Circuit for adaptively identifying temperature sensor and temperature identification device

Abstract

The utility model discloses a circuit for adaptively identifying a temperature sensor and a temperature identification device, and belongs to the technical field of power electronics, and the circuit comprises a constant current source which is used for providing constant current for a PT temperature sensor; the PT detection module is used for receiving the voltage detection signal output by the PT temperature sensor to obtain a target detection signal, and comparing the target detection signal with a preset voltage value by using a comparator to obtain a target comparison signal; and the signal amplification module is used for amplifying the target detection signal with a first preset threshold value to obtain a first amplified signal when the target comparison signal is at a high level, and amplifying the target detection signal with a second preset threshold value to obtain a second amplified signal when the target comparison signal is at a low level. Through the circuit structure, the same circuit can be used for identifying and processing voltage detection data output by the PT100 temperature sensor and the PT1000 temperature sensor.

Description

Technical Field

[0001] The utility model relates to the technical field of power electronics, in particular to a circuit for adaptively identifying a temperature sensor and a temperature identification device. Background Technique

[0002] Since the resistance value of a PT resistor (platinum resistance thermometer) changes with temperature, in practical applications, PT resistors are often used to make temperature sensors. Among them, PT100 temperature sensors and PT1000 temperature sensors are two temperature sensors that are widely used in the market at present. However, in the prior art, two sets of independent identification circuits are usually used to identify and process the voltage detection signals detected by the PT100 temperature sensor and the PT1000 temperature sensor, which greatly reduces the user experience when people use these two temperature sensors. At present, there is no relatively effective solution to this technical problem.

[0003] Therefore, it can be seen that how to provide a circuit that can identify PT100 temperature sensors and PT1000 temperature sensors simultaneously to further improve the user experience when people use PT100 temperature sensors and PT1000 temperature sensors is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Utility Model

[0004] In view of this, the purpose of the utility model is to provide a circuit for adaptively identifying a temperature sensor and a temperature identification device to solve the technical problem that two sets of independent identification circuits are required in the prior art to identify and process the voltage detection signals detected by the PT100 temperature sensor and the PT1000 temperature sensor. The specific scheme is as follows:

[0005] To solve the above technical problem, the utility model provides a circuit for adaptively identifying a temperature sensor, including:

[0006] A constant current source for providing a constant current to the PT temperature sensor;

[0007] A PT detection module connected to the constant current source, for receiving the voltage detection signal output by the PT temperature sensor, obtaining a target detection signal, and using a comparator to compare the target detection signal with a preset voltage value to obtain a target comparison signal; wherein, the PT temperature sensor is a PT100 temperature sensor or a PT1000 temperature sensor; the preset voltage value is set according to the resistance value change ranges corresponding to the PT100 temperature sensor and the PT1000 temperature sensor, with the goal of distinguishing the PT100 temperature sensor and the PT1000 temperature sensor;

[0008] A signal amplification module connected to the PT detection module, which is used to amplify the target detection signal with a first preset threshold to obtain a first amplified signal when the target comparison signal is at a high level, and amplify the target detection signal with a second preset threshold to obtain a second amplified signal when the target comparison signal is at a low level.

[0009] Preferably, the constant current source includes: a voltage regulator, a first operational amplifier, a first resistor, a second resistor, and a third resistor;

[0010] Wherein, the first end of the voltage regulator is respectively connected to the first end of the first resistor and the first end of the second resistor. The second end of the first resistor is used to receive a first power supply voltage, the first end of the second resistor is used to receive a second power supply voltage, the second end of the voltage regulator is connected to the second end of the second resistor, and the third end of the voltage regulator is grounded;

[0011] The positive input terminal of the first operational amplifier is used to receive the second power supply voltage. The negative input terminal of the first operational amplifier is connected to the first end of the third resistor. The second end of the third resistor is grounded. The PT temperature sensor is connected between the output terminal and the negative input terminal of the first operational amplifier.

[0012] Preferably, it further includes: a fourth resistor;

[0013] Wherein, the first end of the fourth resistor is connected to the second end of the voltage regulator, and the second end of the fourth resistor is grounded.

[0014] Preferably, the PT detection module includes: the comparator, a fifth resistor, a sixth resistor, and a seventh resistor;

[0015] Wherein, the negative input terminal of the comparator is respectively connected to the first end of the fifth resistor and the first end of the sixth resistor. The second end of the fifth resistor is grounded. The second end of the sixth resistor is used to receive a third power supply voltage. The output terminal of the comparator is connected to the first end of the seventh resistor. The second end of the seventh resistor is used to receive the third power supply voltage;

[0016] The positive input terminal of the comparator is used to receive the target detection signal, and the output terminal of the comparator is used to output the target comparison signal.

[0017] Preferably, it further includes: an eighth resistor, a ninth resistor, and a first capacitor;

[0018] Among them, the first end of the eighth resistor is correspondingly replaced with being used to receive the target detection signal. The second end of the eighth resistor is respectively connected to the first end of the first capacitor and the positive input end of the comparator. The second end of the first capacitor is grounded. The first end of the ninth resistor is connected to the output end of the comparator. The output end of the ninth resistor is correspondingly replaced with being used to output the target comparison signal.

[0019] Preferably, the signal amplification module includes: a second operational amplifier, a first NMOS transistor, a second NMOS transistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, and a sixteenth resistor;

[0020] Among them, the positive input end of the second operational amplifier is respectively connected to the first end of the tenth resistor, the first end of the eleventh resistor, and the first end of the twelfth resistor. The negative input end of the second operational amplifier is respectively connected to the first end of the thirteenth resistor, the first end of the fourteenth resistor, and the first end of the fifteenth resistor. The PT temperature sensor is connected between the second end of the twelfth resistor and the second end of the fifteenth resistor. The second end of the eleventh resistor is connected to the drain of the first NMOS transistor. The source of the first NMOS transistor and the second end of the tenth resistor are both grounded. The output end of the second operational amplifier is respectively connected to the second end of the thirteenth resistor, the source of the second NMOS transistor, and the first end of the sixteenth resistor. The drain of the second NMOS transistor is connected to the second end of the fourteenth resistor;

[0021] The gates of the first NMOS transistor and the second NMOS transistor are both used to receive the target comparison signal. The output end of the second operational amplifier is used to output the second amplified signal. The second end of the sixteenth resistor is used to output the first amplified signal.

[0022] Preferably, it further includes: a seventeenth resistor and an eighteenth resistor;

[0023] Among them, the first end of the seventeenth resistor is connected to the output end of the second operational amplifier. The second end of the seventeenth resistor is respectively connected to the first end of the sixteenth resistor and the first end of the eighteenth resistor. The second end of the eighteenth resistor is correspondingly replaced with being used to output the second amplified signal.

[0024] Preferably, it further includes:

[0025] A step-down module connected to the signal amplification module and used to perform step-down processing on the first amplified signal to obtain a target step-down signal; among them, both the second amplified signal and the target step-down signal are within the processing range of the low-voltage processor.

[0026] Preferably, the voltage reduction module includes: a third operational amplifier, a nineteenth resistor, a twentieth resistor, a twenty-first resistor, a twenty-second resistor, a twenty-third resistor, a twenty-fourth resistor, and a twenty-fifth resistor;

[0027] Wherein, the first end of the nineteenth resistor is used to receive the third power supply voltage, the second end of the nineteenth resistor is respectively connected to the first end of the twentieth resistor and the first end of the twenty-first resistor, the second end of the twentieth resistor is grounded, the second end of the twenty-first resistor is respectively connected to the negative input end of the third operational amplifier and the first end of the twenty-fourth resistor, the output end of the third operational amplifier is respectively connected to the second end of the twenty-fourth resistor and the first end of the twenty-fifth resistor, the positive input end of the third operational amplifier is respectively connected to the first end of the twenty-second resistor and the first end of the twenty-third resistor, the second end of the twenty-third resistor is grounded, the second end of the twenty-second resistor is used to receive the first amplified signal, and the second end of the twenty-fifth resistor is used to output the target voltage reduction signal.

[0028] In order to solve the above technical problems, the present invention also provides a temperature recognition device, including a circuit of an adaptive recognition temperature sensor as disclosed above.

[0029] Beneficial effects: In the circuit of the adaptive recognition temperature sensor provided by the present invention, a constant current source, a PT detection module, and a signal amplification module are provided. Also, a preset voltage value is set in advance according to the resistance value change ranges corresponding to the PT100 temperature sensor and the PT1000 temperature sensor, with the goal of being able to distinguish between the PT100 temperature sensor and the PT1000 temperature sensor. In this circuit, the constant current source can provide a constant current to the PT temperature sensor; the PT detection module can receive the voltage detection signal output by the PT temperature sensor, obtain a target detection signal, and use a comparator to compare the target detection signal with the preset voltage value to obtain a target comparison signal. And the signal amplification module can amplify the target detection signal with a first preset threshold when the target comparison signal is at a high level to obtain a first amplified signal, and amplify the target detection signal with a second preset threshold when the target comparison signal is at a low level to obtain a second amplified signal. Compared with the prior art, in this setting method, the same circuit can be used to identify and process the voltage detection signals output by the PT100 temperature sensor and the PT1000 temperature sensor, thereby significantly improving the user experience when people use these two types of temperature sensors.

[0030] Correspondingly, a temperature recognition device provided by the present invention also has the beneficial effects of a circuit of an adaptive recognition temperature sensor as disclosed above. Description of the Drawings

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can also be obtained based on the provided drawings.

[0032] Figure 1 It is the working principle diagram of a PT100 temperature sensor provided by an embodiment of the present invention;

[0033] Figure 2 It is the working principle diagram of a PT1000 temperature sensor provided by an embodiment of the present invention;

[0034] Figure 3 It is the structural diagram of a circuit for an adaptive recognition temperature sensor provided by an embodiment of the present invention;

[0035] Figure 4 It is the structural diagram of a constant current source provided by an embodiment of the present invention;

[0036] Figure 5 It is the structural diagram of a PT detection module provided by an embodiment of the present invention;

[0037] Figure 6 It is the structural diagram of another PT detection module provided by an embodiment of the present invention;

[0038] Figure 7 It is the structural diagram of a signal amplification module provided by an embodiment of the present invention;

[0039] Figure 8 It is the structural diagram of another signal amplification module provided by an embodiment of the present invention;

[0040] Figure 9 It is the structural diagram of a voltage reduction module provided by an embodiment of the present invention. Specific Embodiments

[0041] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0042] In order to enable those skilled in the art to more clearly understand the implementation principle of the technical solution provided by this application, the working principles of PT100 temperature sensors and PT1000 temperature sensors will be briefly described here. Among them, the temperature detection principle of PT100 temperature sensors and PT1000 temperature sensors is as follows: PT100 temperature sensors and PT1000 temperature sensors are made of PT resistors, and the resistance value of the PT resistor changes with the change of temperature. Therefore, by giving a constant current value at the front end of the PT resistor, then the PT resistor will generate different voltage values at different temperatures. At this time, by detecting the voltage value generated by the PT resistor, the temperature value of the PT resistor in different environments can be determined.

[0043] Please refer to Figure 1 and Figure 2 , Figure 1 is the working principle diagram of a PT100 temperature sensor provided by an embodiment of the present utility model; Figure 2 is the working principle diagram of a PT1000 temperature sensor provided by an embodiment of the present utility model. Since the PT100 temperature sensor is a three-wire sensor, so, in Figure 1 When the PT100 temperature sensor is connected to the circuit shown, it is necessary to short-circuit PT1_B1 and PT1_B2, and connect the PT100 temperature sensor between PT1_B1, PT1_B2 and PT1_A1. When the PT100 temperature sensor is connected to the circuit, the PT100 temperature sensor is equivalent to a PT resistor. Through the constant current given by the operational amplifier U11, a corresponding voltage value will be generated on the PT resistor. At this time, by detecting and amplifying the voltage value generated by the PT resistor through the operational amplifier U12, the corresponding temperature value of the PT resistor can be determined, and thus the purpose of detecting the temperature by using the PT100 temperature sensor can be achieved.

[0044] Similarly, since the PT1000 temperature sensor is a three-wire sensor, so, in Figure 2 When the PT1000 temperature sensor is connected to the circuit shown, it is necessary to short-circuit PT2_B1 and PT2_B2, and connect the PT1000 temperature sensor between PT2_B1, PT2_B2 and PT2_A1. When the PT1000 temperature sensor is connected to the circuit, the PT1000 temperature sensor is equivalent to a PT resistor. Through the constant current given by the operational amplifier U21, a corresponding voltage value will be generated on the PT resistor. At this time, by detecting and amplifying the voltage value generated by the PT resistor through the operational amplifier U22, the corresponding temperature value of the PT resistor can be determined, and thus the purpose of detecting the temperature by using the PT1000 temperature sensor can be achieved.

[0045] In the prior art, two sets of independent identification circuits are usually used to identify and process the temperature data detected by PT100 temperature sensors and PT1000 temperature sensors, which greatly reduces the user experience when people use these two types of temperature sensors. To solve this technical problem, in this application, a circuit capable of adaptively identifying PT100 temperature sensors and PT1000 temperature sensors is provided.

[0046] Please refer to Figure 3 , Figure 3 which is a circuit for adaptively identifying a temperature sensor provided by an embodiment of the present invention. The circuit includes:

[0047] A constant current source 11 for providing a constant current to the PT temperature sensor;

[0048] A PT detection module 12 connected to the constant current source 11, for receiving the voltage detection signal output by the PT temperature sensor, obtaining a target detection signal, and using a comparator to compare the target detection signal with a preset voltage value to obtain a target comparison signal. Wherein, the PT temperature sensor is a PT100 temperature sensor or a PT1000 temperature sensor; the preset voltage value is set according to the resistance value change ranges corresponding to the PT100 temperature sensor and the PT1000 temperature sensor, with the goal of distinguishing between the PT100 temperature sensor and the PT1000 temperature sensor;

[0049] A signal amplification module 13 connected to the PT detection module 12, for amplifying the target comparison signal with a first preset threshold to obtain a first amplified signal when the target comparison signal is at a high level, and amplifying the target comparison signal with a second preset threshold to obtain a second amplified signal when the target comparison signal is at a low level.

[0050] In this embodiment, a circuit for adaptively identifying a temperature sensor is provided. The circuit includes: a constant current source 11, a PT detection module 12, and a signal amplification module 13. Among them, the constant current source 11 can provide a constant current to the PT100 temperature sensor or the PT1000 temperature sensor. When the PT100 temperature sensor and the PT1000 temperature sensor are connected to the circuit, the PT100 temperature sensor and the PT1000 temperature sensor are equivalent to a PT resistor. After the constant current source 11 provides a constant current to the PT100 temperature sensor or the PT1000 temperature sensor, a voltage value will be generated on the PT resistor, and there is a corresponding relationship between the voltage value and the temperature value of the environment where the PT resistor is located. Therefore, by detecting the voltage value generated on the PT resistor, the temperature value of the environment where the PT resistor is located can be determined.

[0051] By querying the resistance value range tables of PT100 temperature sensors and PT1000 temperature sensors, it can be known that the highest resistance value of the PT resistance corresponding to the PT100 temperature sensor is 332.79Ω, while the lowest resistance value of the PT resistance corresponding to the PT1000 temperature sensor is 803.063. On this basis, since the current received by the PT100 temperature sensor and the PT1000 temperature sensor is constant, therefore, even the maximum value of the voltage detection value output by the PT100 temperature sensor will be much smaller than the minimum value of the voltage detection value output by the PT1000 temperature sensor. At this time, according to the resistance value change ranges corresponding to the PT100 temperature sensor and the PT1000 temperature sensor, a voltage value that can distinguish between the PT100 temperature sensor and the PT1000 temperature sensor can be set in advance, that is, the preset voltage value.

[0052] In this case, if the voltage detection signal output by the PT temperature sensor is less than the preset voltage value, then it can be determined that the PT temperature sensor is a PT100 temperature sensor. If the voltage detection signal output by the PT temperature sensor is greater than the preset voltage value, then it can be determined that the PT temperature sensor is a PT1000 temperature sensor.

[0053] From the above discussion, it can be seen that after the constant current source 11 provides a constant current to the PT100 temperature sensor or the PT1000 temperature sensor, the PT detection module 12 can use a comparator to compare the voltage detection signal output by the PT100 temperature sensor or the PT1000 temperature sensor with the preset voltage value. And, through the target comparison signal output by the comparator, it can be determined whether the PT temperature sensor connected in the circuit is a PT100 temperature sensor or a PT1000 temperature sensor.

[0054] Specifically, when the target comparison signal is at a high level, it means that the comparator is comparing the voltage detection signal output by the PT1000 temperature sensor with the preset voltage value. At this time, the signal amplification module 13 will amplify the target detection signal with a first preset threshold to obtain a first amplified signal. When the target comparison signal is at a low level, it means that the comparator is comparing the voltage detection signal output by the PT100 temperature sensor with the preset voltage value. At this time, the signal amplification module 13 will amplify the target detection signal with a second preset threshold to obtain a second amplified signal.

[0055] Obviously, in this setting mode, the same circuit structure can be used to identify and process the voltage detection signals output by the PT100 temperature sensor and the PT1000 temperature sensor. Compared with the prior art in which two independent identification circuits are required to identify and process the voltage detection signals output by the PT100 temperature sensor and the PT1000 temperature sensor, the user experience of people using the PT100 temperature sensor and the PT1000 temperature sensor can be significantly improved through this circuit.

[0056] Based on the above embodiments, the technical solutions are further described and optimized in this embodiment. Please refer to Figure 4 , Figure 4 which is a structural diagram of a constant current source provided by an embodiment of the present invention. As a preferred implementation manner, the above constant current source 11 includes: a voltage stabilizer Z, a first operational amplifier U1, a first resistor R1, a second resistor R2, and a third resistor R3;

[0057] Among them, the first end of the voltage stabilizer Z is respectively connected to the first end of the first resistor R1 and the first end of the second resistor R2. The second end of the first resistor R1 is used to receive the first power supply voltage VCC1, and the first end of the second resistor R2 is used to receive the second power supply voltage VCC2. The second end of the voltage stabilizer Z is connected to the second end of the second resistor R2, and the third end of the voltage stabilizer Z is grounded;

[0058] The positive input terminal of the first operational amplifier U1 is used to receive the second power supply voltage VCC2. The negative input terminal of the first operational amplifier U1 is connected to the first end of the third resistor R3. The second end of the third resistor R3 is grounded, and a PT temperature sensor is connected between the output terminal and the negative input terminal of the first operational amplifier U1.

[0059] In this embodiment, a circuit diagram of a specific implementation structure of a constant current source is provided. In the constant current source shown in Figure 4 , a precise preset voltage is mainly generated by the voltage stabilizer Z, and a constant current will be generated after the preset voltage passes through the third resistor R3. When the PT temperature sensor is connected to the circuit, it can be equivalent to a resistor R0. The resistor R0 will generate a corresponding voltage value on the PT temperature sensor through the constant current provided at the front end.

[0060] Specifically, in actual applications, the first power supply voltage VCC1 can be set to 5V, and the second power supply voltage VCC2 can be set to 2.5V. At the same time, the voltage stabilizer Z can be set to TL431, and TL431 is used to generate a voltage of 2.5V. On this basis, by adjusting the resistance value of the third resistor R3, a constant current of 0.5 mA can be generated after the 2.5V voltage passes through the third resistor R3. In Figure 4In the constant current source shown, the voltage detection signal output by the PT temperature sensor is PT_B2.

[0061] As a preferred embodiment, the above constant current source further includes: a fourth resistor R4;

[0062] Wherein, the first end of the fourth resistor R4 is connected to the second end of the voltage regulator Z, and the second end of the fourth resistor R4 is grounded.

[0063] In this embodiment, in order to facilitate the adjustment of the voltage output by the voltage regulator Z in practical applications, a fourth resistor R4 can also be provided in the constant current source. That is, by adjusting the resistance value of the fourth resistor R4, the purpose of adjusting the output voltage value of the voltage regulator Z can be achieved.

[0064] Obviously, through the technical solution provided by this embodiment, the constant current source can provide a constant current to the PT temperature sensor.

[0065] Based on the above embodiment, this embodiment further illustrates and optimizes the technical solution. Please refer to Figure 5 , Figure 5 This is the structural diagram of a PT detection module provided by an embodiment of the present invention. As a preferred embodiment, the PT detection module 12 includes: a comparator A, a fifth resistor R5, a sixth resistor R6, and a seventh resistor R7;

[0066] Wherein, the negative input terminal of the comparator A is respectively connected to the first ends of the fifth resistor R5 and the sixth resistor R6. The second end of the fifth resistor R5 is grounded, and the second end of the sixth resistor R6 is used to receive the third power supply voltage VCC3. The output terminal of the comparator A is connected to the first end of the seventh resistor R7, and the second end of the seventh resistor R7 is used to receive the third power supply voltage VCC3;

[0067] The positive input terminal of the comparator A is used to receive the target detection signal PT_B2, and the output terminal of the comparator A is used to output the target comparison signal PT_DET.

[0068] In this embodiment, the circuit structure of the PT detection module 12 is specifically described. In Figure 5 , by adjusting the resistance values of the fifth resistor R5 and the sixth resistor R6, the voltage at the negative input terminal of the comparator A can be set to a preset voltage value by using the third power supply voltage VCC3.

[0069] By querying the resistance value range tables of PT100 temperature sensors and PT1000 temperature sensors, it can be known that the highest resistance value of the PT resistor corresponding to the PT100 temperature sensor is 332.79Ω, while the lowest resistance value of the PT resistor corresponding to the PT1000 temperature sensor is 803.063. Therefore, in order to distinguish between PT100 temperature sensors and PT1000 temperature sensors, the voltage value corresponding to the PT resistor at 700Ω can be used to distinguish and identify PT100 temperature sensors and PT1000 temperature sensors. Among them, the preset voltage value V0 = 2.5V + 700Ohm * 0.5mA * 0.001 = 2.85V.

[0070] In this case, comparator A can compare the voltage detection signal PT_B2 output by the PT temperature sensor with the preset voltage value of 2.85V. If comparator A outputs a high level, it indicates that the PT temperature sensor connected to the circuit is a PT1000 temperature sensor. If comparator A outputs a low level, it indicates that the PT temperature sensor connected to the circuit is a PT100 temperature sensor.

[0071] Please refer to Figure 6 , Figure 6 which is the structural diagram of another PT detection module provided by the embodiment of the present invention. As a preferred implementation manner, the above PT detection module further includes: an eighth resistor R8, a ninth resistor R9, and a first capacitor;

[0072] Among them, the first end of the eighth resistor R8 is correspondingly replaced with a terminal for receiving the target detection signal PT_B2. The second end of the eighth resistor R8 is respectively connected to the first end of the first capacitor C1 and the positive input terminal of comparator A. The second end of the first capacitor C1 is grounded. The first end of the ninth resistor R9 is connected to the output terminal of comparator A. The output end of the ninth resistor R9 is correspondingly replaced with a terminal for outputting the target comparison signal PT_DET.

[0073] In this embodiment, the eighth resistor R8 and the first capacitor C1 can also be used to filter the target detection signal PT_B2 to eliminate the noise signal existing in the target detection signal PT_B2. And the ninth resistor R9 can also be used to adjust the impedance in the circuit, so as to achieve the purpose of improving the safe and stable operation of the circuit.

[0074] Obviously, through the technical solution provided by this embodiment, the stability and reliability of the circuit provided by this application during actual operation can be further improved.

[0075] Based on the above embodiment, this embodiment further explains and optimizes the technical solution. Please refer to Figure 7 , Figure 7The figure is a structural diagram of a signal amplification module provided by an embodiment of the present invention. As a preferred implementation, the signal amplification module 13 includes: a second operational amplifier U2, a first NMOS transistor N1, a second NMOS transistor N2, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, and a sixteenth resistor R16;

[0076] Among them, the positive input terminal of the second operational amplifier U2 is respectively connected to the first terminal of the tenth resistor R10, the first terminal of the eleventh resistor R11, and the first terminal of the twelfth resistor R12. The negative input terminal of the second operational amplifier U2 is respectively connected to the first terminal of the thirteenth resistor R13, the first terminal of the fourteenth resistor R14, and the first terminal of the fifteenth resistor R15. A PT temperature sensor is connected between the second terminal of the twelfth resistor R12 and the second terminal of the fifteenth resistor R15. The second terminal of the eleventh resistor R11 is connected to the drain of the first NMOS transistor N1. The source of the first NMOS transistor N1 and the second terminal of the tenth resistor R10 are both grounded. The output terminal of the second operational amplifier U2 is respectively connected to the second terminal of the thirteenth resistor R13, the source of the second NMOS transistor N2, and the first terminal of the sixteenth resistor R16. The drain of the second NMOS transistor N2 is connected to the second terminal of the fourteenth resistor R14;

[0077] The gates of the first NMOS transistor N1 and the second NMOS transistor N2 are both used to receive the target comparison signal PT_DET. The output terminal of the second operational amplifier U2 is used to output a second amplified signal PT100_AMP. The second terminal of the sixteenth resistor R16 is used to output a first amplified signal PT1000_AMP.

[0078] When the target comparison signal PT_DET is at a high level, it indicates that a PT1000 temperature sensor is connected in the circuit. At this time, both the first NMOS transistor N1 and the second NMOS transistor N2 are in the conducting state. In this case, the signal amplification module will amplify the target detection signal PT_B2 with a first preset threshold to obtain a first amplified signal PT1000_AMP. That is, the first amplified signal PT1000_AMP is a signal obtained by amplifying the voltage detection signal output by the P1000 temperature sensor.

[0079] When the target comparison signal is at a low level, it indicates that a PT100 temperature sensor is connected in the circuit. At this time, both the first NMOS transistor N1 and the second NMOS transistor N2 are in the off state. In this case, the signal amplification module will amplify the target detection signal PT_B2 with a second preset threshold to obtain a second amplified signal PT100_AMP. That is to say, the second amplified signal PT100_AMP is a signal obtained by amplifying the voltage detection signal output by the PT100 temperature sensor. Specifically, in practical applications, the first preset threshold can be set to 5, and the second preset threshold can be set to 20. That is to say, the first amplified signal PT1000_AMP is a signal obtained by amplifying the target detection signal PT_B2 by 5 times, and the second amplified signal PT100_AMP is a signal obtained by amplifying the target detection signal PT_B2 by 20 times.

[0080] Please refer to Figure 8 , Figure 8 which is a structural diagram of another signal amplification module provided by the embodiment of the present invention. As a preferred implementation manner, the above signal amplification module further includes: a seventeenth resistor R17 and an eighteenth resistor R18;

[0081] wherein, the first end of the seventeenth resistor R17 is connected to the output end of the second operational amplifier U2, the second end of the seventeenth resistor R17 is respectively connected to the first end of the sixteenth resistor R16 and the first end of the eighteenth resistor R18, and the second end of the eighteenth resistor R18 is correspondingly replaced with the one for outputting the second amplified signal PT100_AMP.

[0082] In this embodiment, the seventeenth resistor R17 and the eighteenth resistor R18 can also be used to adjust the impedance in the circuit where the signal amplification module is located, so as to make the operating state of the signal amplification module more stable and reliable.

[0083] Obviously, through the technical solution provided by this embodiment, the signal amplification module can be used to amplify the voltage detection signal output by the PT100 temperature sensor or the PT1000 temperature sensor.

[0084] Based on the above embodiment, this embodiment further illustrates and optimizes the technical solution. As a preferred implementation manner, the above circuit for adaptively identifying a temperature sensor further includes:

[0085] a buck module connected to the signal amplification module and used for bucking the first amplified signal PT1000_AMP to obtain a target bucked signal PT1000_BMP; wherein, both the second amplified signal PT100_AMP and the target bucked signal PT1000_BMP are within the processing range of the low-voltage processor.

[0086] In practical applications, a low-voltage processor with 3.3V is usually used to perform subsequent identification and processing on the first amplified signal PT1000_AMP and the second amplified signal PT100_AMP. In this application, after the PT100 temperature sensor is connected to the circuit, the comparator in the PT detection module outputs a low level, and at this time, the first NMOS transistor and the second NMOS transistor are in the cut-off state. When the voltage detection signal output by the PT100 temperature sensor is amplified with the second preset threshold, it generally does not exceed the processing range of the 3.3V low-voltage processor. After the PT1000 temperature sensor is connected to the circuit, the comparator in the PT detection module outputs a high level, and at this time, the first NMOS transistor and the second NMOS transistor are turned on. When the voltage detection signal output by the PT1000 temperature sensor is amplified with the first preset threshold, it exceeds the processing range of the 3.3V low-voltage processor.

[0087] Specifically, if the second preset threshold is set to 20, when the PT100 temperature sensor detects the temperature in the range of -200°C to 660°C, the signal amplification module amplifies the voltage detection signal detected by the PT100 temperature sensor, and the voltage value range of the obtained second amplified signal PT100_AMP is: 0.1852V~3.328V, which is basically full-scale on the 3.3V low-voltage processor. At this time, the 3.3V low-voltage processor can be used to accurately sample the voltage detection signal detected by the PT100 temperature sensor.

[0088] If the first preset threshold is set to 5, when the PT1000 temperature sensor detects the temperature in the range of -50°C to 300°C, the signal amplification module amplifies the voltage detection signal detected by the PT1000 temperature sensor, and the voltage value range of the obtained first amplified signal PT1000_AMP is: 2.008V~5.301V, and the difference between the high and low voltages is 3.293V. In this way, it exceeds the processing range of the 3.3V low-voltage processor, and thus there will be a problem that the 3.3V low-voltage processor cannot accurately sample the first amplified signal PT1000_AMP.

[0089] In this application, to avoid the above situation, a buck module is also set in the circuit of the adaptive identification temperature sensor, and the buck module is used to perform buck processing on the first amplified signal PT1000_AMP. When the buck module performs buck processing on the first amplified signal PT1000_AMP to obtain the target buck signal PT1000_BMP, it can be ensured that the target buck signal PT1000_BMP does not exceed the processing range of the 3.3V low-voltage processor, and thus the accuracy of sampling the voltage detection signal output by the PT1000 temperature sensor can be further improved.

[0090] Please refer to Figure 9 , Figure 9 which is a structural diagram of a voltage reduction module provided by an embodiment of the present invention. As a preferred embodiment, the voltage reduction module includes: a third operational amplifier U3, a nineteenth resistor R19, a twentieth resistor R20, a twenty-first resistor R21, a twenty-second resistor R22, a twenty-third resistor R23, a twenty-fourth resistor R24, and a twenty-fifth resistor R25;

[0091] Among them, the first end of the nineteenth resistor R19 is used to receive the third power supply voltage VCC3. The second end of the nineteenth resistor R19 is connected to the first ends of the twentieth resistor R20 and the twenty-first resistor R21 respectively. The second end of the twentieth resistor R20 is grounded. The second end of the twenty-first resistor R21 is connected to the negative input end of the third operational amplifier U3 and the first end of the twenty-fourth resistor R24 respectively. The output end of the third operational amplifier U3 is connected to the second end of the twenty-fourth resistor R24 and the first end of the twenty-fifth resistor R25 respectively. The positive input end of the third operational amplifier U3 is connected to the first ends of the twenty-second resistor R22 and the twenty-third resistor R23 respectively. The second end of the twenty-third resistor R23 is grounded. The second end of the twenty-second resistor R22 is used to receive the first amplified signal. The second end of the twenty-fifth resistor R25 is used to output the target voltage reduction signal PT1000_BMP.

[0092] In this embodiment, the circuit structure of the voltage reduction module is specifically described. This voltage reduction module is equivalent to a subtractor, and this subtractor can be used to perform voltage reduction processing on the first amplified signal PT1000_AMP and obtain the target voltage reduction signal PT1000_BMP.

[0093] It should be noted that in practical applications, the first operational amplifier U1, the second operational amplifier U2, and the third operational amplifier U3 can all be set to SGM8270-4XS14G / TR. Moreover, the voltage reduction value of the voltage reduction module can be set to 2V. In this way, after the voltage reduction module performs voltage reduction processing on the first amplified signal PT1000_AMP, the voltage value range of the obtained target voltage reduction signal PT1000_BMP is 0.008~3.301V, which just meets the processing range of the 3.3V low-voltage processor, and thus the accuracy of sampling the voltage detection signal output by the PT1000 temperature sensor can be improved.

[0094] It should be noted that in the prior art, when using a 3.3V low-voltage processor to process the voltage detection signal output by a PT1000 temperature sensor, since the voltage value range of the voltage detection signal output by the PT1000 temperature sensor is approximately between 2.008V and 5.301V. Basically, it is concentrated in the latter half of the processing range of the 3.3V low-voltage processor. The value of the voltage detection signal of the PT1000 temperature sensor is relatively dense in the processing range of the 3.3V low-voltage processor, which will also reduce the accuracy of the 3.3V low-voltage processor when sampling the voltage detection signal of the PT1000 temperature sensor.

[0095] In this application, after signal amplification and voltage reduction processing of the voltage detection signal of the PT1000 temperature sensor, not only can the voltage detection signal detected by the PT1000 temperature sensor be just within the processing range of the low-voltage processor, but also the voltage detection signal detected by the PT1000 temperature sensor can be made to cover as much as possible the processing range of the low-voltage processor. In this way, the accuracy and reliability of the 3.3V low-voltage processor when sampling the voltage detection signal output by the PT1000 temperature sensor can be further improved.

[0096] Obviously, through the technical solution provided by this embodiment, the accuracy of sampling the voltage detection signal output by the PT1000 temperature sensor can be further improved.

[0097] Correspondingly, the embodiment of the present utility model further provides a temperature recognition device, including a circuit for adaptively recognizing a temperature sensor as disclosed above.

[0098] The temperature recognition device provided by the embodiment of the present utility model has the beneficial effects of a circuit for adaptively recognizing a temperature sensor as disclosed above.

[0099] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present utility model. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present utility model. Therefore, the present utility model will not be limited to these embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A circuit for adaptively identifying a temperature sensor, characterized in that: include: A constant current source for providing a constant current to the PT temperature sensor; A PT detection module connected to the constant current source, used to receive the voltage detection signal output by the PT temperature sensor, obtain a target detection signal, and compare the target detection signal with a preset voltage value using a comparator to obtain a target comparison signal; wherein the PT temperature sensor is a PT100 temperature sensor or a PT1000 temperature sensor; the preset voltage value is set according to the resistance variation range corresponding to the PT100 temperature sensor and the PT1000 temperature sensor, and is set to distinguish the PT100 temperature sensor from the PT1000 temperature sensor; A signal amplification module connected to the PT detection module, used to amplify the target detection signal with a first preset threshold value to obtain a first amplified signal when the target comparison signal is at a high level, and to amplify the target detection signal with a second preset threshold value to obtain a second amplified signal when the target comparison signal is at a low level.

2. A circuit for adaptively identifying a temperature sensor according to claim 1, characterized in that: The constant current source comprises: a voltage stabilizing source, a first operational amplifier, a first resistor, a second resistor and a third resistor; The first end of the voltage stabilizing source is connected to the first end of the first resistor and the first end of the second resistor respectively, the second end of the first resistor is used to receive a first power supply voltage, the first end of the second resistor is used to receive a second power supply voltage, the second end of the voltage stabilizing source is connected to the second end of the second resistor, and the third end of the voltage stabilizing source is grounded; The positive input terminal of the first operational amplifier is used to receive the second power supply voltage, the negative input terminal of the first operational amplifier is connected to the first end of the third resistor, the second end of the third resistor is grounded, and the PT temperature sensor is connected between the output terminal and the negative input terminal of the first operational amplifier.

3. A circuit for adaptively identifying a temperature sensor according to claim 2, characterized in that: Also includes: a fourth resistor; The first end of the fourth resistor is connected to the second end of the voltage stabilizing source, and the second end of the fourth resistor is grounded.

4. The circuit for adaptively identifying a temperature sensor according to claim 1, characterized in that: The PT detection module includes: the comparator, a fifth resistor, a sixth resistor and a seventh resistor; The negative input terminal of the comparator is connected to the first terminal of the fifth resistor and the first terminal of the sixth resistor respectively, the second terminal of the fifth resistor is grounded, the second terminal of the sixth resistor is used to receive a third power supply voltage, the output terminal of the comparator is connected to the first terminal of the seventh resistor, and the second terminal of the seventh resistor is used to receive the third power supply voltage; The positive input terminal of the comparator is used to receive the target detection signal, and the output terminal of the comparator is used to output the target comparison signal.

5. A circuit for adaptively identifying a temperature sensor according to claim 4, characterized in that: Also includes: an eighth resistor, a ninth resistor and a first capacitor; Among them, the first end of the eighth resistor is correspondingly replaced for receiving the target detection signal, the second end of the eighth resistor is respectively connected to the first end of the first capacitor and the positive input end of the comparator, the second end of the first capacitor is grounded, the first end of the ninth resistor is connected to the output end of the comparator, and the output end of the ninth resistor is correspondingly replaced for outputting the target comparison signal.

6. The circuit for adaptively identifying a temperature sensor according to claim 1, characterized in that: The signal amplification module includes: a second operational amplifier, a first NMOS transistor, a second NMOS transistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor and a sixteenth resistor; Wherein, the positive input terminal of the second operational amplifier is respectively connected to the first end of the tenth resistor, the first end of the eleventh resistor and the first end of the twelfth resistor, the negative input terminal of the second operational amplifier is respectively connected to the first end of the thirteenth resistor, the first end of the fourteenth resistor and the first end of the fifteenth resistor, the PT temperature sensor is connected between the second end of the twelfth resistor and the second end of the fifteenth resistor, the second end of the eleventh resistor is connected to the drain of the first NMOS tube, the source of the first NMOS tube and the second end of the tenth resistor are both grounded, the output terminal of the second operational amplifier is respectively connected to the second end of the thirteenth resistor, the source of the second NMOS tube and the first end of the sixteenth resistor, and the drain of the second NMOS tube is connected to the second end of the fourteenth resistor; The gate of the first NMOS tube and the gate of the second NMOS tube are both used to receive the target comparison signal, the output end of the second operational amplifier is used to output the second amplified signal, and the second end of the sixteenth resistor is used to output the first amplified signal.

7. A circuit for adaptively identifying a temperature sensor according to claim 6, characterized in that: Also includes: a seventeenth resistor and an eighteenth resistor; Among them, the first end of the seventeenth resistor is connected to the output end of the second operational amplifier, the second end of the seventeenth resistor is respectively connected to the first end of the sixteenth resistor and the first end of the eighteenth resistor, and the second end of the eighteenth resistor is correspondingly replaced to output the second amplified signal.

8. A circuit for adaptively identifying a temperature sensor according to any one of claims 1 to 7, characterized in that: Also includes: A voltage reduction module connected to the signal amplification module, used for reducing the voltage of the first amplified signal to obtain a target voltage reduction signal; wherein the second amplified signal and the target voltage reduction signal are both within the processing range of the low-voltage processor.

9. The circuit for adaptively identifying a temperature sensor according to claim 8, characterized in that: The step-down module includes: a third operational amplifier, a nineteenth resistor, a twentieth resistor, a twenty-first resistor, a twenty-second resistor, a twenty-third resistor, a twenty-fourth resistor and a twenty-fifth resistor; Among them, the first end of the nineteenth resistor is used to receive the third power supply voltage, the second end of the nineteenth resistor is respectively connected to the first end of the twentieth resistor and the first end of the twenty-first resistor, the second end of the twentieth resistor is grounded, the second end of the twenty-first resistor is respectively connected to the negative input terminal of the third operational amplifier and the first end of the twenty-fourth resistor, the output terminal of the third operational amplifier is respectively connected to the second end of the twenty-fourth resistor and the first end of the twenty-fifth resistor, the positive input terminal of the third operational amplifier is respectively connected to the first end of the twenty-second resistor and the first end of the twenty-third resistor, the second end of the twenty-third resistor is grounded, the second end of the 22nd resistor is used to receive the first amplified signal, and the second end of the 25th resistor is used to output the target voltage reduction signal.

10. A temperature recognition device, characterized in that: A circuit comprising a temperature sensor adaptively identified as claimed in any one of claims 1 to 9.

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