Overvoltage protection circuit and power equipment comprising same

Abstract

The utility model relates to the field of circuit protection, and provides an overvoltage protection circuit and power equipment comprising the same, the protection circuit comprises an input sub-circuit and a monitoring sub-circuit, the input sub-circuit is used for dividing the input voltage of the overvoltage protection circuit, the monitoring sub-circuit is connected with the input sub-circuit, and the input sub-circuit is connected with the monitoring sub-circuit. The monitoring sub-circuit comprises a triode, a three-terminal adjustable shunt voltage stabilizer, a first resistor, a second resistor, a third resistor and a filter capacitor, one end of the first resistor is connected with a collector of the triode, the other end of the first resistor is grounded, one end of the second resistor is connected with an emitter, the other end of the second resistor is connected with a base of the triode, and one end of the third resistor is connected with the base of the triode; the other end is connected with the cathode of the three-end adjustable parallel voltage stabilizer, and the anode of the three-end adjustable parallel voltage stabilizer is grounded. According to the invention, the input voltage can be monitored in real time, the response is quickly made when the voltage is abnormal, the input voltage is cut off or other protection measures are taken, and thus the safe operation of the circuit and equipment is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of circuit protection, in particular to an overvoltage protection circuit and a power device comprising the same. BACKGROUND

[0002] In electronic systems and devices, the stability and safety of voltage are key factors to ensure normal operation of the system. However, due to the instability of external power supply, the sudden change of load or the aging of internal components, etc., abnormal situations such as overvoltage, reverse voltage or overcurrent often occur in the circuit, which not only affects the normal work of the circuit, but also may cause permanent damage to the circuit components, and even cause fire accidents and other safety accidents.

[0003] The traditional overvoltage protection circuit usually adopts simple fuse, varistor or transient voltage suppressor, etc. These components can play a protective role to a certain extent, but they have the disadvantages of slow response speed and low protection accuracy. With the continuous development of electronic technology, people's requirements for circuit protection are also getting higher and higher, and the traditional protection method has been unable to meet the needs of modern electronic systems. CONTENT OF THE INVENTION

[0004] In order to help solve the problem of slow response speed and low protection accuracy of the existing overvoltage protection circuit, the present application provides an overvoltage protection circuit and a power device comprising the same.

[0005] In the first aspect, the present application provides an overvoltage protection circuit, which adopts the following technical scheme:

[0006] An overvoltage protection circuit, wherein the protection circuit comprises an input sub-circuit and a monitoring sub-circuit, the input sub-circuit is used for dividing the input voltage of the overvoltage protection circuit,

[0007] The monitoring sub-circuit is connected to the input sub-circuit, and the monitoring sub-circuit comprises a triode, a three-terminal adjustable shunt regulator, a first resistor, a second resistor, a third resistor and a filter capacitor, the emitter of the triode is used for connecting a DC voltage source, one end of the first resistor is connected to the collector of the triode, and the other end is grounded, one end of the second resistor is connected to the emitter, and the other end is connected to the base of the triode, one end of the third resistor is connected to the base of the triode, and the other end is connected to the cathode of the three-terminal adjustable shunt regulator, the anode of the three-terminal adjustable shunt regulator is grounded, one end of the filter capacitor is connected to the reference terminal of the three-terminal adjustable shunt regulator, and the other end is grounded, and the reference terminal is connected to the input sub-circuit,

[0008] The three-terminal adjustable shunt regulator is used for controlling the conduction and cut-off of the triode, the triode is used for outputting a change signal according to the three-terminal adjustable shunt regulator, the first resistor is used for adjusting the voltage of the collector, the second resistor and the third resistor are used for adjusting the voltage of the base, and the filter capacitor is used for filtering the input voltage.

[0009] By adopting the technical scheme, the input subcircuit divides the input voltage, the triode, the three-terminal adjustable shunt regulator and other elements in the monitoring subcircuit work together to monitor the voltage after voltage division. When the voltage exceeds the set threshold, the three-terminal adjustable shunt regulator controls the triode to conduct or cut off, thereby realizing the protection of the overvoltage. The protection circuit can monitor the input voltage in real time and quickly respond when the voltage is abnormal, thereby protecting the protection circuit from damage caused by overvoltage.

[0010] Preferably, the input subcircuit comprises a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor and an eighth resistor connected in series, the fourth resistor is used for connecting the input voltage, the output end of the sixth resistor is connected to the reference end, one end of the eighth resistor is connected to the seventh resistor, and the other end is grounded, and the input subcircuit is used for turning on the three-terminal adjustable shunt regulator.

[0011] By adopting the technical scheme, the input subcircuit is composed of a plurality of resistors connected in series to form a voltage dividing circuit. By reasonably selecting the resistance values of the resistors, accurate voltage division of the input voltage can be realized, thereby providing an accurate voltage signal for the monitoring subcircuit, and improving the accuracy and reliability of voltage monitoring, thereby ensuring that the protection circuit can correctly act when the voltage is abnormal.

[0012] Preferably, the resistance value of the fourth resistor is 475kΩ, the resistance value of the fifth resistor is 475kΩ, the resistance value of the sixth resistor is 33kΩ, the resistance value of the seventh resistor is 5.6kΩ, and the resistance value of the eighth resistor is 330Ω.

[0013] By adopting the technical scheme, the resistance values of the resistors in the input subcircuit are specifically given. The selection of these resistance values is based on the needs of circuit design to ensure that the output voltage of the voltage dividing circuit is within a suitable range. By accurately setting the resistance values, the output of the voltage dividing circuit is more stable, thereby improving the performance and reliability of the protection circuit.

[0014] Preferably, the protection circuit further comprises an output subcircuit connected to the monitoring subcircuit, the output subcircuit comprises a ninth resistor and a protection diode, the positive electrode of the protection diode is connected to the collector, the negative electrode of the protection diode is connected to the ninth resistor, the protection diode is used for isolating reverse voltage input into the monitoring subcircuit, and the ninth resistor is used for limiting the current passing through the output subcircuit.

[0015] By adopting the technical scheme, the protection diode and the ninth resistor in the output sub-circuit are used for isolating reverse voltage and limiting current. When the input voltage is reversed or the current is too large, the protection diode can quickly conduct to isolate the reverse voltage or the excessive current outside the monitoring sub-circuit, thereby protecting the circuit elements from damage, enhancing the reverse voltage and overcurrent protection capability of the protection circuit, and improving the safety and stability of the circuit.

[0016] Preferably, the protection circuit further comprises a control chip and a driving sub-circuit, the control chip has an input interface and an output interface, the input interface is connected to the output end of the ninth resistor, the output interface is connected to the driving sub-circuit, and the control chip is used to control the driving sub-circuit to cut off the input voltage according to the change signal.

[0017] By adopting the technical scheme, the control chip controls the driving sub-circuit to cut off the input voltage according to the change signal output by the monitoring sub-circuit. When an overvoltage is monitored, the control chip outputs a control signal, and the driving sub-circuit responds and cuts off the input voltage, thereby realizing intelligent overvoltage protection, automatically detecting and cutting off the overvoltage, and improving the automation degree and response speed of the protection circuit.

[0018] Preferably, the three-terminal adjustable shunt regulator is TL431, and the control chip is UC2854B.

[0019] By adopting the technical scheme, the model of the three-terminal adjustable shunt regulator and the control chip (TL431 and UC2854B) is specified. The selection of these two components is based on their stable performance, high reliability, and the ability to meet the design requirements of the circuit. By selecting high-performance components, the overall performance and reliability of the protection circuit are improved, ensuring stable operation of the circuit in harsh environments.

[0020] Preferably, the resistance value of the first resistor is 6.8kΩ, the resistance value of the second resistor is 1kΩ, the resistance value of the third resistor is 5.6kΩ, and the cathode of the three-terminal adjustable shunt regulator is used to control the voltage of the base of the triode.

[0021] By adopting the technical scheme, the specific resistance values of the resistors in the monitoring sub-circuit and the connection mode of the cathode of the three-terminal adjustable shunt regulator are given. These settings are to ensure that the triode can be correctly controlled during normal operation and overvoltage protection. By accurately setting the resistance values and reasonably connecting the circuit, the working stability and accuracy of the monitoring sub-circuit are improved, thereby enhancing the performance of the entire protection circuit.

[0022] In a second aspect, the application provides a power device, which adopts the following technical scheme:

[0023] The power device comprises the protection circuit according to any one of the first aspect.

[0024] By adopting the technical scheme, since the power device is internally provided with the high-performance protection circuit, the power device can quickly and accurately respond to abnormal conditions such as overvoltage, reverse voltage or overcurrent, and cut off or adjust the input voltage, thereby effectively preventing the abnormal conditions from damaging the power device. This greatly improves the safety and reliability of the power device.

[0025] In summary, the application realizes an efficient and reliable overvoltage protection circuit by reasonably designing the input sub-circuit, the monitoring sub-circuit and the output sub-circuit, and selecting high-performance components. The circuit can monitor the input voltage in real time and quickly respond when the voltage is abnormal, cutting off the input voltage or taking other protective measures, thereby ensuring the safe operation of the circuit and the device. In addition, the circuit also has reverse voltage and overcurrent protection capabilities, further improving the safety and stability of the circuit. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 FIG. 1 is a structural schematic diagram of an embodiment of an overvoltage protection circuit according to the application.

[0027] Reference signs: 1, driving sub-circuit; 2, output sub-circuit; 3, monitoring sub-circuit; 4, input sub-circuit. DETAILED DESCRIPTION

[0028] With reference to the drawings and specific embodiments, the structure, composition, characteristics and advantages of an overvoltage protection circuit according to the application and a power device comprising the same will be described below by way of example, however, all descriptions shall not be used to form any limitation on the application.

[0029] In addition, for any single technical feature described or implied in the embodiments mentioned herein, or any single technical feature shown or implied in the drawings, the application still allows any combination or deletion between these technical features (or their equivalents) to continue without any technical obstacles, so it should be considered that more embodiments according to the application are also within the scope of the description herein.

[0030] It should also be noted that the terms such as "provided" should be understood broadly, for example, it can be fixedly connected, or detachably connected, or integrated; it can be directly connected, or indirectly connected through an intermediate medium. Unless otherwise explicitly limited, the specific meaning of the above terms in the application can be understood by the person skilled in the art according to the specific circumstances.

[0031] Figure 1Fig. 1 is a structural schematic diagram of an embodiment of the overvoltage protection circuit of the present application. As can be seen from Fig. 1, the overvoltage protection circuit can include an input sub-circuit 4, a monitoring sub-circuit 3, an output sub-circuit 2, a control chip UC2854B and a driving sub-circuit 1 connected in sequence. The input sub-circuit 4 is used to divide the input voltage of the overvoltage protection circuit, the monitoring sub-circuit 3 is used to monitor the voltage output by the input sub-circuit 4, the output sub-circuit 2 is used to output the change signal output by the monitoring sub-circuit 3, and the control chip UC2854B is used to receive the change signal and control the driving sub-circuit 1 to cut off the input voltage according to the change signal. Figure 1

[0032] Specifically, the monitoring sub-circuit 3 is connected to the input sub-circuit 4 and includes a transistor V1, a three-terminal adjustable shunt regulator TL431, a first resistor R1, a second resistor R2, a third resistor R3 and a filter capacitor C1. The emitter of the transistor V1 is used to connect a DC voltage source VCC, one end of the first resistor R1 is connected to the collector of the transistor V1, and the other end is grounded. One end of the second resistor R2 is connected to the emitter, and the other end is connected to the base of the transistor V1. One end of the third resistor R3 is connected to the base of the transistor V1, and the other end is connected to the cathode of the three-terminal adjustable shunt regulator TL431. The anode of the three-terminal adjustable shunt regulator TL431 is grounded. One end of the filter capacitor C1 is connected to the reference terminal of the three-terminal adjustable shunt regulator TL431, and the other end is grounded. The reference terminal is connected to the input sub-circuit. The three-terminal adjustable shunt regulator TL431 is used to control the conduction and cutoff of the transistor V1. The transistor V1 is used to output a change signal according to the three-terminal adjustable shunt regulator TL431. The first resistor R1 is used to adjust the voltage of the collector. The second resistor R2 and the third resistor R3 are used to adjust the voltage of the base. The filter capacitor C1 is used to filter the input voltage.

[0033] The input sub-circuit 4 includes a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7 and an eighth resistor R8 connected in series. The fourth resistor R4 is used to connect the input voltage. The output end of the sixth resistor R6 is connected to the reference terminal. One end of the eighth resistor R8 is connected to the seventh resistor R7, and the other end is grounded. The input sub-circuit 4 is used to conduct the three-terminal adjustable shunt regulator TL431. The output sub-circuit 2 includes a ninth resistor R9 and a protection diode D1. The positive electrode of the protection diode D1 is connected to the collector, and the negative electrode of the protection diode D1 is connected to the ninth resistor R9. The protection diode D1 is used to isolate the reverse voltage input monitoring sub-circuit 3. The ninth resistor R9 is used to limit the current passing through the output sub-circuit 2. The control chip UC2854B has an input interface and an output interface. The input interface is connected to the output end of the ninth resistor R9, and the output interface is connected to the driving sub-circuit 1. The control chip UC2854B is used to control the driving sub-circuit 1 to cut off the input voltage according to the change signal.

[0034] ​In this embodiment, the values of the various components are as follows: the resistance of the first resistor R1 is 6.8 kΩ, the resistance of the second resistor R2 is 1 kΩ, and the resistance of the third resistor R3 is 5.6 kΩ. The resistance of the fourth resistor R4 is 475 kΩ, the resistance of the fifth resistor R5 is 475 kΩ, the resistance of the sixth resistor R6 is 33 kΩ, the resistance of the seventh resistor R7 is 5.6 kΩ, the resistance of the eighth resistor R8 is 330 Ω, and the DC voltage source VCC provides a voltage of 12 V.

[0035] In this embodiment, the A terminal in the figure represents the input terminal of the input voltage. The input voltage is divided by the fourth resistor R4 to the eighth resistor R8 in the input sub-circuit 4, and the divided voltage is input to the reference terminal of the three-terminal adjustable shunt regulator TL431. When the input voltage exceeds 400 V, the voltage at the reference terminal will exceed 2.5 V, thereby turning on the three-terminal adjustable shunt regulator TL431, and then the cathode of TL431 will pull down the voltage at the base of the transistor V1. When the base voltage of the PNP-type transistor V1 is less than the emitter voltage and greater than the collector voltage, the transistor V1 will change from the off state to the on state, thereby outputting a change signal to the output circuit through the collector. The ninth resistor R9 in the output circuit is used to limit the current through the output sub-circuit 2, and the diode D1 is used to isolate the reverse voltage input to the monitoring sub-circuit 3. After receiving the change signal, the input interface of the control chip UC2854B controls the driving sub-circuit 1 to cut off the input voltage through the output interface, thereby protecting the circuit from damage caused by overvoltage.

[0036] The application also provides a power device comprising the aforementioned protection circuit. Since the power device is built-in with a high-performance protection circuit, it can quickly and accurately respond to abnormal conditions such as overvoltage, reverse voltage, or overcurrent, and cut off or adjust the input voltage, thereby effectively preventing damage to the power device caused by these abnormal conditions. This greatly improves the safety and reliability of the power device.

[0037] In summary, the application achieves a high-efficiency and reliable overvoltage protection circuit by reasonably designing the input sub-circuit 4, the monitoring sub-circuit 3, and the output sub-circuit 2, as well as selecting high-performance components. The circuit can monitor the input voltage in real time and quickly respond when the voltage is abnormal, cutting off the input voltage or taking other protective measures, thereby ensuring the safe operation of the circuit and the device. In addition, the circuit also has reverse voltage and overcurrent protection capabilities, further improving the safety and stability of the circuit.

[0038] The above are preferred embodiments of the application, which do not limit the protection scope of the application. Therefore, any equivalent changes made in accordance with the structure, shape, and principle of the application should be covered within the protection scope of the application.

Claims

1. An overvoltage protection circuit, characterized by, The protection circuit comprises an input sub-circuit and a monitoring sub-circuit, the input sub-circuit is used for voltage division of an input voltage of the overvoltage protection circuit, The monitoring sub-circuit is connected to the input sub-circuit, and the monitoring sub-circuit comprises a triode, a three-terminal adjustable shunt regulator, a first resistor, a second resistor, a third resistor and a filter capacitor, the emitter of the triode is used for connecting a DC voltage source, one end of the first resistor is connected to the collector of the triode, and the other end is grounded, one end of the second resistor is connected to the emitter, and the other end is connected to the base of the triode, one end of the third resistor is connected to the base of the triode, and the other end is connected to the cathode of the three-terminal adjustable shunt regulator, the anode of the three-terminal adjustable shunt regulator is grounded, one end of the filter capacitor is connected to the reference terminal of the three-terminal adjustable shunt regulator, and the other end is grounded, and the reference terminal is connected to the input sub-circuit, The three-terminal adjustable shunt regulator is used for controlling the conduction and cutoff of the triode, the triode is used for outputting a change signal according to the three-terminal adjustable shunt regulator, the first resistor is used for adjusting the voltage of the collector, the second resistor and the third resistor are used for adjusting the voltage of the base, and the filter capacitor is used for filtering the input voltage.

2. The protection circuit of claim 1, wherein, The input sub-circuit comprises a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor and an eighth resistor connected in series, the fourth resistor is used for connecting the input voltage, the output end of the sixth resistor is connected to the reference terminal, one end of the eighth resistor is connected to the seventh resistor, and the other end is grounded, and the input sub-circuit is used for conducting the three-terminal adjustable shunt regulator.

3. The protection circuit of claim 2, wherein, The resistance value of the fourth resistor is 475kΩ, the resistance value of the fifth resistor is 475kΩ, the resistance value of the sixth resistor is 33kΩ, the resistance value of the seventh resistor is 5.6kΩ, and the resistance value of the eighth resistor is 330Ω.

4. The protection circuit of claim 1, wherein, The protection circuit further comprises an output sub-circuit connected to the monitoring sub-circuit, the output sub-circuit comprises a ninth resistor and a protection diode, the positive electrode of the protection diode is connected to the collector, the negative electrode of the protection diode is connected to the ninth resistor, the protection diode is used for isolating a reverse voltage input into the monitoring sub-circuit, and the ninth resistor is used for limiting the current passing through the output sub-circuit.

5. The protection circuit of claim 4, wherein, The protection circuit further comprises a control chip and a driving sub-circuit, the control chip has an input interface and an output interface, the input interface is connected to the output end of the ninth resistor, the output interface is connected to the driving sub-circuit, and the control chip is used for controlling the driving sub-circuit to cut off the input voltage according to the change signal.

6. The protection circuit of claim 5, wherein, The three-terminal adjustable shunt regulator is TL431, and the control chip is UC2854B.

7. The protection circuit of claim 1, wherein, The resistance value of the first resistor is 6.8kΩ, the resistance value of the second resistor is 1kΩ, the resistance value of the third resistor is 5.6kΩ, and the cathode of the three-terminal adjustable shunt regulator is used for controlling the voltage of the base of the triode.

8. An electric power device, characterized by The power equipment comprises the protection circuit according to any one of claims 1 to 7.

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