Temperature sensing circuit, temperature sensor, and electronic device

Abstract

This application provides a temperature sensing circuit, a temperature sensor, and an electronic device, including: a bandgap reference module, a current processing module, and a conversion output module; the bandgap reference module outputs a positive temperature coefficient current and a reference voltage; the current processing module is connected to the bandgap reference module and outputs a reference current based on the reference voltage and a first impedance element in the current processing module; the conversion output module is connected to the bandgap reference module and the current processing module and outputs a temperature-related output voltage based on the difference between the positive temperature coefficient current and the reference current, and a second impedance element in the conversion output module. By adjusting the resistance values ​​of the first and second impedance elements, decoupling and independent optimization of the intercept and slope of the temperature-voltage conversion characteristic are achieved, enabling the temperature sensing circuit to output a voltage signal with a wider dynamic range over a wide temperature range, significantly improving the accuracy of the temperature sensor.

Description

Technical Field

[0001] This application relates to the field of temperature sensing, and more particularly to a temperature sensing circuit, a temperature sensor, and an electronic device. Background Technology

[0002] Temperature sensors, as key devices for measuring temperature, play an important role in home appliances, consumer electronics, and other fields. The front-end temperature sensing circuit of a temperature sensor is its core component, which converts the ambient temperature into an analog quantity.

[0003] Traditional temperature sensing circuits struggle to balance signal amplitude across a wide temperature measurement range, affecting the accuracy of temperature sensors. Summary of the Invention

[0004] This application provides a temperature sensing circuit, a temperature sensor, and an electronic device to improve the accuracy of the temperature sensor.

[0005] In a first aspect, embodiments of this application provide a temperature sensing circuit, including:

[0006] The bandgap reference module is used to output positive temperature coefficient current and reference voltage.

[0007] A current processing module, connected to the bandgap reference module, is used to output a reference current based on the reference voltage and the first impedance element in the current processing module;

[0008] The conversion output module is connected to the bandgap reference module and the current processing module, and is used to output a temperature-related output voltage based on the difference between the positive temperature coefficient current and the reference current, and the second impedance element in the conversion output module.

[0009] The intercept of the temperature characteristic curve of the output voltage is adjusted by the resistance value of the first impedance element, and the slope of the temperature characteristic curve is adjusted by the resistance value of the second impedance element.

[0010] Optionally, the current processing module includes:

[0011] A voltage-to-current conversion unit, whose input terminal is connected to the first output terminal of the bandgap reference module, receives the reference voltage. The voltage-to-current conversion unit is used to generate a reference current based on the reference voltage and the resistance value of the first impedance element.

[0012] The mirror unit has its input and output terminals connected to the output terminal of the voltage-current conversion unit and the input terminal of the conversion output module, respectively, and is used to mirror the reference current to the conversion output module.

[0013] Optionally, the voltage-to-current conversion unit includes:

[0014] An operational amplifier, the non-inverting input of which receives the reference voltage;

[0015] An adjustable current source has its control terminal connected to the output terminal of the operational amplifier, its first terminal connected to the inverting input terminal of the operational amplifier, and its second terminal connected to the input terminal of the mirror unit.

[0016] The first impedance element has its first end connected to the first end of the adjustable current source, and its second end receiving the ground voltage.

[0017] Optionally, the adjustable current source includes:

[0018] The first transistor has its gate as the control terminal of the adjustable current source, its source as the first terminal of the adjustable current source, and its drain as the second terminal of the adjustable current source.

[0019] And / or,

[0020] The mirror unit includes:

[0021] The first current mirror receives the power supply voltage at its first end and serves as the input terminal of the mirror unit at its second end.

[0022] The second current mirror has its first end connected to the third end of the first current mirror, its second end receiving the ground voltage, and its third end connected to the input end of the conversion output module.

[0023] Optionally, the first current mirror includes:

[0024] The second transistor has its source serving as the first terminal of the first current mirror, and its gate and drain connected together to serve as the second terminal of the first current mirror.

[0025] The third transistor has its source connected to the source of the second transistor, its gate connected to the gate of the second transistor, and its drain serving as the third terminal of the first current mirror.

[0026] And / or, the second current mirror includes:

[0027] The fourth transistor has its gate and drain connected and serves as the first terminal of the second current mirror, while its source receives the ground voltage.

[0028] The fifth transistor has its gate connected to the gate of the fourth transistor, its source receives the power supply voltage, and its drain serves as the third terminal of the second current mirror.

[0029] Optionally, the conversion output module includes:

[0030] The sixth transistor has its gate serving as the control terminal of the conversion output module, receiving a bias voltage; its source receiving the power supply voltage; and its drain serving as the input terminal of the conversion output module.

[0031] The second impedance element has its first end connected to the drain of the sixth transistor and serves as the output terminal of the conversion output module, while its second end receives the ground voltage.

[0032] Optionally, the bandgap reference module includes:

[0033] The third current mirror has a first end that receives the power supply voltage and a third end that serves as the first output terminal of the bandgap reference module.

[0034] An error amplifier has its non-inverting input terminal connected to the second terminal of the third current mirror, its inverting input terminal connected to the third terminal of the third current mirror, and its output terminal connected to the fourth terminal of the third current mirror and serving as the second output terminal of the bandgap reference module.

[0035] The first transistor has its emitter connected to the non-inverting input of the error amplifier, and its collector and base connected to receive the ground voltage.

[0036] The second transistor has its emitter connected to the inverting input of the error amplifier, and its base and collector connected to the base of the first transistor.

[0037] The third impedance element is connected between the non-inverting input of the error amplifier and the second end of the third current mirror;

[0038] The fourth impedance element is connected between the inverting input terminal of the error amplifier and the third terminal of the third current mirror.

[0039] The fifth impedance element is connected between the non-inverting input of the error amplifier and the emitter of the first transistor.

[0040] Optionally, the third current mirror includes:

[0041] The seventh transistor has its source as the first terminal of the third current mirror, its gate as the fourth terminal of the third current mirror, and its drain as the second terminal of the third current mirror.

[0042] The eighth transistor has its source connected to the source of the seventh transistor, its gate connected to the gate of the seventh transistor, and its drain serving as the third terminal of the third current mirror.

[0043] Secondly, this application provides a temperature sensor, including the temperature sensing circuit described in the first aspect.

[0044] Thirdly, this application provides an electronic device including the temperature sensor described in the second aspect.

[0045] The temperature sensing circuit, temperature sensor, and electronic device provided in this application include: a bandgap reference module, a current processing module, and a conversion output module. The bandgap reference module outputs a positive temperature coefficient current and a reference voltage. The current processing module is connected to the bandgap reference module and outputs a reference current based on the reference voltage and a first impedance element in the current processing module. The conversion output module is connected to the bandgap reference module and the current processing module and outputs a temperature-related output voltage based on the difference between the positive temperature coefficient current and the reference current, and a second impedance element in the conversion output module. By increasing the resistance of the second impedance element, the slope of the curve can be significantly improved, thereby obtaining a larger voltage change rate under the same temperature change, allowing the temperature information to more fully occupy the quantization range of the analog-to-digital converter and improving resolution. Simultaneously, by adjusting the resistance of the first impedance element, the intercept of the curve can be independently adjusted, thereby shifting the entire output curve to the optimal position at 20% of the analog-to-digital converter input, avoiding premature saturation or exceeding the range at the low-temperature end. Based on this, the temperature sensing circuit proposed in this application achieves decoupling and independent optimization of the slope and intercept of the temperature-voltage conversion characteristic, resolving the contradiction of mutual constraint between the two in traditional circuits. This enables the temperature sensing circuit to output a voltage signal with a wider dynamic range over a wide temperature range, significantly improving the quantization efficiency of the ADC and the accuracy of the temperature sensor. Attached Figure Description

[0046] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0047] Figure 1 This is a schematic diagram of a temperature sensing circuit.

[0048] Figure 2 This is a schematic diagram of the temperature sensing circuit provided in this application;

[0049] Figure 3 A schematic diagram of the voltage-temperature curve provided in this application.

[0050] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0051] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0052] Temperature sensors, as key devices for measuring temperature, play an important role in home appliances, consumer electronics, and other fields. The front-end temperature sensing circuit of a temperature sensor is the core component. The temperature sensing circuit can convert the ambient temperature into an analog quantity. Typically, a positive temperature coefficient voltage in a bandgap reference is used as the analog signal carrying temperature information, which is then quantized into a digital signal by an analog-to-digital converter (ADC).

[0053] like Figure 1 As shown, a bipolar junction transistor (BJT) with different emitter areas is used to generate a voltage V that is related to thermal voltage. T proportional voltage difference ∆V BE Then, it is amplified through a resistor network, and finally outputs a positive temperature coefficient (PTAT) voltage V. PTAT ,Right now The voltage signal V PTAT As an analog quantity carrying temperature information, it can be directly sampled by an analog-to-digital converter and quantized into a digital signal for microprocessor to read and process.

[0054] However, this traditional approach has a significant limitation. For example... Figure 3 As shown in curve a, V PTAT The output voltage amplitude variation range is narrow within the target measurement temperature range. Although increasing the ratio of resistors R4 to R3 can improve the slope of the temperature-voltage conversion curve, thereby increasing the signal amplitude, this also causes the entire curve to shift upwards, thus increasing the output voltage intercept. The result is as follows... Figure 3 As shown in curve b, at the lowest point of the measured temperature range, the output voltage is already at a relatively high level, resulting in a smaller output signal amplitude within the measured temperature range, which affects the accuracy of the temperature sensor.

[0055] To address this, this application proposes a temperature sensing circuit, including a current processing module and a conversion output module. The current processing module includes a first impedance element, and the conversion output module includes a second impedance element. By increasing the resistance value of the second impedance element, the slope of the curve can be significantly improved, thereby obtaining a larger voltage change rate under the same temperature change. This allows the temperature information to more fully occupy the quantization range of the analog-to-digital converter, improving resolution. Simultaneously, by adjusting the resistance value of the first impedance element, the curve intercept can be independently adjusted, thereby shifting the entire output curve to the optimal position at 20% of the analog-to-digital converter input, avoiding premature saturation or exceeding the measurement range at the low-temperature end.

[0056] Based on this, the temperature sensing circuit proposed in this application achieves decoupling and independent optimization of the slope and intercept of the temperature-voltage conversion characteristic, resolving the contradiction between the two in traditional circuits. This enables the temperature sensing circuit to output a voltage signal with a wider dynamic range over a wide temperature range, significantly improving the quantization efficiency of the ADC and the accuracy of the temperature sensor.

[0057] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0058] Figure 2 A schematic diagram of the temperature sensing circuit provided in this application is shown below. Figure 2 As shown, the temperature sensing circuit provided in this embodiment includes:

[0059] Bandgap reference module 101 is used to output positive temperature coefficient current I. PTAT and reference voltage V REF ;

[0060] The current processing module 102 is connected to the bandgap reference module 101 and is used to process the current based on the reference voltage V. REF The first impedance element R5 in the current processing module 102 outputs a reference current I. REF ;

[0061] The conversion output module 103, connected to the bandgap reference module 101 and the current processing module 102, is used to convert the current I based on the positive temperature coefficient. PTAT With reference current I REF The difference between the two, and the second impedance element R4 in the conversion output module 103, output a temperature-dependent output voltage V. Tem ;

[0062] Among them, the output voltage V TemThe intercept of the temperature characteristic curve is adjusted by the resistance value of the first impedance element R5, and the output voltage V Tem The slope of the temperature characteristic curve is adjusted by the resistance value of the second impedance element R4.

[0063] In this embodiment of the application, the temperature sensing circuit includes a bandgap reference module 101, a current processing module 102, and a conversion output module 103. The current processing module 102 includes a first impedance element R5, and the conversion output module 103 includes a second impedance element R4.

[0064] The current processing module 102 is connected to the bandgap reference module 101 and receives the reference voltage V generated by the bandgap reference module 101. REF According to the reference voltage V REF The reference current I is generated by the resistance of the first impedance element R5. REF The conversion output module 103 is connected to the bandgap reference module 101 and the current processing module 102, and receives the positive temperature coefficient current I. PTAT and reference current I REF And based on the positive temperature coefficient current I PTAT With reference current I REF The difference between the two, and the resistance of the second impedance element R4, generate a temperature-dependent output voltage V. Tem .

[0065] The intercept of the temperature characteristic curve of the output voltage is adjusted by the resistance value of the first impedance element, and the slope of the temperature characteristic curve is adjusted by the resistance value of the second impedance element. Increasing the resistance of the second impedance element significantly improves the curve slope, resulting in a larger voltage change rate under the same temperature variation. This allows temperature information to more fully occupy the quantization range of the analog-to-digital converter, improving resolution. Simultaneously, adjusting the resistance of the first impedance element independently adjusts the curve intercept, shifting the entire output curve to the optimal position at 20% of the analog-to-digital converter input, preventing premature saturation or exceeding the range at low temperatures. Based on this, decoupling and independent optimization of the slope and intercept of the temperature-voltage conversion characteristic are achieved, such as... Figure 3 As shown by curve c, this allows the temperature sensing circuit to output a voltage signal with a wider dynamic range over a wide temperature range, significantly improving the quantization efficiency of the ADC and the accuracy of the temperature sensor.

[0066] For example, the bandgap reference module 101 includes a first terminal, a second terminal, a first output terminal, and a second output terminal. The first terminal of the bandgap reference module 101 receives a power supply voltage VDD, the second terminal of the bandgap reference module 101 receives a ground voltage VSS, and the first output terminal of the bandgap reference module 101 is used to output a reference voltage V. REF The second terminal of the bandgap reference module 101 is used to output the bias voltage V. B1 .

[0067] The current processing module 102 includes a first terminal, a second terminal, an input terminal, and an output terminal. The first terminal of the current processing module 102 receives the power supply voltage VDD, and the second terminal of the current processing module 102 receives the ground voltage VSS. The input terminal of the current processing module 102 is connected to the output terminal of the bandgap reference module 101, and the output terminal of the current processing module 102 outputs the reference current I. REF .

[0068] The conversion output module 103 includes a first terminal, a second terminal, a control terminal, an input terminal, and an output terminal. The first terminal of the conversion output module 103 receives the power supply voltage VDD, and the second terminal of the conversion output module 103 receives the ground voltage VSS. The input terminal of the conversion output module 103 is connected to the output terminal of the current processing module 102 and receives the reference current I. REF The control terminal of the conversion output module 103 is connected to the second output terminal of the bandgap reference module 101 to receive the bias voltage V. B1 The output terminal of the conversion output module 103 is used to output a temperature-related output voltage V. Tem .

[0069] Optionally, the current processing module 102 includes a voltage-to-current conversion unit 1021 and a mirror unit 1022. The voltage-to-current conversion unit 1021 includes an input terminal and an output terminal, and the mirror unit 1022 includes an input terminal and an output terminal.

[0070] The input terminal of the current conversion unit 1021 serves as the input terminal of the current processing module 102, and is connected to the first output terminal of the bandgap reference module 101 to receive the reference voltage V. REF The current conversion unit 1021 is used to convert the reference voltage V. REF The reference current I is generated by the resistance of the first impedance element R5. REF .

[0071] The input terminal of the mirror unit 1022 is connected to the output terminal of the voltage-to-current conversion unit 1011, and the output terminal of the mirror unit 1022 serves as the output terminal of the current processing module 102, connected to the input terminal of the conversion output module 103; the mirror unit 1022 is used to convert the reference current I... REF Mirror to conversion output module 103.

[0072] Voltage-to-current conversion unit 1021 receives reference voltage V provided by bandgap reference module 101. REF And based on its internal first impedance element R5, it generates a precise, temperature-independent reference current I. REF The mirror unit 1022 is connected between the voltage-to-current conversion unit 1021 and the conversion output module 103, and is used to convert the reference current I... REFThe high-precision copy is injected into the input terminal of the conversion output module 103.

[0073] In this architecture, the voltage-to-current conversion unit 1011 (typically including an operational amplifier) ​​ensures the reference current I through a negative feedback mechanism. REF Based solely on the reference voltage V REF The slope and intercept are determined by the resistance value of the first impedance element R5 and are independent of the subsequent circuit state. Simultaneously, the high output impedance of the mirror unit 1022 makes its output mirror current extremely insensitive to changes in the output voltage of the conversion output module 103. These two factors work together to avoid mutual interference during the adjustment process, which is key to achieving independent adjustment of the slope and intercept.

[0074] For example, the mirror unit 1022 also includes a first terminal and a second terminal. The first terminal of the mirror unit 1022 serves as the first terminal of the current processing module 102 and receives the power supply voltage VDD. The second terminal of the mirror unit 1-22 serves as the second terminal of the current processing module 102 and receives the ground voltage VSS.

[0075] In some embodiments, the voltage-to-current conversion unit 1021 includes an operational amplifier OPA, an adjustable current source, and the aforementioned first impedance element R5. The non-inverting input of the operational amplifier OPA serves as the input of the voltage-to-current conversion unit 1021, receiving a reference voltage V. REF The control terminal of the adjustable current source is connected to the output terminal of the operational amplifier OPA. The first terminal of the adjustable current source is connected to the inverting input terminal of the operational amplifier OPA. The second terminal of the adjustable current source serves as the output terminal of the voltage-to-current conversion unit 1021 and is connected to the input terminal of the mirror unit 1022. The first terminal of the first impedance element R5 is connected to the first terminal of the adjustable current source, and the second terminal of the first impedance element R5 receives the ground voltage VSS.

[0076] The operational amplifier (OPA) automatically adjusts its output voltage by comparing its non-inverting input voltage V+ and its inverting input voltage V-, driving an adjustable current source and causing a change in the current flowing through the adjustable current source and the first impedance element R5. The goal of negative feedback is to make the voltages at the two input terminals of the op-amp equal, i.e., V- = V+ = V-. REF Since V- is the voltage across the first terminal of the first impedance element R5, and the second terminal of the first impedance element R5 is grounded, the current I flowing through the first impedance element R5 is... R5 =V- / R5=V REF / R5. Therefore, the current I output from the second terminal of the adjustable current source REF ≈I R5 =V REF / R5.

[0077] The negative feedback of the operational amplifier (OPA) multiplies the output impedance of the adjustable current source. Any disturbances that change the voltage at the second terminal of the adjustable current source will be detected and compensated by the op-amp through the feedback loop, thereby strongly maintaining a constant reference current.

[0078] In other examples, the current processing module 102 may employ other existing circuits capable of voltage-to-current conversion. The voltage-to-current conversion unit 1021 may employ other existing circuits capable of voltage-to-current conversion.

[0079] For example, the first impedance element R5 and the second impedance element R4 are resistors, but other existing impedance elements may also be used.

[0080] In some examples, the adjustable current source includes a first transistor M6, the gate of the first transistor M6 serving as the control terminal of the adjustable current source, the source of the first transistor M6 serving as the first terminal of the adjustable current source, and the drain of the first transistor M6 serving as the second terminal of the adjustable current source.

[0081] The gate of the first transistor M6 is controlled by the operational amplifier output, the source of the first transistor M6 is grounded through the first impedance element R5, and the drain of the first transistor M6 outputs a reference current I. REF This constitutes a source-degenerated common-source amplifier, improving the accuracy of voltage-to-current conversion.

[0082] In other examples, the adjustable current source can also be any other existing current source.

[0083] For example, the first transistor M6 is an N-type transistor.

[0084] In some embodiments, the mirror unit 1022 includes a first current mirror and a second current mirror. The first end of the first current mirror serves as the first end of the mirror unit 1022, receiving the power supply voltage VDD. The second end of the first current mirror serves as the input end of the mirror unit 1022, receiving the reference current I. REF The first end of the second current mirror is connected to the third end of the first current mirror. The second end of the second current mirror receives the ground voltage VSS. The third end of the second current mirror serves as the output end of the mirror unit 1022 and is connected to the input end of the conversion output module 103.

[0085] The mirror unit 1022 employs a two-stage current mirror series structure, forming a complete current path from power supply to ground. This structure converts the input reference current I... REF The image is "flipped" with high precision and transmitted to the conversion output module 103 via the first mirror image of the first current mirror (PMOS current mirror) and the second mirror image of the second current mirror (NMOS current mirror).

[0086] This common-source, common-gate connection makes the output terminal of the mirror unit (i.e., the third terminal of the second current mirror) present an extremely high output impedance, ensuring that the output mirror current value is almost unaffected by the voltage fluctuations at the output terminal of the conversion output module 103, thereby providing a stable and accurate current source for the subsequent current subtraction operation.

[0087] In some examples, the first current mirror includes a second transistor M3 and a third transistor M4; the source of the second transistor M3 serves as the first terminal of the first current mirror, and the gate and drain of the second transistor M3 are connected and serve as the second terminal of the first current mirror; the source of the third transistor M4 is connected to the source of the second transistor M3, the gate of the third transistor M4 is connected to the gate of the second transistor M3, and the drain of the third transistor M4 serves as the third terminal of the first current mirror.

[0088] The gate and drain of the second transistor M3 are shorted, serving as the input reference branch of the first current mirror. The gate of the third transistor M4 is connected to the gate of the second transistor M3, serving as the output branch of the first current mirror. The sources of both transistors are connected to the same power supply. When the reference current I... REF When current flows into the drain of the second transistor M3, a corresponding voltage Vgs is generated at the gate-source of the second transistor M3. This Vgs is also applied to the third transistor M4. Since the source voltages of the second transistor M3 and the third transistor M4 are the same, under the condition that the resistance values ​​of the two devices are matched, the drain of the third transistor M4 will generate a voltage equal to the reference current I. REF A mirror current is formed in a certain ratio (e.g., 1:1) and output from the third terminal of the first current mirror.

[0089] For example, the second transistor M3 and the third transistor M4 are P-type transistors.

[0090] In some examples, the second current mirror includes a fourth transistor M7 and a fifth transistor M8. The gate and drain of the fourth transistor M7 are connected and serve as the first terminal of the second current mirror. The source of the fourth transistor M7 receives the ground voltage VSS. The gate of the fifth transistor M8 is connected to the gate of the fourth transistor M7. The source of the fifth transistor M8 receives the power supply voltage. The drain of the fifth transistor M8 serves as the third terminal of the second current mirror.

[0091] The gate and drain of the fourth transistor M7 are shorted to serve as the input reference branch of the second current mirror. The gate of the fifth transistor M8 is connected to the gate of the fourth transistor M7 to serve as the output branch of the second current mirror. The sources of both transistors are connected to the ground voltage.

[0092] The current from the first current mirror flows into the drain of the fourth transistor M7, generating a voltage Vgs at the gate-source of M7. This Vgs is also applied to the fifth transistor M8. Since the source voltages of the fourth transistor M7 and the fifth transistor M8 are the same (both are grounded), and given the matched resistance values ​​of the two devices, the drain of the fifth transistor M8 will generate a mirror current proportional to the input current, thereby reflecting the reference current I. REF Mirror to conversion output module 103.

[0093] For example, the fourth transistor M7 and the fifth transistor M8 are N-type transistors.

[0094] In other examples, the mirror unit 1022 may also employ existing devices or circuits with mirroring capabilities.

[0095] In some embodiments, the conversion output module 103 includes a sixth transistor M5 and the aforementioned second impedance element R4; the gate of the sixth transistor M5 serves as the control terminal of the conversion output module 103, is connected to the second output terminal of the bandgap reference module 101, and receives the bias voltage V. B1 The drain of the sixth transistor M5 serves as the input terminal of the conversion output module 103; the first terminal of the second impedance element R4 is connected to the drain of the sixth transistor M5 and serves as the output terminal of the conversion output module 103, and the second terminal of the second impedance element R4 receives the ground voltage VSS.

[0096] The bias voltage V output by the bandgap reference module 101 B1 Used to control the sixth transistor M5, so that the sixth transistor M5 accurately replicates the positive temperature coefficient current I. PTAT The reference current I of the mirror cell 1022. REF and the positive temperature coefficient current I output by the bandgap reference module 101 PTAT The current converges at the drain node of the sixth transistor M5 (i.e., the output terminal of the conversion output module 103), then the net current Inet at the output terminal of the conversion output module 103 is Inet = Inet. PTAT -I REF Because the sixth transistor M5 is biased at voltage V... B1 Under the influence of the current, the device operates in the saturation region, and its current remains essentially constant. Therefore, the change in net current Inet will be almost entirely reflected in the change in current flowing through the second impedance element R4, resulting in a varying voltage drop across the second impedance element R4, i.e., V. Tem =I R4 ×R4≈Inet×R4=(I PTAT -I REF )×R4.

[0097] In other examples, the conversion output module 103 may also employ existing devices or circuits with current-to-voltage conversion capabilities.

[0098] In some embodiments, the bandgap reference module 101 includes a third current mirror, an error amplifier EA, a first transistor Q1, a second transistor Q2, a third impedance element R1, a fourth impedance element R2, and a fifth impedance element R3; the first terminal of the third current mirror receives the power supply voltage VDD, and the third terminal of the third current mirror serves as the first output terminal of the bandgap reference module 101; the non-inverting input terminal of the error amplifier EA is connected to the second terminal of the third current mirror, the inverting input terminal of the error amplifier EA is connected to the third terminal of the third current mirror, and the output terminal of the error amplifier EA is connected to the fourth terminal of the third current mirror and serves as the second output terminal of the bandgap reference module 101; the emitter of the first transistor Q1 is connected to the inverting input terminal of the error amplifier EA, and the collector and base of the first transistor Q1 are connected and receive the ground voltage VSS; the emitter of the second transistor Q2 is connected to the inverting input terminal of the error amplifier EA, and the base and collector of the second transistor Q2 are connected and connected to the base of the first transistor Q1. The third impedance element R1 is connected between the non-inverting input of the error amplifier EA and the second terminal of the third current mirror; the fourth impedance element R2 is connected between the inverting input of the error amplifier EA and the third terminal of the third current mirror; the fifth impedance element R3 is connected between the non-inverting input of the error amplifier EA and the emitter of the first transistor Q1.

[0099] The first transistor Q1 and the second transistor Q2 are typically PNP transistors, and their emitter junction areas are proportional (for example, the emitter area of ​​the first transistor Q1 is n times the emitter junction area of ​​the second transistor Q2). Their bases are connected together and grounded, forming a diode connection.

[0100] The third current mirror is a PMOS current mirror, whose second and third terminals drive the emitters of the first transistor Q1 and the second transistor Q2, respectively. The output of the error amplifier EA controls the gate of this current mirror (the fourth terminal of the third current mirror).

[0101] To prevent the channel length modulation effect of the seventh transistor M1 and the eighth transistor M2, the third impedance element R1 and the fourth impedance element R2 must be the same; due to the effect of the error amplifier EA, the voltage at point X is equal to the voltage at point Y, and the voltage at point Y is V. BE2 Therefore, the voltage drop across the fifth impedance element R3 is ΔV. BE Therefore, the currents in the two branches are I1 = I2 = ΔV BE / R3=(kT / q)×ln(n) / R3,V REF =V BE2 +ΔV BE ×R2 / R3.

[0102] As can be seen from the above formula, the current I1 flowing through the first transistor Q1 and the current I2 flowing through the second transistor Q2 are proportional to the absolute temperature T.

[0103] Reference voltage V REF This can be generated in the branch of the second transistor Q2. It is the emitter voltage of the second transistor Q2 plus the voltage drop across the fifth impedance element R2. That is:

[0104] V REF =V BE2 +I²×R²;

[0105] Substituting I2=(kT / q)×ln(n) / R2, we get:

[0106] V REF =V BE2 +(R2 / R3)×(kT / q)×ln(n);

[0107] By selecting the resistance ratio R3 / R2, the positive temperature coefficient term (R2 / R3)×(kT / q)×ln(n) in the above formula can be precisely canceled out by V. BE2 The negative temperature coefficient allows for the theoretical acquisition of a reference voltage with a zero temperature coefficient at a specific temperature.

[0108] In some examples, the third current mirror includes a seventh transistor M1 and an eighth transistor M2. The source of the seventh transistor M1 serves as the first terminal of the third current mirror, the gate of the seventh transistor M1 serves as the fourth terminal of the third current mirror, and the drain of the seventh transistor M1 serves as the second terminal of the third current mirror. The source of the eighth transistor M2 is connected to the source of the seventh transistor M1, the gate of the eighth transistor M2 is connected to the gate of the seventh transistor M1, and the drain of the eighth transistor M2 serves as the third terminal of the third current mirror.

[0109] In other examples, the third current mirror can also be an existing device or circuit with mirroring capabilities.

[0110] For example, the third impedance element R1, the fourth impedance element R2, and the fifth impedance element R3 can also be other existing impedance elements.

[0111] The temperature sensing circuit provided in this application has been described in detail above. The temperature sensing circuit proposed in this application achieves decoupling and independent optimization of the slope and intercept of the temperature-voltage conversion characteristic, enabling the temperature sensing circuit to output a voltage signal with a larger dynamic range over a wide temperature range. This significantly improves the quantization efficiency of the ADC and the overall measurement accuracy of the temperature sensor, while also enhancing its adaptability to different application scenarios and ADC specifications.

[0112] This application also provides a temperature sensor, including the temperature sensing circuit described above.

[0113] This application also provides an electronic device, including the temperature sensor described above.

[0114] For example, electronic devices may include home appliances, consumer electronics, medical devices, and automotive electronics.

[0115] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A temperature sensing circuit, characterized in that, include: The bandgap reference module (101) is used to output positive temperature coefficient current and reference voltage; A current processing module (102) is connected to the bandgap reference module (101) and is used to output a reference current based on the reference voltage and the first impedance element (R5) in the current processing module (102). The conversion output module (103) is connected to the bandgap reference module (101) and the current processing module (102) and is used to output a temperature-related output voltage based on the difference between the positive temperature coefficient current and the reference current, and the second impedance element (R4) in the conversion output module (103). The intercept of the temperature characteristic curve of the output voltage is adjusted by the resistance value of the first impedance element (R5), and the slope of the temperature characteristic curve is adjusted by the resistance value of the second impedance element (R4).

2. The circuit according to claim 1, characterized in that, The current processing module (102) includes: A voltage-to-current conversion unit (1021) has its input terminal connected to the first output terminal of the bandgap reference module (101) and receives the reference voltage. The voltage-to-current conversion unit (1021) is used to generate a reference current based on the reference voltage and the resistance value of the first impedance element (R1). The mirror unit (1022) has its input and output terminals connected to the output terminal of the voltage-current conversion unit (1021) and the input terminal of the conversion output module (103), respectively, and is used to mirror the reference current to the conversion output module (103).

3. The circuit according to claim 2, characterized in that, The voltage-to-current conversion unit (1021) includes: An operational amplifier (OPA) whose non-inverting input receives the reference voltage; An adjustable current source has its control terminal connected to the output terminal of the operational amplifier (OPA), its first terminal connected to the inverting input terminal of the operational amplifier (OPA), and its second terminal connected to the input terminal of the mirror unit (1022). The first impedance element (R5) has its first end connected to the first end of the adjustable current source, and its second end receiving the ground voltage.

4. The circuit according to claim 3, characterized in that, The adjustable current source includes: The first transistor (M6) has its gate as the control terminal of the adjustable current source, its source as the first terminal of the adjustable current source, and its drain as the second terminal of the adjustable current source. The mirror unit (1022) includes: The first current mirror receives the power supply voltage at its first end and serves as the input terminal of the mirror unit (1022) at its second end. The second current mirror has its first end connected to the third end of the first current mirror, its second end receiving the ground voltage, and its third end connected to the input end of the conversion output module (103).

5. The circuit according to claim 4, characterized in that, The first current mirror includes: The second transistor (M3) has its source as the first terminal of the first current mirror, and its gate and drain are connected and serve as the second terminal of the first current mirror. The third transistor (M4) has its source connected to the source of the second transistor (M3), its gate connected to the gate of the second transistor (M3), and its drain serving as the third terminal of the first current mirror. And / or, the second current mirror includes: The fourth transistor (M7) has its gate and drain connected and serves as the first terminal of the second current mirror, while its source receives the ground voltage. The fifth transistor (M8) has its gate connected to the gate of the fourth transistor (M7), its source receives the power supply voltage, and its drain serves as the third terminal of the second current mirror.

6. The circuit according to claim 1, characterized in that, The conversion output module (103) includes: The sixth transistor (M5) has its gate as the control terminal of the conversion output module (103) and receives the bias voltage, its source as the power supply voltage, and its drain as the input terminal of the conversion output module (103). The second impedance element (R4) has its first end connected to the drain of the sixth transistor (M5) and serves as the output of the conversion output module (103), while its second end receives the ground voltage.

7. The circuit according to claim 1, characterized in that, The bandgap reference module (101) includes: The third current mirror has a first end that receives the power supply voltage and a third end that serves as the first output terminal of the bandgap reference module (101). An error amplifier (EA) has its non-inverting input connected to the second terminal of the third current mirror, its inverting input connected to the third terminal of the third current mirror, and its output connected to the fourth terminal of the third current mirror and serving as the second output terminal of the bandgap reference module (101). The first transistor (Q1) has its emitter connected to the non-inverting input of the error amplifier (EA), and its collector and base connected to and receiving ground voltage. The second transistor (Q2) has its emitter connected to the inverting input of the error amplifier (EA), and its base and collector connected to the base of the first transistor (Q1). The third impedance element (R1) is connected between the non-inverting input terminal of the error amplifier (EA) and the second terminal of the third current mirror; The fourth impedance element (R2) is connected between the inverting input terminal of the error amplifier (EA) and the third terminal of the third current mirror; The fifth impedance element (R3) is connected between the non-inverting input of the error amplifier (EA) and the emitter of the first transistor (Q1).

8. The circuit according to claim 7, characterized in that, The third current mirror includes: The seventh transistor (M1) has its source as the first terminal of the third current mirror, its gate as the fourth terminal of the third current mirror, and its drain as the second terminal of the third current mirror. The eighth transistor (M2) has its source connected to the source of the seventh transistor (M7), its gate connected to the gate of the seventh transistor (M1), and its drain serving as the third terminal of the third current mirror.

9. A temperature sensor, characterized in that, The temperature sensing circuit includes any one of claims 1-8.

10. An electronic device, characterized in that, Including the temperature sensor as described in claim 9.

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