensuring stable operation of operational amplifier IC1.
[0056] The functions and beneficial effects of other components in this embodiment can be referred to in the foregoing embodiments, and will not be repeated here.
[0057] The various embodiments in this specification are described in a progressive manner. For the same or similar parts between the various embodiments, please refer to each other. Each embodiment focuses on describing the differences from other embodiments.
[0058] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit this application. 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 or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of this application.
Claims
1. An overvoltage protection circuit for a high-voltage circuit, characterized in that, include: Voltage acquisition module, reference voltage acquisition module, overvoltage detection module, shunt module; The input terminals of the voltage detection module are electrically connected to the high-voltage bus and one end of the shunt module, respectively. The output terminal of the voltage detection module is electrically connected to one input terminal of the overvoltage detection module. The output terminal of the reference voltage acquisition module is electrically connected to the other input terminal of the overvoltage detection module. The output terminal of the overvoltage detection module is electrically connected to the other end of the shunt module. The voltage acquisition module is used to divide the input high-voltage bus voltage and output the detection voltage; The reference voltage acquisition module is used to output a reference voltage; The overvoltage detection module is used to compare the detected voltage with the reference voltage and output either a no-overvoltage signal or an overvoltage signal. The shunt module is used to shunt the current of the high-voltage bus according to the overvoltage signal to achieve overvoltage protection.
2. The overvoltage protection circuit for a high-voltage circuit according to claim 1, characterized in that, The voltage detection acquisition module includes: First resistor R1, third resistor R3; One end of the first resistor R1 is connected to the first high-voltage bus node Vo1, the second high-voltage bus node Vo2, and one end of the shunt module, respectively. The other end of the first resistor R1 is connected to one end of the third resistor R3 and one input terminal of the overvoltage detection module, respectively. The other end of the third resistor R3 is grounded.
3. The overvoltage protection circuit for a high-voltage circuit according to claim 2, characterized in that, The voltage detection acquisition module further includes: The third capacitor C3 is connected in parallel with the third resistor R3.
4. The overvoltage protection circuit for a high-voltage circuit according to claim 1, characterized in that, The reference voltage acquisition module includes: 12V regulated power supply, fifth resistor R5, eighth resistor R8; One end of the fifth resistor R5 is connected to a 12V regulated power source, and the other end of the fifth resistor R5 is connected to one end of the eighth resistor R8 and the other input terminal of the overvoltage detection module. The other end of the eighth resistor R8 is grounded.
5. The overvoltage protection circuit for a high-voltage circuit according to claim 4, characterized in that, The reference voltage acquisition module further includes: The fourth capacitor C4 is connected in parallel with the eighth resistor R8.
6. The overvoltage protection circuit for a high-voltage circuit according to claim 1, characterized in that, The overvoltage detection module includes: Ninth resistor R9, operational amplifier IC1, seventh resistor R7; One end of the ninth resistor R9 is connected to the output terminal of the detection voltage acquisition module, and the other end of the ninth resistor R9 is connected to the negative inverting input terminal of the operational amplifier IC1. The non-inverting input terminal of operational amplifier IC1 is connected to the reference voltage acquisition module, the output terminal of operational amplifier IC1 is connected to one end of the seventh resistor R7, and the other end of the seventh resistor R7 is connected to the other end of the shunt module.
7. The overvoltage protection circuit for a high-voltage circuit according to claim 6, characterized in that, The overvoltage detection module also includes: The tenth resistor is R10, the fifth capacitor is C5, and the sixth capacitor is C6; One end of the tenth resistor R10 is connected to the other end of the ninth resistor R9, the negative inverting input terminal of the operational amplifier IC1, and one end of the fifth capacitor C5. The other end of the tenth resistor R10 is connected to one end of the sixth capacitor C6. The other end of the sixth capacitor C6 is connected to the other end of the fifth capacitor C5, the output terminal of the operational amplifier IC1, and one end of the seventh resistor R7.
8. The overvoltage protection circuit for a high-voltage circuit according to claim 1, characterized in that, The traffic splitting module includes: First diode D1, fourth resistor R4, first transistor VT1, second resistor R2; One end of the second resistor R2 is connected to the first high-voltage bus node Vo1, the second high-voltage bus node Vo2, and the input terminal of the voltage detection module, respectively. One end of the fourth resistor R4 is connected to a 12V regulated power source, and the other end of the fourth resistor R4 is connected to the positive terminal of the first diode D1. The negative terminal of the first diode D1 is connected to the base of the first transistor VT1. The collector of the first transistor VT1 is connected to the other end of the second resistor R2. The emitter of the first transistor VT1 is connected to the output terminal of the overvoltage detection module.
9. The overvoltage protection circuit for a high-voltage circuit according to claim 8, characterized in that, The traffic splitting module also includes: The sixth resistor R6 and the second diode D2; One end of the sixth resistor R6 is connected to the negative terminal of the first diode D1 and the base of the first transistor VT1, respectively. The other end of the sixth resistor R6 is connected to the positive terminal of the second diode D2. The negative terminal of the second diode D2 is connected to the other end of the second resistor R2 and the collector of the first transistor VT1, respectively.
10. The overvoltage protection circuit for a high-voltage circuit according to claim 1, characterized in that, The overvoltage protection circuit of the high-voltage circuit also includes: First bus filter capacitor C1, second bus filter capacitor C2; One end of the first bus filter capacitor C1 is connected to the high-voltage bus, the input terminal of the voltage detection module, one end of the shunt module, and one end of the second bus filter capacitor C2. The other end of the first bus filter capacitor C1 is grounded, and the other end of the second bus filter capacitor C2 is grounded.