A PT100 and NTC sensor compatible sampling circuit and sampling method

Abstract

This specification discloses a PT100 and NTC sensor compatible sampling circuit and sampling method. The circuit includes a temperature sensor RT, a reference voltage VCC, a MOS transistor Q1, a first voltage divider resistor RP, a second voltage divider resistor RN, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a first operational amplifier U1A, and a second operational amplifier U1B. Depending on the type of temperature sensor RT, the MOS transistor Q1 is controlled to be on and off, and different sampling channels are selected to implement PT100 and NTC temperature sampling. The circuit can adapt to the resistance ranges of different types of temperature sensors. The method selects a voltage divider or Wheatstone bridge signal conditioning circuit to achieve temperature-compatible sampling, solving the problem of low sampling accuracy of the two temperature sensors under extreme temperature conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicle motor controllers and generator controllers, and in particular to a PT100 and NTC sensor compatible sampling circuit and sampling method. Background Art

[0002] Motor controllers need to collect motor temperature data for diagnostic and protection purposes during operation, with a temperature range of -50°C to 200°C. In actual engineering applications, motor temperature sensors may use either PT100 or NTC temperature sensors, depending on the design or customer requirements. NTC refers to semiconductor materials or components with a very large negative temperature coefficient. NTC thermistors are commonly used. NTC100K or NTC10K sensors have a wide resistance range, ranging from several hundred ohms to tens of megohms between -50°C and 200°C. PT100 is a platinum resistor whose resistance increases with temperature. From -50°C to 200°C, its resistance typically ranges from 80 to 170°C, a narrow resistance range. Due to differences in sensor characteristics, NTC sensors with a wide resistance range typically use a pull-up resistor to divide the voltage. Using the same method with PT100 sensors with a smaller resistance range results in a narrow voltage range and low sampling resolution. Therefore, a Wheatstone bridge circuit is often used to amplify the voltage and sample the signal.

[0003] If a controller needs to consider compatibility with two sensor samplings, the circuits are usually designed separately, and the components are selected and soldered in different controller versions, resulting in multiple controller versions and the need to disassemble the machine and solder the circuit board to temporarily change the status. In the existing related technology, the Wheatstone bridge samples PT100. In the circuit, in order to adapt to the PT100 resistance value, the pull-up resistor of the sampling circuit has a small value, but the NTC voltage division situation must be considered at the same time. A small pull-up resistor will lead to insufficient low-temperature accuracy. At this time, it is necessary to add a resistor with a smaller resistance in parallel with the temperature sensor. If the value of this resistor is too large, the voltage division will be too high when the PT100 is sampled, affecting the high-temperature accuracy of the PT100. If the value is too small, when the NTC low-temperature resistance is large (MΩ level), the resistance change has no effect on the parallel resistor, resulting in insufficient sampling accuracy of the NTC at low temperatures. In summary, the existing technology cannot simultaneously take into account the sampling accuracy of the two sensors at extreme temperatures.

[0004] Therefore, it is urgent to study a sampling circuit and sampling method to achieve the compatibility of the same circuit for sampling PT100 and NTC sensors and ensure the sampling accuracy. Summary of the Invention

[0005] This specification provides a PT100 and NTC sensor compatible sampling circuit and sampling method to overcome at least one technical problem existing in the related art.

[0006] According to a first aspect of an embodiment of the present specification, a PT100 and NTC sensor compatible sampling circuit is provided, comprising: a temperature sensor RT, a reference voltage VCC, a MOS transistor Q1, a first voltage-dividing resistor RP, a second voltage-dividing resistor RN, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a first operational amplifier U1A, and a second operational amplifier U1B, wherein the first resistor R1 and the second resistor R2 are connected in series, one end of the first resistor R1 is connected to the reference voltage VCC, and one end of the second resistor R2 is connected to a MOS control signal; the gate of the MOS transistor Q1 is connected between the first resistor R1 and the second resistor R2, the source of the MOS transistor Q1 is connected to the reference voltage VCC, and the drain of the MOS transistor Q1 is connected to the first voltage-dividing resistor RP; the first voltage-dividing resistor RP and the temperature sensor RT are connected in series, and one end of the temperature sensor RT is grounded; the second voltage-dividing resistor RN and the third resistor R3 are connected in parallel, and the parallel connection One end of the resistor R3 is connected to the reference voltage VCC, and the other end is connected between the first voltage-dividing resistor RP and the temperature sensor RT; the third resistor R3 is connected in series with the seventh resistor R7, and one end of the seventh resistor R7 is grounded; one end of the fifth resistor R5 is connected between the first voltage-dividing resistor RP and the temperature sensor RT, and the other end is connected to the non-inverting input terminal 5 pin of the second operational amplifier U1B; one end of the fourth resistor R4 is connected between the fifth resistor R5 and the non-inverting input terminal of the second operational amplifier U1B, and the other end is grounded; the inverting input terminal 6 pin of the second operational amplifier U1B is connected between the third resistor R3 and the seventh resistor R7 through the sixth resistor R6; one end of the eighth resistor R8 is connected to the inverting input terminal of the second operational amplifier U1B, and the other end is connected to the output terminal 7 pin of the second operational amplifier U1B; one end of the ninth resistor R9 is connected to the second voltage-dividing resistor RN, and the other end is connected to the non-inverting input terminal 3 pin of the first operational amplifier U1A; the inverting input terminal 2 pin of the first operational amplifier U1A is connected to the output terminal 1 pin of the first operational amplifier U1A through the tenth resistor R10.

[0007] Optionally, the temperature sensor RT is a PT100 resistor or an NTC resistor.

[0008] Optionally, the resistance of the second voltage-dividing resistor RN is in the range of 30 to 100K ohms.

[0009] Optionally, the resistance of the first voltage-dividing resistor RP is 1K ohm.

[0010] Optionally, the resistance of the fifth resistor R5 is equal to the resistance of the sixth resistor R6.

[0011] Optionally, the resistance of the fourth resistor R4 is equal to the resistance of the eighth resistor R8.

[0012] According to a second aspect of an embodiment of this specification, a sampling method based on a PT100 and NTC sensor compatible circuit is provided, including: controlling the on / off of a MOS tube Q1 according to the type of a temperature sensor RT, and selecting a first sampling channel or a second sampling channel for temperature sampling; wherein the types of the temperature sensor RT include a PT100 resistor and an NTC resistor, the first sampling channel includes a second voltage divider resistor RN, the temperature sensor RT, a ninth resistor R9, a tenth resistor R10, and a first operational amplifier U1A, the second sampling channel includes a first voltage divider resistor RP, the temperature sensor RT, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, and a second operational amplifier U1B, the first sampling channel corresponds to the NTC resistor type, and the second sampling channel corresponds to the PT100 resistor type.

[0013] Optionally, the step of controlling the on and off of the MOS tube Q1 and selecting the first sampling channel or the second sampling channel for temperature sampling according to the type of the temperature sensor RT includes: in the case of NTC sampling, setting the MOS control signal to a high voltage position and selecting the first sampling channel for temperature sampling; in the case of PT100 sampling, setting the MOS control signal to a low voltage position and selecting the second sampling channel for temperature sampling.

[0014] Optionally, when performing NTC sampling, the MOS control signal is set to a high voltage position, and the step of selecting the first sampling channel for temperature sampling includes: setting the MOS control signal to a high voltage position, and dividing the voltage in series by the second voltage divider resistor RN and the temperature sensor RT; obtaining the voltage value of the temperature sensor RT through the voltage follower composed of the ninth resistor R9, the tenth resistor R10 and the first operational amplifier U1A to complete the NTC sampling.

[0015] Optionally, when performing PT100 sampling, the MOS control signal is set to a low voltage position, and the step of selecting a second sampling channel for temperature sampling includes: setting the MOS control signal to a low voltage position, and dividing the voltage in series by a first voltage-dividing resistor RP and a temperature sensor RT; obtaining the voltage value of the temperature sensor RT after differential amplification by a Wheatstone bridge amplifier circuit composed of a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8 and a second operational amplifier U1B, thereby completing PT100 sampling.

[0016] The beneficial effects of the embodiments of this specification are as follows:

[0017] The embodiments of this specification provide a PT100 and NTC sensor compatible sampling circuit and sampling method. The circuit, through a voltage divider circuit and a Wheatstone bridge, can adapt to the sampling characteristics of PT100 and NTC sensors respectively, eliminating the need for separate circuit design, reducing the complexity of the controller circuit, and effectively reducing costs. The sampling method, based on a compatible sampling circuit, controls the on-off of MOS tube Q1 according to the type of temperature sensor RT, and achieves temperature-compatible sampling by selecting a voltage divider or Wheatstone bridge signal conditioning circuit. Based on the characteristics of the large resistance range of NTC resistors and the small resistance range of PT100 resistors, different sampling channels are selected to achieve temperature sampling of PT100 and NTC. This can take into account the sampling accuracy of different types of temperature sensors at extreme temperatures, solving the problem of low sampling accuracy of the two temperature sensors under extreme temperature conditions.

[0018] The innovative features of the embodiments of this specification include:

[0019] 1. In this specification, MOS tubes are used to implement switching of the sampling circuits of the two sensors, which can ensure the sampling accuracy of different types of temperature sensors within the temperature range, avoid the loss of measurement accuracy of compatible circuits at extreme temperatures in the existing technology, and better achieve compatibility of the temperature sampling circuit with PT100 and NTC sensors, which is one of the innovations of the embodiments of this specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of this specification or related technologies, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 This is a schematic diagram of a PT100 and NTC sensor compatible sampling circuit provided in an embodiment of this specification;

[0022] Figure 2 A flow chart of a sampling method based on a PT100 and NTC sensor compatible circuit provided in an embodiment of this specification;

[0023] Figure 3 This is a schematic diagram of the control logic of a sampling method based on a PT100 and NTC sensor compatible circuit provided in an embodiment of this specification. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of this specification to clearly and completely describe the technical solutions in the embodiments of this specification. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] It should be noted that the terms "including" and "having" and any variations thereof in the embodiments of this specification and the accompanying drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units that are inherent to the process, method, product, or apparatus.

[0026] The embodiments of this specification disclose a sampling circuit and a sampling method compatible with PT100 and NTC sensors, which are described in detail below.

[0027] Figure 1 This is a schematic diagram of a PT100 and NTC sensor compatible sampling circuit provided in one embodiment of this specification. Figure 1 As shown, a PT100 and NTC sensor compatible sampling circuit includes: a temperature sensor RT-101, a reference voltage VCC-102, a MOS tube Q1-103, a first voltage divider resistor RP-104, a second voltage divider resistor RN-105, a first resistor R1-106, a second resistor R2-107, a third resistor R3-108, a fourth resistor R4-109, a fifth resistor R5-110, a sixth resistor R6-111, a seventh resistor R7-112, an eighth resistor R8-113, a ninth resistor R9-114, a tenth resistor R10-115, a first operational amplifier U1A-116, and a second operational amplifier U1B-117.

[0028] The first resistor R1-106 and the second resistor R2-107 are connected in series, one end of the first resistor R1-106 is connected to the reference voltage VCC-102, and one end of the second resistor R2-107 is connected to the MOS control signal; the gate of the MOS transistor Q1-103 is connected between the first resistor R1-106 and the second resistor R2-107, the source of the MOS transistor Q1-103 is connected to the reference voltage VCC-102, and the drain of the MOS transistor Q1-103 is connected to the first voltage divider resistor RP-104; the first divider The voltage-dividing resistor RP-104 is connected in series with the temperature sensor RT-101, and one end of the temperature sensor RT-101 is grounded; the second voltage-dividing resistor RN-105 is connected in parallel with the third resistor R3-108, one end of which is connected to the reference voltage VCC-102, and the other end is connected between the first voltage-dividing resistor RP-104 and the temperature sensor RT-101; the third resistor R3-108 is connected in series with the seventh resistor R7-112, and one end of the seventh resistor R7-112 is grounded; one end of the fifth resistor R5-110 is connected to Between the first voltage divider resistor RP-104 and the temperature sensor RT-101, the other end is connected to the non-inverting input terminal 5 pin of the second operational amplifier U1B-117; one end of the fourth resistor R4-109 is connected between the fifth resistor R5-110 and the non-inverting input terminal of the second operational amplifier U1B-117, and the other end is grounded; the inverting input terminal 6 pin of the second operational amplifier U1B-117 is connected between the third resistor R3-108 and the seventh resistor R7-112 through the sixth resistor R6-111; One end of the eighth resistor R8-113 is connected to the inverting input terminal of the second operational amplifier U1B-117, and the other end is connected to the output terminal 7 pin of the second operational amplifier U1B-117; one end of the ninth resistor R9-114 is connected to the second voltage divider resistor RN-105, and the other end is connected to the non-inverting input terminal 3 pin of the first operational amplifier U1A-116; the inverting input terminal 2 pin of the first operational amplifier U1A-116 is connected to the output terminal 1 pin of the first operational amplifier U1A-116 through the tenth resistor R10-115.

[0029] In a specific embodiment, the temperature sensor RT-101 is a PT100 resistor or an NTC resistor.

[0030] In a specific embodiment, the resistance of the second voltage-dividing resistor RN-105 is in the range of 30 to 100K ohms.

[0031] In a specific embodiment, the resistance of the first voltage-dividing resistor RP- 104 is 1K ohm.

[0032] In a specific embodiment, the resistance of the fifth resistor R5-110 is equal to the resistance of the sixth resistor R6-111.

[0033] In a specific embodiment, the resistance of the fourth resistor R4-109 is equal to the resistance of the eighth resistor R8-113.

[0034] In the embodiment of this specification, two ADCs respectively sample the voltages of two types of sensors through a combination of a Wheatstone bridge and a voltage divider circuit.

[0035] Figure 2 This is a flow chart of a sampling method based on a PT100 and NTC sensor compatible circuit provided in one embodiment of this specification. Figure 2 As shown, a sampling method based on a PT100 and NTC sensor compatible circuit includes:

[0036] S200: Control the on / off state of the MOS transistor Q1 according to the type of the temperature sensor RT, and select a first sampling channel or a second sampling channel for temperature sampling. The types of the temperature sensor RT include a PT100 resistor and an NTC resistor. The first sampling channel includes a second voltage divider resistor RN, the temperature sensor RT, a ninth resistor R9, a tenth resistor R10, and a first operational amplifier U1A. The second sampling channel includes a first voltage divider resistor RP, the temperature sensor RT, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, and a second operational amplifier U1B. The first sampling channel corresponds to an NTC resistor type, and the second sampling channel corresponds to a PT100 resistor type.

[0037] In a specific embodiment, the step S200 of controlling the on / off of the MOS transistor Q1 and selecting the first sampling channel or the second sampling channel for temperature sampling according to the type of the temperature sensor RT includes:

[0038] S210 : In the case of NTC sampling, the MOS control signal is set to a high voltage level, and the first sampling channel is selected to perform temperature sampling.

[0039] In a specific embodiment, the step S210 of setting the MOS control signal to a high voltage level and selecting the first sampling channel for temperature sampling when performing NTC sampling includes:

[0040] S212, setting the MOS control signal to a high voltage level, and dividing the voltage by connecting the second voltage divider resistor RN and the temperature sensor RT in series;

[0041] S214 , obtaining the voltage value of the temperature sensor RT through a voltage follower composed of a ninth resistor R9 , a tenth resistor R10 , and a first operational amplifier U1A, thereby completing NTC sampling.

[0042] When performing NTC sampling, the actual working device of the sampling circuit is the voltage follower composed of the resistor RN and the temperature sensor voltage divider through R9, R10, and U1A. This is equivalent to RN and the NTC sensor voltage divider being directly transmitted to the ADC for sampling. At this time, the RN resistance is relatively large, approximately 30 to 100k ohms, depending on the NTC resistance range.

[0043] S220 : When performing PT100 sampling, set the MOS control signal to a low voltage position and select the second sampling channel for temperature sampling.

[0044] In a specific embodiment, the step S220 of setting the MOS control signal to a low voltage level and selecting the second sampling channel for temperature sampling when performing PT100 sampling includes:

[0045] S222, setting the MOS control signal to a low voltage level, and dividing the voltage by connecting the first voltage divider resistor RP and the temperature sensor RT in series;

[0046] S224 , obtain the voltage value of the temperature sensor RT after differential amplification through a Wheatstone bridge amplifier circuit composed of a third resistor R3 , a fourth resistor R4 , a fifth resistor R5 , a sixth resistor R6 , a seventh resistor R7 , an eighth resistor R8 and a second operational amplifier U1B, and complete PT100 sampling.

[0047] When sampling a PT100, the actual working components of the sampling circuit are resistor RP and the temperature sensor's voltage divider. This is then differentially amplified by a Wheatstone bridge amplifier circuit consisting of R3, R4, R5, R6, R7, R8, and U1B before being transmitted to the ADC for sampling. At this point, the processor needs to set the MOS control low, turning on PMOS transistor Q1 and connecting the smaller resistor RP (lower resistance) in parallel with RN, significantly reducing the pull-up resistor's value to match the PT100's resistance. The RP resistance can be 1k ohms.

[0048] Figure 3 This is a schematic diagram of the control logic of a sampling method based on a PT100 and NTC sensor compatible circuit provided in an embodiment of this specification. Figure 3As shown, the temperature sampling in the embodiments of this specification can be divided into NTC type and PT100 type according to the type of temperature sensor. For the NTC type, based on the large range of resistance variation of the NTC resistor, the Q1MOS tube is set to a high voltage, so that the voltage divider circuit composed of RN and the sensor is used to implement temperature sampling of the NTC thermistor, ensuring the sampling accuracy of the NTC resistor temperature sampling under low temperature conditions. For the PT100 type, the Q1MOS tube is set to a low voltage, so that the RP resistor with a smaller resistance is used to divide the voltage with the temperature sensor, and then differential amplification is performed through the Wheatstone bridge amplifier circuit, ensuring the accuracy of the PT100 resistor temperature sampling under high temperature conditions.

[0049] Therefore, the sampling circuit and sampling method of the embodiments of this specification can take into account the sampling accuracy of different types of temperature sensors under extreme temperatures, solving the problem of low sampling accuracy of two temperature sensors under extreme temperatures.

[0050] In summary, the embodiments of this specification provide a PT100 and NTC sensor compatible sampling circuit and sampling method. The circuit can adapt to the sampling characteristics of PT100 and NTC sensors respectively through a voltage divider circuit and a Wheatstone bridge, thereby eliminating the need to design separate circuits, reducing the complexity of the controller circuit, and effectively reducing costs. The sampling method is based on a compatible sampling circuit, controls the on and off of the MOS tube Q1 according to the type of temperature sensor RT, and achieves temperature-compatible sampling by selecting a voltage divider or Wheatstone bridge signal conditioning circuit. Based on the characteristics of the large resistance range of NTC resistors and the small resistance range of PT100 resistors, different sampling channels are selected to achieve temperature sampling of PT100 and NTC. This can take into account the sampling accuracy of different types of temperature sensors at extreme temperatures, solving the problem of low sampling accuracy of the two temperature sensors under extreme temperature conditions.

[0051] Those skilled in the art will appreciate that the accompanying drawings are merely schematic diagrams of an embodiment, and the modules or processes in the accompanying drawings are not necessarily required to implement the present invention.

[0052] Those skilled in the art will appreciate that the modules in the apparatuses of the embodiments may be distributed in the apparatuses of the embodiments as described in the embodiments, or may be located in one or more apparatuses different from the embodiments with corresponding changes. The modules in the above embodiments may be combined into one module or further divided into multiple sub-modules.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A PT100 and NTC sensor compatible sampling circuit, characterized in that: include: Temperature sensor RT, reference voltage VCC, MOS tube Q1, first voltage divider resistor RP, second voltage divider resistor RN, first resistor R1, second resistor R2, third resistor R3, fourth resistor R4, fifth resistor R5, sixth resistor R6, seventh resistor R7, eighth resistor R8, ninth resistor R9, tenth resistor R10, first operational amplifier U1A, second operational amplifier U1B, wherein A first resistor R1 and a second resistor R2 are connected in series, one end of the first resistor R1 is connected to a reference voltage VCC, and one end of the second resistor R2 is connected to a MOS control signal; The gate of the MOS transistor Q1 is connected between the first resistor R1 and the second resistor R2, the source of the MOS transistor Q1 is connected to the reference voltage VCC, and the drain of the MOS transistor Q1 is connected to the first voltage-dividing resistor RP; The first voltage divider resistor RP is connected in series with the temperature sensor RT, and one end of the temperature sensor RT is grounded; The second voltage-dividing resistor RN is connected in parallel with the third resistor R3, one end of the parallel connection is connected to the reference voltage VCC, and the other end is connected between the first voltage-dividing resistor RP and the temperature sensor RT; The third resistor R3 is connected in series with the seventh resistor R7, and one end of the seventh resistor R7 is grounded; One end of the fifth resistor R5 is connected between the first voltage divider resistor RP and the temperature sensor RT, and the other end is connected to the non-inverting input terminal 5 of the second operational amplifier U1B; One end of the fourth resistor R4 is connected between the fifth resistor R5 and the non-inverting input terminal of the second operational amplifier U1B, and the other end is grounded; The inverting input terminal 6 of the second operational amplifier U1B is connected between the third resistor R3 and the seventh resistor R7 through the sixth resistor R6; One end of the eighth resistor R8 is connected to the inverting input terminal of the second operational amplifier U1B, and the other end is connected to the output terminal 7 of the second operational amplifier U1B; One end of the ninth resistor R9 is connected to the second voltage divider resistor RN, and the other end is connected to the non-inverting input terminal 3 of the first operational amplifier U1A; The inverting input terminal 2 of the first operational amplifier U1A is connected to the output terminal 1 of the first operational amplifier U1A via the tenth resistor R10.

2. The PT100 and NTC sensor compatible sampling circuit according to claim 1, characterized in that: The temperature sensor RT is a PT100 resistor or an NTC resistor.

3. The PT100 and NTC sensor compatible sampling circuit according to claim 1, characterized in that: The resistance of the second voltage-dividing resistor RN is in the range of 30-100K ohms.

4. The PT100 and NTC sensor compatible sampling circuit according to claim 1, characterized in that: The resistance of the first voltage-dividing resistor RP is 1K ohm.

5. The PT100 and NTC sensor compatible sampling circuit according to claim 1, characterized in that: The resistance of the fifth resistor R5 is equal to the resistance of the sixth resistor R6.

6. The PT100 and NTC sensor compatible sampling circuit according to claim 1, characterized in that: The resistance of the fourth resistor R4 is equal to the resistance of the eighth resistor R8.

7. A sampling method based on a PT100 and NTC sensor compatible circuit, applicable to the PT100 and NTC sensor compatible sampling circuit according to any one of claims 1 to 6, characterized in that: include: According to the type of temperature sensor RT, the MOS tube Q1 is controlled to be on or off, and the first sampling channel or the second sampling channel is selected for temperature sampling; Among them, the types of the temperature sensor RT include PT100 resistor and NTC resistor, the first sampling channel includes a second voltage divider resistor RN, a temperature sensor RT, a ninth resistor R9, a tenth resistor R10 and a first operational amplifier U1A, the second sampling channel includes a first voltage divider resistor RP, a temperature sensor RT, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8 and a second operational amplifier U1B, the first sampling channel corresponds to the NTC resistor type, and the second sampling channel corresponds to the PT100 resistor type.

8. The sampling method based on the PT100 and NTC sensor compatible circuit according to claim 7, characterized in that: The step of controlling the on / off of the MOS tube Q1 and selecting the first sampling channel or the second sampling channel for temperature sampling according to the type of the temperature sensor RT includes: In the case of NTC sampling, the MOS control signal is set to a high voltage position and the first sampling channel is selected for temperature sampling; In the case of PT100 sampling, the MOS control signal is set to a low voltage position and the second sampling channel is selected for temperature sampling.

9. The sampling method based on the PT100 and NTC sensor compatible circuit according to claim 8, characterized in that: The step of setting the MOS control signal to a high voltage and selecting the first sampling channel for temperature sampling when performing NTC sampling includes: The MOS control signal is set to a high voltage position, and the voltage is divided by the second voltage divider resistor RN and the temperature sensor RT in series; The voltage value of the temperature sensor RT is obtained through the voltage follower composed of the ninth resistor R9, the tenth resistor R10 and the first operational amplifier U1A to complete NTC sampling.

10. The sampling method based on the PT100 and NTC sensor compatible circuit according to claim 8, characterized in that: The step of setting the MOS control signal to a low voltage position and selecting the second sampling channel for temperature sampling when performing PT100 sampling includes: The MOS control signal is set to a low voltage position, and the voltage is divided by the first voltage divider resistor RP and the temperature sensor RT in series; The voltage value of the temperature sensor RT is obtained after differential amplification through the Wheatstone bridge amplifier circuit composed of the third resistor R3, the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, the seventh resistor R7, the eighth resistor R8 and the second operational amplifier U1B, thereby completing PT100 sampling.

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