WO2023085045A1 - Temperature detection device, temperature detection method, and computer program - Google Patents

Abstract

In this temperature detection device, a regulator applies a constant voltage to a series circuit that includes a temperature resistor and a variable resistor. The temperature resistor and the variable resistor divide the constant voltage. The resistance value of the temperature resistor changes in accordance with the temperature of the temperature resistor. A microcomputer adjusts the resistance value of the variable resistor in accordance with the resistance value of the temperature resistor. After adjusting the resistance value of the variable resistor, the microcomputer converts, into a digital value, the divided voltage divided by the temperature resistor and the variable resistor, and determines the temperature of the temperature resistor on the basis of the digital value thus converted.

Description

TEMPERATURE DETECTION DEVICE, TEMPERATURE DETECTION METHOD AND COMPUTER PROGRAM

The present disclosure relates to a temperature detection device, a temperature detection method, and a computer program.
This application claims priority based on Japanese application No. 2021-183472 filed on November 10, 2021, and incorporates all the descriptions described in the Japanese application.

Patent Document 1 discloses a configuration for detecting temperature using a thermistor. The resistance value of the thermistor changes according to the temperature of the thermistor. A thermistor is arranged in the vicinity of a semiconductor switch chip mounted on a vehicle. The temperature of the chip of the semiconductor switch is detected by calculating the temperature of the thermistor.

JP 2019-192950 A

A temperature detection device according to an aspect of the present disclosure is a temperature detection device mounted on a vehicle, comprising: a variable resistor connected to a temperature resistor whose resistance value changes according to temperature; A voltage application unit that applies a constant voltage to a series circuit including a variable resistor, a conversion unit that converts the divided voltage divided by the temperature resistor and the variable resistor into a digital value, and a processing unit that executes processing. wherein the temperature is the temperature of the temperature resistor, the processing unit adjusts the resistance value of the variable resistor according to the resistance value of the temperature resistor, and adjusts the resistance value of the variable resistor to The temperature of the temperature resistor is specified based on the digital value converted by the conversion unit after the adjustment.

In a temperature detection method according to an aspect of the present disclosure, adjusting a resistance value of a variable resistor connected to a temperature resistor according to a resistance value of the temperature resistor whose resistance value changes according to temperature; determining the temperature based on the digital value of the divided voltage obtained by dividing the constant voltage by the temperature resistor and the variable resistor after the resistance value of the variable resistor is adjusted; is executed by the computer, and the temperature is the temperature of the temperature resistor.

A computer program according to an aspect of the present disclosure adjusts a resistance value of a variable resistor connected to a temperature resistor according to a resistance value of the temperature resistor whose resistance value changes according to temperature; determining the temperature based on a digital value of a divided voltage obtained by dividing a constant voltage by the temperature resistor and the variable resistor after the resistance value of the variable resistor is adjusted; Used to run a computer, said temperature is the temperature of said temperature resistor.

The present disclosure can be realized not only as a temperature detection device having such a characteristic processing unit, but also as a temperature detection method including such characteristic processing as steps, or as a temperature detection method in which such steps are executed by a computer. It can be implemented as a computer program for execution. Further, the present disclosure can be implemented as a semiconductor integrated circuit that implements part or all of the temperature detection device, or as a temperature detection system that includes the temperature detection device.

2 is a block diagram showing the configuration of main parts of the temperature detection system according to Embodiment 1. FIG. It is a graph which shows the temperature characteristic of a temperature resistor. It is a circuit diagram of a variable resistor. 3 is a block diagram showing the configuration of main parts of a microcomputer; FIG. FIG. 4 is an explanatory diagram of conversion into digital values; FIG. 4 is an explanatory diagram of resolution according to the resistance value of a variable resistor; FIG. 4 is an explanatory diagram of timing for changing the resistance value of a variable resistor; 4 is a chart showing contents of a temperature table; 5 is a flow chart showing a procedure of temperature detection processing; 10 is a flow chart showing the procedure of temperature detection processing according to the second embodiment. FIG. 11 is a circuit diagram of a variable resistor according to Embodiment 3;

[Problems to be Solved by the Present Disclosure]
Patent Document 1 does not consider the accuracy of temperature detection.

An object of the present disclosure is to provide a temperature detection device, a temperature detection method, and a computer program that can accurately detect temperature.

[Effect of the present disclosure]
According to the present disclosure, temperature can be detected with high accuracy.

[Description of Embodiments of the Present Disclosure]
First, embodiments of the present disclosure are enumerated and described. At least some of the embodiments described below may be combined arbitrarily.

(1) A temperature detection device according to an aspect of the present disclosure is a temperature detection device mounted on a vehicle, comprising: a variable resistor connected to a temperature resistor whose resistance value changes according to temperature; A voltage application unit that applies a constant voltage to a series circuit including a resistor and a variable resistor; a conversion unit that converts the divided voltage divided by the temperature resistor and the variable resistor into a digital value; wherein the temperature is the temperature of the temperature resistor, the processing unit adjusts the resistance value of the variable resistor according to the resistance value of the temperature resistor, and After adjusting the resistance value, the temperature of the temperature resistor is specified based on the digital value converted by the conversion unit.

(2) In the temperature detection device according to an aspect of the present disclosure, the variable resistor includes a first resistor and a second resistor, a series switch connected in series with the first resistor, and turning on or turning on the series switch. a switching circuit for switching off, wherein the second resistor is connected in parallel to a series circuit including the first resistor and a series switch, and the processing unit switches on or off the series switch. The resistance value of the variable resistor is adjusted by instructing the switching circuit.

(3) In the temperature detection device according to an aspect of the present disclosure, the processing unit increases the resistance value of the variable resistor to a first predetermined value when the resistance value of the temperature resistor exceeds a threshold value, The resistance value of the variable resistor is decreased to a second predetermined value when the resistance value of the temperature resistor decreases to a value less than the threshold value, and the first predetermined value exceeds the second predetermined value.

(4) A temperature detection device according to an aspect of the present disclosure includes a temperature storage unit that stores a plurality of first temperatures and second temperatures corresponding to a plurality of digital values, and the processing unit stores the variable When the resistance value of the resistor is the first predetermined value, the temperature of the temperature resistor is identified as the first temperature corresponding to the digital value converted by the conversion unit among the plurality of first temperatures. and when the resistance value of the variable resistor is the second predetermined value, the temperature of the temperature resistor is a second temperature corresponding to the digital value converted by the conversion unit among the plurality of second temperatures. value.

(5) A temperature detection device according to an aspect of the present disclosure includes a calculation formula storage unit that stores a first calculation formula and a second calculation formula for calculating temperature using voltage as a variable, and the processing unit , when the resistance value of the variable resistor is the first predetermined value, the temperature is calculated by substituting the divided voltage indicated by the digital value converted by the conversion unit into the variable of the first calculation formula, and When the resistance value of the variable resistor is the second predetermined value, the temperature is calculated by substituting the divided voltage indicated by the digital value converted by the conversion unit into the variable of the second calculation formula, and the temperature resistance The temperature of the vessel is specified as the calculated temperature.

(6) In the temperature detection device according to one aspect of the present disclosure, the resistance value of the temperature resistor decreases when the temperature of the temperature resistor increases.

(7) In the temperature detection method according to one aspect of the present disclosure, the resistance value of the variable resistor connected to the temperature resistor is adjusted according to the resistance value of the temperature resistor whose resistance value changes according to temperature. and determining the temperature based on the digital value of the divided voltage obtained by dividing the constant voltage by the temperature resistor and the variable resistor after the resistance value of the variable resistor is adjusted. and wherein the temperature is the temperature of the temperature resistor.

(8) A computer program according to an aspect of the present disclosure adjusts the resistance value of a variable resistor connected to the temperature resistor according to the resistance value of the temperature resistor whose resistance value changes according to temperature. and determining the temperature based on the digital value of the divided voltage obtained by dividing the constant voltage by the temperature resistor and the variable resistor after the resistance value of the variable resistor is adjusted. and the temperature is the temperature of the temperature resistor.

In the temperature detection device, temperature detection method, and computer program according to the above aspects, the resistance value of the variable resistor is adjusted according to the resistance value of the temperature resistor. A plurality of voltages are associated with each of the plurality of digital values. The divided voltage is, for example, converted into a digital value of the closest voltage among the plurality of voltages. If the difference between the resistance values of the variable resistor and the temperature resistor is sufficiently large, the divided voltage hardly changes due to the change in the resistance value of the temperature resistor. In this case, the digital value does not change.

However, in the above aspect, for example, when the resistance value of the temperature resistor decreases, the resistance value of the variable resistor is decreased. When the resistance value of the temperature resistor increases, the resistance value of the variable resistor is increased. Therefore, the difference between the resistance values of the variable resistor and the temperature resistor is prevented from increasing to a large value. As a result, since the divided voltage changes greatly, the temperature can be detected with high accuracy.

In the temperature detection device according to the above aspect, the resistance value of the second resistor is greater than the resistance value of the parallel circuit of the first resistor and the second resistor. When the series switch switches from on to off, the resistance of the variable resistor increases from the resistance of the parallel circuit to the resistance of the second resistor. When the series switch switches from on to off, the resistance of the variable resistor drops from the resistance of the second resistor to the resistance of the parallel circuit.

In the temperature detection device according to the above aspect, when the resistance value of the temperature resistor exceeds the resistance threshold value, the resistance value is increased from the second predetermined value to the first predetermined value. If the resistance of the thermal resistor drops below the resistance threshold, it is lowered from the first predetermined value to the second predetermined value. As a result, the accuracy of a certain value or more is maintained.

In the temperature detection device according to the above aspect, the temperature of the temperature resistor is specified using pre-stored memory contents. Therefore, it is possible to specify the temperature of the temperature resistor with a simple configuration.

In the temperature detection device according to the above aspect, the temperature of the temperature resistor is specified using the first calculation formula and the second calculation formula. Thus, accurate temperature determination of the temperature resistor is achieved.

In the temperature detection device according to the above aspect, the temperature resistor has, for example, an NTC (Negative Temperature Coefficient) thermistor.

[Details of the embodiment of the present disclosure]
A specific example of the temperature detection system according to the embodiment of the present disclosure will be described below with reference to the drawings. The present invention is not limited to these exemplifications, but is indicated by the scope of the claims, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims.

(Embodiment 1)
<Configuration of temperature detection system>
FIG. 1 is a block diagram showing the main configuration of a temperature detection system 1 according to Embodiment 1. As shown in FIG. A temperature detection system 1 is mounted on a vehicle C. As shown in FIG. A temperature detection system 1 includes a DC power supply 10 , a temperature detection device 11 and a temperature resistor 12 . DC power supply 10 is, for example, a battery. The negative electrode of DC power supply 10 is grounded. Grounding is realized by connection to the body of the vehicle C, for example. A positive electrode of the DC power supply 10 and one end and the other end of the temperature resistor 12 are connected to the temperature detection device 11 . The temperature sensing device 11 is also grounded. A DC power supply 10 supplies power to the temperature detection device 11 .

FIG. 2 is a graph showing temperature characteristics of the temperature resistor 12. FIG. FIG. 2 shows the relationship between the resistance value of the temperature resistor 12 and temperature. As shown in FIG. 2, the resistance of temperature resistor 12 decreases when the temperature of temperature resistor 12 increases. Specifically, in a range where the temperature of the temperature resistor 12 is low, when the temperature of the temperature resistor 12 rises, the resistance value of the temperature resistor 12 drops rapidly. In the range where the temperature of the temperature resistor 12 is high, when the temperature of the temperature resistor 12 rises, the resistance value of the temperature resistor 12 gradually decreases.

The temperature detection device 11 detects the temperature of the temperature resistor 12 based on the voltage that varies according to the resistance value of the temperature resistor 12 . Temperature resistors 12 are placed at various locations. When the temperature inside the vehicle C is to be detected, the temperature resistor 12 is placed inside the vehicle C. As shown in FIG. When sensing the temperature of a semiconductor switch, the temperature resistor 12 is arranged in the vicinity of the semiconductor switch. The temperature range to be detected includes a temperature range in which the resistance value of the temperature resistor 12 drops rapidly and a temperature range in which the resistance value of the temperature resistor 12 drops gradually.

<Configuration of temperature resistor 12>
As shown in FIG. 1, temperature resistor 12 has an NTC thermistor 20 . NTC is an abbreviation for Negative Temperature Coefficient. The resistance value of NTC thermistor 20 changes according to the temperature of NTC thermistor 20 . The resistance value and temperature of temperature resistor 12 are the resistance value and temperature of NTC thermistor 20, respectively. The temperature characteristics shown in FIG. 2 are the temperature characteristics of the NTC thermistor 20. FIG.

Note that the temperature resistor 12 may be implemented using a circuit element different from the NTC thermistor 20, such as a resistance temperature detector. An example in which the temperature resistor 12 is implemented using an NTC thermistor 20 will be described below.

<Configuration of temperature detection device 11>
The temperature detection device 11 has a regulator 30 , a variable resistor 31 and a microcomputer (hereinafter referred to as microcomputer) 32 . Regulator 30 is connected to the positive electrode of DC power supply 10 and variable resistor 31 . A variable resistor 31 is connected to one end of the NTC thermistor 20 of the temperature resistor 12 . The other end of NTC thermistor 20 is grounded.

A connection node between the regulator 30 and the variable resistor 31 and a connection node between the variable resistor 31 and the temperature resistor 12 are connected to the microcomputer 32 . The variable resistor 31 is also connected to the microcomputer 32 . The regulator 30 and microcomputer 32 are grounded.

Current flows from the positive electrode of the DC power supply 10 to the regulator 30 and the negative electrode of the DC power supply 10 in this order. Thus, power is supplied from the DC power supply 10 to the regulator 30 . The positive electrode voltage of the DC power supply 10 with respect to the ground potential is referred to as the power supply voltage. The DC power supply 10 supplies power to one or a plurality of in-vehicle devices (not shown) mounted in the vehicle C. FIG. The power supply voltage of the DC power supply 10 fluctuates according to the operating state of one or more in-vehicle devices.

The regulator 30 steps down the power supply voltage to a constant target voltage. The target voltage is a voltage below the minimum value of the power supply voltage. The power supply voltage varies, for example, within a range from 8V to 14V. The target voltage is, for example, 5V. Since the target voltage is a voltage equal to or lower than the minimum value of the power supply voltage, the regulator 30 stably outputs the target voltage regardless of fluctuations in the power supply voltage.

The regulator 30 applies a constant target voltage generated by stepping down to the microcomputer 32 . As a result, the current flows from the positive electrode of the DC power supply 10 to the regulator 30 , the microcomputer 32 and the negative electrode of the DC power supply 10 in this order. As a result, power is supplied from the DC power supply 10 to the microcomputer 32 .

The regulator 30 also applies a constant target voltage to the series circuit including the variable resistor 31 and the temperature resistor 12 . Therefore, the regulator 30 functions as a voltage applying section. A variable resistor 31 and a temperature resistor 12 divide the target voltage. A divided voltage obtained by dividing the voltage by the variable resistor 31 and the temperature resistor 12 is input to the microcomputer 32 . The divided voltage is the voltage across temperature resistor 12 .

A target voltage is described as Vg. The resistance values of the variable resistor 31 and the temperature resistor 12 are denoted as Rv and Rt, respectively. A divided voltage obtained by voltage division by the variable resistor 31 and the temperature resistor 12 is denoted as Vd. The divided voltage Vd is represented by the following formula.
Vd=Vg·Rt/(Rv+Rt)

The divided voltage Vd increases as the resistance value Rt of the temperature resistor 12 increases. The microcomputer 32 detects the temperature of the temperature resistor 12 based on the divided voltage Vd. The microcomputer 32 increases the resistance value of the variable resistor 31 to a first predetermined value when the resistance value of the temperature resistor 12 increases to a value equal to or higher than the resistance threshold value. The microcomputer 32 reduces the resistance value of the variable resistor 31 to a second predetermined value when the resistance value of the temperature resistor 12 has decreased to a value less than the resistance threshold value. As a result, as will be described later, the accuracy of temperature detection is maintained at a certain value or higher. The first predetermined value exceeds the second predetermined value.

<Configuration of Variable Resistor 31>
FIG. 3 is a circuit diagram of the variable resistor 31. As shown in FIG. The variable resistor 31 has a series switch 40 , a first resistor 41 , a second resistor 42 and a switching circuit 43 . The series switch 40 is connected in series with the first resistor 41 . A second resistor 42 is connected in parallel with a series circuit including the series switch 40 and the first resistor 41 . In addition, in the example of FIG. 3, the series switch 40 is arranged on the regulator 30 side of the first resistor 41 . However, the series switch 40 may be arranged on the temperature resistor 12 side of the first resistor 41 .

A connection node between the series switch 40 and the second resistor 42 is connected to the regulator 30 . A connection node between the first resistor 41 and the second resistor 42 is connected to one end of the NTC thermistor 20 of the temperature resistor 12 . The switching circuit 43 is connected to the microcomputer 32 .

The resistance values of the first resistor 41 and the second resistor 42 are denoted as R1 and R2, respectively. The resistance value Rv of the variable resistor 31 is the resistance value R2 of the second resistor 42 when the series switch 40 is off. When the series switch 40 is on, the resistance value Rv of the variable resistor 31 is the resistance value of a parallel circuit in which the first resistor 41 and the second resistor 42 are connected in parallel. Therefore, the resistance value Rv of the variable resistor 31 when the series switch 40 is on is represented by the following formula.
Rv=R1·R2/(R1+R2)

The microcomputer 32 outputs a high level voltage or a low level voltage to the switching circuit 43 . When the microcomputer 32 switches the output voltage from the low level voltage to the high level voltage, the switching circuit 43 switches the serial switch 40 from off to on. R2 is greater than R1·R2/(R1+R2). Therefore, when the series switch 40 is switched from off to on, the resistance value Rv of the variable resistor 31 decreases.

When the microcomputer 32 switches the output voltage from the high level voltage to the low level voltage, the switching circuit 43 switches the series switch 40 from on to off. As a result, the resistance value Rv of the variable resistor 31 increases. As described above, the microcomputer 32 adjusts the resistance value of the variable resistor 31 to the first predetermined value or the second predetermined value. The first predetermined value is R2. The second predetermined value is R1·R2/(R1+R2).

<Configuration of microcomputer 32>
FIG. 4 is a block diagram showing the main configuration of the microcomputer 32. As shown in FIG. The microcomputer 32 has an output section 50 , an A/D conversion section 51 , a storage section 52 and a control section 53 . These are connected to the internal bus 54 . The output section 50 is further connected to the switching circuit 43 of the variable resistor 31 . The A/D converter 51 is connected to a connection node between the variable resistor 31 and the temperature resistor 12 .

The output unit 50 outputs a high level voltage or a low level voltage to the switching circuit 43 of the variable resistor 31. The output voltage of the output section 50 is the output voltage of the microcomputer 32 described above. The output unit 50 switches the output voltage to a high level voltage or a low level voltage according to instructions from the control unit 53 .

A divided voltage divided by the variable resistor 31 and the temperature resistor 12 is input to the A/D converter 51 . The A/D converter 51 converts the divided voltage obtained by dividing the voltage by the variable resistor 31 and the temperature resistor 12 into a digital value.

FIG. 5 is an explanatory diagram of conversion into digital values. The A/D converter 51 converts the divided voltage into an n-bit digital value. Here, n is an integer of 2 or more. Divide the target voltage by (2 ⁿ -1). 2 ⁿ scales from 0 V to the target voltage are set at intervals of this division value. 2 ⁿ digital values are assigned to each of the 2 ⁿ graduations. The digital value corresponding to a scale with a large value is large. FIG. 5 shows decimal digital values and voltages corresponding to 2 ⁿ digital values expressed in binary. The unit of voltage is volts.

FIG. 5 shows an example where n is 3 and the target voltage is 5V. Eight scales from 0V to 5V are set at intervals of 0.71 (=5/7)V. Eight digital values from 0 to 7 are assigned to each of the eight graduations. "000" is assigned to 0V. "111" is assigned to 5V.

The A/D converter 51 converts the input divided voltage into a digital value with a scale closest to the input divided voltage. In the example of FIG. 5, the A/D converter 51 converts the divided voltage near 5V into "111". The A/D converter 51 converts the divided voltage near 2.86V to "100". The A/D converter 51 converts the divided voltage near 0.71V to "001". A control unit 53 of the microcomputer 32 shown in FIG. 4 acquires the digital value converted by the A/D conversion unit 51 .

The storage unit 52 is composed of, for example, a volatile memory and a nonvolatile memory. A computer program P is stored in the storage unit 52 . The control unit 53 has a processing element that executes processing, such as a CPU (Central Processing Unit). The control unit 53 functions as a processing unit. A processing element (computer) of the control unit 53 executes a computer program P to perform temperature detection processing for detecting the temperature of the temperature resistor 12 and the like.

The computer program P may be provided to the microcomputer 32 using a non-temporary storage medium A that stores the computer program P in a readable manner. Storage medium A is, for example, a portable memory. Examples of portable memory include CD-ROM, USB (Universal Serial Bus) memory, SD card, micro SD card, compact flash (registered trademark), and the like. If the storage medium A is a portable memory, the processing element of the control unit 53 may read the computer program P from the storage medium A using a reading device (not shown). The read computer program P is written in the storage unit 52 . Furthermore, the computer program P may be provided to the microcomputer 32 by a communication section (not shown) of the microcomputer 32 communicating with an external device. In this case, the processing element of the control unit 53 acquires the computer program P through the communication unit. The acquired computer program P is written in the storage unit 52 .

Also, the number of processing elements that the control unit 53 has is not limited to one, and may be two or more. When the control unit 53 has a plurality of processing elements, the plurality of processing elements may cooperate to perform temperature detection processing and the like.

<Temperature detection resolution>
In the temperature detection process, the control unit 53 instructs the output unit 50 to switch the output voltage to a high level voltage or a low level voltage. Thereby, the controller 53 adjusts the resistance value of the variable resistor 31 to the first predetermined value or the second predetermined value. As a result, the accuracy of temperature detection is maintained above a certain value. The reason for this is explained.

FIG. 6 is an explanatory diagram of the resolution according to the resistance value of the variable resistor 31. As shown in FIG. FIG. 6 shows a voltage graph showing the relationship between the divided voltage and the temperature of the temperature resistor 12, and a resolution graph showing the relationship between the resolution and the temperature of the temperature resistor 12. FIG. In each graph, multiple scales of temperature are provided at intervals of constant temperature, eg, 1 degree. A plurality of scales of the divided voltage correspond to each of the 2 ⁿ digital values mentioned above. As described above, the scale interval is (target voltage Vg)/(2 ⁿ -1). FIG. 6 shows an example in which the A/D converter 51 converts the divided voltage into a 3-bit digital value. Therefore, the number of division voltage scales is eight.

The resolution is the difference between the decimal digital values corresponding to the two temperatures. For example, the resolution of 10 degrees is the difference value between the decimal digital value corresponding to 9 degrees and the decimal digital value corresponding to 10 degrees. The larger the difference value, the more clearly the temperature difference of the temperature resistor 12 can be indicated.

As described above, when the temperature of the temperature resistor 12 is low, the resistance value of the temperature resistor 12 is large (see FIG. 2). When the temperature of the temperature resistor 12 is high, the resistance value of the temperature resistor 12 is small (see FIG. 2). Also, the first predetermined value exceeds the second predetermined value.

When the resistance value of the variable resistor 31 is the first predetermined value, the divided voltage drops rapidly as the temperature of the temperature resistor 12 rises in the range where the temperature of the temperature resistor 12 is low. In the range where the temperature of the temperature resistor 12 is low, the difference between the resistance value of the temperature resistor 12 and the first predetermined value is small. Therefore, the change in the divided voltage in accordance with the change in the resistance value of the temperature resistor 12 is large. As a result, the divided voltage drops rapidly as the temperature of the temperature resistor 12 rises. Therefore, the resolution is high in the range where the temperature of the temperature resistor 12 is low. When the temperature of the temperature resistor 12 changes, the digital value converted by the A/D converter 51 also changes.

When the resistance value of the variable resistor 31 is the first predetermined value, the divided voltage gradually decreases as the temperature of the temperature resistor 12 rises in the range where the temperature of the temperature resistor 12 is high. In the range where the temperature of the temperature resistor 12 is high, the resistance value of the temperature resistor 12 is sufficiently smaller than the first predetermined value. Therefore, the change in the divided voltage corresponding to the change in the resistance value of the temperature resistor 12 is small. As a result, the divided voltage gradually decreases as the temperature of the temperature resistor 12 rises. Therefore, the resolution is low in the range where the temperature of the temperature resistor 12 is high. As shown in FIG. 6, even if the temperature of the temperature resistor 12 changes, the digital value converted by the A/D converter 51 does not change. For example, two divided voltages corresponding to 99 degrees and 100 degrees are converted to the same digital value.

When the resistance value of the variable resistor 31 is the second predetermined value, the divided voltage gradually decreases as the temperature of the temperature resistor 12 rises in the range where the temperature of the temperature resistor 12 is low. In the range where the temperature of the temperature resistor 12 is low, the resistance value of the temperature resistor 12 is sufficiently higher than the second predetermined value. Therefore, the change in the divided voltage corresponding to the change in the resistance value of the temperature resistor 12 is small. As a result, the divided voltage gradually decreases as the temperature of the temperature resistor 12 rises. Therefore, the resolution is low in the range where the temperature of the temperature resistor 12 is low. As shown in FIG. 6, even if the temperature of the temperature resistor 12 changes, the digital value that the A/D converter 51 changes does not change. For example, two divided voltages corresponding to -20 degrees and -19 degrees are converted to the same digital value.

When the resistance value of the variable resistor 31 is the second predetermined value, the divided voltage drops rapidly as the temperature of the temperature resistor 12 rises in the range where the temperature of the temperature resistor 12 is high. In the range where the temperature of the temperature resistor 12 is high, the difference value between the resistance value of the temperature resistor 12 and the second predetermined value is small. Therefore, the change in the divided voltage in accordance with the change in the resistance value of the temperature resistor 12 is large. As a result, the divided voltage drops rapidly as the temperature of the temperature resistor 12 rises. Therefore, the resolution is high in the range where the temperature of the temperature resistor 12 is high. When the temperature of the temperature resistor 12 changes, the digital value converted by the A/D converter 51 also changes.

The control unit 53 of the microcomputer 32 adjusts the resistance value of the variable resistor 31 to the first predetermined value when the temperature of the temperature resistor 12 is low, that is, when the resistance value of the temperature resistor 12 is high. When the temperature of the temperature resistor 12 is high, that is, when the resistance value of the temperature resistor 12 is low, the controller 53 adjusts the resistance value of the variable resistor 31 to the second predetermined value. Thereby, the accuracy of temperature detection is maintained at a certain value or higher.

<Timing for changing the resistance value of the variable resistor 31>
FIG. 7 is an explanatory diagram of the timing of changing the resistance value of the variable resistor 31. As shown in FIG. FIG. 7 shows the temperature characteristics of the temperature resistor 12 (see FIG. 2), voltage graph and resolution graph. When the resistance value of the variable resistor 31 is the first predetermined value, the resolution graphs corresponding to the first predetermined value and the second predetermined value are indicated by solid lines and broken lines, respectively. When the resistance value of the variable resistor 31 is the second predetermined value, the resolution graphs corresponding to the first predetermined value and the second predetermined value are indicated by dashed lines and solid lines.

In FIG. 7, the resistance value of the variable resistor corresponding to the intersection of the two resolution graphs (the temperature of the temperature resistor 12) is indicated by Rth. Rth is the resistance threshold. Further, when the resistance value of the variable resistor 31 is the first predetermined value, among the 2 ^{n voltages corresponding to the 2 n digital} values, V1 is represented by V1 is the first voltage threshold. When the resistance value of the variable resistor 31 is the second predetermined value, among the 2 n voltages corresponding to the ^{2 n} digital values, the voltage closest to the divided voltage corresponding to the intersection is represented by V2. ing. V2 is a second voltage threshold.

When the resistance value of the variable resistor 31 is the first predetermined value, the microcomputer 32 controls when the resistance value of the temperature resistor 12 decreases to a value less than the resistance threshold value Rth, that is, when the divided voltage is the first voltage. When the resistance value drops below the threshold value V1, the resistance value of the variable resistor 31 is lowered to the second predetermined value. When the resistance value of the variable resistor 31 is the second predetermined value, the microcomputer 32 detects when the resistance value of the temperature resistor 12 exceeds the resistance threshold value Rth, that is, when the divided voltage exceeds the second voltage threshold value V2. If exceeded, the resistance value of the variable resistor 31 is increased to the first predetermined value. Thereby, the accuracy of temperature detection is maintained at a certain value or higher.

<Temperature table T>
In the temperature detection process, the controller 53 shown in FIG. 4 identifies the temperature of the temperature resistor 12 based on the digital value acquired from the A/D converter 51 . A temperature table T is used to specify the temperature of the temperature resistor 12 . A temperature table T is stored in the storage unit 52 .

FIG. 8 is a table showing contents of the temperature table T. As shown in FIG. The temperature table T shows 2 ⁿ first temperatures and second temperatures corresponding to 2 ⁿ digital values. The units for the first temperature and the second temperature are degrees. The storage unit 52 functions as a temperature storage unit. In FIG. 8, an example in which n is 10 is shown. Therefore, a decimal digital value is an integer in the range 0-1023.

When the resistance value of the variable resistor 31 is the first predetermined value, the microcomputer 32 refers to the first temperature corresponding to the digital value converted by the A/D converter 51 . As shown in FIG. 7, the lower the divided voltage, the smaller the decimal digital value and the higher the temperature of the temperature resistor 12 . Therefore, the higher the temperature of the temperature resistor 12, the smaller the decimal digital value. When the resistance value of the variable resistor 31 is the first predetermined value and the temperature of the temperature resistor 12 is high, the resolution is small. Therefore, when the decimal digital value is small, the plurality of first temperatures corresponding to the plurality of digital values are the same.

When the resistance value of the variable resistor 31 is the second predetermined value, the microcomputer 32 refers to the second temperature corresponding to the digital value converted by the A/D converter 51 . As shown in FIG. 7, the higher the divided voltage, the higher the decimal digital value and the lower the temperature of the temperature resistor 12 . Therefore, the lower the temperature of the temperature resistor 12, the larger the decimal digital value. When the resistance value of the variable resistor 31 is the second predetermined value, the resolution is small when the temperature of the temperature resistor 12 is low. Therefore, when the decimal digital value is large, the plurality of second temperatures corresponding to the plurality of digital values are the same.

<Temperature detection processing>
FIG. 9 is a flow chart showing the procedure of temperature detection processing. The control unit 53 of the microcomputer 32 repeatedly executes the temperature detection process. The storage unit 52 of the microcomputer 32 stores flag values. The flag value is changed to 1 or 2 by the control unit 53 . Regarding the value of the flag, "1" indicates that the resistance value of the variable resistor 31 is the first predetermined value. "2" indicates that the resistance value of the variable resistor 31 is the second predetermined value.

In the temperature detection process, the control unit 53 first acquires a digital value converted by the A/D conversion unit 51 (step S1). Next, the control unit 53 determines whether or not the value of the flag is 1 (step S2). If the value of the flag is not 1, the value of the flag is 2. When determining that the value of the flag is 1 (S2: YES), the control unit 53 determines whether the resistance value of the temperature resistor 12 is less than the resistance threshold (step S3). In the example of FIG. 7, when the divided voltage corresponding to the digital value acquired in step S1 by the control unit 53 is equal to or less than the first voltage threshold value V1, the resistance value of the temperature resistor 12 is determined to be less than the resistance threshold value Rth. do. When the divided voltage corresponding to the digital value acquired in step S1 by the controller 53 exceeds the first voltage threshold V1, the resistance value of the temperature resistor 12 is determined to be equal to or greater than the resistance threshold Rth.

When the control unit 53 determines that the resistance value of the temperature resistor 12 is less than the resistance threshold value (S3: YES), the control unit 53 instructs the output unit 50 to switch the output voltage to a high level voltage, so that the variable resistance The resistance value of the device 31 is lowered to a second predetermined value (step S4). Instructing the output section 50 to switch the output voltage to the high level voltage corresponds to instructing the switching circuit 43 to switch the series switch 40 to ON. After executing step S4, the control unit 53 changes the value of the flag to 2 (step S5). Next, the control unit 53 acquires again the digital value converted by the A/D conversion unit 51 after the resistance value of the variable resistor 31 is adjusted to the second predetermined value (step S6).

When the control unit 53 determines that the value of the flag is not 1 (S2: NO), it determines whether the resistance value of the temperature resistor 12 exceeds the resistance threshold (step S7). In the example of FIG. 7, when the divided voltage corresponding to the digital value acquired by the control unit 53 in step S1 exceeds the second voltage threshold value V2, the resistance value of the temperature resistor 12 exceeds the resistance threshold value Rth. I judge. When the divided voltage corresponding to the digital value acquired in step S1 by the controller 53 is equal to or less than the second voltage threshold V2, the resistance value of the temperature resistor 12 is determined to be equal to or less than the resistance threshold Rth.

When the control unit 53 determines that the resistance value of the temperature resistor 12 exceeds the resistance threshold value (S7: YES), the control unit 53 instructs the output unit 50 to switch the output voltage to a low level voltage, thereby making the variable The resistance value of the resistor 31 is raised to the first predetermined value (step S8). Instructing the output unit 50 to switch the output voltage to the low level voltage corresponds to instructing the switching circuit 43 to switch the series switch 40 off. After executing step S8, the control unit 53 changes the value of the flag to 1 (step S9). Next, the control unit 53 acquires again the digital value converted by the A/D conversion unit 51 after the resistance value of the variable resistor 31 is adjusted to the first predetermined value (step S10).

When the control unit 53 determines that the resistance value of the temperature resistor 12 is equal to or greater than the resistance threshold value (S3: NO), or after executing step S10, the temperature table T stores 2 ⁿ first temperatures. The first temperature corresponding to the digital value acquired in step S1 or step S10 is read (step S11). Step S11 is executed when the resistance value of the variable resistor 31 is the first predetermined value. In step S11 immediately after executing step S3, the controller 53 reads out the first temperature corresponding to the digital value acquired in step S1. In step S11 immediately after executing step S10, the controller 53 reads the first temperature corresponding to the digital value acquired in step S10. Next, the controller 53 identifies the temperature of the temperature resistor 12 (step S12). At step S12, the controller 53 identifies that the temperature of the temperature resistor 12 is the first temperature read at step S11. After executing step S12, the control unit 53 terminates the temperature detection process.

After executing step S6, or when determining that the resistance value of the temperature resistor 12 is equal to or lower than the resistance threshold value (S7: NO), the control unit 53 stores 2 ⁿ second temperature values in the temperature table T. The second temperature corresponding to the digital value acquired in step S1 or step S6 is read out (step S13). Step S13 is executed when the resistance value of the variable resistor 31 is the second predetermined value. In step S13 immediately after executing step S6, the controller 53 reads the second temperature corresponding to the digital value acquired in step S6. In step S13 immediately after executing step S7, the controller 53 reads the second temperature corresponding to the digital value acquired in step S1. Next, the controller 53 identifies the temperature of the temperature resistor 12 (step S14). At step S14, the controller 53 identifies that the temperature of the temperature resistor 12 is the second temperature read at step S13. After executing step S12, the control unit 53 terminates the temperature detection process. After completing the temperature detection process, the control unit 53 executes the temperature detection process again.

<effect>
As described above, in the temperature detection device 11, the control unit 53 of the microcomputer 32 sets the resistance value of the variable resistor 31 to the second predetermined value when the resistance value of the temperature resistor 12 drops below the resistance threshold value. Lower. When the resistance value of the temperature resistor 12 exceeds the resistance threshold value, the control section 53 increases the resistance value of the variable resistor 31 to the first predetermined value. Therefore, the difference between the resistance values of the temperature resistor 12 and the variable resistor 31 is prevented from increasing to a large value. As a result, since the divided voltage changes greatly, the temperature can be detected with high accuracy. Also, the accuracy of a certain value or more is maintained.

As described in the temperature detection process, the control unit 53 of the microcomputer 32 identifies the temperature of the temperature resistor 12 based on the temperature table T stored in advance in the storage unit 52. Therefore, the temperature of the temperature resistor 12 can be specified with a simple configuration.

(Embodiment 2)
In the first embodiment, the controller 53 of the microcomputer 32 uses the temperature table T to identify the temperature of the temperature resistor 12 . However, the method of specifying the first temperature and the second temperature is not limited to the method using the temperature table T.
Below, the points of the second embodiment that are different from the first embodiment will be described. Configurations other than those described later are common to those of the first embodiment. For this reason, the same reference numerals as in Embodiment 1 are given to the components that are common to Embodiment 1, and the description of those components is omitted.

<Configuration of microcomputer 32>
In the second embodiment, instead of the temperature table T, the storage unit 52 stores the first calculation formula and the second calculation formula. The first calculation formula is used to calculate the first temperature using the voltage as the first variable. The control unit 53 calculates the first temperature by substituting the divided voltage corresponding to the digital value for the first variable. Similarly, the second calculation formula is used to calculate the second temperature using the voltage as the second variable. The control unit 53 calculates the second temperature by substituting the divided voltage corresponding to the digital value for the second variable. In the second embodiment, the storage unit 52 functions as a calculation formula storage unit. The first calculation formula is different from the second calculation formula.

<Temperature detection processing>
FIG. 10 is a flow chart showing the procedure of temperature detection processing according to the second embodiment. As described in the first embodiment, the controller 53 of the microcomputer 32 executes temperature detection processing. The control unit 53 executes steps S1 to S10, S12, and S14 of the temperature detection process in the same manner as in the first embodiment. Therefore, detailed description of steps S1 to S10, S12, and S14 is omitted.

When the control unit 53 determines that the resistance value of the temperature resistor 12 is equal to or greater than the resistance threshold value (S3: NO), or after executing step S10, the control unit 53 determines the digital value corresponding to the digital value acquired in step S1 or step S10. A first temperature is calculated by substituting the divided voltage for the first variable of the first calculation formula (step S21). Step S21 is executed when the resistance value of the variable resistor 31 is the first predetermined value. In step S21 immediately after step S3 is executed, the control unit 53 uses the divided voltage corresponding to the digital value acquired in step S1. In step S21 immediately after step S10 is executed, the control unit 53 uses the divided voltage corresponding to the digital value acquired in step S10.

After executing step S21, the control unit 53 executes step S12. At step S12, the controller 53 determines that the temperature of the temperature resistor 12 is the first temperature calculated at step S21.

Similarly, after executing step S6, or when determining that the resistance value of the temperature resistor 12 is equal to or less than the resistance threshold value (S7: NO), the control unit 53 controls the digital value acquired in step S1 or step S6. A second temperature is calculated by substituting the divided voltage corresponding to the second variable of the second calculation formula (step S22). Step S22 is executed when the resistance value of the variable resistor 31 is the second predetermined value. In step S22 immediately after step S6 is executed, the control unit 53 uses the divided voltage corresponding to the digital value acquired in step S6. In step S22 immediately after step S7 is executed, the control unit 53 uses the divided voltage corresponding to the digital value acquired in step S1.

After executing step S22, the control unit 53 executes step S14. At step S14, the controller 53 determines that the temperature of the temperature resistor 12 is the second temperature calculated at step S22.

<effect>
In the temperature detection device 11 according to the second embodiment, the controller 53 of the microcomputer 32 identifies the temperature of the temperature resistor 12 using the first calculation formula and the second calculation formula. Therefore, accurate temperature determination of the temperature resistor 12 is achieved. The temperature detection device 11 according to the second embodiment has the same effects as those of the temperature detection device 11 according to the first embodiment except for the effect obtained by reading the first temperature and the second temperature from the temperature table T. play to

(Embodiment 3)
In Embodiment 1, the variable resistor 31 may have any configuration as long as the resistance value can be adjusted. Therefore, the configuration of the variable resistor 31 is not limited to the configuration in which the second resistor 42 is connected in parallel to the series circuit including the series switch 40 and the first resistor 41 .
In the following, the points of the third embodiment that are different from the first embodiment will be described. Configurations other than those described later are common to those of the first embodiment. For this reason, the same reference numerals as in Embodiment 1 are given to the components that are common to Embodiment 1, and the description of those components is omitted.

<Configuration of Variable Resistor 31>
FIG. 11 is a circuit diagram of the variable resistor 31 according to the third embodiment. A variable resistor 31 in the third embodiment has a switching circuit 43 as in the first embodiment. The variable resistor 31 in Embodiment 3 further has a connector 44 and u fixed resistors E1, E2, . . . Eu. Here, u is an integer of 2 or more. Connector 44 is connected to regulator 30 . The connector 44 is further connected to one end of u fixed resistors E1, E2, . . . , Eu. , Eu are connected to one end of the NTC thermistor 20 of the temperature resistor 12 .

The switching circuit 43 changes the connection destination of the regulator 30 to one of u fixed resistors E1, E2, . In the microcomputer 32 , the output section 50 outputs a connection destination signal indicating the connection destination of the regulator 30 to the switching circuit 43 according to the instruction of the control section 53 . When the connection destination signal is input to the switching circuit 43, the switching circuit 43 changes the connection destination of the regulator 30 to the connection destination indicated by the input connection destination signal. The resistance values of the fixed resistors E1, E2, . . . , Eu are different from each other.

<Temperature detection processing>
When the integer u is 2, the controller 53 executes the temperature detection process as in the first embodiment. The resistance values of the fixed resistors E1 and E2 are a first predetermined value and a second predetermined value. In step S4, the control unit 53 instructs the output unit 50 to cause the switching circuit 43 to output a connection destination signal indicating the fixed resistor E2 as the connection destination of the regulator 30, thereby changing the resistance value of the variable resistor 31 to 2 Decrease to a predetermined value.

Similarly, in step S8, the control unit 53 instructs the output unit 50 to cause the switching circuit 43 to output a connection destination signal indicating the fixed resistor E1 as the connection destination of the regulator 30, thereby increasing the resistance of the variable resistor 31. Raise the value to a first predetermined value.

When the integer u is 3 or more, the controller 53 adjusts the resistance value of the variable resistor 31 according to the resistance value of the temperature resistor 12 . The temperature table T stores the relationship between digital values and temperatures for each of the fixed resistors E1, E2, . . . Eu.

An integer greater than or equal to 1 and less than or equal to u is represented by i. When the regulator 30 is connected to the fixed resistor Ei, the controller 53 reads from the temperature table T the temperature corresponding to the digital value acquired from the A/D converter 51 for the fixed resistor Ei. The controller 53 determines that the temperature of the temperature resistor 12 is the read temperature. When the integer u is 3 or more, the temperature of the temperature resistor 12 can be detected with higher accuracy.

<effect>
The temperature detection device 11 according to the third embodiment has the same effects as the temperature detection device 11 according to the first embodiment.

<Modification>
In the third embodiment, the controller 53 of the microcomputer 32 may specify the temperature of the temperature resistor 12 using a calculation formula as in the second embodiment. In this case, the storage unit 52 stores u calculation formulas corresponding to the fixed resistors E1, E2, . . . Eu. They are different from each other. The calculation formula is used to calculate the temperature using the voltage as a variable. In the temperature detection process, when the connection destination of the regulator 30 is the fixed resistor Ei, the control unit 53 converts the divided voltage corresponding to the digital value acquired from the A/D conversion unit 51 to the calculation formula corresponding to the fixed resistor Ei. Calculate the temperature by substituting in the variables of The control unit 53 specifies that the temperature of the temperature resistor 12 is the calculated temperature.

The configuration of the variable resistor 31 in Embodiment 3 may be any configuration as long as the resistance value can be adjusted. Therefore, the variable resistor 31 may have a variable resistor instead of the connector 44 and u fixed resistors E1, E2, . . . , Eu. A variable resistor is connected between the regulator 30 and the temperature resistor 12 . A voltage is applied to the variable resistor from the output section 50 of the microcomputer 32, for example. The resistance value of the variable resistor is adjusted according to the output voltage of the output section 50 . The control unit 53 adjusts the resistance value of the variable resistor 31 by causing the output unit 50 to change the output voltage.

In Embodiments 1 to 3, the configuration of the temperature resistor 12 is not limited to a configuration in which the resistance value decreases when the temperature of the temperature resistor 12 rises. The configuration of the temperature resistor 12 may be, for example, a configuration in which the resistance value increases when the temperature of the temperature resistor 12 increases. In this case, temperature resistor 12 has, for example, a PTC thermistor instead of NTC thermistor 20 . PTC is an abbreviation for Positive Temperature Coefficient.

Also in this case, in the temperature detection processing in Embodiments 1 and 2, and in Embodiment 3 in which the integer u is 2, the control unit 53 causes the variable resistance The resistance value of the device 31 is increased by a first predetermined value. The control unit 53 reduces the resistance value of the variable resistor 31 to a second predetermined value when the resistance value of the temperature resistor 12 has decreased to a value less than the resistance threshold value.

In Embodiments 1 to 3, the place where the temperature resistor 12 is arranged is not limited to the outside of the temperature detection device 11, and may be inside the temperature detection device 11. In this case, the temperature sensing device 11 has a temperature resistor 12 . The divided voltage in Embodiments 1 to 3 is not limited to the voltage across the temperature resistor 12 and may be the voltage across the variable resistor 31 . In this case, the higher the resistance value of the temperature resistor 12, the lower the divided voltage.

In the first to third embodiments, the temperature resistor 12 may be connected between the regulator 30 and the variable resistor 31. In this case, variable resistor 31 is grounded. Current flows from the positive terminal of the DC power supply 10 to the regulator 30, the temperature resistor 12, the variable resistor 31, and the negative terminal of the DC power supply 10 in this order. The divided voltage is the voltage across the temperature resistor 12 or the variable resistor 31 .

The disclosed embodiments 1 to 3 should be considered illustrative in all respects and not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the meaning described above, and is intended to include all changes within the meaning and scope equivalent to the scope of the claims.

Reference Signs List 1 temperature detection system 10 DC power supply 11 temperature detection device 12 temperature resistor 20 NTC thermistor 30 regulator (voltage application unit)
31 Variable Resistor 32 Microcomputer 40 Series Switch 41 First Resistor 42 Second Resistor 43 Switching Circuit 44 Connector 50 Output Unit 51 A/D Converter 52 Storage Unit (Temperature Storage Unit, Calculation Formula Storage Unit)
53 control unit (processing unit)
54 internal bus A storage medium C vehicle E1, E2, ..., Eu fixed resistor P computer program T temperature table

Claims (8)

1. A temperature detection device mounted on a vehicle,
   a variable resistor connected to a temperature resistor whose resistance value changes according to temperature;
   a voltage applying unit that applies a constant voltage to a series circuit including the temperature resistor and the variable resistor;
   a converter that converts the divided voltage divided by the temperature resistor and the variable resistor into a digital value;
   a processing unit that executes processing;
   the temperature is the temperature of the temperature resistor,
   The processing unit is
   adjusting the resistance value of the variable resistor according to the resistance value of the temperature resistor;
   A temperature detection device that identifies the temperature of the temperature resistor based on the digital value converted by the conversion unit after adjusting the resistance value of the variable resistor.
2. The variable resistor is
   a first resistor and a second resistor;
   a series switch connected in series with the first resistor;
   a switching circuit for switching the series switch on or off;
   The second resistor is connected in parallel to a series circuit including the first resistor and a series switch,
   The temperature sensing device according to claim 1, wherein the processing unit adjusts the resistance value of the variable resistor by instructing the switching circuit to turn on or off the series switch.
3. The processing unit is
   increasing the resistance value of the variable resistor to a first predetermined value when the resistance value of the temperature resistor exceeds a threshold;
   decreasing the resistance value of the variable resistor to a second predetermined value when the resistance value of the temperature resistor decreases to a value less than the threshold;
   3. The temperature detection device according to claim 1, wherein said first predetermined value exceeds said second predetermined value.
4. A temperature storage unit storing a plurality of first temperatures and second temperatures corresponding to the plurality of digital values,
   The processing unit is
   When the resistance value of the variable resistor is the first predetermined value, the temperature of the temperature resistor is the first temperature corresponding to the digital value converted by the conversion unit among the plurality of first temperatures. identified as
   When the resistance value of the variable resistor is the second predetermined value, the temperature of the temperature resistor is the second temperature value corresponding to the digital value converted by the conversion unit among the plurality of second temperatures. 4. The temperature sensing device of claim 3, wherein there is a temperature sensing device.
5. a calculation formula storage unit that stores a first calculation formula and a second calculation formula for calculating temperature using voltage as a variable;
   The processing unit is
   when the resistance value of the variable resistor is the first predetermined value, calculating the temperature by substituting the divided voltage indicated by the digital value converted by the conversion unit into the variable of the first calculation formula;
   when the resistance value of the variable resistor is the second predetermined value, calculating the temperature by substituting the divided voltage indicated by the digital value converted by the conversion unit into the variable of the second calculation formula;
   The temperature sensing device according to claim 3, wherein the temperature of the temperature resistor is specified as a calculated temperature.
6. The temperature detection device according to any one of claims 1 to 5, wherein the resistance value of the temperature resistor decreases when the temperature of the temperature resistor increases.
7. adjusting the resistance value of a variable resistor connected to the temperature resistor according to the resistance value of the temperature resistor, the resistance value of which changes according to the temperature;
   determining the temperature based on the digital value of the divided voltage obtained by dividing the constant voltage by the temperature resistor and the variable resistor after the resistance value of the variable resistor is adjusted; the computer runs
   The temperature sensing method, wherein the temperature is the temperature of the temperature resistor.
8. adjusting the resistance value of a variable resistor connected to the temperature resistor according to the resistance value of the temperature resistor, the resistance value of which changes according to the temperature;
   determining the temperature based on the digital value of the divided voltage obtained by dividing the constant voltage by the temperature resistor and the variable resistor after the resistance value of the variable resistor is adjusted; used to make a computer execute
   The computer program, wherein the temperature is the temperature of the temperature resistor.
   

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