Overvoltage protection circuit

Abstract

The utility model discloses an overvoltage protection circuit. The overvoltage protection circuit comprises an output module and a control module. The first end of the output module is electrically connected with the first signal end, the second end of the output module is an output end, and the control end of the output module is electrically connected with the control module. The control module is also electrically connected with the first signal end, and the control module is configured to control the output module to be disconnected under the condition that the voltage of the first signal end is greater than or equal to a preset voltage threshold value; and under the condition that the voltage of the first signal end is smaller than the preset voltage threshold value, the output module is controlled to be switched on. According to the embodiment of the invention, the circuit can be controlled to be switched off when abnormal voltage injection exists, the input source is cut off in time to avoid the problem caused by heating, and the stability and reliability of the whole circuit system are improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of power electronics, and particularly relates to an overvoltage protection circuit. BACKGROUND

[0002] Analog quantity sampling circuits are generally divided into voltage signals and current signals.

[0003] Analog quantity voltage signals can generally be filtered to remove interference and abnormal voltage inputs by being connected in series with RC and a large resistor for current limiting and clamping. Analog quantity current signals are generally output as current sources, and the receiving end needs to convert them into voltage values for sampling detection. In normal signal reception, the current signal will not damage the current-to-voltage module. However, if the external wiring is incorrect and the input voltage is high, the power will exceed the bearing range of the current-to-voltage module, causing damage, so a protection circuit is needed to disconnect the connection with the current-to-voltage module when the input signal is overvoltage.

[0004] Traditional overvoltage protection methods, such as using a small resistor to ground, can meet the needs of the normal current range, but in harsh working environments, the input interface has a short power supply risk, which leads to excessive resistor power and further causes heat dissipation problems. CONTENT OF THE INVENTION

[0005] The application embodiment provides an overvoltage protection circuit which can control the circuit to be disconnected when there is an abnormal voltage injection, timely cut off the input source to avoid the problems caused by heating, and improve the stability and reliability of the entire circuit system.

[0006] In a first aspect, the application embodiment provides an overvoltage protection circuit, comprising an output module and a control module;

[0007] The first end of the output module is electrically connected with a first signal end, the second end of the output module is an output end, and the control end of the output module is electrically connected with the control module.

[0008] The control module is further electrically connected with the first signal end, and is configured to control the output module to be disconnected when the voltage of the first signal end is greater than or equal to a preset voltage threshold, and control the output module to be turned on when the voltage of the first signal end is less than the preset voltage threshold.

[0009] In a possible embodiment of the first aspect, the control module comprises:

[0010] a control submodule, a first end of the control submodule being electrically connected with the first signal end;

[0011] a switch module, a control end of the switch module being electrically connected with a second end of the control submodule, a first end of the switch module being electrically connected with the control end of the output module, and a second end of the switch module being electrically connected with a first power supply end.

[0012] In a possible implementation of the first aspect, the switch module comprises:

[0013] a first switch module, a control terminal of which is electrically connected to the second terminal of the control submodule, a first terminal of which is electrically connected to the first power terminal, and a second terminal of which is electrically connected to a control terminal of an output module.

[0014] a second switch module, a control terminal of which is electrically connected to the second terminal of the first switch module, a first terminal of which is electrically connected to the first power terminal, and a second terminal of which is electrically connected to the control terminal of the output module.

[0015] In a possible implementation of the first aspect, the control submodule comprises:

[0016] a voltage stabilizing diode, a first terminal of which is electrically connected to the first signal terminal, and a second terminal of which is electrically connected to the control terminal of the switch module;

[0017] a first resistor, which is electrically connected between the second terminal of the voltage stabilizing diode and the first power terminal;

[0018] a first capacitor, which is electrically connected between the second terminal of the voltage stabilizing diode and the first power terminal.

[0019] In a possible implementation of the first aspect, the control submodule comprises:

[0020] a comparator, a first input terminal of which is electrically connected to the first signal terminal, a second input terminal of which is electrically connected to a preset voltage terminal, and an output terminal of which is electrically connected to the control terminal of the switch module, the preset voltage terminal being configured to preset a voltage threshold.

[0021] In a possible implementation of the first aspect, the first switch module comprises:

[0022] a first switch, a control terminal of which is electrically connected to the second terminal of the control submodule, a first terminal of which is electrically connected to the first power terminal, and a second terminal of which is electrically connected to a control terminal of a second switch module;

[0023] a second resistor, which is electrically connected between the second terminal of the control submodule and the control terminal of the first switch;

[0024] a third resistor, which is electrically connected between the control terminal of the first switch and the first power terminal.

[0025] In a possible implementation of the first aspect, the second switch module comprises:

[0026] a second switch, a control terminal of which is electrically connected to the second terminal of the first switch module, a first terminal of which is electrically connected to the first power terminal, and a second terminal of which is electrically connected to the control terminal of the output module;

[0027] a fourth resistor, a first terminal of which is electrically connected to the first signal terminal, and a second terminal of which is electrically connected to the second terminal of the first switch module.

[0028] In a possible implementation of the first aspect, the control module further includes:

[0029] a second capacitor electrically connected between the first signal terminal and the first power terminal.

[0030] In a possible implementation of the first aspect, the control module includes:

[0031] a control sub-module, a first end of which is electrically connected to the first signal terminal;

[0032] a multiplexer, a control end of which is electrically connected to a second end of the control sub-module, a first input end of which is electrically connected to the first type of signal terminal, a second input end of which is electrically connected to the second type of signal terminal, and an output end of which is electrically connected to a control end of the output module.

[0033] In a possible implementation of the first aspect, the output module includes:

[0034] a third switch, a first end of which is electrically connected to the first signal terminal, and a second end of which serves as an output terminal of the output module.

[0035] a fifth resistor electrically connected between the first signal terminal and the control module;

[0036] a sixth resistor electrically connected between a control end of the third switch and the control module.

[0037] In a possible implementation of the first aspect, the output module further includes:

[0038] a seventh resistor, a first end of which is electrically connected to the second end of the third switch, and a second end of which is electrically connected to the first power terminal; and / or

[0039] a third capacitor electrically connected between the first end of the seventh resistor and the second end of the seventh resistor; and / or

[0040] an eighth resistor, a first end of which is electrically connected to the first end of the seventh resistor, and a second end of which serves as an output terminal of the overvoltage protection circuit; and / or

[0041] a fourth capacitor electrically connected between the second end of the eighth resistor and the first power terminal.

[0042] The overvoltage protection circuit provided in the embodiments of the present application comprises an output module and a control module. The first end of the output module is electrically connected with the first signal end, the second end of the output module is an output end, and the control end of the output module is electrically connected with the control module. The control module is further electrically connected with the first signal end, and is configured to control the output module to be turned off when the voltage of the first signal end is greater than or equal to a preset voltage threshold, and control the output module to be turned on when the voltage of the first signal end is less than the preset voltage threshold. The case that the voltage of the first signal end is greater than or equal to the preset voltage threshold indicates that there is an abnormal voltage injection, and the case that the voltage of the first signal end is less than the preset voltage threshold indicates that there is no abnormal voltage injection. Therefore, the control module can control the output module to be turned on when there is no abnormal voltage injection, and can control the output module to be turned off when there is an abnormal voltage injection. After the output module is turned off, the input source can be cut off in time, which not only avoids the overheating problem caused by long-time work of the resistor in the traditional method, but also reduces the number of components through the high integration of the module, effectively solves the problems of heat dissipation and space occupation in the traditional protection method, and can realize effective monitoring and overvoltage protection of the signal of the first signal end, thereby effectively improving the stability and reliability of the entire circuit system. BRIEF DESCRIPTION OF DRAWINGS

[0043] Other characteristics, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments, with reference to the attached drawings, in which the same or similar characters denote the same or similar features, and the drawings are not drawn to scale.

[0044] Figure 1 is a circuit structure schematic diagram of an overvoltage protection circuit provided in the embodiments of the present application;

[0045] Figure 2 is another circuit structure schematic diagram of an overvoltage protection circuit provided in the embodiments of the present application;

[0046] Figure 3 is another circuit structure schematic diagram of an overvoltage protection circuit provided in the embodiments of the present application;

[0047] Figure 4 is a circuit structure schematic diagram of a control sub-module in an overvoltage protection circuit provided in the embodiments of the present application;

[0048] Figure 5 is another circuit structure schematic diagram of a control sub-module in an overvoltage protection circuit provided in the embodiments of the present application;

[0049] Figure 6 is another circuit structure schematic diagram of an overvoltage protection circuit provided in the embodiments of the present application;

[0050] Figure 7is another circuit structure schematic diagram of the overvoltage protection circuit provided by the embodiment of the present application;

[0051] Figure 8 is another circuit structure schematic diagram of the overvoltage protection circuit provided by the embodiment of the present application;

[0052] Figure 9-A is a circuit working state schematic diagram of the overvoltage protection circuit provided by the embodiment of the present application when there is no abnormal voltage injection;

[0053] Figure 9-B is a circuit working state schematic diagram of the overvoltage protection circuit provided by the embodiment of the present application when there is abnormal voltage injection;

[0054] Figure 10 is another circuit structure schematic diagram of the overvoltage protection circuit provided by the embodiment of the present application. DETAILED DESCRIPTION

[0055] The features and exemplary embodiments of various aspects of the present application will be described in detail below with reference to the drawings. To make the purpose, technical solutions and advantages of the present application more clear, the present application will be further described in detail below with reference to the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present application, and are not configured to limit the present application. The present application can be implemented without some of these specific details for those skilled in the art. The following description of the embodiments is only to provide a better understanding of the present application by showing examples of the present application.

[0056] It should be noted that, in this paper, the relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the elements defined by the statement "include" do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0057] It should be understood that the term "and / or" used herein is only a description of the association relationship between the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in this paper generally represents that the front and rear associated objects are a "or" relationship.

[0058] Many modifications and variations of this application can be carried out without departing from its spirit or scope as set forth in the claims. Therefore, it is intended that the present application cover modifications and variations of this application provided they come within the scope of the claims and their equivalents. It is to be under stood that the embodiments provided in this application are combinable with each other without contradiction, if possible.

[0059] Before the technical solutions provided by the embodiments of the present application are described, the problems existing in the related art are first described in detail in order to facilitate the understanding of the embodiments of the present application:

[0060] Analog quantity sampling circuits are generally divided into voltage type signals and current type signals.

[0061] Analog quantity voltage type signals can generally be filtered by being connected to RC and a large resistance current limiting and clamping to filter out interference and abnormal voltage input. However, analog quantity current type signals are generally output as current sources, and the receiving end needs to convert them into voltage values for sampling detection. In normal signal reception, the current signal will not damage the current-to-voltage module. However, if the external wiring is wrong and the input voltage is high, the power will exceed the bearing range of the current-to-voltage module, causing damage, so a protection circuit is needed to disconnect the connection with the current-to-voltage module when the input signal is overvoltage.

[0062] The current-to-voltage module of the traditional current type analog quantity receiving end generally adopts a low-cost small resistance grounding method. The current range of a conventional current type analog quantity is 4-20 mA, and the voltage after conversion is generally in the 0-5 V interval, which can be met by using a suitable resistance package. However, when the system operating environment is relatively harsh, there is a risk of short power supply at the input interface. At this time, in order to prevent the resistance power from exceeding, increasing the package and size of the resistance is one of the coping strategies, but it brings the problem of heat dissipation and larger board space placement. In automotive electronics, the PCB is generally placed in a sealed space and has no active cooling capacity, so optimization design is needed to ensure stability and the impact on other surrounding circuits.

[0063] Based on this, the embodiments of the present application provide an overvoltage protection circuit which can control the circuit to be disconnected when there is an abnormal voltage injection, and timely cut off the input source to avoid the problem caused by heating, and improve the stability and reliability of the entire circuit system.

[0064] The overvoltage protection circuit provided by the embodiments of the present application will be described in detail below in conjunction with the drawings.

[0065] Figure 1 is a circuit structure schematic diagram of an overvoltage protection circuit provided by the embodiments of the present application, as shown in Figure 1 The overvoltage protection circuit 100 includes an output module 10 and a control module 20.

[0066] The first end of the output module 10 is electrically connected with the first signal end, the second end of the output module 10 is an output end, and the control end of the output module 10 is electrically connected with the control module 20.

[0067] The control module 20 is also electrically connected with the first signal end.

[0068] The control module 20 is configured to control the output module 10 to be turned off when the voltage of the first signal end is greater than or equal to a preset voltage threshold, and control the output module 10 to be turned on when the voltage of the first signal end is less than the preset voltage threshold.

[0069] The voltage of the first signal end greater than or equal to the preset voltage threshold indicates abnormal voltage injection, and the voltage of the first signal end less than the preset voltage threshold indicates no abnormal voltage injection. The control module 20 can control the output module 10 to be normally turned on when there is no abnormal voltage injection, and control the output module 10 to be turned off to protect the circuit when there is abnormal voltage injection.

[0070] Specifically, the overvoltage protection circuit 100 can include an output module 10 and a control module 20. The control module 20 can monitor the voltage of the first signal end in real time. When the voltage of the first signal end reaches or exceeds a preset voltage threshold, it indicates that there is abnormal voltage injection, and the output module 10 is controlled to be turned off to protect the circuit. When the voltage of the first signal end is lower than the preset voltage threshold, it indicates that there is no abnormal voltage injection, and the output module 10 is allowed to be normally turned on.

[0071] According to the overvoltage protection circuit 100 provided by the embodiment of the present application, the overvoltage protection circuit 100 can include an output module 10 and a control module 20. The first end of the output module 10 is electrically connected with the first signal end, the second end of the output module 10 is an output end, and the control end of the output module 10 is electrically connected with the control module 20. The control module 20 is also electrically connected with the first signal end, and is configured to control the output module 10 to be turned off when the voltage of the first signal end is greater than or equal to a preset voltage threshold, and control the output module 10 to be turned on when the voltage of the first signal end is less than the preset voltage threshold. Wherein, the case that the voltage of the first signal end is greater than or equal to the preset voltage threshold indicates that there is an abnormal voltage injection, and the case that the voltage of the first signal end is less than the preset voltage threshold indicates that there is no abnormal voltage injection, so the control module 20 can control the output module 10 to be turned on when there is no abnormal voltage injection, and the control module 20 can control the output module 10 to be turned off when there is an abnormal voltage injection, and the output module 10 can be turned off in time after the input source is cut off, which not only avoids the overheating problem caused by long-time work of the resistor in the traditional method, but also reduces the number of components through the high integration of the module, effectively solves the problems of heat dissipation and space occupation in the traditional protection method, and can realize effective monitoring and overvoltage protection of the signal of the first signal end, effectively improving the stability and reliability of the entire circuit system.

[0072] Figure 2 is another circuit structure schematic diagram of the overvoltage protection circuit 100 provided by the embodiment of the present application.

[0073] In some embodiments, as shown in Figure 2 the control module 20 can include a control submodule 21 and a switch module 22.

[0074] The first end of the control submodule 21 is electrically connected with the first signal end.

[0075] The control end of the switch module 22 is electrically connected with the second end of the control submodule 21, the first end of the switch module 22 is electrically connected with the control end of the output module 10, and the second end of the switch module 22 is electrically connected with the first power supply end.

[0076] Wherein, the switch module 22 can perform switching action under the control of the control submodule 21, and can selectively transmit the voltage signal of the first power supply end to the control end of the output module 10 to control the turn-on and turn-off of the output module 10.

[0077] Specifically, the control submodule 21 can monitor the voltage of the first signal end in real time. When the voltage of the first signal end reaches or exceeds a preset voltage threshold, it indicates that there is an abnormal voltage injection. At this time, the control submodule 21 can control the switch module 22 to act, so as to control the output module 10 to be turned off to protect the circuit. Similarly, when the voltage of the first signal end is lower than the preset voltage threshold, it indicates that there is no abnormal voltage injection. At this time, the control submodule 21 can control the switch module 22 to act, so as to control the output module 10 to be normally turned on.

[0078] The overvoltage protection circuit 100 of the embodiment of the present application can monitor the voltage of the first signal end in real time through the control submodule 21 in the control module 20. When an abnormal voltage is detected, the first switch module 23 and the second switch module 24 are controlled to be turned on and turned off, so as to effectively control the output module 10 to be turned off to cut off the transmission path of the abnormal voltage, thereby protecting the circuit from damage. At the same time, it can ensure that the circuit can work normally when the voltage is normal, thereby improving the safety and reliability of the circuit.

[0079] In some embodiments, as shown in FIG. 1, the switch module 22 can include a first switch module 23 and a second switch module 24. Figure 3

[0080] The control end of the first switch module 23 is electrically connected with the second end of the control submodule 21, and the first end of the first switch module 23 is electrically connected with the first power supply end.

[0081] The control end of the second switch module 24 is electrically connected with the second end of the first switch module 23, the first end of the second switch module 24 is electrically connected with the first power supply end, and the second end of the second switch module 24 is electrically connected with the control end of the output module 10.

[0082] Specifically, the control submodule 21 can monitor the voltage of the first signal end in real time. When the voltage of the first signal end reaches or exceeds a preset voltage threshold, it indicates that there is an abnormal voltage injection. At this time, the control submodule 21 can control the first switch module 23 to be turned on, and after the first switch module 23 is turned on, the second switch module 24 can be controlled to be turned off. After the second switch module 24 is turned off, the output module 10 can be controlled to be turned off to protect the circuit. Similarly, when the voltage of the first signal end is lower than the preset voltage threshold, it indicates that there is no abnormal voltage injection. At this time, the control submodule 21 can control the first switch module 23 to be turned off, and after the first switch module 23 is turned off, the second switch module 24 can be controlled to be turned on. After the second switch module 24 is turned on, the output module 10 can be controlled to be normally turned on.

[0083] The overvoltage protection circuit 100 of the embodiment of the present application can monitor the voltage of the first signal end in real time through the control submodule 21 in the control module 20. When an abnormal voltage is detected, the first switch module 23 and the second switch module 24 are controlled to be turned on and turned off, so as to effectively control the output module 10 to be turned off to cut off the transmission path of the abnormal voltage, thereby protecting the circuit from damage. At the same time, it can ensure that the circuit can work normally when the voltage is normal, thereby improving the safety and reliability of the circuit.​

[0084] Figure 4 is a circuit structure schematic diagram of a control submodule 21 in an overvoltage protection circuit 100 provided by an embodiment of the present application.

[0085] In some embodiments, as shown in Figure 4 the control submodule 21 can include a comparator.

[0086] The first input end of the comparator is electrically connected with the first signal end, the second input end of the comparator is electrically connected with the preset voltage end, and the output end of the comparator is electrically connected with the control end of the switch module. The preset voltage end is configured with a voltage of a preset voltage threshold.

[0087] The control submodule 21 of the embodiment of the present application realizes the function by using a voltage comparator. In normal working (in the case that the voltage of the first signal end is less than the preset voltage threshold), the comparator outputs a non-enable signal to control the first switch module 23 to be turned off, so as to make the second switch module 24 conductive and the output module 10 conductive. In the case of overvoltage input (in the case that the voltage of the first signal end is greater than or equal to the preset voltage threshold), the comparator outputs an enable signal to control the first switch module 23 to be conductive, so as to make the second switch module 24 and the output module 10 be turned off. The abnormal voltage is intercepted by the output module 10, thereby playing a protection effect on the rear-end circuit.

[0088] Figure 5 is another circuit structure schematic diagram of the control submodule 21 in the overvoltage protection circuit 100 provided by an embodiment of the present application.

[0089] In some embodiments, as shown in Figure 5 the control submodule 21 can include a voltage stabilizing diode 211, a first resistor 212 and a first capacitor 213.

[0090] The first end of the voltage stabilizing diode 211 is electrically connected with the first signal end, and the second end of the voltage stabilizing diode 211 is electrically connected with the control end of the switch module 22.

[0091] The first resistor 212 is electrically connected between the second end of the voltage stabilizing diode 211 and the first power supply end.

[0092] The first capacitor 213 is electrically connected between the second end of the voltage stabilizing diode 211 and the first power supply end.

[0093] Among them, the first resistor 25 has a current limiting effect, which can prevent the current of the voltage stabilizing diode from being too large when the voltage stabilizing diode is reversely broken down, and at the same time, by introducing the first capacitor, the misoperation of the switch module can be prevented, thereby improving the stability and reliability of the circuit.

[0094] The control submodule 21 of the embodiment of the present application adopts a stabilizing diode to realize the function. In normal operation (in the case that the voltage of the first signal end is less than the preset voltage threshold), the cathode voltage of the stabilizing diode does not reach the reverse breakdown point, so the first switch module 23 is off, the second switch module 24 is on, and the output module 10 is on. In the case of overvoltage input (in the case that the voltage of the first signal end is greater than or equal to the preset voltage threshold), the cathode voltage of the stabilizing diode reaches the reverse breakdown point, the current of the control end of the first switch module 23 rises, and the first switch module 23 is on, so that the second switch module 24 and the output module 10 are off. The abnormal voltage is intercepted by the output module 10, and the effect of protecting the rear-end circuit is achieved.

[0095] Figure 6 FIG. 6 is another circuit structure schematic diagram of the overvoltage protection circuit 100 provided by the embodiment of the present application.

[0096] In some embodiments, as shown in FIG. 5, the first switch module 23 can include a first switch 231, a second resistor 232, and a third resistor 233. Figure 6

[0097] The control end of the first switch 231 is electrically connected to the second end of the control submodule 21, the first end of the first switch 231 is electrically connected to the first power supply end, and the second end of the first switch 231 is electrically connected to the control end of the second switch module 24.

[0098] The second resistor 232 is electrically connected between the second end of the control submodule 21 and the control end of the first switch 231.

[0099] The third resistor 233 is electrically connected between the control end of the first switch 231 and the first power supply end.

[0100] The first switch module 23 provided by the embodiment of the present application can include a first switch 231, a second resistor 232, and a third resistor 233. The second resistor 232 can be used for current limiting, and the control end of the first switch 231 is electrically connected to the first power supply end through the third resistor 233, which can ensure that the first switch 231 maintains an off state when there is no abnormal voltage in the first signal end, thereby improving the stability and reliability of the circuit.

[0101] In some embodiments, still referring to FIG. 5, the second switch module 24 can include a second switch 241 and a fourth resistor 242. Figure 6

[0102] The control end of the second switch 241 is electrically connected to the second end of the first switch module 23, the first end of the second switch 241 is electrically connected to the first power supply end, and the second end of the second switch 241 is electrically connected to the control end of the output module 10.

[0103] ​​The first end of the fourth resistor 242 is electrically connected with the first signal end, and the second end of the fourth resistor 242 is electrically connected with the second end of the first switch module 23.

[0104] The second switch module 24 provided by the embodiment of the present application can include a second switch 241 and a fourth resistor 242.

[0105] Specifically, the control submodule 21 can monitor the voltage of the first signal end in real time. When the voltage of the first signal end reaches or exceeds a preset voltage threshold, it indicates that there is an abnormal voltage injection. At this time, the control submodule 21 can control the first switch 231 to be turned on. After the first switch 231 is turned on, the current signal of the first signal end flows into the first power supply end via the fourth resistor 242 and the first switch 231, so that the control end of the second switch 241 has no enable signal, so that the second switch 241 is turned off. After the second switch 241 is turned off, the output module 10 can be controlled to be turned off to protect the circuit. Similarly, when the voltage of the first signal end is lower than the preset voltage threshold, it indicates that there is no abnormal voltage injection. At this time, the control submodule 21 can control the first switch 231 to be turned off. After the first switch 231 is turned off, the current signal of the first signal end flows into the control end of the second switch 241 via the fourth resistor 242. After the control end of the second switch 241 receives the enable signal, the second switch 241 is turned on. After the second switch 241 is turned on, the output module 10 can be controlled to be normally turned on.

[0106] The overvoltage protection circuit 100 of the embodiment of the present application can monitor the voltage of the first signal end on the input side in real time through the control submodule 21 in the control module 20. When an abnormal voltage is detected, the transmission path of the abnormal voltage can be effectively controlled to be turned off by controlling the turn-on and turn-off of the first switch 231 and the second switch 241, so as to protect the circuit from damage, while ensuring that the circuit can work normally when the voltage is normal, thereby improving the safety and reliability of the circuit.

[0107] In some embodiments, the above description can be continued with reference to Figure 6 The control module further includes a second capacitor 25.

[0108] The second capacitor 25 is electrically connected between the first signal end and the first power supply end.

[0109] The embodiment of the present application introduces the second capacitor 25. The second capacitor 25 is an interface end capacitor, can filter out the peak voltage, has the electrostatic protection effect, and further improves the stability and reliability of the circuit.

[0110] Figure 7 FIG. 6 is another circuit structure schematic diagram of the overvoltage protection circuit 100 provided by the embodiment of the present application.

[0111] In some embodiments, the above description can be continued with reference to Figure 7As shown, the control module 20 can include a control submodule 21 and a multiplexer 26.

[0112] The first end of the control submodule 21 is electrically connected to the first signal end.

[0113] The control end of the multiplexer 26 is electrically connected to the second end of the control submodule 21, the first input end of the multiplexer 26 is electrically connected to the first type signal end, the second input end of the multiplexer 26 is electrically connected to the second type signal end, and the output end of the multiplexer 26 is electrically connected to the control end of the output module 10.

[0114] The first type signal end can be configured with a first type signal, and the first type signal is used to control the output module 10 to turn on. The second type signal end can be configured with a second type signal, and the second type signal is used to control the output module 10 to turn off.

[0115] The overvoltage protection circuit 100 provided in the embodiments of the present application introduces a control module 20 including a control submodule 21 and a multiplexer 26. The control submodule 21 is connected to the first signal end and is used to control one of the multiplexers 26 to open when detecting that the voltage of the first signal end is abnormal, so as to transmit the first type signal of the first type signal end to the control end of the output module 10, thereby controlling the output module 10 to turn off. The control submodule 21 is also used to control another of the multiplexers 26 to open when detecting that the voltage of the first signal end is normal, so as to transmit the second type signal of the second type signal end to the control end of the output module 10, thereby controlling the output module 10 to turn on. Therefore, the control submodule 21 can control the multiplexer 26 to select a signal from the first type signal end or the second type signal end for output according to the size of the input voltage of the first signal end, thereby realizing accurate control of the output module 10. The adaptability, flexibility and reliability of the circuit are improved, so that the overvoltage protection circuit can more flexibly cope with different working scenarios and requirements.

[0116] Figure 8 FIG. 1 is a circuit structure schematic diagram of an output module 10 in an overvoltage protection circuit 100 provided in the embodiments of the present application.

[0117] In some embodiments, as shown in FIG. 1, the output module 10 can include a third switch 11, a fifth resistor 12 and a sixth resistor 13. Figure 8

[0118] The first end of the third switch 11 is electrically connected to the first signal end, and the second end of the third switch 11 serves as the output end of the output module 10.

[0119] The fifth resistor 12 is electrically connected between the first signal end and the control module 20.

[0120] ​The sixth resistor 13 is electrically connected between the control end of the third switch 11 and the control module 20.

[0121] The output module 10 provided by the embodiment of the present application realizes the accurate control of the output signal by introducing the third switch 11, the fifth resistor 12 and the sixth resistor 13. The first end of the third switch 11 is connected to the first signal end, the output end of the third switch 11 is used as the output of the entire output module 10, and the control end of the third switch 11 is connected to the control module 20. The control module 20 can flexibly control the on-off of the third switch 11 according to the voltage of the first signal end, thereby effectively managing the output signal of the output module 10, effectively monitoring and overvoltage protecting the signal of the first signal end, and effectively improving the stability and reliability of the entire circuit system.

[0122] In some embodiments, the output module 10 can further include a seventh resistor 14, a third capacitor 15, an eighth resistor 16 and / or a fourth capacitor 17. Figure 8

[0123] The first end of the seventh resistor 14 is electrically connected to the second end of the third switch 11, and the second end of the seventh resistor 14 is electrically connected to the first power supply end.

[0124] The seventh resistor 14 can convert the current signal of the first signal end into a voltage signal, for example, can convert the 4-20mA current signal of the first signal end into a corresponding 0-5V voltage signal.

[0125] The third capacitor 15 is electrically connected between the first end of the seventh resistor 14 and the second end of the seventh resistor 14.

[0126] The third capacitor 15 is a bypass capacitor of the seventh resistor 14 and has a filtering effect.

[0127] The first end of the eighth resistor 16 is electrically connected to the first end of the seventh resistor 14, and the second end of the eighth resistor 16 is used as the output end of the overvoltage protection circuit 100.

[0128] The fourth capacitor 17 is electrically connected between the second end of the eighth resistor 16 and the first power supply end.

[0129] The eighth resistor 16 and the fourth capacitor 17 have a current limiting and filtering effect.

[0130] ​The output module 10 of this embodiment of the application realizes signal conversion, filtering, and current limiting functions by introducing components such as a seventh resistor 14, a third capacitor 15, an eighth resistor 16, and / or a fourth capacitor 17. The seventh resistor 14 can convert the current signal into a voltage signal, while the third capacitor 15 acts as a bypass capacitor to perform filtering; the eighth resistor 16 and the fourth capacitor 17 together perform current limiting and secondary filtering, thereby improving the signal processing capability and output signal stability of the overvoltage protection circuit 100.

[0131] Figure 9-A This is a schematic diagram of the overvoltage protection circuit 100 provided in this application embodiment when there is no abnormal voltage injection.

[0132] In one example, such as Figure 9-A As shown, when the circuit normally receives a current-type analog signal, the cathode voltage of the Zener diode has not reached the reverse breakdown point. Therefore, the first switch 231 is off, the second switch 241 is on, and the third switch 11 is on. The current and voltage flow is as follows. Figure 9-A As shown by the middle arrow. After the third switch 11 is turned on, the current signal passes through the seventh resistor 14 to ground, generating a proportional voltage value across the seventh resistor 14. After initial filtering by the third capacitor 15, it is then output to the MCU sampling port after current limiting and filtering by the eighth resistor 16 and the fourth capacitor 17.

[0133] It should be noted that the overvoltage point, i.e., the preset voltage threshold, can be configured by selecting the parameters of the Zener diode. Therefore, the preset voltage threshold for overvoltage protection can be adjusted according to requirements, making it suitable for systems of different specifications.

[0134] The overvoltage protection circuit 100 provided in this application embodiment enables the output module 10 to operate normally when there is no abnormal voltage, and ensures that a stable and reliable signal is provided to the MCU sampling port through multi-level filtering and current limiting measures during current signal transmission. At the same time, the protection threshold can be adjusted according to different system specifications, which enhances the applicability and flexibility of the circuit, while also saving board space and reducing the difficulty of manufacturing process.

[0135] Figure 9-B This is a schematic diagram of the overvoltage protection circuit 100 provided in this application embodiment when there is an abnormal voltage injection.

[0136] In one example, such as Figure 9-B As shown, when an excessively high abnormal voltage is injected, the cathode voltage of the Zener diode reaches the reverse breakdown point, the Ib current of the first switch 231 increases, the first switch 231 conducts, and the second switch 241 and the third switch 11 are turned off; the current and voltage flow is as follows. Figure 9-B As indicated by the middle arrow, the abnormal voltage is blocked by the third switch 11, thus protecting the downstream circuitry.

[0137] It should be noted that the resistance values ​​of the fourth resistor 242, the fifth resistor 12, and the sixth resistor 13 should not be too small, so as to prevent the control module 20 from shunting the current.

[0138] It should also be noted that the withstand voltage values ​​of the first switch 231, the second switch 241, and the third switch 11 should exceed the required maximum overvoltage value.

[0139] The overvoltage protection circuit 100 provided in this embodiment can quickly trigger the first switch 231 to conduct through the reverse breakdown characteristic of the Zener diode when an abnormally high voltage is encountered at the input terminal, thereby turning off the second switch 241 and the third switch 11. This effectively blocks the damage of abnormal voltage to the downstream circuit and achieves efficient protection. At the same time, by reasonably setting the resistance value, the shunting of the control module 20 can be avoided, and the selection of switching elements with a withstand voltage exceeding the maximum overvoltage requirement ensures the reliability and stability of the protection circuit.

[0140] It should be noted that the above embodiments and accompanying drawings are illustrated using the example of all transistors in the pixel circuit being bipolar transistors. However, the pixel circuits provided in this application are also applicable to field-effect transistors. Those skilled in the art can replace some or all of the bipolar transistors in the pixel circuit with field-effect transistors according to actual needs.

[0141] Figure 10 This is another circuit structure diagram of the overvoltage protection circuit 100 provided in the embodiments of this application.

[0142] In one example, such as Figure 10 As shown, the control submodule 21 may include a comparator, and the multiplexer 26 may include switching transistors T1 and T2. The control signals for switching transistors T1 and T2 are opposite. For example, switching transistor T1 is an N-type metal-oxide-semiconductor field-effect transistor (N-MOSFET), while switching transistor T2 is a P-type metal-oxide-semiconductor field-effect transistor (P-MOSFET). This design ensures that when T1 is on, T2 is off; conversely, when T2 is on, T1 is off, thus achieving effective control of the circuit path.

[0143] When the circuit normally receives the current mode analog signal, since the voltage of the first signal end is less than the voltage of the preset voltage end, the comparator outputs the first signal, T1 is turned on, T2 is turned off, and after T1 is turned on, the first signal of the first signal end is transmitted to the control end of the output module 10, so as to control the output module 10 to be turned on.

[0144] When there is an abnormal high voltage injection, since the voltage of the first signal end is greater than or equal to the voltage of the preset voltage end, the comparator outputs the second signal, T1 is turned off, T2 is turned on, and after T2 is turned on, the second signal of the second signal end is transmitted to the control end of the output module 10, so as to control the output module 10 to be turned off.

[0145] The overvoltage protection circuit 100 provided by the embodiment of the present application can allow the current mode analog signal to pass smoothly in the normal working state, and can quickly turn off the output module 10 once an abnormal high voltage is encountered, so as to prevent the voltage abnormality from causing damage to the circuit, and greatly improve the reliability and stability of the circuit.

[0146] The above is merely a specific implementation of the present application, and those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the system, module and unit described above can refer to the corresponding process in the foregoing method embodiments, which will not be described herein. It should be understood that the protection scope of the present application is not limited to this, and any person skilled in the art can easily think of various equivalent modifications or replacements within the technical range disclosed in the present application, and these modifications or replacements should be covered in the protection scope of the present application.

Claims

1. An overvoltage protection circuit, characterized by, The output module and the control module are included. The first end of the output module is electrically connected with the first signal end, the second end of the output module is an output end, and the control end of the output module is electrically connected with the control module. The control module is further electrically connected with the first signal end, and the control module is configured to control the output module to be turned off when the voltage of the first signal end is greater than or equal to a preset voltage threshold. The control module is configured to control the output module to be turned on when the voltage of the first signal end is less than the preset voltage threshold. The control module includes: The first end of the control submodule is electrically connected with the first signal end. The control end of the switch module is electrically connected with the second end of the control submodule, the first end of the switch module is electrically connected with the control end of the output module, and the second end of the switch module is electrically connected with the first power supply end. The control submodule includes: The first end of the voltage stabilizing diode is electrically connected with the first signal end, and the second end of the voltage stabilizing diode is electrically connected with the control end of the switch module. The first resistor is electrically connected between the second end of the voltage stabilizing diode and the first power supply end. The first capacitor is electrically connected between the second end of the voltage stabilizing diode and the first power supply end. Alternatively, the control submodule includes: The first input end of the comparator is electrically connected with the first signal end, the second input end of the comparator is electrically connected with a preset voltage end, the output end of the comparator is electrically connected with the control end of the switch module, and the preset voltage end is configured with a voltage of a preset voltage threshold.

2. The overvoltage protection circuit of claim 1, wherein, The switch module includes: The control end of the first switch module is electrically connected with the second end of the control submodule, and the first end of the first switch module is electrically connected with the first power supply end. The control end of the second switch module is electrically connected with the second end of the first switch module, the first end of the second switch module is electrically connected with the first power supply end, and the second end of the second switch module is electrically connected with the control end of the output module.

3. The overvoltage protection circuit of claim 2, wherein, The first switch includes: The control end of the first switch is electrically connected with the second end of the control submodule, the first end of the first switch is electrically connected with the first power supply end, and the second end of the first switch is electrically connected with the control end of the second switch module. The second resistor is electrically connected between the second end of the control submodule and the control end of the first switch. The third resistor is electrically connected between the control end of the first switch and the first power supply end. The second switch includes:

4. The overvoltage protection circuit of claim 2, wherein, The control end of the second switch is electrically connected with the second end of the first switch module, the first end of the second switch is electrically connected with the first power supply end, and the second end of the second switch is electrically connected with the control end of the output module. The fourth resistor is electrically connected between the first signal end and the second end of the first switch module. The control module further includes:

5. The overvoltage protection circuit of claim 1, wherein, The second capacitor is electrically connected between the first signal end and the first power supply end. The control submodule includes:

6. The overvoltage protection circuit of claim 1, wherein, The first end of the control submodule is electrically connected with the first signal end. The control end of the multiplexer is electrically connected with the second end of the control submodule, the first input end of the multiplexer is electrically connected with the first type signal end, the second input end of the multiplexer is electrically connected with the second type signal end, and the output end of the multiplexer is electrically connected with the control end of the output module. The output module includes:

7. The overvoltage protection circuit according to any one of claims 1 to 6, characterized in that, The first end of the third switch is electrically connected with the first signal end, and the second end of the third switch is an output end of the output module. ​ A fifth resistor is electrically connected between the first signal end and the control module; A sixth resistor is electrically connected between the control end of the third switch and the control module.

8. The overvoltage protection circuit of claim 7, wherein, The output module further comprises: A seventh resistor, a first end of which is electrically connected to the second end of the third switch, and a second end of which is electrically connected to the first power supply end; and / or A third capacitor is electrically connected between the first end of the seventh resistor and the second end of the seventh resistor; and / or An eighth resistor, a first end of which is electrically connected to the first end of the seventh resistor, and a second end of which is used as an output end of the overvoltage protection circuit; and / or A fourth capacitor is electrically connected between the second end of the eighth resistor and the first power supply end.

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