Self-adaptive range temperature measurement circuit and method

Abstract

The invention relates to the technical field of precision measurement, and provides a self-adaptive range temperature measurement circuit and method. The circuit comprises an induction bridge module composed of a reference resistor and a thermistor, a differential operational amplifier chip, a direct current transceiver chip and a signal processing module. Wherein an induced voltage signal output by the induced bridge module is subjected to differential amplification of the differential operational amplifier chip to obtain a measurement voltage signal, and the measurement voltage signal is transmitted to the signal processing module through the direct current transceiver chip; the signal processing module judges whether the current measuring range exceeds the specified measuring range in the corresponding interval or not, if yes, the balance point voltage is updated based on a preset temperature-balance point voltage model according to the balance point temperature corresponding to the target measuring range, and the direct current transceiver chip is controlled to output a balance point voltage signal to the differential operational amplifier chip; the temperature measurement interval is switched; and otherwise, obtaining a current temperature measurement value based on a preset temperature-voltage model and outputting the current temperature measurement value.

Description

Technical Field

[0001] The present invention relates to the field of precision measurement technology, and more specifically, to a temperature measurement circuit and method with an adaptive range. Background Art

[0002] The space environment refers to the environment in the vast space tens of kilometers above the ground and extending to the sun, which affects human activities. Compared with the ground environment, the space environment can provide a more stable and less disturbed experimental environment for space science research missions. However, due to the lack of atmosphere in space, the thermal effect caused by space thermal radiation will affect the satellite's scientific payload and reduce the accuracy of the measurement results. Therefore, it is necessary to perform precise temperature measurement and temperature control on the optical payload inside the satellite.

[0003] At present, the temperature measurement technology that has been proven to be mature in space missions is the resistance thermometer, which uses NTC thermistors as temperature probes, unbalanced bridges as detection methods, and precision voltage reference chips, differential op amp chips, analog-to-digital converter (ADC) chips, etc. to achieve low-noise temperature measurement. Limited by the analog input range of the ADC, high-precision thermometers at the mK or sub-mK level usually have a measurement range of only about ±10°C. In the space satellite environment, due to the variable temperature environment and the uncertainty of the temperature equilibrium point within the satellite, when the temperature equilibrium point is stable, the temperature at the temperature measurement point may exceed the range of the traditional resistance thermometer, causing the thermometer to fail to work properly.

[0004] The LISAPathfinder, a preliminary verification satellite of the existing space gravitational wave detection mission Laser Interferometer Space Exploration (LISA), is equipped with a high-precision resistance thermometer. It changes the balance point of the unbalanced bridge by setting 6 reference resistors, and divides it into 6 scales, each corresponding to a central temperature, which improves the temperature measurement range while ensuring low noise. Although this technology has excellent noise performance and has made certain improvements to the range of the thermometer, the nominal resistance of the fixed resistor is fixed, and the flexibility of resistance selection is low, resulting in the unbalanced bridge not strictly working at the balance point when the ambient temperature is the central temperature. This difference will be amplified after gain, which will cause serious zero drift, thereby affecting the accuracy of temperature measurement. Summary of the invention

[0005] In order to overcome the defect of the above-mentioned existing resistance thermometer that the range is insufficient when the temperature stabilization point in the satellite is uncertain, the present invention provides a temperature measurement circuit and method with an adaptive range, which can realize adaptive measurement of ambient temperature and maintain low noise performance while meeting a large range.

[0006] In order to solve the above technical problems, the technical solution of the present invention is as follows:

[0007] A temperature measurement circuit with an adaptive range includes an induction bridge module composed of a reference resistor and a thermistor, a differential operational amplifier chip, a DC transceiver chip and a signal processing module;

[0008] The induced voltage signal output from the inductive bridge module is differentially amplified by the differential operational amplifier chip to obtain a measured voltage signal, and is transmitted to the signal processing module through the DC transceiver chip;

[0009] The signal processing module determines whether the current value exceeds the range specified in the corresponding interval. If so, based on the preset temperature-balance point voltage model, the balance point voltage is updated according to the balance point temperature corresponding to the target range, and the DC transceiver chip is controlled to output the balance point voltage signal to the differential operational amplifier chip to switch the temperature measurement interval;

[0010] Otherwise, the current temperature measurement value is obtained based on a preset temperature-voltage model and outputted.

[0011] Furthermore, the present invention also proposes a temperature measurement method with an adaptive range, which uses the temperature measurement circuit with an adaptive range described in the present invention. The method includes the following steps:

[0012] Place the induction bridge module in the temperature environment to be measured or in contact with the temperature component to be measured to generate an induced voltage signal V R ;

[0013] The induced voltage signal V R Transmitted to the inverting input terminal of the differential op amp chip, the equilibrium point voltage signal V′ D The in-phase input terminal of the differential operational amplifier chip is input, and the induced voltage signal and the equilibrium point voltage signal are differentially amplified to obtain a measured voltage signal V O ;

[0014] Based on the measured voltage signal V O Determine whether the current value exceeds the specified range within the corresponding interval. If so, based on the preset temperature-balance point voltage model, update the balance point voltage V according to the balance point temperature corresponding to the target range. D , and control the DC transceiver chip to output the balance point voltage signal to the differential operational amplifier chip to switch the temperature measurement interval; otherwise, the current temperature measurement value T is obtained based on the preset temperature-voltage model and output.

[0015] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0016] The present invention uses a thermistor as a temperature probe, connects a reference resistor and a thermistor in series to form an electric bridge, and uses a differential operational amplifier chip, a DC transceiver chip, and a signal processing module to output an analog voltage to adjust the balance point of the unbalanced electric bridge, thereby achieving adaptive switching of the temperature measurement interval and effectively expanding the temperature measurement range;

[0017] The present invention has more precise control over the balance point, has a larger number of sub-temperature measurement interval divisions, and a larger measuring range, while being able to maintain low noise performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The figure is a circuit diagram of a temperature measurement circuit with an adaptive range according to an embodiment of the present invention.

[0019] Figure 2 FIG. 4 is a schematic diagram of a temperature-voltage model according to an embodiment of the present invention.

[0020] Figure 3 The figure is a schematic diagram showing the noise performance of a temperature measurement circuit according to an embodiment of the present invention.

[0021] Figure 4 The figure is a flow chart of a temperature measurement method with an adaptive range according to an embodiment of the present invention. DETAILED DESCRIPTION

[0022] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are merely examples of devices and methods consistent with some aspects of the present invention as detailed in the appended claims.

[0023] The terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The singular forms "a", "the" and "the" used in the present invention and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0024] It should be understood that although the terms first, second, third, etc. may be used in the present invention to describe various information, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present invention, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0025] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] Example 1

[0027] This embodiment provides a temperature measurement circuit with an adaptive range, such as Figure 1 , which is a circuit diagram of the temperature measurement circuit with an adaptive range of this embodiment.

[0028] The temperature measurement circuit with an adaptive range proposed in this embodiment includes an induction bridge module composed of a reference resistor and a thermistor, a differential operational amplifier chip, a DC transceiver chip and a signal processing module.

[0029] The induced voltage signal output from the inductive bridge module is differentially amplified by the differential operational amplifier chip to obtain a measured voltage signal, which is then transmitted to the signal processing module through the DC transceiver chip.

[0030] The signal processing module determines whether the current value exceeds the specified range within the corresponding interval. If so, based on the preset temperature-balance point voltage model, the balance point voltage is updated according to the balance point temperature corresponding to the target range, and the DC transceiver chip is controlled to output the balance point voltage signal to the differential operational amplifier chip to switch the temperature measurement interval; otherwise, the current temperature measurement value is obtained based on the preset temperature-voltage model and output.

[0031] In this embodiment, a thermistor is used as a temperature probe, a reference resistor and a thermistor are connected in series to form a bridge, and a differential operational amplifier chip, a DC transceiver chip and a signal processing module are used to output an analog voltage to adjust the balance point of the unbalanced bridge, thereby realizing the switching of the temperature measurement range and achieving the purpose of expanding the temperature measurement range.

[0032] Among them, the temperature measurement range is set according to actual needs, and the corresponding range step and judgment threshold are set. When the threshold range of the corresponding range is exceeded, the signal processing module recalculates the new balance point voltage based on the balance point temperature corresponding to the target range and the temperature-balance point voltage model, and further controls the DC transceiver chip to output this voltage to the differential op amp chip to control the bridge balance point, thereby switching the temperature measurement interval.

[0033] Compared with the traditional unbalanced bridge thermometer, the present embodiment has more precise control over the balance point, a greater number of sub-temperature measurement intervals, a larger measurement range, and can maintain low noise performance.

[0034] Exemplarily, the reference resistor in this embodiment is a resistor with a fixed resistance.

[0035] Exemplarily, the DC transceiver chip in this embodiment uses a low-noise and high-resolution DC transceiver chip, has the functions of receiving and sending DC voltage, and can reduce the impact of quantization errors and reduce signal noise.

[0036] The resolution of the DC transceiver chip determines the range of the circuit and the sensitivity of each working interval. In the specific implementation process, a DC transceiver chip with an adaptive resolution can be selected according to actual needs to adapt to the temperature measurement range requirements.

[0037] For example, using a DC transceiver chip with a resolution of 16 bits, 65536 temperature measurement intervals can be set.

[0038] In addition, the DC voltage transmission function of the high-resolution DC transceiver chip has the ability to refine the output DC voltage value to meet the needs of subdivided working ranges.

[0039] Exemplarily, the inductive bridge module in this embodiment is connected to a reference voltage source, and the reference voltage source uses a low-noise voltage reference chip to provide a stable, low-noise DC source for the inductive bridge module.

[0040] Furthermore, the DC transceiver chip and the inductive bridge module in this embodiment are connected to the same reference voltage source, and the reference voltage source noise is suppressed as common mode noise after being input into the differential operational amplifier chip.

[0041] Exemplarily, the thermistor comprises an NTC thermistor.

[0042] In an optional embodiment, the signal processing module includes a digital control chip and a data storage device; the data storage device stores a temperature-voltage model for calculating the temperature measurement value of the thermistor based on the measured voltage signal, and a temperature-balance point voltage model for calculating the balance point voltage of the corresponding temperature measurement interval based on the target balance point temperature, for the digital control chip to call.

[0043] In this embodiment, the temperature-voltage model and the temperature-equilibrium point voltage model are obtained by calibration and stored in a data storage device in advance, and are called by a digital control chip during the measurement process.

[0044] Furthermore, in an optional embodiment, when the digital control chip determines that the current value exceeds the specified range within the corresponding interval, the digital control chip calls the temperature-equilibrium point voltage model from the data storage device and calculates and updates the equilibrium point voltage, generates a corresponding control signal and transmits it to the DC transceiver chip to control the DC transceiver chip to output the equilibrium point voltage signal to the in-phase input terminal of the differential operational amplifier chip.

[0045] The equilibrium point voltage in the temperature-equilibrium point voltage model is based on the equilibrium state of the induction bridge module (i.e., V O =0) to set; its expression is:

[0046]

[0047] Among them, V D is the equilibrium point voltage signal, V R is the induced voltage signal, i.e. the bridge voltage; B is the characteristic constant; T′ is the target equilibrium point temperature, and T0 is the rated temperature of the thermistor calibrated by ground test.

[0048] When the digital control chip determines that the current exceeds the specified range within the corresponding interval, it calls the temperature-balance point voltage model V D -T and based on the balance point temperature T′ of the target range to the balance point voltage V D Update, and then control the DC transceiver chip to output V to the differential op amp chip D , to achieve the switching of temperature measurement range.

[0049] Optionally, the target equilibrium point temperature T′ of each temperature measurement interval is calibrated according to the temperature measurement interval step length, stored in a data storage device, and called by the digital control chip during the equilibrium point voltage update process.

[0050] In an optional embodiment, the temperature-voltage model is divided into a plurality of sub-temperature measurement intervals according to a fixed step size, and an upper voltage threshold and a lower voltage threshold are set in each temperature measurement interval.

[0051] When the digital control chip determines whether the current value exceeds the specified range in the corresponding interval, the digital control chip calls the temperature-voltage model from the data storage device and makes a judgment based on the upper voltage threshold and the lower voltage threshold in the current temperature measurement interval: if the current measured voltage signal is greater than or equal to the upper voltage threshold, or the current measured voltage signal is less than or equal to the lower voltage threshold, it is judged that the current value exceeds the specified range in the corresponding interval.

[0052] In this embodiment, the range is divided into several sub-temperature measurement intervals according to a fixed step size, each temperature measurement interval corresponds to a balance point temperature, and each balance point temperature corresponds to a bridge balance point voltage. The digital control chip determines the bridge balance point voltage according to the temperature-balance point voltage model and then controls the DC transceiver chip to send the balance point voltage signal to ensure that each working interval works accurately at the bridge balance point.

[0053] Further, in an optional embodiment, the expression of the temperature-voltage model is:

[0054]

[0055] Among them, V O To measure the voltage signal, V R is the induced voltage signal; V′ D It is the equilibrium point voltage signal input to the non-inverting input terminal of the current differential operational amplifier chip, which is used to determine the current temperature measurement range; G is the gain multiple of the differential operational amplifier chip; B is the characteristic constant; T is the temperature measurement value, and T0 is the rated temperature of the thermistor calibrated by ground test.

[0056] In the inductive bridge module, when the external temperature fluctuates, the resistance of the thermistor fluctuates, causing the induced voltage signal V at the inverting input terminal of the input differential op amp chip to r changes, and the induced voltage signal V R and the current equilibrium voltage signal V′ D Differentiate and obtain the measured voltage signal V through G times gain O .

[0057] Among them, for any temperature measurement interval, the measured voltage signal V O It can be expressed as follows:

[0058]

[0059] Thermistor R NTC It can be expressed as:

[0060]

[0061] In the formula, T0 and R0 are the rated temperature and nominal value of the thermistor. Combining the above formula, we can get the temperature-voltage model V O -T relationship.

[0062] For example, Figure 2 As shown, the temperature-voltage model V of this embodiment is O -T. The range of each temperature measurement interval is determined by the upper threshold temperature T a , lower threshold temperature T bDetermine. Upper threshold temperature T a Corresponding upper voltage threshold V max =aV, lower threshold temperature T b Corresponding lower voltage threshold V min =bV.

[0063] When the circuit works in a certain temperature measurement range and the external temperature is equal to the equilibrium point temperature of the working range, V O =0; When the external temperature changes, the resistance of the thermistor changes, which in turn causes the induced voltage signal V R Fluctuation, at this time, the DC transceiver chip receives the measurement voltage signal V output by the differential op amp chip o The signal processing module measures the voltage signal V O Determine whether the current value exceeds the interval V O -Threshold range [aV, bV] specified by the T curve.

[0064] If the measured voltage signal V O If the voltage signal V O If the voltage is less than or equal to the voltage threshold bV corresponding to the lower threshold temperature, the signal processing module controls the output voltage of the DC transceiver chip to decrease and switch to the working range for measuring low temperature.

[0065] Furthermore, in an optional embodiment, in each temperature measurement interval in the temperature-voltage model, the absolute value of the lower voltage threshold is greater than the absolute value of the upper voltage threshold.

[0066] In this embodiment, the absolute value of the lower voltage threshold within the temperature measurement interval is different from the absolute value of the upper voltage threshold, and a buffer zone can be set between adjacent temperature measurement intervals, thereby avoiding the voltage fluctuation problem caused by the different sensitivities of adjacent temperature measurement intervals when switching between intervals.

[0067] For example, Figure 3 The figure shows the noise performance of the temperature measurement circuit of this embodiment. The blue spectrum is the noise power spectrum of the traditional unbalanced bridge resistance thermometer, and its background noise is about 200μK / √Hz@0.01~1Hz; while the red spectrum is the noise power spectrum of the present invention under the same test environment and hardware model, and its background noise is about 100μK / √Hz@0.01~1Hz.

[0068] Exemplarily, the temperature measurement circuit with an adaptive range proposed in this embodiment is further described below in conjunction with a specific implementation process.

[0069] Assume that the current temperature measurement interval is numbered t nThe temperature step length of the equilibrium point between adjacent temperature measurement intervals is 2°C, and the upper voltage threshold V max =9V, lower voltage threshold V min =-10V.

[0070] After the measurement process is started, the default temperature measurement interval is t n , the induced voltage signal V R The balance point voltage signal V′ output by the DC transceiver chip D Input differential op amp chip, V R and V′ D After differential and gain amplification, the measured voltage signal V is obtained. O , which is transmitted from the DC transceiver chip to the signal processing module, and the signal processing module determines the current measured voltage signal V O Is it higher than 9V or lower than -10V:

[0071] (1) When V O ≥9V, the signal processing module is based on the temperature-balance point voltage model V D -T updates the balance point voltage and sends instructions to the DC transceiver chip to control the DC transceiver chip to output the updated balance point voltage signal V D , switch the temperature measurement interval to the temperature measurement interval corresponding to the next equilibrium point temperature.

[0072] For example, the equilibrium point temperature of the current temperature measurement interval is 25°C, and the signal processing module determines to switch to the next temperature measurement interval t n+1 , then the equilibrium point temperature becomes 27℃ and substitute it into the temperature-equilibrium point voltage model V D -T is calculated to obtain the V output of the DC transceiver chip D Amplitude, the DC transceiver chip will output the equilibrium point voltage signal V to the differential op amp chip after receiving the control command D If the current temperature is still not within the temperature measurement range of the current temperature measurement interval, continue to increase the equilibrium point temperature by a fixed step size to switch the temperature measurement interval until the current temperature can be measured correctly.

[0073] (2) When V O When ≤-10V, the signal processing module sends instructions to the DC transceiver chip to control the DC transceiver chip to reduce the amplitude of the output voltage to V D , switch the temperature measurement interval to the temperature measurement interval corresponding to the previous equilibrium point temperature.

[0074] For example, the equilibrium point temperature of the current temperature measurement interval is 25°C, and the signal processing module determines to switch to the previous temperature measurement interval t n-1 , then the equilibrium point temperature becomes 23℃ and substitute it into the temperature-equilibrium point voltage model V D -T is calculated to obtain the V output of the DC transceiver chipD Amplitude, the DC transceiver chip will output the equilibrium point voltage signal V to the differential op amp chip after receiving the control command D If the current temperature is still not within the temperature measurement range of the current temperature measurement interval, continue to reduce the equilibrium point temperature by a fixed step size to switch the temperature measurement interval until the current temperature can be measured correctly.

[0075] Example 2

[0076] This embodiment proposes an adaptive range temperature measurement method, which is applied to the adaptive range temperature measurement circuit proposed in Embodiment 1. Figure 4 As shown, it is a flow chart of the temperature measurement method with adaptive range of this embodiment.

[0077] The temperature measurement method with an adaptive range proposed in this embodiment includes the following steps:

[0078] Place the induction bridge module in the temperature environment to be measured or in contact with the temperature component to be measured to generate an induced voltage signal V R ;

[0079] The induced voltage signal V R Transmitted to the inverting input terminal of the differential op amp chip, the equilibrium point voltage signal V′ D The in-phase input terminal of the differential operational amplifier chip is input, and the induced voltage signal and the equilibrium point voltage signal are differentially amplified to obtain a measured voltage signal V O ;

[0080] Based on the measured voltage signal V O Determine whether the current value exceeds the specified range within the corresponding interval. If so, based on the preset temperature-balance point voltage model, update the balance point voltage V according to the balance point temperature corresponding to the target range. D , and control the DC transceiver chip to output the balance point voltage signal to the differential operational amplifier chip to switch the temperature measurement interval; otherwise, the current temperature measurement value T is obtained based on the preset temperature-voltage model and output.

[0081] In an optional embodiment, the temperature-voltage model is divided into a plurality of sub-temperature measurement intervals according to a fixed step size, and an upper voltage threshold and a lower voltage threshold are set in each temperature measurement interval; then, when judging whether the current range exceeds the specified range in the corresponding interval based on the measured voltage signal, the following steps are included:

[0082] Call the temperature-voltage model and make a judgment based on the upper voltage threshold and the lower voltage threshold in the current temperature measurement interval: if the current measured voltage signal is greater than or equal to the upper voltage threshold, or the current measured voltage signal is less than or equal to the lower voltage threshold, it is judged that the current range exceeds the specified range in the corresponding interval;

[0083] The expression of the temperature-voltage model is:

[0084]

[0085] Among them, V O To measure the voltage signal, V R is the induced voltage signal; V′ D It is the equilibrium point voltage signal input to the non-inverting input terminal of the current differential operational amplifier chip, which is used to determine the current temperature measurement range; G is the gain multiple of the differential operational amplifier chip; B is the characteristic constant; T is the temperature measurement value, and T0 is the rated temperature of the thermistor calibrated by ground test.

[0086] In an optional embodiment, the equilibrium point voltage in the temperature-equilibrium point voltage model is set based on the equilibrium state of the induction bridge module; its expression is:

[0087]

[0088] Among them, V D is the equilibrium point voltage signal, V R is the induced voltage signal; B is the characteristic constant; T′ is the target equilibrium point temperature, and T0 is the rated temperature of the thermistor calibrated by ground test.

[0089] It can be understood that the method of this embodiment is applied to the temperature measurement circuit with an adaptive range in the above-mentioned embodiment 1, and the options in the above-mentioned embodiment 1 are also applicable to this embodiment, so they will not be described repeatedly here.

[0090] Example 3

[0091] This embodiment provides a temperature measurement device, including the temperature measurement circuit with adaptive range provided in Embodiment 1.

[0092] It can be understood that the device of this embodiment includes the temperature measurement circuit with adaptive range of the above-mentioned embodiment 1, and the optional items in the above-mentioned embodiment 1 are also applicable to this embodiment, so they will not be described repeatedly here.

[0093] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A temperature measurement circuit with an adaptive range, characterized in that: It includes an inductive bridge module composed of a reference resistor and a thermistor, as well as a differential operational amplifier chip, a DC transceiver chip and a signal processing module; The induced voltage signal output from the inductive bridge module is differentially amplified by the differential operational amplifier chip to obtain a measured voltage signal, and is transmitted to the signal processing module through the DC transceiver chip; The signal processing module determines whether the current value exceeds the range specified in the corresponding interval. If so, based on the preset temperature-balance point voltage model, the balance point voltage is updated according to the balance point temperature corresponding to the target range, and the DC transceiver chip is controlled to output the balance point voltage signal to the differential operational amplifier chip to switch the temperature measurement interval; Otherwise, the current temperature measurement value is obtained based on a preset temperature-voltage model and outputted.

2. The temperature measurement circuit with an adaptive range according to claim 1, characterized in that: The signal processing module includes a digital control chip and a data storage device; the data storage device stores a temperature-voltage model for calculating the temperature measurement value of the thermistor based on the measured voltage signal, and a temperature-balance point voltage model for calculating the balance point voltage of the corresponding temperature measurement interval based on the target balance point temperature, for the digital control chip to call.

3. The temperature measurement circuit with an adaptive range according to claim 2, characterized in that: When the digital control chip determines that the current value exceeds the specified range within the corresponding interval, the digital control chip calls the temperature-equilibrium point voltage model from the data storage device and calculates and updates the equilibrium point voltage, generates a corresponding control signal and transmits it to the DC transceiver chip, so as to control the DC transceiver chip to output the equilibrium point voltage signal to the non-inverting input terminal of the differential operational amplifier chip; The equilibrium point voltage in the temperature-equilibrium point voltage model is set based on the equilibrium state of the induction bridge module; its expression is: Among them, V D is the equilibrium point voltage signal, V R is the induced voltage signal; B is the characteristic constant; T′ is the target equilibrium point temperature, and T0 is the rated temperature of the thermistor calibrated by ground test.

4. The temperature measurement circuit with an adaptive range according to claim 2, characterized in that: The temperature-voltage model is divided into a number of sub-temperature measurement intervals according to a fixed step size, and an upper voltage threshold and a lower voltage threshold are set in each temperature measurement interval; When the digital control chip determines whether the current value exceeds the specified range in the corresponding interval, the digital control chip calls the temperature-voltage model from the data storage device and makes a judgment based on the upper voltage threshold and the lower voltage threshold in the current temperature measurement interval: if the current measured voltage signal is greater than or equal to the upper voltage threshold, or the current measured voltage signal is less than or equal to the lower voltage threshold, it is judged that the current value exceeds the specified range in the corresponding interval.

5. The temperature measurement circuit with an adaptive range according to claim 4, characterized in that: The expression of the temperature-voltage model is: Among them, V O To measure the voltage signal, V R is the induced voltage signal; V′ D It is the equilibrium point voltage signal input to the non-inverting input terminal of the current differential operational amplifier chip, which is used to determine the current temperature measurement range; G is the gain multiple of the differential operational amplifier chip; B is the characteristic constant; T is the temperature measurement value, and T0 is the rated temperature of the thermistor calibrated by ground test.

6. The temperature measurement circuit with an adaptive range according to claim 4, characterized in that: In each temperature measurement interval in the temperature-voltage model, the absolute value of the lower voltage threshold is greater than the absolute value of the upper voltage threshold.

7. The temperature measurement circuit with an adaptive range according to any one of claims 1 to 6, characterized in that: The thermistor includes an NTC thermistor.

8. An adaptive range temperature measurement method, applied to the adaptive range temperature measurement circuit according to any one of claims 1 to 7, characterized in that: The following steps are involved: Place the induction bridge module in the temperature environment to be measured or in contact with the temperature component to be measured to generate an induced voltage signal V R ; The induced voltage signal V R Transmitted to the inverting input terminal of the differential op amp chip, the equilibrium point voltage signal V′ D The in-phase input terminal of the differential operational amplifier chip is input, and the induced voltage signal and the equilibrium point voltage signal are differentially amplified to obtain a measured voltage signal V O ; Based on the measured voltage signal V O Determine whether the current value exceeds the specified range within the corresponding interval. If so, based on the preset temperature-balance point voltage model, update the balance point voltage V according to the balance point temperature corresponding to the target range. D , and control the DC transceiver chip to output the balance point voltage signal to the differential operational amplifier chip to switch the temperature measurement interval; otherwise, the current temperature measurement value T is obtained based on the preset temperature-voltage model and output.

9. The temperature measurement method with an adaptive range according to claim 8, characterized in that: The temperature-voltage model is divided into several sub-temperature measurement intervals according to a fixed step size, and an upper voltage threshold and a lower voltage threshold are set in each temperature measurement interval; then, when judging whether the current range is beyond the specified range in the corresponding interval based on the measured voltage signal, the following steps are included: Call the temperature-voltage model and make a judgment based on the upper voltage threshold and the lower voltage threshold in the current temperature measurement interval: if the current measured voltage signal is greater than or equal to the upper voltage threshold, or the current measured voltage signal is less than or equal to the lower voltage threshold, it is judged that the current range exceeds the specified range in the corresponding interval; The expression of the temperature-voltage model is: Among them, V O To measure the voltage signal, V R is the induced voltage signal; V′ D It is the equilibrium point voltage signal input to the non-inverting input terminal of the current differential operational amplifier chip, which is used to determine the current temperature measurement range; G is the gain multiple of the differential operational amplifier chip; B is the characteristic constant; T is the temperature measurement value, and T0 is the rated temperature of the thermistor calibrated by ground test.

10. The temperature measurement method with an adaptive range according to claim 8, characterized in that: The equilibrium point voltage in the temperature-equilibrium point voltage model is set based on the equilibrium state of the induction bridge module; its expression is: Among them, V D is the equilibrium point voltage signal, V R is the induced voltage signal; B is the characteristic constant; T′ is the target equilibrium point temperature, and T0 is the rated temperature of the thermistor calibrated by ground test.

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