Temperature detection circuit and electronic equipment

Abstract

The utility model relates to the technical field of temperature detection, and discloses a temperature detection circuit and electronic equipment, and the temperature detection circuit comprises a first current amplification module, a second current amplification module, a temperature sensing module and an anti-interference module. The first end of the first current amplification module is connected with a power supply, the second end of the first current amplification module is connected with the first end of the second current amplification module and the first end of the anti-interference module, the second end of the anti-interference module is connected with the power supply, and the third end of the first current amplification module is grounded; the second end of the second current amplification module is connected with the power supply, the third end of the second current amplification module is connected with the first end of the temperature sensing module, and the second end of the temperature sensing module is grounded; the second current amplification module follows and amplifies the output current of the first current amplification module to obtain a target current; and the temperature sensing module performs temperature detection based on the target current. The temperature detection circuit realizes temperature detection with low cost, simple circuit structure and high reliability.

Description

Technical Field

[0001] The present application relates to the field of temperature detection technology, and in particular to a temperature detection circuit and electronic equipment. Background Art

[0002] The detection circuit of a linear temperature sensor is used to measure the output voltage signal of the linear temperature sensor. The most commonly used detection circuit for linear temperature sensors is a bridge circuit, which has a relatively complex circuit structure and is expensive. With the development of technology and the reduction of costs, modern bridge-structured linear temperature sensor detection circuits no longer meet the application requirements of compactness, integration, efficiency, and portability. There is a need for low-cost and highly reliable linear temperature sensor detection circuits to meet the needs of various applications. Utility Model Content

[0003] In view of this, embodiments of the present application provide a temperature detection circuit and an electronic device to solve the problems of complex detection circuit structure and high cost of linear temperature sensors.

[0004] In a first aspect, an embodiment of the present application provides a temperature detection circuit, comprising: a first current amplification module, a second current amplification module, a temperature sensing module, and an anti-interference module;

[0005] A first end of the first current amplifying module is connected to a power supply, a second end of the first current amplifying module is respectively connected to a first end of the second current amplifying module and a first end of the anti-interference module, a second end of the anti-interference module is connected to the power supply, and a third end of the first current amplifying module is grounded;

[0006] The second end of the second current amplifying module is connected to the power supply, the third end of the second current amplifying module is connected to the first end of the temperature sensing module, and the second end of the temperature sensing module is grounded;

[0007] The second current amplifying module is used to follow and amplify the output current of the first current amplifying module to obtain a target current;

[0008] The temperature sensing module is used to perform temperature detection based on the target current.

[0009] In a first possible embodiment of the first aspect, both the first current amplification module and the second current amplification module include a triode;

[0010] The second current amplifying module is further configured to amplify the collector current according to the base current through the transistor to obtain the target current;

[0011] The first current amplifying module is used to perform temperature compensation on the target current through the transistor.

[0012] In a second possible embodiment of the first aspect, the first current amplification module includes a first current limiting resistor, a first transistor, and a second current limiting resistor;

[0013] The first end of the first current limiting resistor is connected to the power supply, the second end of the first current limiting resistor is connected to the emitter of the first transistor, the base of the first transistor is respectively connected to the second end of the anti-interference module and the first end of the second current limiting resistor, the collector of the first transistor is connected to the first end of the second current limiting resistor, and the second end of the second current limiting resistor is grounded.

[0014] In a third possible embodiment of the first aspect, the second current amplification module includes a third current limiting resistor and a second transistor;

[0015] The first end of the third current limiting resistor is connected to the power supply, the second end of the third current limiting resistor is connected to the emitter of the second transistor, the base of the second transistor is connected to the series node of the base and collector of the first transistor and the second current limiting resistor, and the collector of the second transistor is connected to the first end of the temperature sensing module.

[0016] In a fourth possible embodiment of the first aspect, the anti-interference module includes a fourth current limiting resistor;

[0017] A first end of the fourth current limiting resistor is connected to the base and collector of the first transistor and a series node of the base of the second transistor and the second current limiting resistor, and a second end of the fourth current limiting resistor is connected to the power supply.

[0018] In a fifth possible embodiment of the first aspect, the temperature sensing module is a linear temperature sensor;

[0019] A first end of the linear temperature sensor is connected to the collector of the second transistor, and a second end of the linear temperature sensor is grounded.

[0020] In a sixth possible embodiment of the first aspect, the resistance of the fourth current limiting resistor is of a different order of magnitude from the resistances of the first current limiting resistor, the second current limiting resistor, and the third current limiting resistor, and the resistance of the fourth current limiting resistor is respectively greater than the resistances of the first current limiting resistor, the second current limiting resistor, and the third current limiting resistor.

[0021] In a seventh possible embodiment of the first aspect, the target current is calculated as follows:

[0022]

[0023] In formula (1), I is the target current, VCC is the voltage of the power supply, Vbe is the voltage difference between the base and emitter of the first transistor, R1 is the resistance of the first current limiting resistor, R2 is the resistance of the second current limiting resistor, and R3 is the resistance of the third current limiting resistor.

[0024] In an eighth possible embodiment of the first aspect, a calculation formula for the output voltage of the linear temperature sensor is:

[0025] V=IR T (2)

[0026] In formula (2), V is the output voltage of the linear temperature sensor, R T is the resistance of the linear temperature sensor, and I is the target current.

[0027] In a second aspect, an embodiment of the present application provides an electronic device, comprising the temperature detection circuit as described above.

[0028] The embodiments of the present application have the following beneficial effects:

[0029] A temperature detection circuit according to this embodiment includes: a first end of a first current amplification module connected to a power supply; a second end of the first current amplification module connected to the first end of a second current amplification module and the first end of an anti-interference module, the second end of the anti-interference module connected to the power supply, and a third end of the first current amplification module connected to ground; a second end of the second current amplification module connected to the power supply, a third end of the second current amplification module connected to the first end of a temperature sensing module, and a second end of the temperature sensing module connected to ground; the second current amplification module configured to follow and amplify the output current of the first current amplification module to obtain a target current; and a temperature sensing module configured to perform temperature detection based on the target current. This temperature detection circuit achieves low-cost, simple, and highly reliable temperature detection by amplifying the current to obtain the target current, so that the temperature sensing module generates a varying output voltage based on a constant target current. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 A schematic structural diagram of a temperature detection circuit according to an embodiment of the present application is shown;

[0032] Figure 2A circuit diagram of a temperature detection circuit according to an embodiment of the present application is shown.

[0033] Description of main component symbols:

[0034] 100 - temperature detection circuit; 110 - first current amplification module; 120 - second current amplification module; 130 - temperature sensing module; 140 - anti-interference module. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0036] The components of the embodiments of the present application generally described and illustrated in the drawings herein may be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but rather merely represents selected embodiments of the present application. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative effort are within the scope of protection of the present application.

[0037] Hereinafter, the terms "including", "having" and their cognates used in various embodiments of the present application are intended only to indicate specific features, numbers, steps, operations, elements, components or combinations of the aforementioned items, and should not be understood as excluding the existence of one or more other features, numbers, steps, operations, elements, components or combinations of the aforementioned items or adding the possibility of one or more features, numbers, steps, operations, elements, components or combinations of the aforementioned items. In addition, the terms "first", "second", "third" and the like are only used to distinguish descriptions and should not be understood as indicating or implying relative importance.

[0038] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art to which the various embodiments of the present application belong. The terms (such as those defined in generally used dictionaries) will be interpreted as having the same meaning as in the context of the relevant technical field and will not be interpreted as having an idealized meaning or an overly formal meaning unless clearly defined in the various embodiments of the present application.

[0039] The following describes some embodiments of the present application in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0040] In an embodiment of the present application, the temperature detection circuit obtains the resistance value of the linear temperature sensor at any temperature based on a constant target current and the output voltage of the linear temperature sensor, and obtains the current temperature based on a table lookup of the resistance value. It can be applied to temperature detection scenarios such as industrial automation equipment, computer accessories, power supplies, drivers, controllers, and motors to achieve low-cost, high-reliability temperature detection.

[0041] Please refer to Figure 1 , is a schematic diagram of the structure of a temperature detection circuit 100 provided in an embodiment of the present application. Exemplarily, the temperature detection circuit 100 includes a first current amplification module 110, a second current amplification module 120, a temperature sensing module 130, and an anti-interference module 140; wherein the first current amplification module 110 and the second current amplification module 120 are connected in parallel, and the temperature sensing module 130 is connected to the second current amplification module 120 so that the second current amplification module 120 follows the first current amplification module 110 to amplify the current and provide a constant target current to the temperature sensing module 130. The first current amplification module 110 and the temperature sensing module 130 are also connected to an output circuit, which can be connected to a data processing device such as a microcontroller or a single-chip microcomputer to determine the current temperature change based on the changing resistance value of the temperature sensing module 130.

[0042] In this embodiment, the first end of the first current amplification module 110 is connected to the power supply, the second end of the first current amplification module 110 is respectively connected to the first end of the second current amplification module 120 and the first end of the anti-interference module 140, the second end of the anti-interference module 140 is connected to the power supply, and the third end of the first current amplification module 110 is grounded GND; the second end of the second current amplification module 120 is connected to the power supply, the third end of the first current amplification module 110 is connected to the first end of the temperature sensing module 130, and the second end of the temperature sensing module 130 is grounded GND; the second current amplification module 120 is used to follow and amplify the output current of the first current amplification module 110 to obtain a target current; the temperature sensing module 130 is used to perform temperature detection based on the target current; and the anti-interference module 140 is used to prevent interference current from affecting the first current amplification module 110 and the second current amplification module 120.

[0043] In one embodiment, the first current amplification module 110 and the second current amplification module 120 both include transistors; the second current amplification module 120 is also used to amplify the collector current according to the base current through the transistor to obtain the target current; the first current amplification module 110 is used to perform temperature compensation on the target current through the transistor.

[0044] Specifically, the temperature detection circuit 100 uses the anti-interference module 140 to prevent interference current from affecting the output of the common base amplifier circuit, thereby increasing the input impedance of the temperature detection circuit 100 and reducing the load effect between the power supply and the temperature detection circuit 100. The first current amplification module 110, according to the amplification working state of the transistor, flows through the base of a weak current, and a current of β times can flow between the emitter and the collector. Usually, the β of the signal transistor is very large, for example, β can be 100 or 200, so the base current of the transistor can be ignored. The second current amplification module 120 is equivalent to a diode by short-circuiting the base and collector of the transistor. The first current amplification module 110 and the transistor of the first current amplification module 110 have the same temperature characteristics. The second current amplification module 120 can compensate for the ambient temperature through the transistor.

[0045] It is understood that at room temperature, the transistor's on-state voltage is 0.7V. At a temperature of 100°C, the transistor's on-state voltage may drop to 0.5V. Since the transistor in the second current amplification module 120 is in an amplified state, the on-state voltage drop between the transistor's collector and emitter will cause a change in the base current. After current amplification, the actual output change will be even greater, resulting in inaccurate temperature detection. Therefore, by short-circuiting the base and collector of the transistor in the first current amplification module 110 and then connecting them to the base of the transistor in the second current amplification module 120, the output voltage of the transistor in the second current amplification module 120 can be temperature compensated, thereby improving the accuracy of temperature detection.

[0046] In order to better understand the temperature detection circuit 100, the various components of the temperature detection circuit 100 are described in detail below. Figure 2 , is a circuit diagram of the temperature detection circuit 100 provided in an embodiment of the present application.

[0047] In one embodiment, the first current amplification module 110 includes a first current limiting resistor R1, a first transistor Q1, and a second current limiting resistor R2; the first end of the first current limiting resistor R1 is connected to the power supply, the second end of the first current limiting resistor R1 is connected to the emitter of the first transistor Q1, the base of the first transistor Q1 is respectively connected to the second end of the anti-interference module 140 and the first end of the second current limiting resistor R2, the collector of the first transistor Q1 is connected to the first end of the second current limiting resistor R2, and the second end of the second current limiting resistor R2 is grounded GND.

[0048] In one embodiment, the second current amplification module 120 includes a third current limiting resistor R3 and a second transistor Q2; the first end of the third current limiting resistor R3 is connected to the power supply, the second end of the third current limiting resistor R3 is connected to the emitter of the second transistor Q2, the base of the second transistor Q2 is connected to the series node of the base and collector of the first transistor Q1 and the second current limiting resistor R2, and the collector of the second transistor Q2 is connected to the first end of the temperature sensing module 130.

[0049] Exemplarily, during the application of the temperature detection circuit 100, the target current can be calculated based on the resistance values ​​of the first current limiting resistor R1, the second current limiting resistor R2, and the third current limiting resistor R3 in the first current amplification module 110, the power supply voltage, and the voltage between the base and emitter of the first transistor Q1. The target current calculation formula is: Wherein, I is the target current, VCC is the power supply voltage, Vbe is the voltage difference between the base and emitter of the first transistor Q1, R1 is the resistance of the first current limiting resistor R1, R2 is the resistance of the second current limiting resistor R2, and R3 is the resistance of the third current limiting resistor R3.

[0050] Specifically, the second transistor Q2 acts as a current amplifier. When in the amplification state, a small change in the base current of the second transistor Q2 causes a large change in the collector current, thereby amplifying the current signal. The collector current is much larger than the base current, so the base current can be ignored. It can be considered that the current flowing through the second current-limiting resistor R2 is equal to the current flowing through the second transistor Q2. The first transistor Q1 acts as a temperature compensation device for the target current. After the base and collector of the first transistor Q1 are short-circuited, they are connected to the base of the second transistor Q2 to perform temperature compensation on the output current of the second transistor Q2 when the temperature changes.

[0051] Optionally, during circuit design, the first transistor Q1 and the second transistor Q2 may be NPN transistors or PNP transistors. The resistance of the first current-limiting resistor R1 may be equal to the resistance of the third current-limiting resistor R3, and the amplification factor of the first transistor Q1 may be equal to the amplification factor of the second transistor Q2. This ensures that the first current amplification module 110 and the second current amplification module 120 amplify the current to the same degree and obtain the same target current, thereby ensuring the temperature detection accuracy of the temperature detection circuit 100.

[0052] In one embodiment, the anti-interference module 140 includes a fourth current limiting resistor R4; the first end of the fourth current limiting resistor R4 is connected to the base and collector of the first transistor Q1 and the series node of the base of the second diode Q2 and the second current limiting resistor R2, and the second end of the fourth current limiting resistor R4 is connected to the power supply.

[0053] Specifically, the second end of the fourth current-limiting resistor R4 is connected to the base of the first transistor Q1 and the base of the second transistor Q2, respectively. To prevent interference current from affecting the inputs of the first transistor Q1 and the second transistor Q2, the bases of the first transistor Q1 and the second transistor Q2 are connected to the fourth current-limiting resistor R4 to achieve anti-interference. The fourth current-limiting resistor R4 is used to allow a weak current to flow through the bases of the first transistor Q1 and the second transistor Q2, so that the interference current does not directly affect the operating states of the first transistor Q1 and the second transistor Q2, thereby ensuring the stable operation of the first transistor Q1 and the second transistor Q2.

[0054] Optionally, the resistance of the fourth current-limiting resistor R4 is of a different order of magnitude from the resistances of the first current-limiting resistor R1, the second current-limiting resistor R2, and the third current-limiting resistor R3, and the resistance of the fourth current-limiting resistor R4 is greater than the resistances of the first current-limiting resistor R1, the second current-limiting resistor R2, and the third current-limiting resistor R3. It is understood that when the fourth current-limiting resistor R4 meets the anti-interference requirement, the fourth current-limiting resistor R4 has a larger resistance value, and when calculating the target current, the current flowing through the fourth current-limiting resistor R4 can be ignored.

[0055] In one embodiment, the temperature sensing module 130 is a linear temperature sensor RT; a first end of the linear temperature sensor RT is connected to the collector of the second transistor Q2 , and a second end of the linear temperature sensor RT is grounded GND.

[0056] Exemplarily, a linear temperature sensor RT is used to detect temperature by exploiting the effect of temperature on the resistance of different materials and converting this resistance change into a voltage output. The output voltage of the linear temperature sensor RT can be calculated based on a target current and its internal resistance. The output voltage of the linear temperature sensor RT is equal to the product of the target current and the internal resistance. The relationship between the output voltage, internal resistance, and target current of the linear temperature sensor RT can be used to determine the internal resistance of the linear temperature sensor RT as it changes with temperature.

[0057] In one embodiment, the output voltage of the linear temperature sensor RT is calculated as follows: V = IR T Where V is the output voltage of the linear temperature sensor RT, R T is the resistance of the linear temperature sensor RT.

[0058] Specifically, the output voltage of the linear temperature sensor RT varies linearly with temperature, and the internal resistance of the linear temperature sensor RT also varies linearly with temperature. Therefore, the output voltage of the linear temperature sensor RT is proportional to the internal resistance. In temperature circuit applications, the internal resistance of the linear temperature sensor RT can be calculated based on the target current and the output voltage of the linear temperature sensor RT. This internal resistance is equal to the output voltage divided by the target current. By comparing the internal resistance of the linear temperature sensor RT with a temperature resistance change table, the current temperature can be determined.

[0059] As can be understood, the temperature detection circuit 100 utilizes the transistor's amplification state to obtain a target current, causing a constant target current to flow through the linear temperature sensor RT. The linear temperature sensor RT then generates a variable output voltage based on temperature variations. The temperature detection circuit 100 utilizes the target current and output voltage to determine the internal resistance of the linear temperature sensor RT, and determines the current temperature based on a table showing the internal resistance of the linear temperature sensor RT and its temperature-dependent resistance. The temperature detection circuit 100 has a simple circuit structure, significantly reducing application costs while achieving highly reliable temperature detection.

[0060] The present application also provides an electronic device for accurately measuring various temperatures, including the temperature of industrial automation equipment, computer components, power supply temperature, driver temperature, controller temperature, and motor temperature. Exemplarily, the electronic device includes the temperature detection circuit 100 of the above-described embodiment. It should be understood that the temperature detection circuit 100 of this embodiment can exist independently in the form of a packaged circuit module, or can be part of the above-described electronic device, i.e., disposed within the electronic device, without limitation herein.

[0061] The above is only a specific implementation method of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with this technical field can easily think of changes or replacements within the technical scope disclosed in this application, which should be covered by the protection scope of the present application.

Claims

1. A temperature detection circuit, characterized in that: include: A first current amplification module, a second current amplification module, a temperature sensing module and an anti-interference module; A first end of the first current amplifying module is connected to a power supply, a second end of the first current amplifying module is respectively connected to a first end of the second current amplifying module and a first end of the anti-interference module, a second end of the anti-interference module is connected to the power supply, and a third end of the first current amplifying module is grounded; The second end of the second current amplifying module is connected to the power supply, the third end of the second current amplifying module is connected to the first end of the temperature sensing module, and the second end of the temperature sensing module is grounded; The second current amplifying module is used to follow and amplify the output current of the first current amplifying module to obtain a target current; The temperature sensing module is used to perform temperature detection based on the target current.

2. The temperature detection circuit according to claim 1, wherein: The first current amplifying module and the second current amplifying module both include triodes; The second current amplifying module is further configured to amplify the collector current according to the base current through the transistor to obtain the target current; The first current amplifying module is used to perform temperature compensation on the target current through the transistor.

3. The temperature detection circuit according to claim 1, wherein: The first current amplification module includes a first current limiting resistor, a first transistor and a second current limiting resistor; The first end of the first current limiting resistor is connected to the power supply, the second end of the first current limiting resistor is connected to the emitter of the first transistor, the base of the first transistor is respectively connected to the second end of the anti-interference module and the first end of the second current limiting resistor, the collector of the first transistor is connected to the first end of the second current limiting resistor, and the second end of the second current limiting resistor is grounded.

4. The temperature detection circuit according to claim 3, wherein: The second current amplification module includes a third current limiting resistor and a second transistor; The first end of the third current limiting resistor is connected to the power supply, the second end of the third current limiting resistor is connected to the emitter of the second transistor, the base of the second transistor is connected to the series node of the base and collector of the first transistor and the second current limiting resistor, and the collector of the second transistor is connected to the first end of the temperature sensing module.

5. The temperature detection circuit according to claim 4, characterized in that: The anti-interference module includes a fourth current limiting resistor; A first end of the fourth current limiting resistor is connected to the base and collector of the first transistor and a series node of the base of the second transistor and the second current limiting resistor, and a second end of the fourth current limiting resistor is connected to the power supply.

6. The temperature detection circuit according to claim 4, characterized in that: The temperature sensing module is a linear temperature sensor; A first end of the linear temperature sensor is connected to the collector of the second transistor, and a second end of the linear temperature sensor is grounded.

7. The temperature detection circuit according to claim 5, characterized in that: The resistance of the fourth current limiting resistor is of a different order of magnitude from the resistances of the first current limiting resistor, the second current limiting resistor and the third current limiting resistor, and the resistance of the fourth current limiting resistor is respectively greater than the resistances of the first current limiting resistor, the second current limiting resistor and the third current limiting resistor.

8. The temperature detection circuit according to claim 4, wherein: The target current is calculated as follows: In formula (1), I is the target current, VCC is the voltage of the power supply, Vbe is the voltage difference between the base and emitter of the first transistor, R1 is the resistance of the first current limiting resistor, R2 is the resistance of the second current limiting resistor, and R3 is the resistance of the third current limiting resistor.

9. The temperature detection circuit according to claim 6, wherein: The calculation formula of the output voltage of the linear temperature sensor is: V=IR T (2) In formula (2), V is the output voltage of the linear temperature sensor, R T is the resistance of the linear temperature sensor, and I is the target current.

10. An electronic device, characterized in that: The temperature detection circuit comprises the temperature detection circuit according to any one of claims 1 to 9.

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