NTC temperature measuring device and control method thereof

Abstract

The invention discloses an NTC (Negative Temperature Coefficient) temperature measuring device and a control method thereof. The NTC temperature measuring device comprises a dynamic current source; the output end of the dynamic current source is connected with the input end of the NTC resistance circuit and the in-phase input end of the differential amplifier; the output end of the NTC resistance circuit is electrically connected with the inverted input end of the differential amplifier; the controller is used for controlling the output end of the dynamic current source to output excitation current corresponding to the reference temperature; the NTC resistance circuit comprises an NTC thermistor and an adjustable parallel resistor which are connected in parallel; the second control output end of the controller is connected with the adjustable parallel resistor and used for adjusting the resistance value of the adjustable parallel resistor to the resistance value corresponding to the reference temperature. According to the NTC temperature measuring device, the influence of the self-heating effect of the NTC thermistor on the temperature measuring result is reduced, errors introduced by resistance temperature characteristic nonlinearity of the NTC thermistor are reduced, and the temperature measuring accuracy of the NTC temperature measuring device is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of NTC temperature measurement, and particularly to an NTC temperature measurement device and a control method thereof. Background Art

[0002] NTC (Negative Temperature Coefficient thermistor) thermistors are widely used in temperature monitoring of industrial control, medical equipment, and new energy batteries due to their low cost and high sensitivity. However, during the use of NTC thermistors as sensors for inductive temperature measurement, their own self-heating effect and the non-linear error of the NTC resistance-temperature characteristic, etc., all affect the accuracy and reliability of NTC thermistor temperature measurement to a certain extent. Summary of the Invention

[0003] The purpose of the present invention is to provide an NTC temperature measurement device and a control method thereof, which can avoid the influence of the self-heating effect of the NTC thermistor on the temperature measurement structure to a certain extent, reduce the non-linear error introduced by the resistance-temperature characteristic of the NTC thermistor, and improve the temperature measurement accuracy of the NTC temperature measurement device.

[0004] To solve the above technical problems, the present invention provides an NTC temperature measurement device, including a dynamic current source, a controller, an NTC resistance circuit, and a differential amplifier;

[0005] The control input terminal of the dynamic current source is connected to the first control output terminal of the controller; the output terminal of the dynamic current source is connected to the input terminal of the NTC resistance circuit and the non-inverting input terminal of the differential amplifier; the output terminal of the NTC resistance circuit is electrically connected to the inverting input terminal of the differential amplifier;

[0006] Wherein, the controller is used to control the output terminal of the dynamic current source to output an excitation current corresponding to the reference temperature according to the current reference temperature of the measured target;

[0007] The NTC resistance circuit includes an NTC thermistor and an adjustable parallel resistor connected in parallel with each other;

[0008] The second control output terminal of the controller is connected to the adjustable parallel resistor, and is used to adjust the resistance value of the adjustable parallel resistor to the resistance value corresponding to the reference temperature.

[0009] In an optional embodiment of the present application, it further includes two LC series adjustable filters, namely a first LC series adjustable filter and a second LC series adjustable filter;

[0010] Among them, the input end of the first LC series adjustable filter is electrically connected to the output end of the NTC resistor circuit, and the output end is connected to the inverting input end of the differential amplifier;

[0011] The input end of the second LC series adjustable filter is electrically connected to the output end of the dynamic current source, and the output end is connected to the non-inverting input end of the differential amplifier;

[0012] Each of the LC series adjustable filters includes an inductive element and an adjustable capacitive element; the first end of the inductive element is the input end of the LC series adjustable filter; the second end of the inductive element is connected to the input end of the adjustable capacitive element; the output end of the adjustable capacitive element is the output end of the LC series adjustable filter;

[0013] The third control output end of the controller is connected to the control input end of the adjustable capacitive element for regulating the capacitance value of the adjustable capacitive element.

[0014] In an alternative embodiment of the present application, a common mode choke is further included; the first terminal and the third terminal of the common mode choke are the two ends of the same coil; the second terminal and the fourth terminal of the common mode choke are the two ends of the same coil;

[0015] Among them, the first terminal of the common mode choke is electrically connected to the output end of the NTC resistor circuit; the second terminal of the common mode choke is connected to the input end of the first LC series adjustable filter; the third terminal of the common mode choke is electrically connected to the output end of the dynamic current source; the fourth terminal of the common mode choke is connected to the input end of the second LC series adjustable filter.

[0016] In an alternative embodiment of the present application, multiple groups of NTC resistor circuits are provided; a first multiplexer is further included;

[0017] The input end of the first multiplexer is connected to the output end of the dynamic current source; multiple output ends of the first multiplexer are respectively connected to the input ends of the NTC resistor circuits one by one; the output ends of the NTC resistor circuits are commonly electrically connected to the inverting input end of the differential amplifier;

[0018] The fourth control output end of the controller is connected to the control input end of the first multiplexer for controlling the excitation current input at the input end of the first multiplexer to output from one output end.

[0019] In an alternative embodiment of the present application, the dynamic current source includes a constant current source and a MOSFET device;

[0020] The output terminal of the constant current source is connected to the drain of the MOSFET device; the second control output terminal of the controller is connected to the gate of the MOSFET device; the source of the MOSFET device is the output terminal of the dynamic current source;

[0021] The controller is configured to input a PWM signal with different duty cycles to the gate of the MOSFET device according to the reference temperature.

[0022] In an optional embodiment of the present application, it further includes a reference temperature sensor connected to the controller for collecting the reference temperature of the measured target.

[0023] In an optional embodiment of the present application, it further includes a second multiplexer, a plurality of reference resistors with different resistance values, and a short - circuit line;

[0024] Wherein, the output terminal of the dynamic current source is connected to the input terminal of the second multiplexer; each output terminal of the second multiplexer is connected to the first end of each reference resistor and the first end of the short - circuit line in one - to - one correspondence; the second ends of each reference resistor and the second end of the short - circuit line are commonly electrically connected to the inverting input terminal of the differential amplifier;

[0025] The fourth control output terminal of the controller is connected to the control output terminal of the multiplexer for controlling the excitation current input to the input terminal of the second multiplexer to be output from one output terminal.

[0026] A control method for an NTC temperature measurement device, applied to the NTC temperature measurement device described in any one of the above; the control method includes:

[0027] Obtain the current reference temperature of the measured target;

[0028] According to the temperature range to which the reference temperature belongs and the excitation signal corresponding to each pre - determined temperature range, control the dynamic current source to output an excitation current corresponding to the reference current;

[0029] Adjust the resistance value of the adjustable parallel resistor to the resistance value corresponding to the reference temperature;

[0030] Collect the temperature - measuring voltage output from the output terminal of the differential amplifier and determine the temperature - measuring data according to the temperature - measuring voltage.

[0031] In an optional embodiment of the present application, after controlling the dynamic current source to output an excitation current corresponding to the reference current and before collecting the temperature - measuring voltage output from the output terminal of the differential amplifier, it further includes:

[0032] Control the switching of the first multiplexer so that the excitation current is output from the output terminal of the first multiplexer to the short - circuit line;

[0033] Collect the reference voltage output from the output terminal of the differential amplifier;

[0034] Analyze and identify the main frequency of the noise in the reference voltage;

[0035] Adjust the capacitance of the first adjustable capacitor device and the capacitance of the second adjustable capacitor device to the first capacitance value and the second capacitance value corresponding to the main frequency of the noise respectively;

[0036] Control the switching of the first multiplexer so that the excitation current is output from the output terminal of the first multiplexer to the NTC circuit.

[0037] In an optional embodiment of the present application, after controlling the dynamic current source to output an excitation current corresponding to the reference current and before controlling the first multiplexer to switch so that the excitation current is output from the output terminal of the multiplexer to the NTC circuit, it further includes:

[0038] Control the switching of the second multiplexer according to the reference temperature so that the excitation current is output to the reference resistor corresponding to the reference temperature;

[0039] Collect the reference voltage output from the output terminal of the differential amplifier and calculate the theoretical voltage of the reference resistor;

[0040] Respectively the reference voltage and the gain coefficient formula , obtain the gain coefficient; where K is the gain coefficient; is the reference voltage; the theoretical voltage of the reference resistor; is the reference voltage;

[0041] Correspondingly, determining the temperature - measurement data according to the temperature - measurement voltage includes:

[0042] Perform a difference operation on the temperature - measurement voltage and the reference voltage to obtain a first calibration voltage;

[0043] Perform a multiplication operation on the gain coefficient and the first calibration voltage to obtain a second calibration voltage;

[0044] Determine the temperature - measurement data according to the second calibration voltage.

[0045] The present invention provides an NTC temperature measurement device and a control method therefor. The NTC temperature measurement device includes a connection between a control input terminal of a dynamic current source and a first control output terminal of a controller; an output terminal of the dynamic current source is connected to an input terminal of an NTC resistance circuit and a non-inverting input terminal of a differential amplifier; an output terminal of the NTC resistance circuit is electrically connected to an inverting input terminal of the differential amplifier; wherein, the controller is configured to control the output terminal of the dynamic current source to output an excitation current corresponding to a reference temperature according to a reference temperature of a measured target and a corresponding relationship between the reference temperature and the excitation current determined in advance; the NTC resistance circuit includes an NTC thermistor and an adjustable parallel resistor connected in parallel with each other; a second control output terminal of the controller is connected to the adjustable parallel resistor and is configured to adjust the resistance value of the adjustable parallel resistor to a resistance value corresponding to the reference temperature.

[0046] In the NTC temperature measurement device of the present application, a dynamic current source with a variable output current signal is configured. Thus, the controller can adjust the excitation current output by the dynamic current source to an excitation current with a magnitude corresponding to the current of the reference temperature according to the reference temperature that roughly represents the current temperature of the measured target, thereby reducing the self-heating effect of the NTC thermistor when the excitation current is turned on, and further reducing the influence of the self-heating effect on the temperature measurement result; in addition, an adjustable parallel resistor is connected in parallel to the NTC thermistor, and the controller can adjust the resistance value of the adjustable parallel resistor according to the reference temperature, so that the resistance-temperature characteristic of the overall NTC resistance circuit formed by the parallel connection of the NTC thermistor and the adjustable parallel resistor becomes more linear. Thus, the temperature of the measured target can be measured by using the resistance-temperature characteristic of the NTC resistance circuit, and the non-linear error introduced by the resistance-temperature characteristic of the NTC thermistor can be effectively reduced, and further the temperature measurement accuracy of the NTC temperature measurement device can be improved. It can be seen that in the present application, the interference of the self-heating effect of the NTC thermistor on the temperature measurement result can be reduced to a certain extent, and the error introduced by the non-linear change of the resistance-temperature characteristic of the NTC thermistor can also be reduced, which greatly improves the temperature measurement accuracy of the NTC temperature measurement device and is conducive to the wide application of the NTC temperature measurement device. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions of the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0048] Figure 1 It is a schematic structural diagram of the NTC temperature measurement device provided by the embodiment of the present application;

[0049] Figure 2Schematic diagram of the resistance-temperature characteristic curve of the NTC thermistor;

[0050] Figure 3 Schematic diagram of the resistance-temperature characteristic curve of the NTC resistance circuit provided by the embodiment of the present application in the first temperature range;

[0051] Figure 4 Schematic diagram of the resistance-temperature characteristic curve of the NTC resistance circuit provided by the embodiment of the present application in the second temperature range;

[0052] Figure 5 Schematic diagram of the resistance-temperature characteristic curve of the NTC resistance circuit provided by the embodiment of the present application in the third temperature range;

[0053] Figure 6 Schematic diagram of the NTC resistance circuit provided by the embodiment of the present application;

[0054] Figure 7 Schematic diagram of the circuit structure between the common-mode choke, the LC series adjustable filter and the differential amplifier in the NTC resistance circuit provided by the embodiment of the present application;

[0055] Figure 8 Another schematic diagram of the NTC temperature measurement device provided by the embodiment of the present application;

[0056] Figure 9 Schematic diagram of a frame structure of the NTC temperature measurement device provided by the embodiment of the present application;

[0057] Figure 10 Schematic diagram of the flow of the control method of the NTC temperature measurement device provided by the embodiment of the present application. Detailed implementation manners

[0058] The core of the present invention is to provide an NTC temperature measurement device, which can, to a certain extent, reduce the influence of the self-heating effect of the NTC thermistor on the accuracy of the temperature measurement result, and also make the temperature-resistance characteristic of the NTC thermistor more linear, thereby further improving the accuracy of the temperature measurement result.

[0059] In order to enable those skilled in the art to better understand the solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific implementation manners. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0060] As Figure 1 shown, Figure 1 Schematic diagram of the structure of the NTC temperature measurement device provided by the embodiment of the present application.

[0061] In a specific embodiment of the present application, the NTC temperature measuring device may include:

[0062] A dynamic current source 10, a controller MCU, an NTC resistor circuit 30, and a differential amplifier U;

[0063] The control input terminal of the dynamic current source 10 is connected to the first control output terminal of the controller MCU; the output terminal of the dynamic current source 10 is connected to the input terminal of the NTC resistor circuit 30 and the non-inverting input terminal of the differential amplifier; the output terminal of the NTC resistor circuit 30 is electrically connected to the inverting input terminal of the differential amplifier U;

[0064] Wherein, the controller MCU is configured to control the output terminal of the dynamic current source 10 to output an excitation current corresponding to the reference temperature according to the corresponding relationship between the reference temperature of the measured target, the pre-determined reference temperature and the excitation current;

[0065] The NTC resistor circuit 30 includes an NTC thermistor and an adjustable parallel resistor connected in parallel with each other;

[0066] The second control output terminal of the controller MCU is connected to the adjustable parallel resistor, and is configured to adjust the resistance value of the adjustable parallel resistor to the resistance value corresponding to the reference temperature.

[0067] It can be understood that in this embodiment, the NTC resistor circuit 30 is also a circuit structure including an NTC thermistor. The resistance value of the NTC thermistor will change with the temperature of the measured target, thereby causing the voltage value across the NTC thermistor to change; therefore, the NTC thermistor is often used as a temperature sensing device to realize temperature measurement under the action of a fixed excitation current. In addition, the dynamic current source 10 in this embodiment also provides the excitation current required for the operation of the NTC resistor circuit 30, and the differential amplifier U detects the voltage signal of the NTC resistor circuit 30 to analyze and determine the temperature data of the measured target.

[0068] On this basis, in order to reduce the influence of the self-heating effect of the NTC thermistor on the temperature measurement accuracy of the NTC thermistor in the present application, the dynamic current source 10 adopted is a current source with adjustable output current magnitude.

[0069] Refer to Figure 1 , in an optional embodiment of the present application, the dynamic current source 10 may at least include a constant current source 11 and a MOSFET device;

[0070] The output terminal of the constant current source 11 is connected to the drain of the MOSFET device; the second control output terminal of the controller MCU is connected to the gate of the MOSFET device; the source of the MOSFET device is the output terminal of the dynamic current source 10;

[0071] The controller MCU is used to input PWM signals with different duty cycles to the gate of the MOSFET device according to the reference temperature.

[0072] In this embodiment, the output terminal of the constant current source 11 can output a constant current, and the MOSFET device is equivalent to a switching device. The controller MCU can control the on and off between the drain and source of the MOSFET device by inputting high and low voltage signals to the gate of the MOSFET device. Thus, as the controller MCU inputs PWM signals with different duty cycles to the gate of the MOSFET device, and then controls the on and off ratio between the drain and source of the MOSFET device, current signals of different magnitudes can be output from the source of the MOSFET device.

[0073] In addition, an LDO voltage regulator can be further provided between the constant current source 11 and the MOSFET device, and a low-pass filter 12 can be provided between the second control output terminal of the controller MCU and the gate of the MOSFET device.

[0074] The LDO voltage regulator converts the high-level electrical signal output by the constant current source 11 into a low-level signal of +3.3V. The LDO voltage regulator can be a TPS7A4700 linear voltage regulator. Its low-noise characteristic ensures the stability of the power supply output and effectively reduces the potential interference to subsequent circuit devices. And the high power supply rejection ratio (PSRR) of the TPS7A4700 linear voltage regulator enables the output voltage to remain stable when the power supply output fluctuates, thus significantly improving the anti-interference ability of the power supply. The low-pass filter 12 can effectively prevent the noise in the PWM signal output by the controller MCU from interfering with the on and off of the MOSFET device.

[0075] Based on the above discussion, in practical applications, the temperature measurement range of the NTC temperature measurement device can be divided into more than 3 temperature intervals, and the optimal excitation current that can ensure that the NTC thermistor can quickly reach the thermal equilibrium state and avoid the self-heating effect in each temperature interval can be determined through repeated tests. As shown in Table 1 below, Table 1 shows the duty cycle of the PWM signal and the excitation current corresponding to four different temperature intervals.

[0076] Table 1:

[0077]

[0078] It can be understood that in Table 1, only the temperature measurement range of the NTC temperature measurement device is divided into four temperature ranges as an example; in actual applications, the division of each temperature range can be smaller. For example, the temperature range covered by each temperature range is 20 °C. Specifically, it can be determined based on the actual requirements for temperature measurement accuracy and the size of the temperature measurement range. There is no specific limitation in this application for this.

[0079] On this basis, in order to provide a more accurate excitation current for the NTC thermistor in this application, a reference temperature sensor 70 can be further set. The reference temperature sensor 70 can measure the temperature of the same measured target as the NTC thermistor, and then obtain the reference temperature of the measured target. The controller MCU can output a PWM signal with the duty cycle corresponding to the temperature range to which the reference temperature belongs to the MOSFET device according to the temperature range to which the reference temperature belongs, combined with the duty cycle and excitation current corresponding to each temperature range determined in advance. In this way, the constant current source 11 can output the excitation current corresponding to the reference temperature through the source electrode of the MOSFET device.

[0080] It should be noted that the measurement accuracy of the reference temperature sensor used to measure the reference temperature in this application does not need to be too high, as long as it can roughly determine the temperature range to which the measured target belongs.

[0081] In addition, in actual applications, it is not necessarily necessary to configure the reference temperature sensor 70. For example, when the NTC temperature measurement device starts to work, an initial reference temperature can be set artificially. The excitation current provided for the NTC thermistor is based on this initial reference temperature. After the NTC thermistor reaches the thermal equilibrium state, the temperature data of a measured target can be measured. Even if the accuracy of this temperature data may not be high, it can still roughly represent the current temperature of the measured target. Therefore, the temperature data of the measured target measured by the NTC thermistor at this time can be used as the reference temperature, and then the excitation current provided for the NTC thermistor can be adjusted to be more accurate; on this basis, when the temperature data of the measured target changes and the excitation current of the NTC thermistor no longer meets the temperature measurement requirements, the controller MCU can use the temperature data measured by the NTC thermistor at the previous moment as the new reference temperature and re-regulate the excitation current output by the dynamic current source 10, thereby effectively improving the measurement accuracy of the NTC thermistor.

[0082] In addition, for the above-mentioned artificially set initial reference temperature, it can be a data estimated based on the current temperature of the measured target artificially, or it can be a fixed temperature data directly written and stored in the chip of the controller MCU. There is no specific limitation in this application for this.

[0083] On this basis, as Figure 2As can be seen from the resistance-temperature characteristic curve of the NTC thermistor shown, in the temperature range from -40°C to 50°C, the resistance decreases rapidly with the increase of temperature, while in the temperature range above 50°C, the resistance of the NTC thermistor decreases slowly with the increase of temperature. It can be seen that the resistance-temperature characteristic curve of the NTC thermistor is non-linear, which inevitably introduces non-linear measurement errors when using the NTC thermistor to measure the temperature data of the measured target.

[0084] Therefore, in this application, a parallel resistor is further provided in parallel with the NTC thermistor, and the temperature measurement of the measured target is realized through the NTC resistance circuit 30 formed by the parallel resistor and the NTC thermistor.

[0085] In this embodiment, the NTC resistance circuit 30 may include an NTC thermistor and an adjustable parallel resistor connected in parallel with each other; the controller MCU can adjust the resistance value of the adjustable parallel resistor according to the reference temperature of the measured target, that is, based on different reference temperatures, parallel resistors with different resistance values are connected in parallel to the NTC thermistor. For example, in the temperature range from -40°C to 0°C, the NTC thermistor can be connected in parallel with a 30KΩ parallel resistor; in the temperature range from 0°C to 70°C, the NTC thermistor can be connected in parallel with a 15KΩ parallel resistor; in the temperature range from 70°C to 150°C, the NTC thermistor can be connected in parallel with a 5KΩ parallel resistor.

[0086] As Figures 3 to 5 shown, Figures 3 to 5 respectively show the schematic diagrams of the resistance-temperature characteristic curves corresponding to the NTC resistance circuit 30 in this embodiment in three temperature ranges. The virtual straight lines in Figures 3 to 5 are the approximate equivalent fitting slope lines of the three resistance-temperature characteristic curves. The difference between the slope of each resistance-temperature characteristic curve and the fitting slope line is relatively small, that is, it is close to linear. Obviously, compared with the resistance-temperature characteristic curve of a single NTC thermistor, in this application, when the NTC thermistor is connected in parallel with parallel resistors with different resistance values in three different temperature ranges, the resistance-temperature characteristic curve of the NTC resistance circuit 30 formed by the NTC thermistor and the parallel resistor is closer to linear in each temperature range. Therefore, in the actual temperature measurement process, the temperature measurement can be realized based on the NTC resistance circuit 30 formed by the NTC thermistor and the parallel resistor, thereby effectively reducing the errors introduced by the non-linear change of the resistance-temperature characteristic curve, and further improving the temperature measurement accuracy of the NTC temperature measurement device.

[0087] In addition, similar to the above excitation current, in the present application, the temperature measurement range of the NTC temperature measurement device can also be divided into several temperature intervals in advance, and a parallel resistor with a corresponding resistance value is determined for each temperature interval. On this basis, the adjustable parallel resistor in this embodiment can have a variety of different implementation manners.

[0088] For example, the adjustable parallel resistor can be a rheostat. In practical applications, the controller MCU can adjust the resistance value of the adjustable parallel resistor to the resistance value corresponding to the temperature interval to which the reference temperature of the measured target belongs.

[0089] For another example, the adjustable parallel resistor can include a plurality of resistive elements connected in series and a short-circuit switch. By the short-circuit switch, the number of resistive elements connected in series to the circuit can be increased or decreased. As the number of resistive elements connected in series to the circuit changes, the overall resistance value of the adjustable parallel resistor can be changed.

[0090] For another example, referring to Figure 1 , the adjustable parallel resistor can also include a plurality of parallel resistors and a single-pole multi-throw switch; each temperature interval corresponds to a parallel resistor; the first ends of the respective parallel resistors are commonly connected to the first end of the NTC thermistor, and the second ends of the respective parallel resistors are respectively connected to the respective fixed terminals of the first single-pole multi-throw switch (i.e., K11 to K1n), and the movable terminal of the first single-pole multi-throw switch is connected to the second end of the NTC thermistor. At the same time, the control input terminal of the first single-pole multi-throw switch is connected to the controller MCU.

[0091] When it is necessary to connect the first parallel resistor in parallel with the NTC thermistor based on the reference temperature, the controller MCU can control the movable terminal of the first single-pole multi-throw switch to conduct with the first fixed terminal, and the first fixed terminal is also the fixed terminal connected to the first parallel resistor, thereby enabling the parallel connection between the first parallel resistor and the NTC thermistor. Similarly, when it is necessary to connect the second parallel resistor in parallel with the NTC thermistor based on the reference temperature, the controller MCU can control the movable terminal of the first single-pole multi-throw switch to conduct with the second fixed terminal, thereby realizing the parallel connection between the second parallel resistor and the NTC thermistor. In a similar manner, the switching of the parallel connection between the NTC thermistor and different parallel resistors can be achieved.

[0092] As Figure 6 shown, Figure 6 is a schematic structural diagram of an NTC resistor circuit provided by an embodiment of the present application; Figure 6 shows the circuit structure of an NTC resistor circuit 30 including three parallel resistors (i.e., R11, R21, R31). The parallel connection between the parallel resistor with different resistance values and the NTC thermistor can be switched through the first single-pole multi-throw switch chip. In Figure 6The fifth and sixth pins of the first single-pole multi-throw switch chip are control input terminals connected to the controller MCU. By inputting different high and low level signals to the two pins, the controller MCU can control the seventh pin of the first single-pole multi-throw switch to be switchably connected to one of the first, second, and third pins.

[0093] It should be noted that the temperature range divided for the adjustable parallel resistor in this application may be the same as or different from the temperature range divided for the excitation current, and no specific limitation is made in this application.

[0094] The NTC temperature measurement device in this application can provide different magnitudes of excitation current for the NTC thermistor according to different temperature magnitudes of the measured target, and at the same time connect parallel resistors with different resistance values in parallel to the NTC thermistor. Thus, on the basis of reducing the self-heating effect interference of the NTC thermistor temperature measurement, the error introduced by the non-linear change of the resistance-temperature characteristic of the NTC thermistor can be reduced, thereby greatly improving the temperature measurement accuracy of the NTC temperature measurement device.

[0095] Based on any of the above embodiments, referring to Figure 1 , in another optional embodiment of this application, the NTC temperature measurement device may further include:

[0096] Two LC series adjustable filters, namely the first LC series adjustable filter 40 and the second LC series adjustable filter 50;

[0097] Among them, the input end of the first LC series adjustable filter 40 is electrically connected to the output end of the NTC resistor circuit 30, and the output end is connected to the inverting input end of the differential amplifier U;

[0098] The input end of the second LC series adjustable filter 50 is electrically connected to the output end of the dynamic current source 10, and the output end is connected to the non-inverting input end of the differential amplifier U;

[0099] Each LC series adjustable filter includes an inductance element L and an adjustable capacitor element C; the first end of the inductance element L is the input end of the LC series adjustable filter; the second end of the inductance element L is connected to the input end of the adjustable capacitor element C; the output end of the adjustable capacitor element C is the output end of the LC series adjustable filter;

[0100] The third control output end of the controller MCU is connected to the control input end of the adjustable capacitor element C for regulating the capacitance magnitude of the adjustable capacitor element C.

[0101] In this embodiment, in order to further improve the temperature measurement accuracy of the NTC temperature measurement device, a first LC series adjustable filter 40 is further provided between the NTC resistance circuit 30 and the inverting input terminal of the differential amplifier U, and a second LC series adjustable filter 50 is provided between the output terminal of the dynamic current source 10 and the non-inverting input terminal of the differential amplifier U. The LC series adjustable filter circuit has the function of passing low frequencies and blocking high frequencies. Two LC series adjustable filters are used to suppress the CAN bus interference caused by different lengths of wires, thereby improving the accuracy of determining the temperature measurement data.

[0102] In the LC series adjustable filter of this embodiment, on the basis of including the inductance element L, an adjustable capacitor device C with adjustable capacitance can be further included; in actual application, the controller MCU can analyze and determine the main noise frequency according to the voltage signal output by the differential amplifier U, and then synchronously adjust the capacitance of the adjustable capacitor device C in the two LC series adjustable filters according to the magnitude of the main noise frequency; specifically, according to the cut-off frequency of the LC series adjustable filter satisfying ; where fc is the cut-off frequency, L is the inductance of the inductance element, and C is the capacitance of the adjustable capacitor device.

[0103] Thus, when the frequency of the main noise frequency is larger, the capacitance of the adjustable capacitor device C can be adjusted to be smaller, thereby increasing the cut-off frequency to a certain extent and enhancing the filtering effect of the LC series adjustable filter; conversely, when the frequency of the main noise frequency is smaller, the capacitance of the adjustable capacitor device C can be adjusted to be larger. Of course, in actual application, if the noise signal interference in the voltage signal output by the differential amplifier is too strong, the controller MCU can also repeatedly debug the capacitance of the adjustable capacitor device C to determine the reasonable capacitance of the adjustable capacitor device C, improve the suppression effect of the LC series adjustable filter on the noise signal, and make the noise in the voltage signal output by the differential amplifier U be suppressed small enough.

[0104] For the LC series adjustable filter of this embodiment, the adjustable capacitor device C can directly use an adjustable capacitor, and the capacitance of the adjustable capacitors in the two LC series adjustable filters increases or decreases synchronously and always remains the same.

[0105] Optionally, the adjustable capacitor device C can also include a capacitor array and a second single-pole multi-throw switch K2. The capacitor array includes at least three capacitor elements (i.e., C1, C2, C3). Through the switching of the second single-pole multi-throw switch K2, a suitable capacitor element is selected from the multiple capacitor elements to be connected in series with the inductance element L.

[0106] Such as Figure 1 and Figure 7As shown, the input end of the second single-pole multi-throw switch K2 is connected to the inductance element L, and each output end is correspondingly connected to one end of each capacitance element. The other ends of each capacitance element are commonly connected to the differential amplifier U. Thus, the controller MCU can control the input end of the two second single-pole multi-throw switch chips K2 to be switchably connected to one of the three output ends, that is, to realize the series connection between one of the three capacitance elements and the inductance element L.

[0107] Based on the above embodiment, in another optional embodiment of the present application, the NTC temperature measurement device may further include a common mode choke DCR;

[0108] The first terminal and the third terminal of the common mode choke DCR are the two ends of the same coil; the second terminal and the fourth terminal of the common mode choke DCR are the two ends of the same coil;

[0109] Wherein, the first terminal of the common mode choke DCR is electrically connected to the output end of the NTC resistance circuit 30; the second terminal of the common mode choke DCR is connected to the input end of the first LC series adjustable filter 40; the third terminal of the common mode choke DCR is electrically connected to the output end of the dynamic current source 10; the fourth terminal of the common mode choke is connected to the input end of the second LC series adjustable filter 50.

[0110] In this embodiment, the electrical signal output by the NTC resistance circuit 30 can be further input to the inverting input end of the differential amplifier U after passing through the first coil in the common mode choke DCR and the first LC series adjustable filter 40 in sequence; and the excitation current output by the output end of the dynamic current source 10 passes through the second coil in the common mode choke DCR and the second LC series adjustable filter 50 in sequence and is input to the non-inverting input end of the differential amplifier U, using the common mode choke DCR to suppress high-frequency noise; thus, through the combined action of the common mode choke DCR and the two-way LC series adjustable filters, the noise in the two-way differential signals is suppressed to the greatest extent, thereby effectively improving the temperature measurement accuracy of the NTC temperature measurement device.

[0111] Based on the above embodiment, as Figure 1 、 Figure 8 and Figure 9 shown, in another optional embodiment of the present application, the NTC temperature measurement device may further include multiple groups of NTC resistance circuits 30; and further include a first multiplexer;

[0112] The input end of the first multiplexer is connected to the output end of the dynamic current source 10; the multiple output ends of the first multiplexer are correspondingly connected to the input ends of each NTC resistance circuit 30; the output ends of each NTC resistance circuit 30 are commonly electrically connected to the inverting input end of the differential amplifier U;

[0113] The fourth control output terminal of the controller MCU is connected to the control input terminal of the first multiplexer, and is used to control the excitation current input to the input terminal of the first multiplexer to output from one output terminal.

[0114] In the NTC temperature measurement device of this embodiment, multiple groups of NTC resistance circuits 30 are provided, that is to say, the NTC temperature measurement device in this embodiment includes multiple NTC temperature measurement channels; and each temperature measurement channel is connected to the output terminal of the first multiplexer and the dynamic current source 10.

[0115] It can be understood that the first multiplexer in this embodiment is a multiplexer with one input terminal and multiple output terminals. Based on different control signals of the controller MCU for the first multiplexer, the electrical signal input to the input terminal of the first multiplexer can be selectively output from one of the multiple output terminals. That is to say, the controller MCU can switch and control the temperature measurement of one channel among multiple NTC temperature measurement channels through the multiplexer. In practical applications, the controller MCU can control the excitation current output by the dynamic current source 10 to sequentially output from each output terminal of the multiplexer, thereby sequentially measuring the temperature of the measured target through each NTC temperature measurement channel; the measured temperature voltage corresponding to each NTC temperature measurement channel can be sequentially output from the output terminal of the same differential amplifier U.

[0116] In addition, the circuit structure between each NTC resistance circuit 30 and the differential amplifier U in this embodiment should be the same; in the embodiment provided with the common mode choke coil DCR and the LC series adjustable filter, the output terminals of each NTC resistance circuit 30 can be connected to the first connection coil of the same common mode choke coil, that is, each NTC resistance circuit 30 is connected to the inverting input terminal of the same differential amplifier U through the same group of common mode choke coil DCR and LC series adjustable filter.

[0117] Of course, as Figure 9 shown, in practical applications, it is not excluded in this application that each NTC temperature measurement channel is respectively configured with a group of common mode choke coil DCR, LC series adjustable filter and differential amplifier U. Thus, the temperature measurements of the measured targets can be carried out synchronously in parallel for each NTC temperature measurement channel, and the random number scheme in this application can also be realized.

[0118] Based on any of the above embodiments, in another optional embodiment of this application, the NTC temperature measurement device may further include a second multiplexer, multiple reference resistors and a short - circuit line;

[0119] Among them, the output end of the dynamic current source 10 is connected to the input end of the second multiplexer; each output end of the multiplexer is correspondingly connected to the first end of each reference resistor and the first end of the short - circuit line; the second ends of each reference resistor and the second end of the short - circuit line are commonly electrically connected to the inverting input end of the differential amplifier U.

[0120] The fourth control output end of the controller MCU is connected to the control output end of the second multiplexer, and is used to control the input end of the second multiplexer to be switchably electrically connected to one of its multiple output ends, so that the excitation current input to the input end of the second multiplexer is output from one output end.

[0121] The short - circuit line in this embodiment can also be understood as a line with a resistance close to 0. In practical applications, the short - circuit line can also be a line of a circuit device directly grounded; that is, the output end of the second multiplexer connected to the short - circuit line is directly connected to the second ends of each reference resistor.

[0122] In addition, the working mode of the second multiplexer is the same as that of the first multiplexer, and it also outputs the signal input to the input end of the second multiplexer from one of its multiple output ends; as Figure 1 shown, the first multiplexer and the second multiplexer can be the same multiplexer 20, and only the first reference resistor R1, the second reference resistor R2, the third reference resistor R3, the short - circuit line and each path of the NTC resistor circuit 30 are respectively connected to different output ends of the multiplexer 20.

[0123] As Figure 1 shown, Figure 1 it is described by taking the reference resistor including three resistors, namely the first reference resistor, the second reference resistor, and the third reference resistor, as an example. As Figure 9 shown, Figure 9It is an 8-way multiplexer of model CD4051; among them, its Z pin is the input pin connected to the output end of the dynamic current source 10, and CH1~CH8 are 8 output pins. The CH1~CH4 pins can be sequentially and respectively connected to the output ends of 4 NTC resistor circuits 30 one by one, and the CH5~CH8 pins can be sequentially and respectively connected to the first reference resistor R1, the second reference resistor R2, the third reference resistor R3, and the short-circuit line one by one. In addition, the CTR1 pin, the CTR2 pin, the CTR3 pin, and the CTR4 pin are all four control input pins connected to the 4 control output ends of the controller MCU. The controller MCU outputs high and low levels to the four control input ends respectively, so that the electrical signals received by the four pins jointly form different control instructions. For example, for the four pins, the input high level is 1 and the low level is 0. When the control signal composed of the electrical signals output to the four pins is 0001, the excitation current input to the Z pin can be output from the CH1 pin. When the control signal is 0010, the excitation current input to the Z pin can be output from the CH2 pin, and so on. In this way, it can be realized that the excitation current can be switched and output from each output end.

[0124] Of course, the first multiplexer and the second multiplexer can also be two different multiplexers, as long as it can make the excitation current input to each reference circuit and each NTC resistor circuit 30 be switched and adjusted.

[0125] In addition, as Figure 1 and Figure 8 shown, for the second ends of each reference resistor and the short-circuit line, the second ends of each NTC resistor circuit 30 can be connected to the same differential amplifier U. At this time, the second ends of each reference resistor and the short-circuit line can be directly connected to the second ends of the NTC resistor circuit 30. The second ends of each reference resistor and the short-circuit line, and the second ends of each NTC resistor circuit 30 can also be connected to the same two differential amplifiers U. In this embodiment, if a common-mode choke coil DCR and an LC series adjustable filter are provided between the NTC resistor circuit 30 and its corresponding differential amplifier U, then the second ends of each reference resistor and the short-circuit line and the corresponding differential amplifier U should also be provided with the same common-mode choke coil DCR and LC series adjustable filter in the same way. The non-inverting input end of this differential amplifier U is also connected to the output end of the dynamic current source 10 through the common-mode choke coil DCR and the LC series adjustable filter. All in all, the circuit structure connected to the second ends of each reference resistor and the short-circuit line should be exactly the same as the circuit structure connected to the output ends of each NTC resistor circuit 30.

[0126] It should be noted that in the embodiment where the reference resistor, the short - circuit line, and the NTC resistor circuit 30 are commonly connected to the same differential amplifier U, and the first multiplexer and the second multiplexer are two multiplexers respectively, it should be ensured that only one of the reference resistors, the short - circuit lines, and the NTC resistor circuit 30 is connected to the excitation current at the same time.

[0127] On this basis, the circuit structure connected to the second ends of the reference resistors and the short - circuit lines in this application should be exactly the same as the circuit structure connected to the output ends of the NTC resistor circuits 30, which is equivalent to making the circuit structures connected to the second ends of each reference resistor and the output ends of the NTC resistor circuits 30 the same; thus, the circuit structures when each reference resistor simulates a parallel resistor with different resistances in parallel with the NTC thermistor can be achieved, and then the temperature - measuring voltage output by the corresponding differential amplifier U can be corrected to obtain a more accurate temperature - measuring result.

[0128] When the controller MCU controls the excitation electrical signal input at the input end of the second multiplexer to output to the short - circuit line, at this time, it is equivalent to short - circuiting between the first end and the third end of the common - mode choke DCR through the short - circuit line, and this short - circuit line is grounded. At this time, it is equivalent that the input voltages at the two input ends of the differential amplifier U are 0; theoretically speaking, the voltage value output at the output end of the differential amplifier U should also be 0 at this time; however, due to errors introduced by factors such as the operational amplifier bias voltage and the multiplexer on - resistance, the output end of the differential amplifier U is not 0 at this time. Therefore, the voltage value output by the differential amplifier U at this time can be used as the reference voltage introduced due to errors.

[0129] When the excitation current is connected to the input end of the subsequent NTC resistor circuit 30, the temperature - measuring voltage output from the differential amplifier U can subtract this reference voltage, that is, remove the voltage part introduced by errors in the measured voltage data, realize the zero - point calibration of the temperature - measuring voltage, and eliminate the output offset error of the system when there is no signal input (error sources: operational amplifier bias voltage, multiplexer on - resistance, etc.); obviously, the corrected temperature - measuring voltage can more accurately reflect the voltage magnitude of the current NTC resistor circuit 30.

[0130] On this basis, the number of reference resistors in this embodiment is the same as the number of temperature intervals corresponding to the resistance value adjustment of the adjustable parallel resistor in the NTC resistor circuit 30. As mentioned above, the resistance value adjusted by the adjustable parallel resistor is adjusted according to the temperature intervals described by the reference temperature, and each temperature interval corresponds to the resistance value of an adjustable parallel resistor. As Figure 1 shown, Figure 1 Taking the example where the adjustable parallel resistor can be switched to adjust three different resistance values of parallel resistors, correspondingly, the number of reference resistors is also 3, and the resistance values of the three reference resistors are approximately the same as the resistance values of the NTC thermistor at three temperature intervals respectively.

[0131] Thus, when the controller MCU controls the excitation electrical signal input at the input end of the second multiplexer to be output to the first reference resistor R1, the reference voltage output by the differential amplifier U and the output voltage at the output end of the dynamic current source 10 at this time are collected; according to the gain coefficient formula calculate the gain system, and the gain coefficient of the first temperature range corresponding to the first reference resistor R1 can be obtained; where is the reference voltage; is the theoretical voltage value of the first reference resistor R1, and its magnitude is equal to the product of the resistance value of the first reference resistor R1 and the excitation current currently output by the dynamic current source 10; is the reference voltage; correspondingly, when the reference temperature of the measured target belongs to the first temperature range, when the controller MCU controls the input end of the NTC resistor circuit 30 to connect the excitation current, the temperature measurement voltage output from the differential amplifier U can be multiplied by this gain coefficient, so as to perform full-scale calibration on the temperature measurement voltage, ensuring that the output of the differential amplifier U is consistent with the theoretical value when the temperature of the measured target is the maximum (error sources: current source accuracy, ADC non-linearity, temperature drift, etc.).

[0132] Theoretically speaking, when the inverting input end of the differential amplifier U is conducted with the NTC resistor circuit 30, the voltage signal output at the output end of the differential amplifier U should be equal to the voltage value of the NTC resistor circuit 30, that is, equal to the product of the resistance value of the NTC resistor circuit 30 and the excitation current; thus, in the actual temperature measurement process, based on the ratio between the voltage signal output by the differential amplifier U and the excitation current, the resistance value of the NTC resistor circuit 30 can be determined, and then the temperature data of the measured target can be determined.

[0133] However, in actual applications, due to reasons such as current source accuracy, ADC non-linearity, temperature drift, etc., the voltage output at the output end of the differential amplifier U does not satisfy that the magnitude of the output voltage signal is equal to the product of the resistance value of the NTC resistor circuit 30 and the excitation current; thus, in the actual temperature measurement process, if the resistance value of the NTC resistor circuit 30 is still determined based on the theoretical relationship that the magnitude of the voltage signal output at the output end of the differential amplifier U is equal to the product of the resistance value of the NTC resistor circuit 30 and the excitation current, and the temperature data of the measured target is determined therefrom, it is obviously inaccurate.

[0134] Therefore, in this embodiment, reference resistors with various different resistance values are used to simulate the NTC resistor circuit 30 at different temperatures. Since the overall resistance value of the NTC resistor circuit 30 is greatly affected by the resistance value of the NTC thermistor, the resistance values of the reference resistors are roughly set based on the resistance values of the NTC thermistor in different temperature ranges, so as to roughly simulate the NTC resistor circuit 30 with different resistance values.

[0135] Thus, when the reference resistor and the inverting input terminal of the differential amplifier U are electrically connected to each other, the current in the reference resistor is the excitation current corresponding to the temperature range. The product of the resistance value of the reference resistor and the excitation current is the theoretical voltage value of the reference resistor. At this time, the voltage value output by the output terminal of the differential amplifier U is the actual voltage value of the reference resistor, that is, the above-mentioned reference voltage. The ratio between the theoretical voltage value and the reference voltage is the gain coefficient between the theoretical value and the measured value. When measuring the temperature of the NTC resistor circuit 30, the voltage value output by the output terminal of the differential amplifier U can be corrected based on this gain coefficient. Obviously, the corrected voltage value is equal to the product of the resistance value of the NTC resistor circuit 30 and the excitation current. Thus, the NTC resistor circuit 30 can be determined more accurately, and further, more accurate temperature data of the measured target can be determined.

[0136] In summary, the NTC temperature measurement device of the present application is configured with a dynamic current source whose output current signal is variable. Thus, the controller can adjust the excitation current output by the dynamic current source to the excitation current corresponding to the current magnitude of the reference temperature according to the reference temperature that roughly represents the current temperature of the measured target, thereby reducing the self-heating effect of the NTC thermistor when the excitation current is turned on, and further reducing the influence of the self-heating effect on the temperature measurement result. In addition, an adjustable parallel resistor is connected in parallel to the NTC thermistor. The controller can adjust the resistance value of the adjustable parallel resistor according to the reference temperature, so that the resistance temperature characteristic of the overall NTC resistor circuit formed by the parallel connection of the NTC thermistor and the adjustable parallel resistor becomes more linear. Thus, the temperature of the measured target can be measured by using the resistance temperature characteristic of the NTC resistor circuit, and the non-linear error introduced by the resistance temperature characteristic of the NTC thermistor can be effectively reduced, and further, the temperature measurement accuracy of the NTC temperature measurement device can be improved. It can be seen that in the present application, the interference of the self-heating effect of the NTC thermistor on the temperature measurement result can be reduced to a certain extent, and the error introduced by the non-linear change of the resistance temperature characteristic of the NTC thermistor can also be reduced, greatly improving the temperature measurement accuracy of the NTC temperature measurement device, which is beneficial to the wide application of the NTC temperature measurement device.

[0137] An embodiment of a control method for an NTC temperature measurement device is also provided in the present application. The control method is applied to the NTC temperature measurement device described in any one of the above; as Figure 10 shown, the control method of the NTC temperature measurement device may include:

[0138] S11: Obtain the current reference temperature of the measured target;

[0139] S12: According to the temperature range to which the reference temperature belongs and the excitation signals corresponding to each temperature range determined in advance, control the dynamic current source to output an excitation current corresponding to the reference current;

[0140] S13: Adjust the resistance value of the adjustable parallel resistor to the resistance value corresponding to the reference temperature.

[0141] S14: Collect the temperature measurement voltage output from the output terminal of the differential amplifier, and determine the temperature measurement data based on the temperature measurement voltage.

[0142] In this embodiment, when controlling the NTC temperature measurement device to measure the temperature of the target to be measured, not only is the excitation current output by the dynamic current source regulated based on the reference temperature representing the approximate temperature of the target to be measured, but also the resistance value of the resistor connected in parallel with the NTC thermistor is adjusted based on this reference temperature. Thus, on the basis of avoiding the self-heating effect problem of the NTC thermistor caused by unreasonable excitation current, the error introduced by the non-linear change of the resistance temperature characteristic of the NTC thermistor is reduced, thereby greatly improving the temperature measurement accuracy of the NTC temperature measurement device.

[0143] Further, in the NTC temperature measurement device provided with a reference circuit and a short circuit line, this control method may further include, after the above S12 and before the above S14:

[0144] S21: Control the first multiplexer to switch so that the excitation current is output from the output terminal of the first multiplexer to the short circuit line.

[0145] S22: Collect the reference voltage output from the output terminal of the differential amplifier.

[0146] S23: Analyze and identify the main frequency of the noise in the reference voltage.

[0147] S24: Adjust the capacitance of the first adjustable capacitor device and the capacitance of the second adjustable capacitor device to the first capacitance value and the second capacitance value corresponding to the main frequency of the noise respectively.

[0148] S25: Control the first multiplexer to switch so that the excitation current is output from the output terminal of the first multiplexer to the NTC circuit.

[0149] In this embodiment, when collecting the voltage signal output by the differential amplifier as the reference voltage when there is no input signal (i.e., no temperature measurement signal, and in this embodiment, both input signals of the differential amplifier are signals of the excitation current), perform a fast Fourier transform (FFT) on this reference voltage to generate a frequency-amplitude spectrum diagram; identify the spikes (such as alternating current interference signals) and the frequency band where the noise energy is concentrated in the spectrum; obtain the main frequency of the noise, and adjust the capacitance of the adjustable capacitor device in the LC series adjustable filter according to this main frequency of the noise. For example, if the current main frequency of the noise is too large, the capacitance of the adjustable capacitor device can be reduced, and conversely, when the main frequency of the noise is relatively small, the capacitance of the adjustable capacitor device can be appropriately increased.

[0150] After the capacitances of the first adjustable capacitor device and the second adjustable capacitor device are both adjusted to appropriate values, the excitation current can be input into the NTC resistor circuit through the first multiplexer to start the temperature measurement process of the NTC resistor circuit. It should be noted that in practical applications, if the measured temperature change rate of the target to be measured is too fast through the NTC resistor circuit, such as the temperature change rate reaches 0.5 °C / s to 2 °C / s, it may cause the thermal inertia of the NTC thermistor to not match the circuit response. At this time, the capacitances of the first adjustable capacitor device and the second adjustable capacitor device can also be adjusted in real time to maintain the temperature measurement accuracy.

[0151] Based on the above discussion, in another optional embodiment of the present application, after the above S12 and before the above S25, it further includes:

[0152] S31: Control the second multiplexer to switch according to the reference temperature, so that the excitation current is output to the reference resistor corresponding to the reference temperature;

[0153] S32: Collect the reference voltage output from the output terminal of the differential amplifier and calculate the theoretical voltage of the reference resistor;

[0154] S33: Refer to the reference voltage and the gain coefficient formula , to obtain the gain coefficient; where K is the gain coefficient; is the reference voltage; is the theoretical voltage of the reference resistor; is the reference voltage;

[0155] Correspondingly, in the above S14, the process of determining the temperature measurement data according to the temperature measurement voltage may include:

[0156] S141: Perform a difference operation on the temperature measurement voltage and the reference voltage to obtain the first calibration voltage;

[0157] S142: Perform a multiplication operation on the gain coefficient and the first calibration voltage to obtain the second calibration voltage;

[0158] S143: Determine the temperature measurement data according to the second calibration voltage.

[0159] In this embodiment, on the basis of zero-degree calibration of the temperature measurement voltage using the reference voltage collected when there is no input signal, further use the reference resistor to simulate the gain coefficient generated by the signal input into the differential amplifier through the NTC resistor circuit at the reference temperature, and use this gain coefficient to further perform full-scale calibration on the temperature measurement voltage. Finally, by combining the temperature measurement voltage after two calibrations with the resistance-temperature characteristics of the NTC resistor circuit, more accurate temperature measurement data can be determined.

[0160] It should be noted that before each start of the NTC temperature measurement device, the measurement of the reference voltage and the gain coefficient corresponding to the temperature range of each reference resistor can be performed once to correct the actually measured temperature measurement voltage in real time; on this basis, the reference voltage and the gain coefficient can be re-measured at regular intervals to ensure the correctness of the calibration and thus ensure the accuracy of the temperature measurement.

[0161] It should be noted that in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that the elements inherent in a process, method, article or device comprising a series of elements are included. Without further limitation, an element defined by the statement "comprising an..." does not exclude the existence of additional identical elements in the process, method, article or device comprising the element. In addition, the parts of the above technical solutions provided in the embodiments of the present application that are consistent with the corresponding technical solutions in the prior art in terms of implementation principles are not described in detail to avoid excessive elaboration.

[0162] In this article, specific examples are used to elaborate on the principles and implementation manners of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the present invention.

Claims

1. An NTC temperature measuring device, characterized in that, including a dynamic current source, a controller, an NTC resistance circuit, and a differential amplifier; The control input terminal of the dynamic current source is connected to the first control output terminal of the controller; the output terminal of the dynamic current source is connected to the input terminal of the NTC resistance circuit and the non-inverting input terminal of the differential amplifier; the output terminal of the NTC resistance circuit is electrically connected to the inverting input terminal of the differential amplifier; wherein, the controller is configured to control the output terminal of the dynamic current source to output an excitation current corresponding to the reference temperature according to the current reference temperature of the target to be measured; The NTC resistance circuit includes an NTC thermistor and an adjustable parallel resistor connected in parallel with each other; The second control output terminal of the controller is connected to the adjustable parallel resistor, and is configured to adjust the resistance value of the adjustable parallel resistor to the resistance value corresponding to the reference temperature.

2. The NTC temperature measuring device according to claim 1, characterized in that, It further includes two LC series adjustable filters, namely a first LC series adjustable filter and a second LC series adjustable filter; wherein, the input terminal of the first LC series adjustable filter is electrically connected to the output terminal of the NTC resistance circuit, and the output terminal is connected to the inverting input terminal of the differential amplifier; The input terminal of the second LC series adjustable filter is electrically connected to the output terminal of the dynamic current source, and the output terminal is connected to the non-inverting input terminal of the differential amplifier; Each of the LC series adjustable filters includes an inductance element and an adjustable capacitor element; the first end of the inductance element is the input terminal of the LC series adjustable filter; the second end of the inductance element is connected to the input terminal of the adjustable capacitor element; the output terminal of the adjustable capacitor element is the output terminal of the LC series adjustable filter; The third control output terminal of the controller is connected to the control input terminal of the adjustable capacitor element, and is configured to adjust the capacitance of the adjustable capacitor element.

3. The NTC temperature measuring device according to claim 2, characterized in that, It further includes a common mode choke; the first terminal and the third terminal of the common mode choke are the two ends of the same coil; the second terminal and the fourth terminal of the common mode choke are the two ends of the same coil; wherein, the first terminal of the common mode choke is electrically connected to the output terminal of the NTC resistance circuit; the second terminal of the common mode choke is connected to the input terminal of the first LC series adjustable filter; the third terminal of the common mode choke is electrically connected to the output terminal of the dynamic current source; the fourth terminal of the common mode choke is connected to the input terminal of the second LC series adjustable filter.

4. The NTC temperature measuring device according to claim 1, characterized in that, Multiple groups of the NTC resistance circuits are provided; it further includes a first multiplexer; The input terminal of the first multiplexer is connected to the output terminal of the dynamic current source; multiple output terminals of the first multiplexer are respectively connected to the input terminals of the NTC resistance circuits one by one; the output terminals of the NTC resistance circuits are commonly electrically connected to the inverting input terminal of the differential amplifier; The fourth control output terminal of the controller is connected to the control input terminal of the first multiplexer, and is configured to control the excitation current input to the input terminal of the first multiplexer to be output from one output terminal.

5. The NTC temperature measurement device according to claim 1, characterized in that, The dynamic current source includes a constant current source and a MOSFET device; The output terminal of the constant current source is connected to the drain of the MOSFET device; the second control output terminal of the controller is connected to the gate of the MOSFET device; the source of the MOSFET device is the output terminal of the dynamic current source; The controller is configured to input a PWM signal with different duty cycles to the gate of the MOSFET device according to the reference temperature.

6. The NTC temperature measurement device according to claim 1, wherein, It further includes a reference temperature sensor connected to the controller for collecting the reference temperature of the measured target.

7. The NTC temperature measuring device according to any one of claims 1 to 6, characterized in that, It further includes a second multiplexer, a plurality of reference resistors with different resistance values, and a short-circuit line; Wherein, the output terminal of the dynamic current source is connected to the input terminal of the second multiplexer; each output terminal of the second multiplexer is connected to the first end of each of the reference resistors and the first end of the short-circuit line in one-to-one correspondence; the second ends of each of the reference resistors and the second end of the short-circuit line are commonly electrically connected to the inverting input terminal of the differential amplifier; The fourth control output terminal of the controller is connected to the control output terminal of the multiplexer for controlling the excitation current input to the input terminal of the second multiplexer to be output from one output terminal.

8. A control method for an NTC temperature measurement device, characterized in that, Applied to the NTC temperature measurement device according to any one of claims 1 to 7; the control method includes: Obtain the current reference temperature of the measured target; According to the temperature range to which the reference temperature belongs and the excitation signal corresponding to each predetermined temperature range, control the dynamic current source to output an excitation current corresponding to the reference current; Adjust the resistance value of the adjustable parallel resistor to the resistance value corresponding to the reference temperature; Collect the temperature measurement voltage output from the output terminal of the differential amplifier, and determine the temperature measurement data according to the temperature measurement voltage.

9. The control method of the NTC temperature measuring device according to claim 8, characterized in that, Before collecting the temperature measurement voltage output from the output terminal of the differential amplifier after controlling the dynamic current source to output an excitation current corresponding to the reference current, it further includes: Control the first multiplexer to switch so that the excitation current is output from the output terminal of the first multiplexer to the short-circuit line; Collect the reference voltage output from the output terminal of the differential amplifier; Analyze and identify the main frequency of the noise in the reference voltage; Adjust the capacitance of the first adjustable capacitor device and the capacitance of the second adjustable capacitor device to the first capacitance value and the second capacitance value corresponding to the main frequency of the noise respectively; Control the first multiplexer to switch so that the excitation current is output from the output terminal of the first multiplexer to the NTC circuit.

10. The control method of the NTC temperature measurement device according to claim 9, characterized in that, Before controlling the first multiplexer to switch so that the excitation current is output from the output terminal of the multiplexer to the NTC circuit after controlling the dynamic current source to output an excitation current corresponding to the reference current, it further includes: Control the second multiplexer to switch according to the reference temperature so that the excitation current is output to the reference resistor corresponding to the reference temperature; Collect the reference voltage output from the output terminal of the differential amplifier, and calculate the theoretical voltage of the reference resistor; The reference voltage and gain coefficient formula respectively , the gain coefficient is obtained; where K is the gain coefficient; is the reference voltage; is the theoretical voltage of the reference resistor; is the reference voltage; Accordingly, determining temperature measurement data based on the temperature measurement voltage includes: Performing a difference operation on the temperature measurement voltage and the reference voltage to obtain a first calibrated voltage; Performing a multiplication operation on the gain coefficient and the first calibrated voltage to obtain a second calibrated voltage; Determining temperature measurement data based on the second calibrated voltage.

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