Double-thermistor temperature measuring circuit

Abstract

The utility model provides a temperature measuring circuit with double thermistors. Comprising a sensor circuit and a Wheatstone bridge, and the Wheatstone bridge comprises a voltage protection module, an anti-interference module, a noise reduction module and a voltage stabilization module. The voltage protection module, the anti-interference module, the noise reduction module and the voltage stabilization module are connected in sequence. The end, away from the anti-interference module, of the voltage protection module is connected with the sensor circuit. The sensor circuit comprises a first thermosensitive resistor RT1 and a second thermosensitive resistor RT2, and the first thermosensitive resistor RT1, the second thermosensitive resistor RT2 and the Wheatstone bridge are electrically connected to form a double-thermistor temperature measurement circuit; according to the double-thermistor temperature measurement circuit, the structure of the thermistor temperature measurement circuit can be simplified, the cost of the temperature measurement circuit is reduced, the measurement accuracy and stability of the temperature measurement circuit are improved, and the safety of the temperature measurement circuit is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of household appliances, in particular to a dual-thermistor temperature measurement circuit. Background Art

[0002] Thermistors are temperature-sensitive resistors with advantages such as high sensitivity, fast response, and low cost. They are widely used for temperature measurement and control in household appliances such as microwave ovens and electric ovens. However, thermistors suffer from nonlinearity, which affects their measurement accuracy and stability, and creates significant difficulties in subsequent signal acquisition and processing.

[0003] At present, in order to reduce the nonlinearity of thermistors and improve their measurement accuracy and stability, the following methods are usually used:

[0004] ①Use a constant current source to power the thermistor;

[0005] ② Use temperature compensation algorithm to compensate the temperature characteristics of the thermistor.

[0006] While these methods have reduced thermistor nonlinearity to a certain extent and improved their measurement accuracy and stability, some issues still exist, such as insufficient stability of the constant current source and the high complexity of the temperature compensation algorithm. This results in increased complexity and cost of thermistor temperature measurement circuits. Therefore, it is of great significance to study how to improve thermistor measurement accuracy and stability while simplifying the structural complexity and cost of the temperature measurement circuit.

[0007] Patent CN113091940B describes a wind speed and direction sensor with integrated heating and temperature measurement. First, four or eight centrally symmetrical thermistors are fabricated on the chip surface using micromachining technology. These thermistors serve both as heating elements to maintain the chip's average temperature above a constant ambient temperature and as temperature measuring elements to sense small temperature differences caused by the fluid on the chip surface. The thermistors form a Wheatstone bridge circuit, powered by a constant temperature differential closed-loop control circuit that provides a voltage that increases with wind speed. This results in a closed-loop Wheatstone bridge with increased sensitivity at high wind speeds. However, since home appliances are typically located indoors, this circuit cannot be used to measure the temperature inside the appliance. Furthermore, even if it were used to control thermistor temperature measurement within the appliance, the centrally symmetrical arrangement of the different thermistors in the circuit does not address the high nonlinearity of the thermistors, which results in poor measurement accuracy. Furthermore, the circuit employs multiple Wheatstone bridges in parallel, which can complicate the overall circuit structure. Utility Model Content

[0008] In view of this, the utility model aims to propose a dual thermistor temperature measurement circuit to solve the problems in the prior art that the thermistor temperature measurement circuit is relatively complex in structure and high in cost, and is limited by the nonlinear shortcomings of the thermistor, resulting in poor measurement accuracy and stability of the thermistor; thereby simplifying the structure of the thermistor temperature measurement circuit, reducing the cost of the temperature measurement circuit, improving the measurement accuracy and stability of the temperature measurement circuit, and improving the safety of the temperature measurement circuit.

[0009] In order to achieve the above-mentioned purpose, the technical solution of the utility model is achieved as follows:

[0010] The utility model relates to a dual-thermistor temperature measurement circuit, which includes a sensor circuit and a Wheatstone bridge. The Wheatstone bridge includes a voltage protection module, an anti-interference module, a noise reduction module and a voltage stabilization module. The voltage protection module, the anti-interference module, the noise reduction module and the voltage stabilization module are connected in sequence, and one end of the voltage protection module away from the anti-interference module is connected to the sensor circuit. The sensor circuit includes a thermistor 1 RT1 and a thermistor 2 RT2. The thermistor 1 RT1, the thermistor 2 RT2 and the Wheatstone bridge are electrically connected to form a dual-thermistor temperature measurement circuit.

[0011] Furthermore, the sensor circuit also includes a first resistor R1 and a third resistor R3; one end of the thermistor RT1 is connected to one end of the first resistor R1 and one end of the third resistor R3 respectively, the other end of the first resistor R1 is connected to one end of the thermistor RT2, and the other end of the thermistor RT1 is connected to the other end of the thermistor RT2 and the third resistor R3 respectively.

[0012] Furthermore, the first resistor R1 and the third resistor R3 are both fixed-value resistors.

[0013] Furthermore, the voltage protection module includes a second resistor R2, a fourth resistor R4, a fifth resistor R5, an operational amplifier A1, and an operational amplifier A2; one end of the second resistor R2 and the fourth resistor R4 is connected to the first power supply Vcc, and the other end of the second resistor R2 is respectively connected to an end of the third resistor R3 close to the first resistor R1 and the positive input end of the operational amplifier A1; the other end of the fourth resistor R4 is respectively connected to one end of the fifth resistor R5 and the positive input end of the operational amplifier A1, and the other end of the fifth resistor R5 is connected to an end of the third resistor R3 away from the first resistor R1 and then grounded.

[0014] Furthermore, the negative input terminal and output terminal of the operational amplifier A1 and the operational amplifier A2 are connected in parallel and are respectively connected to the anti-interference module; the negative power supply pins of the operational amplifier A1 and the operational amplifier A2 are respectively connected to the second power supply VEE, and the positive power supply pins of the operational amplifier A1 and the operational amplifier A2 are respectively connected to the third power supply VDD.

[0015] Furthermore, the operational amplifier A1 and the operational amplifier A2 form a voltage follower.

[0016] Furthermore, the anti-interference module includes a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, and an operational amplifier A3; one end of the sixth resistor R6 is connected to the output end of the operational amplifier A1, and the other end of the sixth resistor R6 is respectively connected to one end of the seventh resistor R7 and the negative input end of the operational amplifier A3, and the other end of the seventh resistor R7 is connected in parallel with the output end of the operational amplifier A3 and then connected to the noise reduction module; the positive input end of the operational amplifier A3 is respectively connected to one end of the eighth resistor R8 and the ninth resistor R9, the other end of the eighth resistor R8 is connected to the output end of the operational amplifier A2, and the other end of the ninth resistor R9 is grounded.

[0017] Furthermore, the operational amplifier A3 is a differential amplifier.

[0018] Furthermore, the noise reduction module includes a first zero resistor R10, a first resistor R11, a first second resistor R12, and an operational four-amplifier A4; one end of the first zero resistor R10 is connected to the output end of the operational three-amplifier A3, and the other end of the first zero resistor R10 is respectively connected to one end of the first first resistor R11 and the negative input end of the operational four-amplifier A4; the other end of the first first resistor R11 is connected in parallel with the output end of the operational four-amplifier A4, and is connected to the voltage stabilization module; the positive input end of the operational four-amplifier A4 is grounded through the first second resistor R12.

[0019] Furthermore, the voltage stabilizing module includes a first three-resistor R13 and a voltage stabilizing diode D1; one end of the first three-resistor R13 is connected to the output end of the operational four-amplifier A4, and the other end of the first three-resistor R13 is grounded through the voltage stabilizing diode D1.

[0020] Compared with the prior art, the dual thermistor temperature measurement circuit described in the present invention has the following beneficial effects:

[0021] This circuit configuration simplifies the structure of the thermistor temperature measurement circuit, reduces its cost, improves its measurement accuracy and stability, and enhances its safety. Furthermore, it significantly reduces the nonlinearity of the thermistor, improves its overall sensitivity over a wider temperature measurement range, and maintains sensitivity stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0023] Figure 1This is a schematic diagram of a circuit for measuring temperature using a voltage divider method commonly used in the prior art;

[0024] Figure 2 This is a schematic diagram of the dual thermistor sensor circuit principle in this application;

[0025] Figure 3 This is a schematic diagram of the overall structure of the dual thermistor temperature measurement circuit in this application;

[0026] Figure 4 Schematic diagram of the characteristic diagram of the sensor circuit before and after the temperature measurement circuit is improved;

[0027] Figure 5 This is a schematic diagram comparing the output voltage of the measurement circuit before and after the temperature measurement circuit is improved;

[0028] Figure 6 This is a schematic diagram comparing the sensitivity of the temperature measurement circuit before and after improvement.

[0029] Explanation of the accompanying symbols: 1. sensor circuit; 2. Wheatstone bridge; 21. voltage protection module; 22. anti-interference module; 23. noise reduction module; 24. voltage stabilization module. DETAILED DESCRIPTION

[0030] The following will describe the utility model concepts of the present disclosure using terms commonly used by those skilled in the art to convey the essence of their work to other persons skilled in the art. However, these utility model concepts can be embodied in many different forms and should not be considered as limited to the embodiments described herein.

[0031] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein can be combined with each other.

[0032] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0033] In the prior art, the resistance of the thermistor at temperature T1 is R T for:

[0034]

[0035] Where R REF It is the nominal resistance of the thermistor at room temperature T2 (usually 25°C);

[0036] B: The material constant of the thermistor, which is an inherent parameter;

[0037] T1 is the current temperature, T2 is the normal temperature, T1 and T2 are Kelvin temperature T k The conversion formula between them is: K =T(℃)+273.15.

[0038] Commonly used circuit diagram for measuring temperature using voltage divider method (such as Figure 1 As shown), the thermistor R T After being connected in series with the fixed resistor R and connected to the power supply, the output voltage U o for:

[0039] Although the combination of a thermistor and a fixed resistor in the voltage divider method temperature measurement circuit in the prior art can improve the circuit's sensitivity and stability to a certain extent, the nonlinear relationship between the thermistor's resistance value and temperature can easily lead to a nonlinear relationship between the output of the voltage divider circuit and temperature. This in turn causes the temperature measurement circuit to have serious nonlinearity, poor interchangeability, and susceptibility to environmental influences.

[0040] To address the problems in the prior art of thermistor temperature measurement circuits, such as the relatively complex structure and high cost, as well as the poor measurement accuracy and stability of thermistor due to the nonlinearity of thermistors, this embodiment proposes a dual-thermistor temperature measurement circuit, including a sensor circuit 1 and a Wheatstone bridge 2. The sensor circuit 1 and the Wheatstone bridge 2 are electrically connected to form a dual-thermistor temperature measurement circuit. The Wheatstone bridge 2 includes a voltage protection module 21, an anti-interference module 22, a noise reduction module 23, and a voltage stabilization module 24. The voltage protection module 21, the anti-interference module 22, the noise reduction module 23, and the voltage stabilization module 24 are connected in sequence, with the end of the voltage protection module 21 away from the anti-interference module 22 being connected to the sensor circuit 1. The sensor circuit 1 includes a thermistor 1 RT1 and a thermistor 2 RT2. The thermistor 1 RT1, the thermistor 2 RT2, and the Wheatstone bridge 2 are electrically connected to form a dual-thermistor temperature measurement circuit.

[0041] By embedding the sensor circuit 1 within the Wheatstone bridge 2 structure, an improved dual-thermistor temperature measurement circuit is constructed. This simplifies the structure of the thermistor temperature measurement circuit, reduces its cost, improves its measurement accuracy and stability, and enhances its safety. Furthermore, the nonlinearity of the thermistor is significantly reduced, and its overall sensitivity is increased over a wider temperature measurement range, while maintaining sensitivity stability.

[0042] The sensor circuit 1 also includes a first resistor R1 and a third resistor R3. One end of the thermistor RT1 is connected to one end of the first resistor R1 and one end of the third resistor R3 respectively, the other end of the first resistor R1 is connected to one end of the thermistor RT2, and the other end of the thermistor RT1 is connected to the other end of the thermistor RT2 and the other end of the third resistor R3 respectively. The first resistor R1 and the third resistor R3 are both fixed resistors, and the specific resistance values ​​are set as required. The equivalent circuit resistance of the sensor circuit 1 is R TEQ .

[0043] Unlike the prior art method of measuring temperature by dividing the thermistor voltage with a fixed resistor R, which fails to address the high nonlinearity of the thermistor, this application uses two thermistors of the same model, RT1 and RT2. Connecting RT2 in series with a first resistor R1 and then in parallel with RT1 and a third resistor R3 effectively reduces the nonlinear output of the dual thermistor and improves its measurement accuracy and stability.

[0044] The voltage protection module 21 includes a second resistor R2, a fourth resistor R4, a fifth resistor R5, an operational amplifier (A1), and an operational amplifier (A2). One end of the second resistor R2 and the fourth resistor R4 are connected to the first power supply Vcc, and the other end of the second resistor R2 is connected to the end of the third resistor R3 in the sensor circuit 1 that is closest to the first resistor R1 and the positive input of the operational amplifier A1. The other end of the fourth resistor R4 is connected to one end of the fifth resistor R5 and the positive input of the operational amplifier A1. The other end of the fifth resistor R5 is connected to the end of the third resistor R3 that is away from the first resistor R1 and then to ground. The negative input and output ends of the operational amplifiers A1 and A2 are connected in parallel and are then connected to the anti-interference module 22. The negative power supply pins of the operational amplifiers A1 and A2 are each connected to the second power supply VEE, and the positive power supply pins of the operational amplifiers A1 and A2 are each connected to the third power supply VDD. The operational amplifiers A1 and A2 form voltage followers. In this embodiment, the first power supply Vcc is 5V, the second power supply VEE is -12V, and the third power supply VDD is +12V. However, the specific values ​​of Vcc, VEE, and VDD are determined based on actual needs and are not limited to these values. Furthermore, the voltage at the junction of the second resistor R2, the third resistor R3, and the operational amplifier A2 (second) is the first input voltage Ui1 of the temperature control circuit; the voltage at the junction of the fourth resistor R4, the fifth resistor R5, and the operational amplifier A1 is the second input voltage Ui2 of the temperature control circuit.

[0045] The setting of a voltage follower with a very high input resistance formed by the operational amplifier A1 and the operational amplifier A2 can effectively protect the precise resistance setting of the Wheatstone bridge 2, thereby helping to improve the overall safety and operational stability of the temperature measurement circuit, and also helping to increase the applicability of the temperature control circuit, and can improve the sensitivity of the thermistor within a wider measurement and control temperature range.

[0046] The anti-interference module 22 includes a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, and an operational amplifier A3. One end of the sixth resistor R6 is connected to the output of the first operational amplifier A1 in the voltage protection module 21. The other end of the sixth resistor R6 is connected to one end of the seventh resistor R7 and the negative input of the third operational amplifier A3. The other end of the seventh resistor R7 is connected in parallel with the output of the third operational amplifier A3 and then connected to the noise reduction module 23. The positive input of the third operational amplifier A3 is connected to one end of the eighth resistor R8 and the ninth resistor R9, respectively. The other end of the eighth resistor R8 is connected to the output of the second operational amplifier A2 in the voltage protection module 21. The other end of the ninth resistor R9 is grounded. The positive power supply pin of the third operational amplifier A3 is connected to the third power supply VDD, and the negative power supply pin of the third operational amplifier A3 is connected to the second power supply VEE. The third operational amplifier A3 is a differential amplifier.

[0047] The placement of three operational amplifiers (A3) within Wheatstone bridge circuit 2 significantly improves measurement accuracy, particularly when measuring small resistance changes. It also helps suppress common-mode interference, ensuring the stability and accuracy of temperature measurement results. Furthermore, it enhances signal strength, facilitating subsequent circuit processing and analysis.

[0048] The noise reduction module 23 includes a first zero resistor R10, a first resistor R11, a first second resistor R12, and an operational quad amplifier A4. One end of the first zero resistor R10 is connected to the output end of the operational triple amplifier A3 in the anti-interference module 22, and the other end of the first zero resistor R10 is connected to one end of the first resistor R11 and the negative input end of the operational quad amplifier A4. The other end of the first first resistor R11 is connected in parallel with the output end of the operational quad amplifier A4 and then connected to the voltage stabilization module 24. The positive input end of the operational quad amplifier A4 is grounded through the first second resistor R12; the positive power supply pin of the operational quad amplifier A4 is connected to the third power supply VDD, and the negative power supply pin of the operational quad amplifier A4 is connected to the second power supply VEE. Among them, the operational quad amplifier A4 is an inverting amplifier.

[0049] The quad operational amplifier A4 within the noise reduction module 23 is configured to improve the accuracy and sensitivity of the temperature measurement signal within the circuit. It also helps to reduce common-mode noise, improve the signal-to-noise ratio of the measurement signal, and thus enhance the stability of the temperature measurement results.

[0050] The voltage stabilization module 24 includes a first three-resistor R13 and a voltage stabilization diode D1. One end of the first three-resistor R13 is connected to the output of the operational quad amplifier A4 in the noise reduction module 23. The other end of the first three-resistor R13 is grounded via the voltage stabilization diode D1. The other end of the first three-resistor R13 is connected to the output terminal Uo of the temperature measurement circuit, which is connected to the main control circuit of the home appliance. In this embodiment, R2, R4, R5, R6, R7, R8, R9, R10, R11, R12, and R13 are all fixed-value resistors, and the specific resistance values ​​are set as required.

[0051] By connecting a first three-resistor R13 and a voltage-stabilizing diode D1 to the output of quad-op amplifier A4, the voltage output by quad-op amplifier A4 is ensured to be within the safe range of the analog-to-digital converter or microcontroller for measurement. This effectively ensures the voltage stability of the temperature measurement circuit, improving its operational safety. Furthermore, the coordinated configuration of these modules simplifies the temperature measurement circuit structure, reduces circuit costs, and makes the circuit easier to implement.

[0052] Specifically, the input voltage Ui of the Wheatstone bridge 2 is:

[0053]

[0054] Op amps A1, A2, A3, and A4 provide the appropriate signal conditioning required for the output voltage of Wheatstone bridge 2. Depending on the resistance values ​​set for op amps A1, A2, A3, and A4, the output voltage of the measurement circuit can be adjusted within the required range.

[0055] The output voltage Uo of Wheatstone bridge 2 is:

[0056]

[0057] Take a thermistor R T For example, its resistance is:

[0058]

[0059] When the thermistor R T When the measured temperature is 0℃, the thermistor R T The resistance value is RT1=RT2=28.704kΩ. Corresponding to the equivalent thermistor resistance value R TEQ =1.762kΩ, the bridge is balanced, the output voltage of Wheatstone bridge 2 is Ui=0, and the output voltage of the entire measurement circuit is Uo=0.

[0060] When the measured temperature is 200℃, RT1=RT2=0.141kΩ, R TEQ=0.124kΩ, the input voltage of Wheatstone bridge 2 is Ui=2.05V, and the output of the measurement circuit is Uo=4.1V.

[0061] In addition, the characteristic diagrams of the sensor circuit 1 before and after the temperature measurement circuit is improved can be obtained through analysis, such as Figure 4 As shown. It can be seen that after the improvement, the linearity of the sensor circuit 1 has been greatly improved. And the linear determination coefficient R of the sensor circuit 1 is 2 Reached 0.9327.

[0062] In addition, the comparison diagram of the output voltage of the measurement circuit before and after the improvement of the temperature measurement circuit is shown in the figure below. Figure 5 As shown. It can be seen that after the improvement, the output signal range of the temperature measurement circuit is expanded, the linearity of the output voltage curve is significantly improved, and the linear determination coefficient R 2 As high as 0.98.

[0063] Next, the temperature range is selected as 0℃-200℃, and the sensitivity change curve of the temperature measurement circuit is drawn at every 10℃ interval, as shown in the figure below. Figure 6 As shown in the figure, it can be seen that due to the nonlinearity of the thermistor, its sensitivity is high at the beginning and low at the end before improvement. When measuring higher temperatures, the sensitivity is generally low.

[0064] The improved measurement circuit maintains minimal sensitivity variation across the entire measurement range. The resulting measurement circuit successfully operates with a variety of thermistor types and has been successfully applied in various industrial applications. This not only expands the temperature measurement circuit's applicability, but also improves its sensitivity and ensures its overall measurement stability.

[0065] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A dual thermistor temperature measurement circuit, characterized in that: The invention comprises a sensor circuit (1) and a Wheatstone bridge (2), wherein the Wheatstone bridge (2) comprises a voltage protection module (21), an anti-interference module (22), a noise reduction module (23) and a voltage stabilizing module (24); the voltage protection module (21), the anti-interference module (22), the noise reduction module (23) and the voltage stabilizing module (24) are connected in sequence, and an end of the voltage protection module (21) away from the anti-interference module (22) is connected to the sensor circuit (1); the sensor circuit (1) comprises a thermistor 1 RT1 and a thermistor 2 RT2, and the thermistor 1 RT1, the thermistor 2 RT2 and the Wheatstone bridge (2) are electrically connected to form a dual-thermistor temperature measurement circuit.

2. A dual thermistor temperature measurement circuit according to claim 1, characterized in that: The sensor circuit (1) further comprises a first resistor R1 and a third resistor R3; one end of the first thermistor RT1 is connected to one end of the first resistor R1 and one end of the third resistor R3 respectively, the other end of the first resistor R1 is connected to one end of the second thermistor RT2, and the other end of the first thermistor RT1 is connected to the other end of the second thermistor RT2 and the other end of the third resistor R3 respectively.

3. A dual thermistor temperature measurement circuit according to claim 2, characterized in that: The first resistor R1 and the third resistor R3 are both fixed-value resistors.

4. A dual thermistor temperature measurement circuit according to claim 2, characterized in that: The voltage protection module (21) comprises a second resistor R2, a fourth resistor R4, a fifth resistor R5, an operational amplifier A1, and an operational amplifier A2; one end of the second resistor R2 and the fourth resistor R4 is connected to a first power supply Vcc, and the other end of the second resistor R2 is respectively connected to an end of the third resistor R3 close to the first resistor R1 and a positive input end of the operational amplifier A1; the other end of the fourth resistor R4 is respectively connected to an end of the fifth resistor R5 and a positive input end of the operational amplifier A1, and the other end of the fifth resistor R5 is connected to an end of the third resistor R3 away from the first resistor R1 and then grounded.

5. A dual thermistor temperature measurement circuit according to claim 4, characterized in that: The negative input terminals and output terminals of the operational amplifier A1 and the operational amplifier A2 are connected in parallel and are respectively connected to the anti-interference module (22); the negative power supply pins of the operational amplifier A1 and the operational amplifier A2 are respectively connected to the second power supply VEE, and the positive power supply pins of the operational amplifier A1 and the operational amplifier A2 are respectively connected to the third power supply VDD.

6. A dual thermistor temperature measurement circuit according to claim 4, characterized in that: The operational amplifier A1 and the operational amplifier A2 form a voltage follower.

7. A dual thermistor temperature measurement circuit according to claim 4, characterized in that: The anti-interference module (22) comprises a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, and an operational amplifier A3; one end of the sixth resistor R6 is connected to the output end of the operational amplifier A1, the other end of the sixth resistor R6 is respectively connected to one end of the seventh resistor R7 and the negative input end of the operational amplifier A3, the other end of the seventh resistor R7 is connected in parallel with the output end of the operational amplifier A3, and then connected to the noise reduction module 23; the positive input end of the operational amplifier A3 is respectively connected to one end of the eighth resistor R8 and the ninth resistor R9, the other end of the eighth resistor R8 is connected to the output end of the operational amplifier A2, and the other end of the ninth resistor R9 is grounded.

8. A dual thermistor temperature measurement circuit according to claim 7, characterized in that: The operational amplifier A3 is a differential amplifier.

9. The dual thermistor temperature measurement circuit according to claim 7, characterized in that: The noise reduction module (23) includes a first zero resistor R10, a first resistor R11, a first second resistor R12, and an operational quad amplifier A4; one end of the first zero resistor R10 is connected to the output end of the operational quad amplifier A3, and the other end of the first zero resistor R10 is respectively connected to one end of the first first resistor R11 and the negative input end of the operational quad amplifier A4; the other end of the first first resistor R11 is connected in parallel to the output end of the operational quad amplifier A4 and then connected to the voltage stabilization module (24); the positive input end of the operational quad amplifier A4 is grounded through the first second resistor R12.

10. The dual thermistor temperature measurement circuit according to claim 9, characterized in that: The voltage stabilizing module (24) comprises a first three-resistor R13 and a voltage stabilizing diode D1; one end of the first three-resistor R13 is connected to the output end of the operational four-amplifier A4, and the other end of the first three-resistor R13 is grounded via the voltage stabilizing diode D1.

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