Overvoltage detection circuit and device

Abstract

The utility model provides an overvoltage detection circuit and device, and relates to the technical field of power electronics. The overvoltage detection circuit comprises an input module, a comparison module and a control module, the input end of the input module is used for inputting sampling signals, and the output end is connected with the input end of the comparison module. The control end of the input module is connected with the control module; the sampling signals are used for representing different input electric signals. Wherein the overvoltage detection circuit comprises a plurality of working states; the working states correspond to different gain output states respectively; and the control module is used for sending different control signals to the input module to adjust the resistance value of the input module, so that the input module is in different gain output states. Therefore, on the basis of ensuring the size of the device, the interference rejection to the ground is increased, the detection range is improved, and the requirement of small-signal high-precision detection is met.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of power electronics, especially to an overvoltage detection circuit and device. BACKGROUND

[0002] The overvoltage detection circuit is usually used for fault detection, overvoltage protection detection and short circuit detection in a circuit. The principle of most overvoltage detection circuits is to sample and amplify the voltage to be detected, and then output a judgment result based on a preset threshold to achieve the above detection purposes.

[0003] However, in order to ensure the size of the device, the overvoltage detection circuit usually adopts the simplest device structure, for example, a resistance voltage dividing circuit is mounted on the basis of a comparator. This device structure is simple, but has the following problems: first, the ground disturbance suppression is poor, which causes the jitter caused by the crosstalk on the ground line to affect the output and the comparator common mode, and interferes with the working state of the comparator; second, it is difficult to detect the voltage in the high voltage range and / or negative voltage range, and it also cannot meet the high-precision detection requirement of small signals.

[0004] Therefore, there is an urgent need for an overvoltage detection scheme that increases the ground disturbance suppression while ensuring the size of the device, improves the detection range, and meets the high-precision detection requirement of small signals. SUMMARY

[0005] The utility model aims at providing an overvoltage detection circuit and device, which increases the ground disturbance suppression while ensuring the size of the device, improves the detection range, and meets the high-precision detection requirement of small signals.

[0006] In a first aspect, the utility model provides an overvoltage detection circuit, which comprises an input module, a comparison module and a control module. The input end of the input module is used for inputting a sampling signal, the output end is connected with the input end of the comparison module, and the control end of the input module is connected with the control module. The sampling signal is used to represent different input electrical signals.

[0007] The overvoltage detection circuit comprises multiple working states, and each working state corresponds to a different gain output state.

[0008] The control module is used for sending different control signals to the input module to adjust the resistance value of the input module, so that the input module is in different gain output states.

[0009] Optionally, the input module comprises multiple voltage dividing resistors, and the resistance values between the voltage dividing resistors meet a preset resistance value ratio, so as to change the output gain of the input module by adjusting the preset resistance value ratio.

[0010] Optionally, when the voltage dividing resistors include at least one target resistor, the input module further comprises a switch unit connected in parallel with the target resistor; wherein the control module is configured to send different control signals to the input module to adjust the on-off state of the switch unit, so as to adjust the resistance ratio of the input module, and make the input module in different gain output states.

[0011] Optionally, when the input module comprises the first input branch, the second input branch, the third input branch, the feedback branch and the operational amplifier, the first end of the first input branch is configured to input a first power supply voltage, and the second end is connected with the first input end of the operational amplifier and the first end of the feedback branch; the second end of the feedback branch is connected with the output end of the operational amplifier; the first end of the second input branch is grounded or configured to receive a second power supply voltage, and the second end is connected with the second input end of the operational amplifier and the second end of the third input branch; the first end of the third input branch is configured to input an adjustment voltage to adjust the output common mode of the operational amplifier.

[0012] The first resistance ratio is formed by the voltage dividing resistors in the first input branch and the feedback branch; the second resistance ratio is formed by the voltage dividing resistors in the second input branch and the third input branch; and the value of the first resistance ratio is equal to the value of the second resistance ratio.

[0013] Optionally, when the first end of the second input branch is configured to receive the second power supply voltage, the input module comprises a differential circuit.

[0014] Optionally, when the first end of the second input branch is grounded, the third input branch comprises a first resistor and a second resistor; the second input branch comprises a third resistor; the first end of the first resistor is configured to input the adjustment voltage; the second end of the first resistor is connected with the first end of the second resistor; the second end of the second resistor is connected with the second input end of the operational amplifier and the first end of the third resistor, respectively; and the second end of the third resistor is grounded.

[0015] The resistance value of the first resistor is greater than the resistance value of the second resistor.

[0016] Optionally, the feedback branch comprises a fourth resistor and a fifth resistor; the first input branch comprises a sixth resistor; the first end of the fourth resistor is connected with the output end of the operational amplifier; the second end of the fourth resistor is connected with the first end of the fifth resistor; the second end of the fifth resistor is connected with the first input end of the operational amplifier and the first end of the sixth resistor, respectively; and the second end of the sixth resistor is configured to input a reference voltage.

[0017] The resistance value of the fourth resistor is equal to the resistance value of the first resistor; the resistance value of the fifth resistor is equal to the resistance value of the second resistor; and the resistance value of the sixth resistor is equal to the resistance value of the third resistor.

[0018] Optionally, when the first resistance and the fourth resistance are the target resistance, the switch unit comprises a first switch and a second switch; the first switch is connected in parallel with the first resistance; and the second switch is connected in parallel with the fourth resistance.

[0019] When in the first working state, the control module is configured to send a first control signal to the first switch and the second switch, the first switch and the second switch are both closed, and the switch unit is in a first gain output state.

[0020] When in the second working state, the control module is configured to send a second control signal to the first switch and the second switch, the first switch and the second switch are both closed, and the switch unit is in a second gain output state.

[0021] The gain value corresponding to the first gain output state is less than the gain value corresponding to the second gain output state.

[0022] Optionally, the input module comprises a voltage dividing unit, the voltage dividing unit comprises a first input end, a second input end and a third input end; the first input end is configured to input a first supply voltage; the second input end is configured to input an adjustment voltage to adjust an output common mode of the input module; and the third input end is grounded.

[0023] The voltage dividing unit further comprises an output end, and the output end is connected with the input end of the comparison module.

[0024] In a second aspect, the utility model also provides a kind of overvoltage detection device, including power supply and the overvoltage detection circuit of any one of the first aspect.

[0025] The overvoltage detection circuit and device provided by the utility model have the following beneficial effects:

[0026] The overvoltage detection circuit in the utility model comprises an input module, a comparison module and a control module, an input end of the input module is configured to input a sampling signal, and an output end of the input module is connected with an input end of the comparison module.A control end of the input module is connected with the control module; the sampling signal is used to represent different input signals. The overvoltage detection circuit comprises multiple working states; each working state corresponds to different gain output states; the control module is configured to send different control signals to the input module to adjust the resistance value of the input module, so that the input module is in different gain output states. Based on this, the utility model can increase the disturbance suppression to ground on the basis of ensuring the size of device, improve the detection range, and meet the demand of small signal high-precision detection. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or the prior art description. Obviously, the drawings described below are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of these drawings.

[0028] Figure 1 The module schematic diagram of the overvoltage detection circuit in the embodiment of the present application;

[0029] Figure 2 The module schematic diagram of the input module in the embodiment of the present application;

[0030] Figure 3 The module schematic diagram of the input module in the embodiment of the present application;

[0031] Figure 4 The module schematic diagram of the input module in the embodiment of the present application;

[0032] Figure 5 The circuit principle diagram of the input module in the embodiment of the present application;

[0033] Figure 6 The circuit principle diagram of the input module in the embodiment of the present application;

[0034] Figure 7 The circuit principle diagram of the input module in the embodiment of the present application;

[0035] Figure 8 The module schematic diagram of the input module in the embodiment of the present application;

[0036] Figure 9 The circuit principle diagram of the input module in the embodiment of the present application.

[0037] Icon: 100-overvoltage detection circuit; 101-input module; 102-comparison module; 103-control module; 201-voltage dividing resistor; 201-1-target resistor; 301-switching unit; 302-first input branch; 303-second input branch; 304-third input branch; 305-feedback branch; U1-operational amplifier; R1-first resistor; R2-second resistor; R3-third resistor; R4-fourth resistor; R5-fifth resistor; R6-sixth resistor; K1-first switch; K2-second switch; 401-voltage dividing unit; R7-seventh resistor; R8-eighth resistor; R9-ninth resistor; K3-third switch; K4-fourth switch; K5-fifth switch; K6-sixth switch. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be described clearly and completely in combination with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, rather than all the embodiments. The components of the embodiments of the utility model described and shown in the drawings can be arranged and designed in various different configurations.

[0039] Therefore, the following detailed description of the embodiments of the utility model provided in the drawings is not intended to limit the scope of the claimed utility model, but only represents selected embodiments of the utility model. Based on the embodiments in the utility model, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the utility model.

[0040] It should be noted that: similar reference numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0041] In the description of the utility model, it should be noted that the terms "first", "second", "third" and the like are only used for differentiation and description, and cannot be understood as indicating or implying relative importance.

[0042] In the description of the utility model, it should also be noted that, unless otherwise explicitly specified and limited, the term "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or the communication inside two elements. For those of ordinary skill in the art, the specific meaning of the above-mentioned terms in the utility model can be understood according to the specific circumstances.

[0043] Some embodiments of the utility model will be described in detail below in combination with the drawings. In the case of no conflict, the following embodiments and features in the embodiments can be combined with each other.

[0044] As described in the background, the device structure corresponding to the conventional overvoltage monitoring circuit is simple, but has the following problems: first, the ground disturbance suppression is poor, which causes the jitter generated by the crosstalk on the ground line to affect the output, and also affects the comparator common mode, interfering with the comparator working state; second, it is difficult to detect the voltage in the high voltage range and / or negative voltage range, and also cannot meet the high-precision detection demand of small signal.

[0045] Based on this, the embodiment provides an overvoltage detection scheme, which increases the disturbance suppression to ground, improves the detection range, and meets the demand of small signal high-precision detection on the basis of ensuring the size of the device.

[0046] The scheme will be described in detail below.

[0047] Please refer to Figure 1 , Figure 1 A module schematic diagram of an overvoltage detection circuit is shown; the overvoltage detection circuit 100 comprises an input module 101, a comparison module 102 and a control module 103, an input end of the input module 101 is used for inputting a sampling signal, an output end of the input module 101 is connected with an input end of the comparison module 102, and a control end of the input module 101 is connected with the control module 103; the sampling signal is used for representing different input electric signals.

[0048] The overvoltage detection circuit comprises multiple working states; each working state corresponds to a different gain output state. The control module is used for sending different control signals to the input module to adjust the resistance value of the input module, so that the input module is in different gain output states.

[0049] In the embodiment, a new overvoltage detection circuit is constructed, which comprises an input module and other device structures; the input end of the output module is used for receiving a sampling signal, i.e. different input electric signals, so as to adjust the output common mode of the input module through the input electric signal and / or eliminate the ground wire interference through the setting of the ground end, for example, the jitter of the comparator can be shielded when the ground wire jumps. At the same time, the gain output state of the input module is adjusted by the control module to realize the detection function of overvoltage in a wide range and under multiple conditions.

[0050] In the embodiment, the structure of the input module is not limited, and the input module can be composed of pure resistance and / or a combination of resistance and operational amplifier.

[0051] Please refer to Figure 1 on the basis of Figure 2 , Figure 2 A module schematic diagram of an input module in the utility model is shown; in a possible implementation mode, the input module 101 comprises multiple voltage division resistors 201, the resistance values between the voltage division resistors 201 meet a preset resistance value ratio, and then the output gain of the input module is changed by adjusting the preset resistance value ratio.

[0052] Please refer to Figure 2 on the basis of Figure 3 , Figure 3The module schematic view of the input module in the utility model is shown; when the voltage dividing resistor 201 includes at least one target resistor 201-1, the input module 101 further includes a switch unit 301, and the switch unit 301 is connected in parallel with the target resistor 201-1; wherein, the control module 103 is used for sending different control signals to the switch unit 301, so as to adjust the on-off state of the switch unit, so as to adjust the resistance ratio of the input module, and make the input module be in different gain output states.

[0053] Embodiment one

[0054] The input module in the embodiment can be composed of resistors and operational amplifiers. It should be noted that two implementation manners are provided in the embodiment.

[0055] First implementation manner

[0056] Please refer to Figure 4 , Figure 4 The module schematic view of the input module in the utility model is shown; wherein, when the input module 101 includes a first input branch 302, a second input branch 303, a third input branch 304, a feedback branch 305 and an operational amplifier U1, the first end of the first input branch 302 is used for inputting a first power supply voltage, and the second end is connected with the first input end of the operational amplifier U1 and the first end of the feedback branch 305; the second end of the feedback branch 305 is connected with the output end of the operational amplifier U1; the first end of the second input branch 303 is grounded or used for receiving a second power supply voltage, and the second end is connected with the second input end of the operational amplifier U1 and the second end of the third input branch 304; the first end of the third input branch 304 is used for inputting an adjustment voltage, so as to adjust the output common mode of the operational amplifier U1.

[0057] Wherein, the first input branch and each voltage dividing resistor under the feedback branch constitute a first resistance ratio; the second input branch and each voltage dividing resistor under the third input branch constitute a second resistance ratio; the value of the first resistance ratio is equal to the value of the second resistance ratio.

[0058] Wherein, in the embodiment, when the first end of the second input branch is grounded, the ground line interference of the operational amplifier can be eliminated, and the jitter of the comparator when the ground line jumps can be shielded. On this basis, the resistance ratio corresponding to the first input branch, the second input branch, the third input branch and the feedback branch in the input module can be adjusted by the control module, and then the detection function of overvoltage in a wide range and multiple situations can be realized. For example, the input voltage of the operational amplifier can be ensured by using the adjustment voltage and the ground in combination with each voltage dividing resistor, the voltage gain corresponding to the proportion is realized, the output common mode of the operational amplifier is controlled on the value range corresponding to the adjustment voltage, the common mode of the comparator is controlled through the adjustment voltage, and the input of the operational amplifier is ensured not to be overvoltage, and the SOA risk is avoided.

[0059] PleaseFigure 4 on the basis of Figure 5 , Figure 5 the first end of the second input branch in the input module in the utility model is grounded, the corresponding circuit principle diagram is shown; the third input branch 304 includes the first resistor R1, the second resistor R2; the second input branch 303 includes the third resistor R3; the first end of the first resistor R1 is used for inputting the adjustment voltage; the second end of the first resistor R1 is connected with the first end of the second resistor R2; the second end of the second resistor R2 is connected with the second input end of the operational amplifier U1 and the first end of the third resistor R3 respectively; the second end of the third resistor R3 is grounded.

[0060] on the basis of Figure 5 , the feedback branch 305 includes the fourth resistor R4 and the fifth resistor R5; the first input branch 302 includes the sixth resistor R6; the first end of the fourth resistor R4 is connected with the output end of the operational amplifier U1; the second end of the fourth resistor R4 is connected with the first end of the fifth resistor R5; the second end of the fifth resistor R5 is connected with the first input end of the operational amplifier U1 and the first end of the sixth resistor R6 respectively; the second end of the sixth resistor R6 is used for inputting the reference voltage.

[0061] When the comparison module includes the comparator, the output end of the operational amplifier U1 is connected with the positive phase input end of the comparator; the negative phase input end of the comparator is used for connecting the reference voltage VREF2.

[0062] It should be noted that the first power supply voltage can be the input voltage Vin; the ground end can be the ground corresponding to the input voltage Vin. The above-mentioned voltage values, the adjustment voltage and the reference voltage can be provided by one or more power supplies to ensure that the overvoltage detection circuit operates normally, wherein the value of the adjustment voltage can be adjusted as needed.

[0063] Based on this, in the embodiment, the output common mode of the operational amplifier can be changed by adjusting the resistance values of the above-mentioned resistors. In the embodiment, the resistance values of the above-mentioned resistors are not limited. In a possible implementation manner, the resistance value of the first resistor is greater than the resistance value of the second resistor; the resistance value of the fourth resistor is equal to the resistance value of the first resistor; the resistance value of the fifth resistor is equal to the resistance value of the second resistor; and the resistance value of the sixth resistor is equal to the resistance value of the third resistor. Since the resistance value of the first resistor is greater than the resistance value of the second resistor, the resistance value of the fourth resistor is greater than the resistance value of the fifth resistor by analogy.

[0064] In the embodiment, when the above-mentioned resistors are resistors with fixed resistance values, the gain of the input module can be adjusted by changing the connection of the resistance values of the first resistor and the fourth resistor to change the corresponding resistance value ratio.

[0065] In a possible implementation manner, on the basis of Figure 5 on the basis of Figure 6 ,Figure 6 The utility model discloses a first end of the second input branch in the input module is grounded, and the corresponding another kind of circuit schematic diagram is shown, when the first resistance R1, fourth resistance R4 are target resistance, switch unit 301 includes first switch K1, second switch K2, first switch K1 is connected in parallel with first resistance R1, and second switch K2 is connected in parallel with fourth resistance R4.

[0066] When being in the first working state, the control module is used to send the first control signal to the first switch K1 and the second switch K2, and the first switch K1 and the second switch K2 are both closed, and the switch unit 301 is in the first gain output state.When being in the second working state, the control module 103 is used to send the second control signal to the first switch K1 and the second switch K2, and the first switch K1 and the second switch K2 are both closed;The switch unit 301 is in the second gain output state.Correspondingly, the gain value corresponding to the first gain output state is less than the gain value corresponding to the second gain output state.

[0067] Among them, the gain value corresponding to the first gain output state is less than 1;The overvoltage detection circuit can be compared to the low positive voltage range of the large high voltage or large negative voltage in a large range.When the gain value corresponding to the second gain output state is greater than 1, the overvoltage detection circuit can amplify the small signal change in a small range and then compare, reduce the resolution requirement of the comparator.Furthermore, the detection function of overvoltage in a large range of multiple situations is realized.

[0068] Second implementation

[0069] Different from the first implementation, the first end of the second input branch is used for receiving the second power supply voltage in the second implementation.

[0070] Among them, when the first end of the second input branch is used for receiving the second power supply voltage, the input module includes differential circuit. Figure 5 On the basis of Figure 7 , Figure 7 The utility model discloses the corresponding circuit schematic diagram when the first end of the second input branch in the input module is used for receiving the second power supply voltage.The circuit diagram is similar to the circuit diagram structure of Figure 5 Corresponding, and the principle can refer to the principle of the corresponding principle of the last embodiment, and the basic principle of differential circuit in prior art.This place does not repeat.

[0071] Embodiment two

[0072] Please refer to Figure 8 , Figure 8The module schematic view of the input module in the utility model is shown; the input module 101 in the embodiment comprises a voltage dividing unit 401, the voltage dividing unit 401 comprises a first input end, a second input end and a third input end; the first input end is used for inputting a first power supply voltage; the second input end is used for inputting an adjustment voltage to adjust the output common mode of an operational amplifier; the third input end is grounded; the voltage dividing unit 401 further comprises an output end, and the output end is connected with the input end of a comparison module 102.

[0073] It should be noted that the utility model is not limited to the structure of the voltage dividing unit described above. For example, the voltage dividing unit can be composed of multiple resistors. In one possible implementation, on the basis of Figure 7 , reference is made to Figure 9 , Figure 9 The circuit principle diagram of the input module in the utility model is shown. The voltage dividing unit 401 comprises a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a third switch K3, a fourth switch K4, a fifth switch K5 and a sixth switch K6, wherein the third switch K3 and the fourth switch K4 are used for adjusting the connection of the voltage dividing resistors and changing the corresponding resistance ratio; the fifth switch K5 and the sixth switch K6 are used for changing the connection of the adjustment voltage and the ground end.

[0074] Specifically, the first end of the seventh resistor R7 is used for inputting the first power supply voltage, the second end of the seventh resistor R7 is connected with the first end of the eighth resistor R8 and the first end of the third switch K3; the second end of the third switch K3 is connected with the positive input end of the comparison module 102, and the negative input end of the comparison module 102 is used for inputting a reference voltage; the second end of the eighth resistor R8 is connected with the first end of the ninth resistor R9 and the first end of the fourth switch K4; the second end of the fourth switch K4 is connected with the positive input end of the comparison module 102; the second end of the ninth resistor R9 is connected with the adjustment voltage and the ground end through the fifth switch K5 and the sixth switch K6 respectively.

[0075] When the comparison module comprises a comparator, the second end of the third switch K3 is connected with the positive input end of the comparator; the negative input end of the comparator is used for connecting the reference voltage VREF2.

[0076] The control ends of the above-mentioned switches are connected with a control module, so as to adjust the conduction and / or shutdown of the corresponding switches through the control module, to correspondingly adjust the connected resistors and meet the preset resistance ratio.

[0077] Based on this, the utility model can increase the disturbance suppression to the ground, improve the detection range and meet the demand of small signal high-precision detection on the basis of ensuring the size of the device.

[0078] With the same idea as the previous embodiment, the utility model still provides a kind of overvoltage detection device, including power supply and the overvoltage detection circuit of any one described in the first aspect, on the basis of guaranteeing device size, increase the disturbance inhibition to ground, improve detection range, and meet the demand of small signal high-precision detection.

[0079] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the utility model, and not limited thereto; Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the utility model.

Claims

1. An overvoltage detection circuit, characterized by comprising: The overvoltage detection circuit comprises an input module, a comparison module and a control module, an input end of the input module is configured to input a sampling signal, an output end of the input module is connected with an input end of the comparison module, and a control end of the input module is connected with the control module; the sampling signal is configured to represent different input electrical signals; The overvoltage detection circuit comprises a plurality of working states; each working state corresponds to a different gain output state. The control module is configured to send different control signals to the input module to adjust the resistance value of the input module, so that the input module is in different gain output states.

2. The overvoltage detection circuit of claim 1, wherein, The input module comprises a plurality of voltage dividing resistors, the resistance values between the voltage dividing resistors satisfy a preset resistance value ratio, so as to change the output gain of the input module by adjusting the preset resistance value ratio.

3. The overvoltage detection circuit of claim 2, wherein, When the voltage dividing resistors comprise at least one target resistor, the input module further comprises a switching unit connected in parallel with the target resistor; the control module is configured to send different control signals to the switching unit to adjust the on-off state of the switching unit, so as to adjust the resistance value ratio of the input module, and make the input module in different gain output states.

4. The overvoltage detection circuit of claim 3, wherein, When the input module comprises a first input branch, a second input branch, a third input branch, a feedback branch and an operational amplifier, a first end of the first input branch is configured to input a first power supply voltage, a second end of the first input branch is connected with a first input end of the operational amplifier and a first end of the feedback branch; a second end of the feedback branch is connected with an output end of the operational amplifier; a first end of the second input branch is grounded or configured to receive a second power supply voltage, a second end of the second input branch is connected with a second input end of the operational amplifier and a second end of the third input branch; a first end of the third input branch is configured to input an adjustment voltage to adjust the output common mode of the operational amplifier; The first input branch and the feedback branch each comprise a voltage dividing resistor, and the voltage dividing resistors form a first resistance ratio; the second input branch and the third input branch each comprise a voltage dividing resistor, and the voltage dividing resistors form a second resistance ratio; the value of the first resistance ratio is equal to the value of the second resistance ratio.

5. The overvoltage detection circuit of claim 4, wherein, When the first end of the second input branch is configured to receive a second power supply voltage, the input module comprises a differential circuit.

6. The overvoltage detection circuit of claim 4, wherein, When the first end of the second input branch is grounded, the third input branch comprises a first resistor and a second resistor; the second input branch comprises a third resistor; a first end of the first resistor is configured to input an adjustment voltage; a second end of the first resistor is connected with a first end of the second resistor; a second end of the second resistor is connected with a second input end of the operational amplifier and a first end of the third resistor, respectively; and a second end of the third resistor is grounded; The resistance value of the first resistor is greater than the resistance value of the second resistor.

7. The overvoltage detection circuit of claim 6, wherein, The feedback branch comprises a fourth resistor and a fifth resistor; the first input branch comprises a sixth resistor; a first end of the fourth resistor is connected with an output end of the operational amplifier; a second end of the fourth resistor is connected with a first end of the fifth resistor; a second end of the fifth resistor is connected with a first input end of the operational amplifier and a first end of the sixth resistor respectively; a second end of the sixth resistor is used for inputting a reference voltage; The resistance value of the fourth resistor is equal to that of the first resistor; the resistance value of the fifth resistor is equal to that of the second resistor; and the resistance value of the sixth resistor is equal to that of the third resistor.

8. The overvoltage detection circuit of claim 7, wherein, When the first resistor and the fourth resistor are target resistors, the switch unit comprises a first switch and a second switch; the first switch is connected in parallel with the first resistor; and the second switch is connected in parallel with the fourth resistor. When in the first working state, the control module is configured to send a first control signal to the first switch and the second switch, the first switch and the second switch are both closed, and the switch unit is in a first gain output state. When in the second working state, the control module is configured to send a second control signal to the first switch and the second switch, the first switch and the second switch are both turned off, and the switch unit is in a second gain output state. The gain value corresponding to the first gain output state is less than that corresponding to the second gain output state.

9. The overvoltage detection circuit of claim 3, wherein, The input module comprises a voltage dividing unit, the voltage dividing unit comprises a first input end, a second input end and a third input end; the first input end is used for inputting a first power supply voltage; the second input end is used for inputting an adjustment voltage to adjust an output common mode of the input module; and the third input end is grounded. The voltage dividing unit further comprises an output end, which is connected with an input end of the comparison module.

10. An overvoltage detection device, characterized by comprising: The overvoltage detection circuit comprises a power supply and the overvoltage detection circuit according to any one of claims 1 to 9.

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