Temperature sensor and temperature measuring method

Abstract

The invention relates to the technical field of temperature measurement, and discloses a temperature sensor and a temperature measurement method, and the temperature sensor is arranged in a target device comprising a band-gap reference circuit. The temperature sensor comprises a comparator circuit and an adjustable voltage circuit. The voltage output end of the band-gap reference circuit is connected with the first input end of the comparator circuit; the voltage output end of the adjustable voltage circuit is connected with the second input end of the comparator circuit; the adjustable voltage circuit is used for changing an output voltage according to an input parameter; the comparator circuit is used for determining the temperature of the target device according to the output voltage value of the adjustable voltage circuit when the output level of the comparator circuit is converted. The function of the temperature sensor is realized by taking the existing functional module in the target device as a basic module. And the design of the temperature sensor meeting the basic performance requirement can be realized without extra power consumption and area as cost.

Description

Technical Field

[0001] The present application relates to the technical field of temperature measurement, and in particular to a temperature sensor and a temperature measurement method. Background Art

[0002] Temperature sensors play an important role in the healthy operation of circuit systems. Typically in ASIC chips, temperature sensors play three important roles: overheat protection, performance optimization, and fault detection. In traditional CMOS process design, there are usually two types of temperature sensor designs: voltage domain temperature sensors and time domain temperature sensors. Generally speaking, voltage domain temperature sensors can achieve higher detection accuracy, but the circuit design area is usually larger, which is not very friendly to area-sensitive applications. As a type of digital circuit, the time domain temperature sensor has the advantage of a small area because of its excellent digital circuit compatibility with the CMOS process, but its measurement accuracy is not as high as that of sensors implemented using analog circuits.

[0003] Therefore, there is an urgent need for a temperature sensor that can overcome the design defects of existing temperature sensors and achieve the basic functions and performance of the temperature sensor without adding circuit functional modules and without requiring additional power consumption and area as a cost. Summary of the invention

[0004] In view of this, the present application provides a temperature sensor and a temperature measurement method, which can achieve the basic functions and performance of the temperature sensor without adding circuit functional modules and without requiring additional power consumption and area as a cost.

[0005] In a first aspect, the present application provides a temperature sensor, which is disposed in a target device including a bandgap reference circuit; the temperature sensor includes a comparator circuit and an adjustable voltage circuit;

[0006] The voltage output terminal of the bandgap reference circuit is connected to the first input terminal of the comparator circuit;

[0007] The voltage output terminal of the adjustable voltage circuit is connected to the second input terminal of the comparator circuit; the adjustable voltage circuit is used to change the output voltage according to the input parameter;

[0008] The comparator circuit is used to determine the temperature of the target device according to the output voltage value of the adjustable voltage circuit when the output level of the comparator circuit is converted.

[0009] In an optional embodiment, the comparator circuit includes a comparator, a first switch and a second switch; the voltage output end of the bandgap reference circuit is connected to the first input end of the comparator via the first switch, and outputs a first voltage; the voltage output end of the adjustable voltage circuit is connected to the second input end of the comparator via the second switch, and outputs a second voltage; the comparator is used to output a corresponding output level according to the magnitude relationship between the first voltage and the second voltage.

[0010] In an optional implementation, the adjustable voltage circuit includes a digital-to-analog conversion circuit; the output end of the digital-to-analog conversion circuit is connected to the second input end of the comparator via the second switch; and the digital-to-analog conversion circuit changes the output voltage according to the input parameters.

[0011] In an optional implementation, the digital-to-analog conversion circuit includes a resistor-resistance type digital-to-analog converter.

[0012] In an optional embodiment, the temperature sensor also includes a multiplexer; the multiplexer is connected to the bandgap reference circuit and is connected to the first input terminal of the comparator circuit through the first switch; the multiplexer is used to select the bandgap reference voltage of the bandgap reference circuit and the base-emitter voltage of the bipolar transistor according to a control signal, and output the bandgap reference voltage or the base-emitter voltage of the bipolar transistor.

[0013] In a second aspect, the present application provides a temperature measurement method, which is applied to a temperature sensor as in the first aspect or any corresponding embodiment thereof, and the method comprises:

[0014] closing the first switch and the second switch;

[0015] Setting the input parameter of the adjustable voltage circuit to a first input parameter so that the output level of the comparator circuit is a first output level; the first input parameter makes the output voltage of the adjustable voltage circuit 0;

[0016] gradually increasing the input parameter of the adjustable voltage circuit until the output level of the comparator circuit is converted to a second output level, thereby obtaining a second input parameter of the adjustable voltage circuit;

[0017] Based on the second input parameter, a target output voltage of the adjustable voltage circuit is obtained; the target output voltage is equal to the output voltage of the bandgap reference circuit;

[0018] Based on the target output voltage, the temperature of the target device is obtained.

[0019] In an optional implementation, obtaining the target output voltage of the adjustable voltage circuit based on the second input parameter includes: acquiring the target output voltage corresponding to the second input parameter according to a preset mapping relationship between the input parameter and the voltage.

[0020] In an optional embodiment, the temperature of the target device is obtained based on the target output voltage, including: based on the target output voltage, respectively performing a multiplexer selection on the bandgap reference voltage of the bandgap reference circuit and the base-emitter voltage of the bipolar transistor to obtain the bandgap reference voltage and the base-emitter voltage of the bipolar transistor; based on the bandgap reference voltage and the base-emitter voltage of the bipolar transistor, obtaining the temperature of the target device.

[0021] In an optional embodiment, the temperature of the target device is obtained based on the bandgap reference voltage and the base-emitter voltage of the bipolar transistor, including: obtaining a linear relationship between temperature and the base-emitter voltage of the bipolar transistor based on a bandgap reference formula; and obtaining the temperature of the target device based on the linear relationship.

[0022] In an optional implementation, the bandgap reference formula is expressed as:

[0023]

[0024] The linear relationship can be expressed as:

[0025]

[0026] In the formula, k1 and k2 are constants, k is the Boltzmann constant 1.38x10 -23 J / K, q is the charge 1.6x10 -19 C, n is the design ratio of the area of ​​the bipolar transistor, R1, R2, R3 are the resistance values ​​of the bandgap reference module; V bg is a voltage constant that is independent of temperature; T is the temperature of the device under test.

[0027] The temperature sensor provided in this application has the following advantages:

[0028] The temperature sensor of the present application is arranged in a target device including a bandgap reference circuit; the temperature sensor includes a comparator circuit and an adjustable voltage circuit. The adjustable voltage circuit can adopt a digital-to-analog converter. The voltage output end of the bandgap reference circuit is connected to the first input end of the comparator circuit for outputting a first voltage; the voltage output end of the adjustable voltage circuit is connected to the second input end of the comparator circuit for outputting a second voltage; the adjustable voltage circuit is used to change the output voltage according to the input parameter; the comparator circuit is used to select the output level according to the magnitude relationship between the first voltage and the second voltage, output the first level signal when the first voltage is greater than the second voltage, and output the second level signal when the first voltage is less than the second voltage, that is, when the output level of the comparator circuit is converted, the first voltage and the second voltage are approximately equal at this time, and the value of the first voltage can be determined according to the value of the second voltage, thereby obtaining the value of the output voltage of the bandgap reference circuit. Based on the output voltage of the bandgap reference circuit at this time, the temperature of the target device can be determined by the bandgap reference formula. The temperature of the target device can also be determined according to the output voltage value of the adjustable voltage circuit at this time. The present application scheme uses the existing functional modules commonly used in analog circuits as basic modules, and combines them on the existing circuit structure to realize the function of the temperature sensor. In this way, the design of the temperature sensor that meets the basic performance requirements can be realized without adding circuit functional modules, and without requiring additional power consumption and area as a cost.

[0029] In addition, the temperature measurement method provided in the present application is applied to the temperature sensor mentioned above, and the beneficial effects are the same as above. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0031] Figure 1 is a system block diagram of a voltage domain temperature sensor according to an exemplary embodiment of the present application.

[0032] Figure 2 is a system block diagram of a time domain temperature sensor according to an exemplary embodiment of the present application.

[0033] Figure 3 is a system block diagram of a temperature sensor according to an exemplary embodiment of the present application.

[0034] Figure 4 It is a schematic diagram of a linear calculation relationship according to an exemplary embodiment of the present application. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of this application.

[0036] First, the terms involved in this application are introduced.

[0037] Bandgap: Bandgap reference circuit;

[0038] ASIC: Application specific integrated circuit;

[0039] ATB: Analog test bus, analog test bus;

[0040] CMOS: Complementary Metal Oxide Semiconductor, is a design process for integrated circuits.

[0041] Temperature sensor is a key IP in ASIC chip, which plays an important role in the healthy operation of circuit system. Typically, in ASIC chip, temperature sensor has the following three important functions:

[0042] The first is overheating protection. The chip generates heat when it is working. When the temperature is too high, the performance will decline or even be damaged. The temperature sensor can monitor the chip temperature in real time. When the temperature reaches the set critical value, the protection mechanism is triggered, such as reducing the operating frequency of the chip or directly suspending some functions to prevent the chip from being damaged due to overheating. The second is performance optimization. It can provide a basis for the dynamic performance adjustment of the chip. The electrical characteristics of the chip (such as the switching speed of the transistor, etc.) will change under different temperature environments. Through the data monitored by the temperature sensor, the chip can adaptively adjust the parameters of the internal circuit so that the performance can remain relatively stable at different temperatures, ensuring the accuracy and processing speed of the calculation. The third is fault detection. Abnormal chip temperature may indicate potential faults in the chip, such as internal short circuits. Temperature sensors can help detect such abnormal temperature changes, provide clues for fault diagnosis, and help improve the reliability of the system.

[0043] In traditional CMOS process design, there are usually two types of temperature sensor designs: voltage domain temperature sensor and time domain temperature sensor.

[0044] The voltage domain temperature sensor is implemented by a front-end sensing circuit, a bandgap reference circuit (Bandgap), an operational amplifier, and an ADC. Figure 1 As shown, the front-end temperature sensing circuit uses the voltage difference V between the base and emitter of the BJT. BE The output voltage is negatively correlated with temperature (CTAT), and the two V BE The difference ΔV BE The output voltage is positively correlated with temperature (PTAT). BE The output value is small. In order to make full use of the accuracy of the digital converter, a fully differential operational amplifier is often used to amplify the signal when designing the circuit. The amplified differential signal is then sampled and quantized by the ADC to output the voltage of the temperature sensing circuit and output a digital code.

[0045] The system block diagram of the traditional time domain temperature sensor is as follows Figure 2 As shown, the basic circuit includes: temperature sensing circuit, frequency digital conversion circuit, external input reference clock device, etc. As shown in the figure below, its basic principle is: the temperature sensing circuit is a temperature-sensitive ring oscillator that generates a frequency signal related to temperature. The reference counter counts the reference clock to generate a strobe pulse. The counter counts the number of cycles of the clock signal that changes with temperature within the strobe pulse period and outputs a digital code related to temperature.

[0046] Generally speaking, voltage domain temperature sensors can achieve higher detection accuracy, but the circuit design area is usually larger, which is not very friendly to area-sensitive applications. As a type of digital circuit, time domain temperature sensors have the advantage of small area due to their excellent compatibility with digital circuits in CMOS technology, but their measurement accuracy is not as high as that of sensors implemented with analog circuits.

[0047] In order to solve the defects of the existing temperature sensor design, the embodiment of the present application provides a temperature sensor, which uses the existing functional modules commonly used in analog circuits as basic modules, and combines them on the existing circuit structure to realize the function of the temperature sensor. In this way, the design of the temperature sensor that meets the basic performance requirements can be realized without adding circuit functional modules, and without requiring additional power consumption and area as a cost.

[0048] A temperature sensor provided in an embodiment of the present application is disposed in a target device including a bandgap reference circuit; the temperature sensor includes a comparator circuit and an adjustable voltage circuit.

[0049] The voltage output terminal of the bandgap reference circuit is connected to the first input terminal of the comparator circuit, and is used to output a first voltage;

[0050] The voltage output terminal of the adjustable voltage circuit is connected to the second input terminal of the comparator circuit for outputting a second voltage; the adjustable voltage circuit is used to change the output voltage according to the input parameter;

[0051] The comparator circuit is used to determine the temperature of the target device according to the output voltage value of the adjustable voltage circuit when the output level of the comparator circuit is converted.

[0052] The temperature sensor of the embodiment of the present application selects different output levels according to the voltage size of the two input terminals through a comparator. When the output level of the comparator is just converted, it indicates that the voltages of the two input terminals of the comparator are almost the same. At this time, the value of the first voltage can be obtained according to the second voltage value, that is, the output voltage value of the bandgap reference circuit, and then the temperature of the bandgap reference circuit at this time can be obtained based on the bandgap reference formula.

[0053] Exemplarily, the comparator circuit includes a comparator, a first switch and a second switch; the voltage output end of the bandgap reference circuit is connected to the first input end of the comparator via the first switch, and outputs a first voltage; the voltage output end of the adjustable voltage circuit is connected to the second input end of the comparator via the second switch, and outputs a second voltage; the comparator is used to output a corresponding output level according to the magnitude relationship between the first voltage and the second voltage.

[0054] Exemplarily, the adjustable voltage circuit includes a digital-to-analog conversion circuit; the output end of the digital-to-analog conversion circuit is connected to the second input end of the comparator via the second switch; the digital-to-analog conversion circuit changes the output voltage according to the input parameter. The digital-to-analog conversion circuit can adopt a resistor-resistance type digital-to-analog converter.

[0055] In another specific embodiment, the temperature sensor also includes a multiplexer; the multiplexer is connected to the bandgap reference circuit and is connected to the first input terminal of the comparator circuit through the first switch; the multiplexer is used to select the bandgap reference voltage of the bandgap reference circuit and the base-emitter voltage of the bipolar transistor according to a control signal, and output the bandgap reference voltage or the base-emitter voltage of the bipolar transistor.

[0056] On the basis of the above embodiment, the embodiment of the present application further provides a temperature measurement method, which uses the temperature sensor provided in the above embodiment, including the following steps:

[0057] closing the first switch and the second switch;

[0058] Setting the input parameter of the adjustable voltage circuit to a first input parameter so that the output level of the comparator circuit is a first output level; the first input parameter makes the output voltage of the adjustable voltage circuit 0;

[0059] gradually increasing the input parameter of the adjustable voltage circuit until the output level of the comparator circuit is converted to a second output level, thereby obtaining a second input parameter of the adjustable voltage circuit;

[0060] Based on the second input parameter, a target output voltage of the adjustable voltage circuit is obtained; the target output voltage is equal to the output voltage of the bandgap reference circuit;

[0061] Based on the target output voltage, the temperature of the target device is obtained.

[0062] In a specific embodiment, obtaining the target output voltage of the adjustable voltage circuit based on the second input parameter includes: obtaining the target output voltage corresponding to the second input parameter according to a preset mapping relationship between the input parameter and the voltage.

[0063] Exemplarily, based on the target output voltage, the temperature of the target device is obtained, specifically including: based on the target output voltage, the bandgap reference voltage of the bandgap reference circuit and the base-emitter voltage of the bipolar transistor are respectively multiplexed to obtain the bandgap reference voltage and the base-emitter voltage of the bipolar transistor; based on the bandgap reference voltage and the base-emitter voltage of the bipolar transistor, the temperature of the target device is obtained.

[0064] Exemplarily, the temperature of the target device is obtained based on the bandgap reference voltage and the base-emitter voltage of the bipolar transistor, specifically including: obtaining a linear relationship between temperature and the base-emitter voltage of the bipolar transistor based on a bandgap reference formula; and obtaining the temperature of the target device based on the linear relationship.

[0065] More specifically, the bandgap reference formula is expressed as:

[0066]

[0067] The linear relationship can be expressed as:

[0068]

[0069] In the formula, k1 and k2 are constants, k is the Boltzmann constant 1.38x10 -23 J / K, q is the charge 1.6x10 -19 C, n is the design ratio of the area of ​​the bipolar transistor, R1, R2, R3 are the resistance values ​​of the bandgap reference module; V bgis a voltage constant that is independent of temperature; T is the temperature of the device under test.

[0070] In summary, the temperature sensor provided in the embodiment of the present application is arranged in a target device including a bandgap reference circuit; the temperature sensor includes a comparator circuit and an adjustable voltage circuit. The adjustable voltage circuit can adopt a digital-to-analog converter. The voltage output end of the bandgap reference circuit is connected to the first input end of the comparator circuit for outputting a first voltage; the voltage output end of the adjustable voltage circuit is connected to the second input end of the comparator circuit for outputting a second voltage; the adjustable voltage circuit is used to change the output voltage according to the input parameter; the comparator circuit is used to select the output level according to the magnitude relationship between the first voltage and the second voltage, output the first level signal when the first voltage is greater than the second voltage, and output the second level signal when the first voltage is less than the second voltage, that is, when the output level of the comparator circuit is converted, the first voltage and the second voltage are approximately equal at this time, and the value of the first voltage can be determined according to the value of the second voltage, thereby obtaining the value of the output voltage of the bandgap reference circuit. Based on the output voltage of the bandgap reference circuit at this time, the temperature of the target device can be determined by the bandgap reference formula. In other words, the temperature of the target device can be determined according to the output voltage value of the adjustable voltage circuit at this time. The present application scheme uses the existing functional modules commonly used in analog circuits as basic modules, and combines them on the existing circuit structure to realize the function of the temperature sensor. In this way, the design of the temperature sensor that meets the basic performance requirements can be realized without adding circuit functional modules, and without requiring additional power consumption and area as a cost.

[0071] For example, the temperature sensor and the temperature measurement method are described by taking an actual circuit structure as an example. Figure 3 . Its basic components are: bandgap reference circuit (Bandgap), resistor-resistance digital-to-analog converter, comparator and several switching elements. In the implementation scheme, the three basic modules of bandgap reference circuit, resistor-resistance digital-to-analog converter and comparator circuit are connected to the ATB bus through switches, so that the functions of these three modules can be combined to jointly realize the function of a temperature sensor. In actual use, it does not affect the basic functions of these three modules in the original circuit, does not require additional development of new circuit modules, does not affect the overall layout of the original circuit structure, and does not require additional area and power consumption. When it is necessary to detect temperature information, a temperature sensor that meets typical performance requirements can be realized through simple switch control and comparison calculation.

[0072] Specifically, the bandgap reference circuit first connects the output end to the multiplexer, then connects to the ATB bus through the first switch, and then connects to the positive input end of the comparator through the third switch; the resistor-resistance digital-to-analog converter is connected to the ATB bus through the second switch, and then connected to the negative input end of the comparator through the fourth switch. By changing the code value of the resistor-resistance digital-to-analog converter, the output voltage of the resistor-resistance digital-to-analog converter is controlled.

[0073] The specific steps of temperature measurement are as follows.

[0074] First, close the four switches and set the code value of the resistor-resistance digital-to-analog converter to the minimum value. In this way, the voltage output by the resistor-resistance digital-to-analog converter to the negative terminal of the comparator is the minimum voltage 0V. Since the negative terminal voltage is less than the positive terminal voltage, the comparator output is 1.

[0075] By gradually increasing the code value of the resistor-resistance digital-to-analog converter, the output voltage of the resistor-resistance digital-to-analog converter will gradually increase. Once the output voltage of the resistor-resistance digital-to-analog converter exceeds the positive terminal voltage of the comparator, the output of the comparator will flip from 1 to 0.

[0076] Record the code value of the resistor-resistance digital-to-analog converter at this time, and then read the code-voltage design mapping table of the resistor-resistance digital-to-analog converter. The mapped voltage value at this time is the size of the positive terminal voltage of the comparator.

[0077] V bg voltage (bandgap reference voltage) and V be1 voltage (base-emitter voltage of bipolar transistor (BJT)) to select the multiplexer, we can get V bg and V be1 Voltage value.

[0078] According to the bandgap reference formula of the above embodiment, the temperature T and V of the above embodiment can be obtained. be1 The linear calculation relationship of Figure 4 shown.

[0079] By substituting V bg Voltage value and current V be1 The voltage value can be used to directly calculate the current temperature.

[0080] In summary, the temperature sensor and temperature measurement method of this example use the existing functional modules commonly used in analog circuits as basic modules, and combine them on the existing circuit structure to realize the function of the temperature sensor. In this way, the design of a temperature sensor that meets basic performance requirements can be realized without adding circuit functional modules, and without requiring additional power consumption and area as a cost.

[0081] In addition, in the above embodiment, it is necessary to change the input parameters of the digital-to-analog converter and perform temperature calculation according to the voltage value obtained by the comparator. Therefore, it is also necessary to set a control module to control the input of each module, read the voltage and parameters, and perform temperature calculation. The specific form of the control module is not required, and the control logic can be stored in the chip, and the above scheme is implemented by the control chip. The specific structure of the control module is not limited, and may include a memory and a processor, the memory is used to store a computer program, and the processor is used to implement the various steps mentioned in the above embodiment when executing the computer program.

[0082] Among them, the processor may include one or more processing cores, such as a 4-core processor, an 8-core processor, etc. The processor can be implemented in at least one hardware form of a digital signal processor (DSP), a field-programmable gate array (FPGA), and a programmable logic array (PLA). The processor may also include a main processor and a coprocessor. The main processor is a processor for processing data in the awake state, also known as a central processing unit (CPU); the coprocessor is a low-power processor for processing data in the standby state. In some embodiments, the processor may be integrated with a graphics processing unit (GPU), which is responsible for rendering and drawing the content to be displayed on the display screen. In some embodiments, the processor may also include an artificial intelligence (AI) processor, which is used to process computing operations related to machine learning.

[0083] The memory may include one or more computer-readable storage media, which may be non-transitory. The memory may also include high-speed random access memory, and non-volatile memory, such as one or more disk storage devices, flash memory storage devices. In this embodiment, the memory is at least used to store the following computer program, wherein, after the computer program is loaded and executed by the processor, it can implement the relevant steps disclosed in any of the aforementioned embodiments. In addition, the resources stored in the memory may also include an operating system and data, etc., and the storage method may be temporary storage or permanent storage. Among them, the operating system may include Windows, Unix, Linux, etc. The data may include but is not limited to the data involved in the above method, etc.

[0084] The above is a detailed introduction to a temperature sensor and a temperature measurement method provided by the present application. The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the various embodiments can be referred to each other. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of the claims of the present application.

[0085] It should also be noted that, in this specification, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprising a ..." do not exclude the presence of other identical elements in the process, method, article or device including the above elements.

Claims

1. A temperature sensor, characterized in that: The temperature sensor is disposed in a target device including a bandgap reference circuit; the temperature sensor includes a comparator circuit and an adjustable voltage circuit; The voltage output terminal of the bandgap reference circuit is connected to the first input terminal of the comparator circuit; The voltage output terminal of the adjustable voltage circuit is connected to the second input terminal of the comparator circuit; the adjustable voltage circuit is used to change the output voltage according to the input parameters; The comparator circuit is used to determine the temperature of the target device according to the output voltage value of the adjustable voltage circuit when the output level of the comparator circuit is converted.

2. The temperature sensor according to claim 1, characterized in that: The comparator circuit includes a comparator, a first switch and a second switch; The voltage output terminal of the bandgap reference circuit is connected to the first input terminal of the comparator via the first switch to output a first voltage; The voltage output terminal of the adjustable voltage circuit is connected to the second input terminal of the comparator via the second switch to output a second voltage; The comparator is used to output a corresponding output level according to the magnitude relationship between the first voltage and the second voltage.

3. The temperature sensor according to claim 2, characterized in that: The adjustable voltage circuit includes a digital-to-analog conversion circuit; The output end of the digital-to-analog conversion circuit is connected to the second input end of the comparator via the second switch; The digital-to-analog conversion circuit changes the output voltage according to the input parameters.

4. The temperature sensor according to claim 3, characterized in that: The digital-to-analog conversion circuit includes a resistor-to-resistance type digital-to-analog converter.

5. The temperature sensor according to claim 3, characterized in that: The temperature sensor also includes a multiplexer; The multiplexer is connected to the bandgap reference circuit and is connected to the first input terminal of the comparator circuit through the first switch; The multiplexer is used to select the bandgap reference voltage of the bandgap reference circuit and the base-emitter voltage of the bipolar transistor according to a control signal, and output the bandgap reference voltage or the base-emitter voltage of the bipolar transistor.

6. A temperature measurement method, characterized in that: Applied to the temperature sensor according to any one of claims 1 to 5, the method comprises: closing the first switch and the second switch; Setting the input parameter of the adjustable voltage circuit to a first input parameter so that the output level of the comparator circuit is a first output level; the first input parameter makes the output voltage of the adjustable voltage circuit 0; gradually increasing the input parameter of the adjustable voltage circuit until the output level of the comparator circuit is converted to a second output level, thereby obtaining a second input parameter of the adjustable voltage circuit; Based on the second input parameter, a target output voltage of the adjustable voltage circuit is obtained; the target output voltage is equal to the output voltage of the bandgap reference circuit; Based on the target output voltage, a temperature of the target device is obtained.

7. The temperature measurement method according to claim 6, characterized in that: Obtaining a target output voltage of the adjustable voltage circuit based on the second input parameter includes: According to a preset mapping relationship between the input parameter and the voltage, a target output voltage corresponding to the second input parameter is obtained.

8. The temperature measurement method according to claim 7, characterized in that: The step of obtaining the temperature of the target device based on the target output voltage includes: Based on the target output voltage, a bandgap reference voltage of the bandgap reference circuit and a base-emitter voltage of the bipolar transistor are respectively selected by a multiplexer to obtain the bandgap reference voltage and the base-emitter voltage of the bipolar transistor; The temperature of the target device is obtained based on the bandgap reference voltage and the base emitter voltage of the bipolar transistor.

9. The temperature measurement method according to claim 8, characterized in that: The step of obtaining the temperature of the target device based on the bandgap reference voltage and the base-emitter voltage of the bipolar transistor comprises: Based on the bandgap reference formula, a linear relationship between temperature and the base-emitter voltage of a bipolar transistor is obtained; Based on the linear relationship, the temperature of the target device is obtained.

10. The temperature measurement method according to claim 9, characterized in that: The bandgap reference formula is expressed as: The linear relationship is expressed as: In the formula, k1 and k2 are constants, k is the Boltzmann constant 1.38x10 -23 J / K, q is the charge 1.6x10 -19 C, n is the design ratio of the area of ​​the bipolar transistor, R1, R2, R3 are the resistance values ​​of the bandgap reference module; V bg is a voltage constant that is independent of temperature; T is the temperature of the device under test.

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