Temperature sensor and method for calibrating the same

Abstract

The application discloses a temperature sensor and a calibration method thereof. The temperature sensor comprises a temperature sensing module and a temperature calibration module. The temperature sensing module is used for generating a corresponding reference voltage difference according to different to-be-measured temperatures. The temperature calibration module is used for outputting a temperature value of the to-be-measured temperature according to the reference voltage difference under the to-be-measured temperature, the reference voltage difference under a preset temperature and a plurality of calibration coefficients. The plurality of calibration coefficients are used for performing multi-order calibration on a difference value of the reference voltage difference under the to-be-measured temperature and the reference voltage difference under the preset temperature. The application can effectively reduce a measurement error and greatly improve the measurement precision of the temperature sensor. Meanwhile, the application adopts a single temperature point test method when calibrating and testing the temperature sensor, and the test cost is low, so that the application has high economy in production.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of testing, in particular to a temperature sensor and a calibration method thereof. BACKGROUND

[0002] A temperature sensor refers to a sensor capable of sensing temperature and converting it into an available output signal. With the continuous improvement of application requirements, the precision requirements of temperature sensors are also continuously improved. In the process of manufacturing temperature sensors, errors are inevitably introduced due to process factors. In order to ensure the accuracy of temperature detection of temperature sensors, various ways are needed to eliminate or reduce these errors to a small enough range.

[0003] When a temperature sensor senses temperature, a bias current is provided to a transistor by a current source. Since the BE junction of the transistor has different BE junction voltages Vbe when passing through different current densities, the voltage difference ΔVbe between the BE junction voltages of different transistors is a function of temperature T. By measuring ΔVbe, the temperature information of the chip to be measured can be obtained. Specifically, ΔVbe has a functional relationship with temperature T, i.e. ΔVbe=F(T). By measuring ΔVbe and bringing the measured value into its inverse function T=F -1 (ΔVbe), the temperature T can be obtained. However, due to process angle deviation and random errors in the chip manufacturing process, the F -1 (ΔVbe) function of each chip is different. In order to enable each chip produced to accurately measure temperature, the F -1 (ΔVbe) function of the chip needs to be calibrated.

[0004] The existing calibration scheme can refer to Figure 2 , which uses an amplifier 110 to amplify the measured voltage difference ΔVbe by a certain multiple, and then uses an analog-to-digital converter (i.e. ADC) 120 to perform analog-to-digital conversion on the amplified voltage difference K*ΔVbe to obtain a corresponding digital signal Dout. After corresponding processing of the digital signal Dout, the temperature value to be obtained is obtained. It can also be understood that the existing calibration scheme uses a first-order function to model the function F -1 (ΔVbe), i.e. T=k*ΔVbe+T0. Wherein, k is the slope of the curve, representing how many volts the voltage difference ΔVbe of the chip changes, and after multiplying by k, it is how many degrees the temperature of the chip changes, T0 is the curve intercept. In this calibration scheme, k is usually a constant value. If it is assumed that the calibration chip T0 is at room temperature of 27℃, and the value of ΔVbe measured at room temperature of 27℃ is ΔVbe_27, then the foregoing temperature curve can be rewritten as: T=k*(ΔVbe-ΔVbe_27)+T27. Wherein, T27 is the temperature value at room temperature, i.e. 27℃.

[0005] This calibration scheme has the following problems:

[0006] 1) The slope k of the curves is actually different for different chips. Using the same k value for different chips will result in a greater sensor error when the actual temperature deviates from room temperature.

[0007] 2)F -1 The (ΔVbe) function also contains higher-order coefficients, which are ignored here, and this can lead to some errors.

[0008] Therefore, it is necessary to provide improved technical solutions to overcome the above-mentioned technical problems existing in the prior art. Summary of the Invention

[0009] To address the aforementioned technical problems, this invention provides a temperature sensor and its calibration method. The calibration degree of temperature error is controllable, effectively reducing measurement errors and significantly improving the measurement accuracy of the temperature sensor. Furthermore, this invention employs a single-temperature-point testing method for temperature sensor calibration and testing, resulting in low testing costs and high economic efficiency in production.

[0010] According to a first aspect of this disclosure, a temperature sensor is provided, comprising: a temperature sensing module for generating a corresponding reference voltage difference based on different temperatures to be measured;

[0011] The temperature calibration module is used to output the temperature value of the target temperature based on the reference voltage difference at the temperature to be measured, the reference voltage difference at a preset temperature, and multiple calibration coefficients.

[0012] The plurality of calibration coefficients are used to perform multi-stage calibration on the difference between the reference voltage difference at the temperature to be measured and the reference voltage difference at the preset temperature.

[0013] Optionally, the temperature sensor further includes:

[0014] An amplifier, connected to the temperature sensing module, is used to amplify and output the reference voltage difference output by the temperature sensing module.

[0015] An analog-to-digital converter, connected to the amplifier, is used to perform analog-to-digital conversion on the amplified reference voltage difference, generate a corresponding digital signal, and output it to the temperature calibration module.

[0016] The plurality of calibration coefficients are used to perform multi-stage calibration on the difference between the digital signal corresponding to the reference voltage difference at the temperature to be measured and the digital signal corresponding to the reference voltage difference at the preset temperature.

[0017] Optionally, the formula for calculating the temperature value to be measured is as follows:

[0018] T = k0+ k1*(AVbe- AVbe_t0) 1 +...+ kn*(AVbe- AVbe_t0) n ,

[0019] wherein, T is a temperature value of the temperature to be measured, k0 corresponds to a temperature value of a preset temperature, k1 corresponds to a calibration coefficient at a first order calibration, kn corresponds to a calibration coefficient at an n order calibration, AVbe corresponds to a reference voltage difference obtained at the temperature to be measured, AVbe_t0 corresponds to a reference voltage difference at the preset temperature, and n is an integer greater than 1.

[0020] Optionally, each of the plurality of calibration coefficients comprises a reference temperature part and a process deviation calibration part,

[0021] wherein, the process deviation calibration parts in the same order calibration coefficients respectively corresponding to the same type of chips to be measured produced by the same production process are the same, and the process deviation calibration parts in the same order calibration coefficients respectively corresponding to different types of chips to be measured produced by the same production process or different chips to be measured produced by different production processes are different.

[0022] Optionally, the temperature sensing module comprises:

[0023] a first current source and a first triode connected in series between a power supply end and a reference ground, the emitter of the first triode being connected with the reference ground, the base being connected with the collector;

[0024] a second current source and a second triode connected in series between the power supply end and the reference ground, the emitter of the second triode being connected with the reference ground, the base being connected with the collector,

[0025] wherein, the difference between the collector voltage of the first triode and the collector voltage of the second triode is the reference voltage difference.

[0026] Optionally, the temperature sensor further comprises:

[0027] a storage module for storing a preset temperature value and reference voltage difference information at the preset temperature.

[0028] According to the second aspect of the present disclosure, a calibration method of a temperature sensor is provided, comprising: obtaining a reference voltage difference at a temperature to be measured;

[0029] obtaining a temperature value of the temperature to be measured based on the reference voltage difference at the temperature to be measured, a reference voltage difference at a preset temperature, and a plurality of calibration coefficients,

[0030] The plurality of calibration coefficients are used to perform multi-order calibration on a difference between the reference voltage difference at the to-be-tested temperature and the reference voltage difference at the preset temperature.

[0031] Optionally, obtaining the reference voltage difference at the to-be-tested temperature comprises:

[0032] providing a first bias current to a BE junction of a first triode at the to-be-tested temperature;

[0033] providing a second bias current to a BE junction of a second triode at the to-be-tested temperature;

[0034] measuring a voltage difference between a collector voltage of the first triode and a collector voltage of the second triode to obtain the reference voltage difference at the to-be-tested temperature.

[0035] Optionally, obtaining the temperature value of the to-be-tested temperature based on the reference voltage difference at the to-be-tested temperature, the reference voltage difference at the preset temperature and the plurality of calibration coefficients comprises: obtaining the temperature value of the to-be-tested temperature by using a calculation formula as follows:

[0036] T=k0+k1*(ΔVbe-ΔVbe_t0) 1 +...+kn*(ΔVbe-ΔVbe_t0) n ,

[0037] wherein T is the temperature value of the to-be-tested temperature, k0 corresponds to a temperature value of a preset temperature, k1 corresponds to a calibration coefficient at a first-order calibration, kn corresponds to a calibration coefficient at an n-order calibration, ΔVbe corresponds to the reference voltage difference at the to-be-tested temperature, ΔVbe_t0 corresponds to the reference voltage difference at the preset temperature, and n is an integer greater than 1.

[0038] Optionally, each calibration coefficient in the plurality of calibration coefficients comprises: a reference temperature part and a process deviation calibration part,

[0039] wherein the process deviation calibration parts in the same-order calibration coefficients respectively corresponding to the same type of to-be-tested chips produced by using the same production process are the same, and the process deviation calibration parts in the same-order calibration coefficients respectively corresponding to different types of to-be-tested chips produced by using the same production process or different to-be-tested chips produced by using different production processes are different.

[0040] The beneficial effects of the present application are: the present disclosure relates to a temperature sensor and a calibration method thereof, wherein a temperature calibration module is arranged in the temperature sensor, and a plurality of calibration coefficients are used to perform multi-order calibration on corresponding items to be calibrated (i.e. the difference between the reference voltage difference at the measured temperature and the reference voltage difference at the preset temperature), compared with the traditional first-order calibration, the multi-order calibration of the plurality of calibration coefficients in the present disclosure can further reduce the measurement error and improve the measurement accuracy of the temperature sensor. At the same time, the order of calibration required can also be selected according to different application scenarios, so as to realize the controllable calibration degree of temperature error.

[0041] On the other hand, each calibration coefficient in the present disclosure is composed of a reference temperature part and a process deviation calibration part, so that different calibration coefficients can be set for the process deviation of different measured chips, avoiding the influence on the sensor when the same calibration coefficient is used for the same order calibration of different measured chips, further reducing the measurement error and greatly improving the measurement accuracy of the temperature sensor.

[0042] On the other hand, each calibration coefficient in the present disclosure is composed of a reference temperature part and a process deviation calibration part, so that different calibration coefficients can be set for the process deviation of different measured chips, avoiding the influence on the sensor when the same calibration coefficient is used for the same order calibration of different measured chips, further reducing the measurement error and greatly improving the measurement accuracy of the temperature sensor.

[0043] It should be noted that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0044] The above and other objects, features and advantages of the present application will become more apparent from the following description of embodiments of the present application, taken in conjunction with the accompanying drawings.

[0045] Figure 1 A structure principle diagram of a temperature sensing module in a temperature sensor according to an embodiment of the present disclosure is shown;

[0046] Figure 2 A structure block diagram of an existing temperature sensor is shown;

[0047] Figure 3 A structure block diagram of a temperature sensor according to an embodiment of the present disclosure is shown;

[0048] Figure 4 A temperature error curve diagram under different calibration degrees according to an embodiment of the present disclosure is shown;

[0049] Figure 5 A flow block diagram of a calibration method of a temperature sensor according to an embodiment of the present disclosure is shown;

[0050] Figure 6 An algorithm block diagram corresponding to a calibration method of a temperature sensor provided by an embodiment of the present disclosure is shown.

[0051] Figure 7 An algorithm block diagram of a calibration coefficient provided by an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0052] For the purpose of facilitating the understanding of the present application, a more complete description of the present application will be given below with reference to the relevant drawings. The preferred embodiments of the present application are shown in the drawings. However, the present application can be realized in different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0053] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used herein in the specification of the present application are only for the purpose of describing the specific embodiments and are not intended to limit the present application.

[0054] Hereinafter, the present application will be described in detail with reference to the accompanying drawings.

[0055] Reference Figure 3 , Figure 3 A structural block diagram of a temperature sensor provided by an embodiment of the present disclosure is shown.

[0056] As Figure 3 shown, in an embodiment of the present disclosure, the temperature sensor comprises a temperature sensing module and a temperature calibration module 230.

[0057] The temperature sensing module is configured to generate a corresponding reference voltage difference according to different to-be-measured temperatures. The temperature calibration module 230 is configured to output a temperature value of the to-be-measured temperature according to the reference voltage difference under the to-be-measured temperature, the reference voltage difference under a preset temperature, and a plurality of calibration coefficients, and the plurality of calibration coefficients are configured to perform multi-order calibration on the difference between the reference voltage difference under the to-be-measured temperature and the reference voltage difference under the preset temperature.

[0058] In the present embodiment, the temperature sensing module comprises a first current source, a second current source, a first transistor Q0 and a second transistor Q1. Figure 1 The first current source and the first transistor Q0 are connected in series between a power supply end VDD and a reference ground, the second current source and the second transistor Q1 are connected in series between the power supply end VDD and the reference ground, and the collector and the base of the first transistor Q0 are connected, the emitter of the first transistor Q0 is connected to the reference ground, and the collector and the base of the second transistor Q1 are connected, the emitter of the second transistor Q1 is connected to the reference ground.

[0059] The first current source is used to provide the first bias current I0 to the BE junction of the first transistor Q0, and the second current source is used to provide the second bias current I1 to the BE junction of the second transistor Q1. Further, when the first bias current I0 and the second bias current I1 with different current densities flow through the BE junctions of the first transistor Q0 and the second transistor Q1 respectively under the same temperature condition, different collector voltages (herein, the collector voltage of the first transistor Q0 is denoted as Vbe1, and the collector voltage of the second transistor Q1 is denoted as Vbe2) are formed at the collector of the first transistor Q0 and the collector of the second transistor Q1 respectively, and a certain voltage difference (herein, denoted as ΔVbe, and ΔVbe = Vbe2 - Vbe1) is formed between the collector of the first transistor Q0 and the collector of the second transistor Q1. Since the voltage Vbe1 and the voltage Vbe2 are both formed by the bias currents I0 and I1 under the same temperature, when a certain multiple relationship (such as I1 = m*I0, m is a positive number) exists between the bias currents I0 and I1, the voltage difference ΔVbe increases with the increase of the temperature, and at this time, the current temperature information can be obtained by measuring the voltage difference.

[0060] Further, since a certain function relationship exists between the voltage difference ΔVbe and the temperature (such as the to-be-measured temperature T), i.e., ΔVbe = F(T), the inverse function thereof can be represented as T = F -1 (ΔVbe), and the current to-be-measured temperature T can be solved through the inverse function.

[0061] Specifically, after the inverse function is expanded by Taylor series, the following can be obtained:

[0062] F -1 (ΔVbe) = b0 + b1*(ΔVbe) + b2*(ΔVbe) 2 +b3*(ΔVbe) 3 +...+bq*(ΔVbe) q ...(1),

[0063] In the above formula (1), b0, b1, b2, b3,..., bq are respectively the 0th power term, the 1st power term, the 2nd power term, the 3rd power term, and the qth power term coefficients of ΔVbe, and q is a positive integer.

[0064] Further, it can be known that not only the 1st order part exists in the function, but also high order parts such as 2nd order, 3rd order, etc. exist, and therefore, when the function is calibrated, the high order parts should also be calibrated correspondingly in order to further improve the temperature accuracy of the sensor.

[0065] In the embodiment, based on the solving principle of the to-be-measured temperature T, the formula (1) can be deformed as follows:

[0066] T = k0+ k1*(AVbe- AVbe_t0) 1 +... + kn*(AVbe- AVbe_t0) n (2).

[0067] The formula (2) is a calculation formula of the temperature value of the temperature to be measured in the present disclosure. In the formula (2), T is the temperature value of the temperature to be measured, k0 corresponds to a calibration coefficient when calibration at a preset temperature, which is equal to the temperature value of the preset temperature (i.e. t0) in value, k1 corresponds to a calibration coefficient when first-order calibration, kn corresponds to a calibration coefficient when n-order calibration, AVbe corresponds to a reference voltage difference measured at the temperature to be measured, AVbe_t0 corresponds to a reference voltage difference at the preset temperature t0, and n is an integer greater than 1. In this paper, AVbe- AVbe_t0 is the item to be calibrated when the temperature calibration module 230 calibrates according to multiple calibration coefficients, which represents the change amount of the reference voltage difference AVbe at different test temperatures.

[0068] It can be understood that when calibrating the function, the calibration order to be calibrated can be selected according to the specific application scenario and actual demand, and the specific numerical examples in the present disclosure are only exemplary, not as a limitation of the present disclosure. However, in the technical solution of the present disclosure, the multi-order calibration of the item to be calibrated is at least 2-order calibration.

[0069] Reference Figure 4 , Figure 4 The temperature error curve under different calibration degrees provided by the embodiments of the present disclosure is shown. It can be seen that Figure 4 As the calibration order of the item to be calibrated increases, the temperature error curve corresponding to the temperature sensor tends to be more flat, that is, the temperature measurement error of the temperature sensor is smaller. Further, the multi-order calibration of the item to be calibrated by multiple calibration coefficients in the present disclosure further reduces the measurement error and improves the measurement accuracy of the temperature sensor. At the same time, the order to be calibrated can be selected for different application scenarios to realize controllable calibration degree of temperature error.

[0070] Further, in the present disclosure, each of the plurality of calibration coefficients comprises a reference temperature part and a process deviation calibration part. For example, assuming that the preset temperature t0 is room temperature of 27℃, then k0 = 27℃ in the aforementioned formula (2), and k1 = k1' * 300 / ΔVbe_27 + k1". Wherein, 300 / ΔVbe_27 is the reference temperature part of the calibration coefficient k1 (wherein, the value 300 is the thermodynamic temperature value corresponding to the Celsius temperature value 27℃, i.e. 300 = 273 + T_27), and k1' and k1" are both process deviation calibration parts of the calibration coefficient k1, and k1' and k1" can be measured by a laboratory. Based on the same principle, the calibration coefficient kn of n-order calibration is kn = kn' * 300 / ΔVbe_27 + kn", which also comprises a corresponding reference temperature part and a process deviation calibration part, and the process deviation calibration parts kn' and kn" can also be measured by a laboratory.

[0071] It can be understood that the above selection of room temperature of 27℃ as the preset temperature is only exemplary. Based on the characteristics of the algorithm, the preset temperature does not need to be accurately 27℃ in actual chip testing, and only the temperature value during testing needs to be recorded for calculation, thereby eliminating the accurate temperature control step, reducing the cost, and improving the efficiency.

[0072] Further, the process deviation calibration parts in the same order calibration coefficients respectively corresponding to the same type of chips produced by the same production process are the same. For example, for a plurality of temperature sensor chips produced by the same production process, the process deviation calibration parts k1' and k1" in the same first-order calibration coefficient, the process deviation calibration parts k2' and k2" in the same second-order calibration coefficient, and the process deviation calibration parts kn' and kn" in the same n-order calibration coefficient can be used during calibration, without the need to test the process deviation calibration parts of each produced temperature sensor chip, thereby helping to save calibration time and improve calibration efficiency. On the other hand, the process deviation calibration parts in the same order calibration coefficients respectively corresponding to different types of chips produced by the same production process or different types of chips produced by different production processes are different. In this way, based on the process deviation calibration parts in the calibration coefficients, the calibration coefficients corresponding to different chips can be distinguished, thereby avoiding the influence on the sensor when the same calibration coefficient is used for the same order calibration of different chips, further reducing the measurement error, and greatly improving the measurement accuracy of the temperature sensor.

[0073] Further, in another embodiment of the present disclosure, the temperature sensor further comprises an amplifier 210 and an analog-to-digital converter 220.

[0074] The amplifier 210 is connected with the temperature sensing module, and is configured to amplify and output the reference voltage difference AVbe measured by the temperature sensing module. The analog-to-digital converter 220 is connected with the amplifier 210, and is configured to perform analog-to-digital conversion on the amplified reference voltage difference K*AVbe to generate a corresponding digital signal D out , and output the digital signal D to the temperature calibration module 230. K is the amplification factor of the amplifier 210 on the reference voltage difference AVbe. In this embodiment, the digital signal obtained after the reference voltage difference AVbe measured by the temperature sensing module is amplified and analog-to-digital converted is convenient for device operation, and is conducive to realizing automation and rapidity of the data processing process when the temperature sensor is calibrated. Correspondingly, the plurality of calibration coefficients in the temperature sensor at this time are used to perform multi-order calibration on the difference between the digital signal corresponding to the reference voltage difference under the to-be-measured temperature and the digital signal corresponding to the reference voltage difference under the preset temperature.

[0075] Based on the above description, when the temperature sensor in the present disclosure is calibrated, only a single-point test at a preset temperature is required to obtain the reference voltage under the preset temperature, so that multi-order calibration of the to-be-measured temperature measured by the temperature sensor can be realized, the test cost is greatly reduced, and higher economic efficiency can be achieved in production.

[0076] Optionally, the reference voltage difference under the preset temperature or the digital signal corresponding to the reference voltage difference under the preset temperature used by the temperature sensor when performing the calibration operation can be obtained by performing single-point measurement at the preset temperature by using the temperature sensing module, so as to improve the accuracy. It can also be obtained by calling the pre-stored reference voltage difference information under the preset temperature or the digital signal information corresponding to the reference voltage difference under the preset temperature, so as to reduce the calibration cost and improve the calibration speed. Furthermore, the temperature sensor further comprises a storage module. The storage module is configured to store the reference voltage difference under the preset temperature or the digital signal corresponding to the reference voltage difference under the preset temperature, and the information of the preset temperature value.

[0077] Reference Figure 5 , Figure 5 A flow chart of a calibration method of a temperature sensor according to an embodiment of the present disclosure is shown.

[0078] As Figure 5 shown, in the embodiment of the present disclosure, the calibration method of the temperature sensor comprises steps S1 to S2.

[0079] In step S1, a reference voltage difference under a to-be-measured temperature is obtained.

[0080] In the embodiment, step S1 further comprises: providing a first bias current to the BE junction of the first triode at the to-be-tested temperature; providing a second bias current to the BE junction of the second triode at the to-be-tested temperature; and measuring a voltage difference between the collector voltage of the first triode and the collector voltage of the second triode to obtain the reference voltage difference at the to-be-tested temperature.

[0081] Further, the first bias current and the second bias current have different current densities respectively.

[0082] In step S2, the temperature value of the to-be-tested temperature is obtained based on the reference voltage difference at the to-be-tested temperature, the reference voltage difference at the preset temperature, and the plurality of calibration coefficients.

[0083] In the embodiment, the temperature value of the to-be-tested temperature obtained based on step S2 can be realized by an algorithm. For example, as shown in Figure 6 and Figure 7 the algorithm is described. As shown in Figure 6 , after the reference voltage difference ΔVbe at the to-be-tested temperature and the reference voltage difference ΔVbe_t0 at the preset temperature are obtained, the to-be-calibrated term ΔVbe-ΔVbe_t0 when the temperature calibration module 230 calibrates based on the plurality of calibration coefficients can be obtained by performing a subtraction operation on the reference voltage difference ΔVbe at the to-be-tested temperature and the reference voltage difference ΔVbe_t0 at the preset temperature. Then, according to the actual calibration requirement, the calibration order to be calibrated is selected, and the to-be-calibrated term is multiplied by the calibration coefficient of the corresponding order after being raised to the power of the corresponding calibration order from low order to high order, to obtain the calibration amount of each order. For example, the calibration amount corresponding to the 0th order is k0*(ΔVbe-ΔVbe_t0)0=k0; the calibration amount corresponding to the 1st order is k1*(ΔVbe-ΔVbe_t0) 1 ; the calibration amount corresponding to the 2nd order is k2*(ΔVbe-ΔVbe_t0) 2 ; and so on, and the calibration amount corresponding to a higher order is kn*(ΔVbe-ΔVbe_t0) n . Finally, the calibration amount of each order is added to obtain the temperature value T of the to-be-tested temperature. The algorithm corresponds to the aforementioned formula (2). Meanwhile, in the preferred embodiment of the present disclosure, the multi-order calibration of the to-be-calibrated term is at least 2nd order calibration.

[0084] Further, the plurality of calibration coefficients k0, k1, k2,..., kn used in the algorithm are used to calibrate the difference between the reference voltage difference at the to-be-tested temperature and the reference voltage difference at the preset temperature. Each calibration coefficient in the plurality of calibration coefficients comprises a reference temperature part and a process deviation calibration part, as shown in Figure 7As shown, the reference temperature part corresponds to (273+T_t0) / ΔVbe_t0, and the process deviation calibration part corresponds to kn' and kn". Furthermore, as long as the reference voltage difference ΔVbe_t0 at the preset temperature, the preset temperature t0, and the process deviation calibration part corresponding to the plurality of calibration coefficients kn' and kn" are obtained in advance, the calibration coefficient kn corresponding to the order can be obtained, where kn=kn'*(273+T_t0) / ΔVbe_t0+kn".

[0085] Further, the process deviation calibration parts in the same order of calibration coefficients corresponding to the same type of to-be-measured chips produced by the same production process are the same. For example, for a plurality of temperature sensor chips produced by the same production process, the process deviation calibration parts k1' and k1" in the same first-order calibration coefficient, the process deviation calibration parts k2' and k2" in the same second-order calibration coefficient, and the process deviation calibration parts kn' and kn" in the same n-order calibration coefficient can be used when calibration is performed, that is, there is no need to test the process deviation calibration parts of each produced temperature sensor chip, which helps to save calibration time and provide calibration efficiency. On the other hand, the process deviation calibration parts in the same order of calibration coefficients corresponding to different types of to-be-measured chips produced by the same production process or different to-be-measured chips produced by different production processes are different.

[0086] In summary, the temperature sensor and the calibration method thereof disclosed in the present disclosure set a temperature calibration module in the temperature sensor, and use a plurality of calibration coefficients to perform multi-order calibration on the corresponding to-be-calibrated items (i.e., the difference between the reference voltage difference at the to-be-measured temperature and the reference voltage difference at the preset temperature). Compared with the traditional first-order calibration, the multi-order calibration of the plurality of calibration coefficients in the present disclosure can further reduce the measurement error and improve the measurement accuracy of the temperature sensor. At the same time, the order of calibration can be selected according to different application scenarios, so as to realize controllable calibration degree of temperature error.

[0087] On the other hand, each calibration coefficient in the present disclosure is composed of a reference temperature part and a process deviation calibration part, so that different calibration coefficients can be set according to the process deviation of different to-be-measured chips, avoiding the influence on the sensor when the same calibration coefficient is used for the same order calibration of different to-be-measured chips, further reducing the measurement error, and greatly improving the measurement accuracy of the temperature sensor.

[0088] It should be pointed out finally that the above embodiments are merely examples for clearly illustrating the present application and are not intended to limit the embodiments. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. It is unnecessary and impossible to enumerate all the embodiments. The changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A temperature sensor, wherein, include: The temperature sensing module is used to generate a corresponding reference voltage difference based on different temperatures to be measured. The temperature calibration module is used to output the temperature value of the target temperature based on the reference voltage difference at the temperature to be measured, the reference voltage difference at a preset temperature, and multiple calibration coefficients. The plurality of calibration coefficients are used to perform multi-stage calibration on the difference between the reference voltage difference at the temperature to be measured and the reference voltage difference at the preset temperature; The formula for calculating the temperature value to be measured is as follows: ， Where T is the temperature value of the temperature to be measured, k0 corresponds to the temperature value of the preset temperature, k1 corresponds to the calibration coefficient during first-order calibration, kn corresponds to the calibration coefficient during n-order calibration, ΔVbe corresponds to the reference voltage difference obtained at the temperature to be measured, ΔVbe_t0 corresponds to the reference voltage difference at the preset temperature, and n is an integer greater than 1.

2. The temperature sensor according to claim 1, wherein, The temperature sensor also includes: An amplifier, connected to the temperature sensing module, is used to amplify and output the reference voltage difference output by the temperature sensing module. An analog-to-digital converter, connected to the amplifier, is used to perform analog-to-digital conversion on the amplified reference voltage difference, generate a corresponding digital signal, and output it to the temperature calibration module. The plurality of calibration coefficients are used to perform multi-stage calibration on the difference between the digital signal corresponding to the reference voltage difference at the temperature to be measured and the digital signal corresponding to the reference voltage difference at the preset temperature.

3. The temperature sensor according to claim 1, wherein, Each of the multiple calibration coefficients includes a reference temperature component and a process deviation calibration component. Among them, the process deviation calibration part of the calibration coefficient of the same order corresponding to the same type of chip under test produced by the same manufacturing process is the same, while the process deviation calibration part of the calibration coefficient of the same order corresponding to different types of chips under test produced by the same manufacturing process or different chips under test produced by different manufacturing processes is different.

4. The temperature sensor according to claim 1, wherein, The temperature sensing module includes: A first current source and a first transistor are connected in series between the power supply terminal and the reference ground. The emitter of the first transistor is connected to the reference ground, and the base is connected to the collector. A second current source and a second transistor are connected in series between the power supply terminal and the reference ground. The emitter of the second transistor is connected to the reference ground, and the base is connected to the collector. The difference between the collector voltage of the first transistor and the collector voltage of the second transistor is the reference voltage difference.

5. The temperature sensor according to claim 1, wherein, The temperature sensor also includes: The storage module is used to store a preset temperature value and the reference voltage difference information at the preset temperature.

6. A calibration method for a temperature sensor, wherein, include: Obtain the reference voltage difference at the temperature to be measured; The temperature value of the temperature to be measured is obtained based on the reference voltage difference at the temperature to be measured, the reference voltage difference at a preset temperature, and multiple calibration coefficients. The plurality of calibration coefficients are used to perform multi-stage calibration on the difference between the reference voltage difference at the temperature to be measured and the reference voltage difference at the preset temperature; The formula for calculating the temperature value to be measured is as follows: ， Where T is the temperature value of the temperature to be measured, k0 corresponds to the temperature value of the preset temperature, k1 corresponds to the calibration coefficient during first-order calibration, kn corresponds to the calibration coefficient during n-order calibration, ΔVbe corresponds to the reference voltage difference obtained at the temperature to be measured, ΔVbe_t0 corresponds to the reference voltage difference at the preset temperature, and n is an integer greater than 1.

7. The calibration method according to claim 6, wherein, Obtaining the reference voltage difference at the temperature to be measured includes: A first bias current is provided to the BE junction of the first transistor at the temperature to be measured; A second bias current is provided to the BE junction of the second transistor at the temperature to be measured; The voltage difference between the collector voltage of the first transistor and the collector voltage of the second transistor is measured to obtain the reference voltage difference at the temperature to be measured.

8. The calibration method according to claim 6, wherein, Each of the multiple calibration coefficients includes a reference temperature component and a process deviation calibration component. Among them, the process deviation calibration part of the calibration coefficient of the same order corresponding to the same type of chip under test produced by the same manufacturing process is the same, while the process deviation calibration part of the calibration coefficient of the same order corresponding to different types of chips under test produced by the same manufacturing process or different chips under test produced by different manufacturing processes is different.

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