Signal conditioning circuit, signal acquisition device and charging pile

Abstract

The utility model discloses a signal conditioning circuit, a signal acquisition device and a charging pile, and relates to the technical field of charging. The signal conditioning circuit is connected with the sensing unit and comprises a first voltage dividing module, a second voltage dividing module, an operational amplifier module and a filter capacitor. The first voltage dividing module and the second voltage dividing module are connected in parallel; the first end of the operational amplifier module is connected with the first voltage dividing module to form a first node, the second end of the operational amplifier module is connected with the second voltage dividing module to form a second node, and the third end of the operational amplifier module is connected with the second voltage dividing module to form a third node; the filter capacitor is connected in parallel to two ends of the sensing unit and is used for filtering interference signals. Therefore, the problem that in the long-distance charging and discharging process, the charging and discharging temperature test is not accurate due to the fact that the temperature collection signal is prone to being interfered is solved, and the reliability and stability of temperature collection are improved.

Description

Technical Field

[0001] This application relates to the field of charging technology, and in particular to a signal conditioning circuit, a signal acquisition device, and a charging pile. Background Technology

[0002] In charging systems, the charging gun head may generate excessive heat due to high current. If this heat is not effectively monitored and controlled, it can lead to overheating of the gun head, causing a series of safety hazards. Therefore, it is necessary to monitor the temperature of the charging gun head.

[0003] Currently, existing temperature detection circuits for detecting the temperature of charging gun heads are relatively complex in design and expensive. Furthermore, in long-distance charging and discharging test scenarios, due to the long signal transmission line of the gun head, temperature acquisition is prone to large jumps, and there is significant crosstalk in the temperature acquisition signal, resulting in inaccurate temperature acquisition results and thus affecting the temperature test results of charging and discharging. Summary of the Invention

[0004] The main purpose of this application is to provide a signal conditioning circuit, a signal acquisition device, and a charging pile to solve the problem that temperature acquisition signals are easily interfered with during long-distance charging and discharging, resulting in inaccurate charging and discharging temperature testing, and to improve the reliability and stability of temperature acquisition.

[0005] To achieve the above objectives, this application provides a signal conditioning circuit connected to a sensing unit, the signal conditioning circuit including a first voltage divider module, a second voltage divider module, an operational amplifier module, and a filter capacitor;

[0006] The first voltage divider module is connected in parallel with the second voltage divider module;

[0007] The first terminal of the operational amplifier module is connected to the first voltage divider module to form a first node, the second terminal of the operational amplifier module is connected to the second voltage divider module to form a second node, and the third terminal of the operational amplifier module is connected to the second voltage divider module to form a third node.

[0008] The filter capacitor is connected in parallel across the two ends of the sensing unit to filter out interference signals.

[0009] Optionally, the first voltage divider module includes a first resistor; one end of the first resistor is connected to an external power supply, the other end of the first resistor is connected to one end of the sensing unit, and the other end of the sensing unit is grounded.

[0010] Optionally, the second voltage divider module further includes a second resistor and a third resistor; one end of the second resistor is connected to an external power supply, and the other end of the second resistor is connected to the second node; one end of the third resistor is connected to the second node, and the other end of the third resistor is connected to the third node, and the third node is grounded.

[0011] Optionally, the operational amplifier module includes an operational amplifier, a balancing unit, and a feedback unit; the first end of the balancing unit is connected to the first node, the second end of the balancing unit is connected to the third node, and the third end of the balancing unit is connected to the non-inverting input terminal of the operational amplifier; the first end of the feedback unit is connected to the second node, the second end of the feedback unit is connected to the output terminal of the operational amplifier, and the third end of the feedback unit is connected to the inverting input terminal of the operational amplifier.

[0012] Optionally, the balancing unit includes a fourth resistor and a fifth resistor; one end of the fourth resistor is connected to the first node, and the other end of the fourth resistor is connected to the non-inverting input terminal of the operational amplifier to form a fourth node; one end of the fifth resistor is connected to the fourth node, and the other end of the fifth resistor is connected to the third node.

[0013] Optionally, the feedback unit includes a sixth resistor and a seventh resistor; one end of the sixth resistor is connected to the second node, and the other end of the sixth resistor is connected to the inverting input terminal of the operational amplifier to form a fifth node; one end of the seventh resistor is connected to the fifth node, and the other end of the seventh resistor is connected to the output terminal of the operational amplifier.

[0014] Optionally, the resistance value of the fourth resistor is the same as that of the sixth resistor.

[0015] Optionally, the resistance value of the fifth resistor is the same as that of the seventh resistor.

[0016] In addition, to achieve the above objectives, this application also provides a signal acquisition device, including a signal conditioning circuit, a sensing unit, and a voltage sampling unit as described above; the signal conditioning circuit is connected to both ends of the sensing unit, the output terminal of the signal conditioning circuit is connected to the input terminal of the voltage sampling unit, and the voltage sampling unit is used to acquire the output voltage of the signal conditioning circuit to determine the temperature acquired by the sensing unit based on the output voltage.

[0017] This application also provides a charging pile, including the signal acquisition device and the charging gun head as described above; the sensing unit in the signal acquisition device is located in the charging gun head, and the sensing unit is used to acquire the temperature of the charging gun head.

[0018] The signal conditioning circuit of this application, by connecting a filter capacitor in parallel across the two ends of the sensing unit, can filter out interference signals on the signal transmission line connecting the sensing unit and the signal conditioning circuit, thereby effectively solving the problem that the temperature acquisition signal is easily interfered with during long-distance charging and discharging, resulting in inaccurate charging and discharging tests, and improving the reliability and stability of temperature acquisition. Attached Figure Description

[0019] Figure 1 This is one of the circuit structure diagrams of the signal conditioning circuit in the embodiments of this application;

[0020] Figure 2 This is a second schematic diagram of the circuit structure of the signal conditioning circuit in an embodiment of this application;

[0021] Figure 3 This is the third schematic diagram of the circuit structure of the signal conditioning circuit in the embodiment of this application;

[0022] Figure 4 This is the fourth schematic diagram of the circuit structure of the signal conditioning circuit in the embodiment of this application;

[0023] Figure 5 This is a schematic diagram of the circuit structure of the signal acquisition device according to an embodiment of this application;

[0024] Figure 6 This is a schematic diagram of the structure of a charging pile according to an embodiment of this application;

[0025] In the diagram, 100 is the signal conditioning circuit; 110 is the first voltage divider module; 120 is the second voltage divider module; 130 is the operational amplifier module; 131 is the balancing unit; 132 is the feedback unit; 200 is the sensing unit; and 300 is the voltage sampling unit.

[0026] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] With the rapid growth of the electric vehicle market, the demand for efficient and safe charging infrastructure is also increasing. During charging, especially in fast charging scenarios, the charging gun head may generate high temperatures due to the large current, posing a potential safety risk to both charging equipment and users. Therefore, accurately monitoring the temperature of the charging gun head is crucial for preventing overheating.

[0029] Currently, existing temperature detection circuits for detecting the temperature of charging gun heads are usually quite complex in design, using a large number of operational amplifiers at the front end of the temperature detection circuit, resulting in higher costs and larger sizes.

[0030] Secondly, the temperature acquisition signal output by the temperature sensor in the charging gun head is usually transmitted to the back end along with other signals via the charging cable. These other signals include the power signal of the high-voltage electricity during charging. When the charging cable is long (e.g., 100 meters), it is prone to introducing noise and interference, causing a "large jump" phenomenon in the temperature acquisition signal—that is, a sudden and significant fluctuation in the temperature reading. Other signals in the cable can also interfere with the temperature acquisition signal output by the temperature sensor, thus affecting the accuracy of the temperature detection results. It should be noted that the temperature acquisition signal is generally the electrical signal output by the thermistor in the temperature sensor.

[0031] Based on this, embodiments of this application provide a signal conditioning circuit, a signal acquisition device, and a charging pile. By adding a filter capacitor to the signal conditioning circuit, the problem of inaccurate charging and discharging temperature testing caused by interference with the temperature acquisition signal during long-distance charging and discharging is solved, thereby improving the reliability and stability of temperature acquisition.

[0032] Figure 1 This is one of the circuit structure diagrams of the signal conditioning circuit in an embodiment of this application. For example... Figure 1 As shown, the signal conditioning circuit 100 is connected to the sensing unit 200. The signal conditioning circuit 100 may include a first voltage divider module 110, a second voltage divider module 120, an operational amplifier module 130, and a filter capacitor C1.

[0033] The first voltage divider module 110 and the second voltage divider module 120 are connected in parallel; the first terminal S1 of the operational amplifier module 130 is connected to the first voltage divider module 110 to form a first node N1, the second terminal S2 of the operational amplifier module 130 is connected to the second voltage divider module 120 to form a second node N2, and the third terminal S3 of the operational amplifier module 130 is connected to the second voltage divider module 120 to form a third node N3; the filter capacitor C1 is connected in parallel across the two ends of the sensing unit 200 to filter out interference signals.

[0034] First, it should be noted that the signal conditioning circuit 100 in this embodiment can be a signal conditioning circuit for temperature sampling signals, and can be applied in any temperature detection scenario, especially in the scenario of temperature detection of a charging gun head with a long charging cable.

[0035] In this embodiment, the sensing unit 200 can be any device, apparatus, or equipment capable of acquiring temperature and outputting a signal. For example, the sensing unit 200 can be a temperature sensor, a thermistor, an RTD (Resistance Temperature Detector), or a thermocouple; no specific limitation is made to the sensing unit 200 here. It should be noted that the temperature sampling signal mentioned in this embodiment refers to the signal output by the sensing unit 200.

[0036] In this embodiment, the signal conditioning circuit 100 is connected to both ends of the sensing unit 200 via two transmission cables. It is used to receive the temperature sampling signal output by the sensing unit 200 and improve the signal quality of the temperature sampling signal by amplifying and filtering it. Finally, the temperature value detected by the sensing unit 200 is determined by the electrical signal output by the signal conditioning circuit 100.

[0037] Furthermore, the first voltage divider module 110 and the second voltage divider module 120 in the signal conditioning circuit 100 are connected in parallel, and one end of the first voltage divider module 110 and the second voltage divider module 120 can be connected to the same external power supply; the first voltage divider module 110 can be connected to the sensing unit 200, and the external power supply can supply power to the sensing unit 200 through the first voltage divider module 110.

[0038] Operational amplifier module 130 is connected to the first voltage divider module 110 and the second voltage divider module 120, respectively. Operational amplifier module 130 can be a subtraction amplifier circuit. By obtaining the output voltage of operational amplifier module 130, the voltage drop of the first voltage divider module 110, and the voltage drop of the second voltage divider module 120, the resistance value of sensing unit 200 can be derived. Since the resistance value of sensing unit 200 has a certain proportional relationship with the detected temperature, the detected temperature value can be further derived from the resistance value of sensing unit 200.

[0039] In this embodiment, the filter capacitor C1 is connected in parallel across the two ends of the sensing unit 200, specifically between the output ends of the two transmission cables, i.e., between the two input ends of the signal conditioning circuit 100. When the transmission cable is long, other signals in the cable can cause crosstalk to the temperature acquisition signal. This embodiment connects a filter capacitor C1 in parallel between the two output ends of the transmission cable, which effectively eliminates crosstalk from other signals to the temperature acquisition signal, thereby improving the stability and reliability of the temperature acquisition signal and ultimately increasing the accuracy of temperature detection. It should be noted that the interference signal mentioned in this embodiment refers to the signal that interferes with the temperature acquisition signal, i.e., the aforementioned other signals, such as power signals.

[0040] The following section uses a PT1000 temperature sensor as the sensing unit 200 to describe in detail the various modules in the signal conditioning circuit 100 of this application embodiment.

[0041] Figure 2 This is a second schematic diagram of the circuit structure of the signal conditioning circuit according to an embodiment of this application. Figure 2 As shown, in some embodiments, the first voltage divider module 110 includes a first resistor R1; one end of the first resistor R1 is connected to an external power supply, and the other end of the first resistor R1 is connected to one end of the sensing unit 200, and the other end of the sensing unit 200 is grounded.

[0042] Specifically, one end of the first resistor R1 can be connected to an external power supply, which can be a +5V power supply; the other end of the first resistor R1 can be connected to one end of the thermistor RT in the temperature sensor through the transmission cable T+. The first node N1 is between the first resistor R1 and the thermistor RT. The other end of the thermistor RT is grounded through the transmission cable T-. The resistance value of the first resistor R1 can be 10K, but this is only an example and the resistance value of the first resistor R1 is not limited here.

[0043] In this embodiment, the first resistor R1 and the thermistor RT in the temperature sensor form a voltage divider circuit, with the first resistor R1 acting as a voltage divider. Figure 2 Ua in the figure represents the voltage drop across the thermistor RT.

[0044] Continue to refer to Figure 2 In some embodiments, the second voltage divider module 120 further includes a second resistor R2 and a third resistor R3; one end of the second resistor R2 is connected to an external power supply, and the other end of the second resistor R2 is connected to a second node N2; one end of the third resistor R3 is connected to the second node N2, and the other end of the third resistor R3 is connected to the third node N3, which is grounded.

[0045] Specifically, one end of the second resistor R2 can also be connected to the aforementioned external power supply, and the other end of the second resistor R2 is connected to one end of the third resistor R3. The second node N2 is located between the second resistor R2 and the third resistor R3. The other end of the third resistor R3 is connected to the third node N3, and the third node N3 is grounded.

[0046] The resistance of the second resistor R2 can be 10KΩ, and the resistance of the third resistor R3 can be 820KΩ. The resistance values ​​of the second resistor R2 and the third resistor R3 are just examples, and the resistance values ​​of the second resistor R2 and the third resistor R3 are not limited here.

[0047] Similarly, in this embodiment, the second resistor R2 and the third resistor R3 form a voltage divider circuit, and both the second resistor R2 and the third resistor R3 serve the function of voltage division. Figure 2 Ub in the equation represents the voltage drop across the third resistor R3.

[0048] Figure 3 This is the third schematic diagram of the circuit structure of the signal conditioning circuit in an embodiment of this application. Figure 3 As shown, in some embodiments, the operational amplifier module 130 includes an operational amplifier U1, a balancing unit 131, and a feedback unit 132.

[0049] In this configuration, the first terminal S1 of the balancing unit 131 is connected to the first node N1, the second terminal S2 of the balancing unit 131 is connected to the third node N3, and the third terminal S3 of the balancing unit 131 is connected to the non-inverting input terminal of the operational amplifier U1; the first terminal S1 of the feedback unit 132 is connected to the second node N2, the second terminal S2 of the feedback unit 132 is connected to the output terminal of the operational amplifier U1, and the third terminal S3 of the feedback unit 132 is connected to the inverting input terminal of the operational amplifier U1.

[0050] It should be noted that the operational amplifier U1 in this embodiment can be a subtraction operational amplifier, which is an operational amplifier that can receive two input signals and output the difference between the two signals.

[0051] The balancing unit 131 and feedback unit 132 of the operational amplifier module 130 are used to implement the virtual short of the operational amplifier U1. The virtual short is an idealized characteristic of the operational amplifier U1 when it operates in a negative feedback configuration. It refers to the fact that, ideally, the voltage difference between the two input terminals (non-inverting input terminal and inverting input terminal) of the operational amplifier U1 is almost zero, even though these two terminals are not actually directly shorted together by a wire. This phenomenon can be used to simplify circuit analysis, thereby facilitating the subsequent derivation of the voltage output by the signal conditioning circuit 100.

[0052] The balancing unit 131 can be composed of multiple resistors, and similarly, the feedback unit 132 can also be composed of multiple resistors. The first terminal S1 of the balancing unit 131 is connected to the first voltage divider module 110 through the first node N1, the second terminal S2 of the balancing unit 131 is connected to the second voltage divider module 120 through the third node N3, and the third terminal S3 of the balancing unit 131 is connected to the non-inverting input terminal of the operational amplifier U1.

[0053] The first terminal S1 of the feedback unit 132 is connected to the second voltage divider module 120 through the second node N2, the second terminal S2 of the feedback unit 132 is connected to the output terminal of the operational amplifier U1, and the third terminal S3 of the feedback unit 132 is connected to the inverting input terminal of the operational amplifier U1. The feedback unit 132 is a feedback amplifier circuit.

[0054] The power supply terminal of operational amplifier U1 can be connected to an external power supply, which can provide +5V power to operational amplifier U1; the ground terminal of operational amplifier U1 is grounded.

[0055] Figure 4 This is the fourth schematic diagram of the circuit structure of the signal conditioning circuit according to an embodiment of this application. Figure 4 As shown, in some embodiments, the balancing unit 131 includes a fourth resistor R4 and a fifth resistor R5; one end of the fourth resistor R4 is connected to the first node N1, and the other end of the fourth resistor R4 is connected to the non-inverting input terminal of the operational amplifier U1 to form the fourth node N4; one end of the fifth resistor R5 is connected to the fourth node N4, and the other end of the fifth resistor R5 is connected to the third node N3.

[0056] In this embodiment, the resistance value of the fourth resistor R4 can be 51K and the resistance value of the fifth resistor R5 can be 510K. The resistance values ​​of the fourth resistor R4 and the fifth resistor R5 are only examples, and the resistance values ​​of the fourth resistor R4 and the fifth resistor R5 are not limited here.

[0057] Continue to refer to Figure 4 In some embodiments, the feedback unit 132 includes a sixth resistor R6 and a seventh resistor R7; one end of the sixth resistor R6 is connected to the second node N2, and the other end of the sixth resistor R6 is connected to the inverting input terminal of the operational amplifier U1 to form the fifth node N5; one end of the seventh resistor R7 is connected to the fifth node N5, and the other end of the seventh resistor R7 is connected to the output terminal of the operational amplifier U1.

[0058] In this embodiment, the resistance value of the sixth resistor R6 can be 51K and the resistance value of the seventh resistor R7 can be 510K. The resistance values ​​of the sixth resistor R6 and the seventh resistor R7 are only examples, and the resistance values ​​of the sixth resistor R6 and the seventh resistor R7 are not limited here.

[0059] In some implementations, the resistance of the fourth resistor R4 is the same as that of the sixth resistor R6. The resistance of the fifth resistor R5 is the same as that of the seventh resistor R7.

[0060] The following uses a thermistor with a positive temperature coefficient (PTC) as an example, combined with... Figure 4 The circuit principle of the signal conditioning circuit 100 in the embodiments of this application will be described in detail.

[0061] It is understandable that the thermistor RT, which has a positive temperature coefficient, collects the ambient temperature. The higher the temperature sampled by the thermistor RT, the greater the resistance of the thermistor RT, and the greater the voltage drop across the thermistor RT.

[0062] When sampling temperature, the positive temperature coefficient thermistor RT can convert the temperature signal into a resistance value; the +5V voltage input from the external power supply is divided by the thermistor RT and then input to the non-inverting input of the operational amplifier U1. Figure 4 The value of Ua in the thermistor changes with the resistance of the thermistor RT.

[0063] Similarly, the +5V voltage from the external power supply is divided by the third resistor R3 and then input to the inverting input of the operational amplifier U1. Figure 4 Ub in the equation represents the voltage drop across the third resistor R3. Since the input voltage, the resistance of the second resistor R2, and the resistance of the third resistor R3 remain unchanged, the value of Ub is a fixed value.

[0064] The inverting input of operational amplifier U1 is grounded through the sixth resistor R6. At this time, the gain of operational amplifier U1 can be changed by adjusting the resistance values ​​of the sixth resistor R6 and the seventh resistor R7. The ratio of the seventh resistor R7 to the sixth resistor R6 is the amplification factor.

[0065] Based on this, we can first obtain the following formula (1) based on the voltage division relationship between the second resistor R2 and the third resistor R3, and then calculate Ub using the following formula (1):

[0066]

[0067] Among them, U z Ub is the input voltage of the external power supply connected to the first voltage divider module 110. In the formula, the resistance values ​​of the second resistor R2, the third resistor R3, and the input voltage of the external power supply are known, therefore Ub can be calculated.

[0068] Ua can be further calculated using the following formula (2):

[0069]

[0070] In the formula, Uo is the output voltage of the signal conditioning circuit 100, which can be obtained through a voltage detection circuit or a voltage detection device. Since the output voltage Uo, the resistance of the seventh resistor R7, the resistance of the sixth resistor R6, and Ub are all known quantities, Ua can be calculated.

[0071] Finally, based on the voltage division relationship between the first resistor R1 and the thermistor RT, the following formula (3) can be obtained. The required resistance value of the thermistor RT can be calculated through formula (3).

[0072]

[0073] In the formula, the resistance value of the first resistor R1 and Ua are both known quantities, so RP can be calculated.

[0074] Therefore, by adding a filter capacitor C1 to the signal conditioning circuit 100, interference signals caused by interference signals to the temperature acquisition signal are eliminated. This solves the problem that the temperature acquisition signal is easily interfered with during long-distance charging and discharging, resulting in inaccurate charging and discharging temperature testing. This improves the reliability and stability of temperature acquisition, thereby enhancing the accuracy of temperature detection. Furthermore, the signal conditioning circuit 100 in this embodiment only requires one operational amplifier U1, using fewer components, thus resulting in lower cost and a smaller PCB board space.

[0075] Figure 5 This is a schematic diagram of the circuit structure of the signal acquisition device according to an embodiment of this application.

[0076] Based on the above embodiments, this application also provides a signal acquisition device. For example... Figure 5 As shown, the signal acquisition device may include the signal conditioning circuit 100, the sensing unit 200 and the voltage sampling unit 300 as described above.

[0077] The signal conditioning circuit 100 is connected to both ends of the sensing unit 200. The output end of the signal conditioning circuit 100 is connected to the input end of the voltage sampling unit 300. The voltage sampling unit 300 is used to collect the output voltage of the signal conditioning circuit 100 in order to determine the temperature collected by the sensing unit 200 based on the output voltage.

[0078] It should be noted that the sensing unit 200 can be any device, apparatus, or equipment capable of acquiring temperature and outputting a signal. For example, the sensing unit 200 can be a temperature sensor or a thermistor RT. The voltage sampling unit 300 can be any device, apparatus, or equipment capable of acquiring voltage and obtaining voltage values. For example, the voltage sampling unit 300 can be an ADC chip.

[0079] In this embodiment, the input terminal of the voltage sampling unit 300 is connected to the output terminal of the signal conditioning circuit 100, that is, to the output terminal of the operational amplifier U1 in the signal conditioning circuit 100. The other end of the seventh resistor R7 in the signal conditioning circuit 100 can be connected between the output terminal of the operational amplifier U1 and the voltage sampling unit 300.

[0080] The voltage sampling unit 300 is used to collect the output voltage Uo of the operational amplifier U1 so that the resistance value of the sensing unit 200 can be calculated from the output voltage Uo of the operational amplifier U1, and then the temperature value sampled by the sensing unit 200 can be calculated.

[0081] It should be noted that for details not disclosed in the signal acquisition device of this embodiment, please refer to the details disclosed in the embodiment of the signal conditioning circuit in this specification, which will not be repeated here.

[0082] Figure 6 This is a schematic diagram of the structure of a charging pile according to an embodiment of this application.

[0083] Based on the above embodiments, this application also provides a charging pile, including the signal acquisition device and the charging gun head as described above; the sensing unit 200 in the signal acquisition device is located in the charging gun head, and the sensing unit 200 is used to collect the temperature of the charging gun head.

[0084] Specifically, the sensing unit 200 is located inside the charging gun head of the charging pile and can sample the temperature of the charging gun head. At the same time, the resistance of the sensing unit 200 will change with the sampling temperature. By determining the resistance of the sensing unit 200, the temperature value of the charging gun head can be obtained.

[0085] It should be noted that for details not disclosed in the charging pile of this embodiment, please refer to the details disclosed in the embodiment of the signal conditioning circuit in this specification, which will not be repeated here.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A signal conditioning circuit, characterized in that, Connected to the sensing unit, the signal conditioning circuit includes a first voltage divider module, a second voltage divider module, an operational amplifier module, and a filter capacitor; The first voltage divider module is connected in parallel with the second voltage divider module; The first terminal of the operational amplifier module is connected to the first voltage divider module to form a first node, the second terminal of the operational amplifier module is connected to the second voltage divider module to form a second node, and the third terminal of the operational amplifier module is connected to the second voltage divider module to form a third node. The filter capacitor is connected in parallel across the two ends of the sensing unit to filter out interference signals.

2. The signal conditioning circuit according to claim 1, characterized in that, The first voltage divider module includes a first resistor; One end of the first resistor is connected to an external power supply, and the other end of the first resistor is connected to one end of the sensing unit, while the other end of the sensing unit is grounded.

3. The signal conditioning circuit according to claim 1, characterized in that, The second voltage divider module also includes a second resistor and a third resistor; One end of the second resistor is connected to an external power supply, and the other end of the second resistor is connected to the second node; One end of the third resistor is connected to the second node, the other end of the third resistor is connected to the third node, and the third node is grounded.

4. The signal conditioning circuit according to claim 1, characterized in that, The operational amplifier module includes an operational amplifier, a balanced unit, and a feedback unit; The first end of the balancing unit is connected to the first node, the second end of the balancing unit is connected to the third node, and the third end of the balancing unit is connected to the non-inverting input of the operational amplifier. The first end of the feedback unit is connected to the second node, the second end of the feedback unit is connected to the output end of the operational amplifier, and the third end of the feedback unit is connected to the inverting input end of the operational amplifier.

5. The signal conditioning circuit according to claim 4, characterized in that, The balancing unit includes a fourth resistor and a fifth resistor; One end of the fourth resistor is connected to the first node, and the other end of the fourth resistor is connected to the non-inverting input terminal of the operational amplifier to form the fourth node; One end of the fifth resistor is connected to the fourth node, and the other end of the fifth resistor is connected to the third node.

6. The signal conditioning circuit according to claim 5, characterized in that, The feedback unit includes a sixth resistor and a seventh resistor; One end of the sixth resistor is connected to the second node, and the other end of the sixth resistor is connected to the inverting input of the operational amplifier to form the fifth node; One end of the seventh resistor is connected to the fifth node, and the other end of the seventh resistor is connected to the output terminal of the operational amplifier.

7. The signal conditioning circuit according to claim 6, characterized in that, The resistance value of the fourth resistor is the same as that of the sixth resistor.

8. The signal conditioning circuit according to claim 6, characterized in that, The resistance value of the fifth resistor is the same as that of the seventh resistor.

9. A signal acquisition device, characterized in that, Includes the signal conditioning circuit, sensing unit, and voltage sampling unit as described in any one of claims 1-8; The signal conditioning circuit is connected to both ends of the sensing unit. The output terminal of the signal conditioning circuit is connected to the input terminal of the voltage sampling unit. The voltage sampling unit is used to collect the output voltage of the signal conditioning circuit to determine the temperature collected by the sensing unit based on the output voltage.

10. A charging pile, characterized in that, Includes the signal acquisition device and charging gun head as described in claim 9; The sensing unit in the signal acquisition device is located in the charging gun head, and the sensing unit is used to collect the temperature of the charging gun head.

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