A temperature measurement circuit, temperature sensor

Abstract

This application discloses a temperature measurement circuit and a temperature sensor, applicable to the field of temperature measurement technology. The temperature measurement circuit includes a first voltage generation circuit, a second voltage generation circuit, and a conversion circuit. Both the first and second voltage generation circuits are connected to the object under test, thereby acquiring the temperature of the object and generating a corresponding voltage. Due to power supply voltage limitations, the measured temperature is inaccurate after the first and second voltages rise to a certain value. Therefore, this application only determines the corresponding temperature when the voltage value is below a threshold, and sets up a first voltage generation circuit where the voltage changes positively with temperature and a second voltage generation circuit where the voltage changes negatively with temperature to ensure that the measured temperature range is not affected. Compared to traditional temperature measurement circuits with monotonic voltage changes, this application not only ensures the temperature measurement range but also improves the accuracy of temperature measurement.

Description

Technical Field

[0001] This application relates to the field of temperature measurement technology, and in particular to a temperature measurement circuit and a temperature sensor. Background Technology

[0002] Currently, Complementary Metal Oxide Semiconductor (CMOS) temperature sensors are widely used for internal temperature detection in system-on-chips (SoCs). Based on the temperature characteristics of PN junctions, parasitic bipolar junction transistors (BJTs) in CMOS technology are connected in a diode configuration (base B and collector C are connected together). In this configuration, the voltage difference (VBE) between the base (B) and emitter (E) changes with temperature at a negative rate, while the difference between the two VBEs, ΔVBE, changes with a positive rate. Current temperature measurement circuits use either a VBE with a negative rate of change (indicating poor process consistency) or a ΔVBE with a positive rate of change (indicating good process consistency). After amplification, a voltage that is monotonic with temperature changes is output, and this voltage is then digitized to output a digital code, thus achieving temperature measurement.

[0003] However, the temperature measurement circuit that uses monotonic voltage changes outputs a temperature value based on the measured voltage value, which is affected by the power supply voltage. For example, if a positive rate of change ΔVBE is used, and the power supply cannot provide sufficient voltage, the voltage change will decrease or even stop changing after the temperature rises to a certain value. This results in a mismatch between the measured voltage and the actual temperature, leading to low accuracy in temperature measurement.

[0004] Therefore, how to avoid the influence of power supply voltage when measuring temperature based on voltage, thereby improving the accuracy of temperature measurement, is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this application is to provide a temperature measurement circuit and a temperature sensor to avoid the influence of power supply voltage when measuring temperature based on voltage, thereby improving the accuracy of temperature measurement.

[0006] To solve the above-mentioned technical problems, this application provides a temperature measurement circuit, including: a first voltage generating circuit, a second voltage generating circuit, and a conversion circuit;

[0007] Both the first voltage generating circuit and the second voltage generating circuit are connected to the object under test and are used to obtain the temperature of the object under test and generate a corresponding voltage; wherein, the first voltage generated by the first voltage generating circuit changes positively with temperature, and the second voltage generated by the second voltage generating circuit changes negatively with temperature.

[0008] The first voltage generating circuit and the second voltage generating circuit are respectively connected to the conversion circuit. The conversion circuit determines the temperature of the object to be tested based on the first voltage when the first voltage generated by the first voltage generating circuit is less than a first threshold, and determines the temperature of the object to be tested based on the second voltage when the second voltage generated by the second voltage generating circuit is less than a second threshold.

[0009] Preferably, the conversion circuit includes: a first switch, a second switch, a control circuit, and an arithmetic unit;

[0010] The first voltage generating circuit is connected to the first terminal of the first switch, the second voltage generating circuit is connected to the first terminal of the second switch, and the second terminals of the first and second switches are respectively connected to the arithmetic unit; wherein, the arithmetic unit receives the first voltage generated by the first voltage generating circuit after the first switch is closed, receives the second voltage generated by the second voltage generating circuit after the second switch is closed, and determines the temperature of the object to be measured based on the magnitude of the received voltage and the voltage generating circuit that generates the voltage;

[0011] The control circuit is connected to the first voltage generating circuit, the second voltage generating circuit, the first switch, and the second switch respectively. It is used to control the first switch to close when the first voltage generated by the first voltage generating circuit is less than the first threshold and to control the first switch to open when the first voltage is greater than the first threshold. It is also used to control the second switch to close when the second voltage generated by the second voltage generating circuit is less than the second threshold and to control the second switch to open when the second voltage is greater than the second threshold.

[0012] Preferably, the first voltage generated by the first voltage generating circuit and the second voltage generated by the second voltage generating circuit have the same range;

[0013] The control circuit includes: a comparator;

[0014] The first terminal of the comparator input is connected to the first voltage generating circuit to obtain the first voltage, the second terminal of the comparator input is connected to the second voltage generating circuit to obtain the second voltage, and the output terminal of the comparator is connected to the first switch and the second switch respectively; the comparator is used to compare the first voltage and the second voltage to control the switch corresponding to the smaller voltage to close.

[0015] Preferably, the conversion circuit further includes: an amplifier circuit;

[0016] The input terminal of the amplifier circuit is connected to the second terminal of the first switch and the second terminal of the second switch, respectively, and the output terminal of the amplifier circuit is connected to the arithmetic unit for amplifying the corresponding voltage signal.

[0017] Preferably, the amplification circuit includes: an amplifier, a first resistor, and a second resistor;

[0018] The non-inverting input terminal of the amplifier is connected to the second terminal of the first switch and the second terminal of the second switch, respectively, and the output terminal of the amplifier is connected to the arithmetic unit.

[0019] The inverting input terminal of the amplifier is connected to the first terminal of the first resistor and the first terminal of the second resistor, respectively. The second terminal of the first resistor is connected to the output terminal of the amplifier, and the second terminal of the second resistor is grounded.

[0020] Preferably, the conversion circuit further includes: an analog-to-digital converter;

[0021] The input terminal of the analog-to-digital converter is connected to the output terminal of the amplifier, and the output terminal of the analog-to-digital converter is connected to the arithmetic unit, used to convert the received voltage signal into a digital signal.

[0022] Preferably, the conversion circuit determines the temperature of the object to be measured based on the corresponding voltage, including:

[0023] When the first voltage generated by the first voltage generating circuit is less than the first threshold, the first voltage is converted into a corresponding temperature value according to the first correspondence between the first voltage and temperature.

[0024] When the second voltage generated by the second voltage generating circuit is less than the second threshold, the second voltage is converted into a corresponding temperature value according to the second correspondence between the second voltage and the temperature.

[0025] Preferably, the first threshold and the second threshold are set according to the power supply voltage of the first voltage generating circuit and the second voltage generating circuit.

[0026] Preferably, the first voltage generated by the first voltage generating circuit and the second voltage generated by the second voltage generating circuit have the same range; the first threshold is equal to the second threshold.

[0027] To address the aforementioned technical problems, this application also provides a temperature sensor, including the temperature measurement circuit described above.

[0028] This application provides a temperature measurement circuit including a first voltage generation circuit, a second voltage generation circuit, and a conversion circuit. Both the first and second voltage generation circuits are connected to the object under test (AUT) to acquire the AUT's temperature and generate a corresponding voltage; both circuits exhibit monotonic voltage changes. Specifically, the first voltage generated by the first voltage generation circuit changes positively with temperature (i.e., as temperature increases, the first voltage also increases); while the second voltage generated by the second voltage generation circuit changes negatively with temperature (i.e., as temperature increases, the second voltage decreases). The first and second voltage generation circuits are respectively connected to the conversion circuit. The conversion circuit determines the AUT's temperature based on the first voltage when the first voltage generated by the first voltage generation circuit is less than a first threshold, and determines the AUT's temperature based on the second voltage when the second voltage generated by the second voltage generation circuit is less than a second threshold. Due to power supply voltage limitations, the measured temperature is inaccurate after the first and second voltages rise to a certain value. Therefore, this application only determines the corresponding temperature when the voltage value is less than the threshold, and uses a first voltage generation circuit with a positive correlation between voltage and temperature and a second voltage generation circuit with a negative correlation between voltage and temperature to ensure a sufficiently wide measured temperature range. Compared to traditional temperature measurement circuits with monotonic voltage changes, this application not only guarantees the temperature measurement range but also improves the accuracy of temperature measurement.

[0029] In addition, the temperature sensor provided in this application includes the temperature measurement circuit mentioned above, and has the same effect. Attached Figure Description

[0030] To more clearly illustrate the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 A structural block diagram of a temperature measurement circuit provided in an embodiment of this application;

[0032] Figure 2 An actual circuit diagram of a temperature measurement circuit provided in an embodiment of this application;

[0033] Figure 3 This is a schematic diagram illustrating the working principle of a temperature measurement circuit provided in an embodiment of this application. Detailed Implementation

[0034] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this application.

[0035] The core of this application is to provide a temperature measurement circuit and a temperature sensor to avoid the influence of power supply voltage when measuring temperature based on voltage, thereby improving the accuracy of temperature measurement.

[0036] To enable those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] To achieve carbon neutrality and peak carbon emissions, and promote green development, increasingly stringent requirements are being placed on the power consumption of electronic products, necessitating low-voltage and wide-voltage applications. CMOS temperature sensors are widely used for internal temperature detection in system-on-chips (SoCs). By linking parasitic BJTs in the CMOS process as diodes, the voltage difference (VBE) between the base (B) and emitter (E) exhibits a negative rate of change with temperature. However, the process consistency of VBE is poor, while the process consistency of ΔVBE is better. Therefore, based on the positive rate of change of ΔVBE with temperature, a temperature voltage Vtemp that changes monotonically with temperature can be obtained. Vtemp is then amplified to output voltage Vts, which, after digital-to-analog conversion, yields a set of temperature-dependent digital codes. However, within the designed temperature range, a design scheme where Vts exhibits a monotonic characteristic with temperature will have its maximum value limited by the power supply voltage when applied to low-voltage or wide-voltage range applications. This limits the rate of change of Vts with temperature, leading to lower accuracy of the temperature sensor. Alternatively, to meet the requirements of applications operating at the upper voltage limit of a wide power supply voltage range, it is necessary to increase the lower voltage limit of the temperature range. In low-voltage applications, the voltage Vts of digital processing (analog-to-digital conversion) is monotonic with temperature, so the maximum value of Vts is limited by the power supply voltage, thus limiting the rate of change of Vts with temperature. Furthermore, in wide-voltage applications, in traditional solutions, since the maximum value of Vts must be lower than the lower limit of the power supply voltage range, when the power supply voltage is high, the least significant bit (LSB) of the analog-to-digital converter increases with increasing power supply voltage, while the slope of Vts is limited by the lower limit of the power supply voltage range. Thus, at high voltage, the accuracy of the temperature sensor also decreases with increasing power supply voltage. Therefore, in wide-voltage applications, the accuracy of the temperature sensor at high power supply voltages is limited by the low power supply voltage.

[0038] To meet the needs of applications requiring low or wide power supply voltages, this application provides a temperature measurement circuit. Figure 1 A structural block diagram of a temperature measurement circuit provided in an embodiment of this application; as shown Figure 1As shown, the temperature measurement circuit includes: a first voltage generating circuit 1, a second voltage generating circuit 2, and a conversion circuit 4. Both the first voltage generating circuit 1 and the second voltage generating circuit 2 are connected to the object to be measured 3, used to acquire the temperature of the object to be measured 3 and generate a corresponding voltage. The first voltage generated by the first voltage generating circuit 1 changes positively with temperature, while the second voltage generated by the second voltage generating circuit 2 changes negatively with temperature. The first voltage generating circuit 1 and the second voltage generating circuit 2 are respectively connected to the conversion circuit 4. The conversion circuit 4 determines the temperature of the object to be measured 3 based on the first voltage when the first voltage generated by the first voltage generating circuit 1 is less than a first threshold, and determines the temperature of the object to be measured 3 based on the second voltage when the second voltage generated by the second voltage generating circuit 2 is less than a second threshold.

[0039] Because the first voltage changes positively with temperature, and the second voltage changes negatively with temperature, at lower temperatures, the first voltage is smaller and the second voltage is larger, making the temperature determined based on the first voltage more accurate; conversely, at higher temperatures, the first voltage is larger and the second voltage is smaller, making the temperature determined based on the second voltage more accurate. The core of this application lies in using a first voltage generating circuit whose voltage changes positively with temperature and a second voltage generating circuit whose voltage changes negatively with temperature to determine temperature. The first and second voltage generating circuits measure the same temperature range, and different temperatures correspond to different voltages. The voltage change ranges of both circuits are generally the same. Within the range from the minimum to the maximum voltage, as the temperature increases, the first voltage generating circuit increases from the minimum to the maximum value, while the second voltage generating circuit decreases from the maximum value to the minimum value. By determining the actual temperature of the object under test through the correspondence between the low-voltage range and temperature in the two voltage generating circuits, not only is a sufficiently wide temperature range ensured, but the measurement accuracy is also guaranteed. Furthermore, it should be noted that the specific values ​​of the first threshold and the second threshold mentioned in the embodiments of this application are not limited. If the ranges of the first voltage and the second voltage generated by the first voltage generating circuit and the second voltage generating circuit are the same, then at a certain temperature value, the first voltage and the second voltage are equal, and this voltage can be set as the first threshold and the second threshold, that is, the first threshold and the second threshold are equal. The specific structures of the first voltage generating circuit, the second voltage generating circuit, and the conversion circuit are not limited.

[0040] The above temperature measurement circuit will be explained here using a practical circuit diagram as an example. Figure 2 This is an actual circuit diagram of a temperature measurement circuit provided in an embodiment of this application; it should be noted that... Figure 2 The circuit structure shown is merely an example provided by an embodiment of this application and does not limit other solutions of this application. Figure 2As shown, the circuit includes a first voltage generation circuit 1 and a second voltage generation circuit 2. The first voltage generation circuit 1 generates a first voltage Vtemp1, and the second voltage generation circuit 2 generates a second voltage Vtemp2. ​​Vtemp1 is a voltage with a positive rate of change with temperature, and Vtemp2 is a voltage with a negative rate of change with temperature. The comparator cmp outputs a signal cmp_out based on the relationship between Vtemp1 and Vtemp2. ​​cmp_out is then passed through an inverter (inv) and a buffer (buf) to output TD and TB respectively. TD and TB control the first switch S1 and the second switch S2 respectively, thereby selecting either Vtemp1 or Vtemp2 as the input signal Vtemp to the amplifier OP. Vtemp is amplified by an amplifier circuit consisting of the amplifier OP, a first resistor R1, and a second resistor R2, and outputs a signal Vts. Vts serves as the input to the analog-to-digital converter (AD). The encoded Code[N-1:0] output by the AD is added to / subtracted from the code3 output by the multiplexer MUX. The multiplexer MUX and the addition / subtraction circuit constitute the arithmetic unit. The multiplexer MUX selects code2 or code1+code1 and performs operations with Code[N-1:0] based on the TD signal (the signal controlling the first switch S1), outputting code[N:0]. When TD = "1", the multiplexer MUX selects code2, and simultaneously the TD signal enables the add / subtract circuit (…). Figure 2 The + / - circuit in the middle performs addition operation, code[N:0] = Code[N-1:0] + code2. When TD = "0", the multiplexer MUX selects code1 + code1, and at the same time TD enables the addition / subtraction circuit ( Figure 2 The + / - circuit in the circuit performs a subtraction operation: code[N:0] = code1 + code1 - Code[N-1:0]. Through the above circuit structure, the temperature of the object under test is converted into voltage, and then into a numerical temperature change.

[0041] Furthermore, in this example, a comparator is used to compare the magnitudes of the first voltage and the second voltage, and the switch corresponding to the smaller voltage is selected to close. That is, at this time, the first threshold and the second threshold are equal. Specifically, at the intersection of the curves of the change of the first voltage and the second voltage, at the corresponding temperature, the first voltage and the second voltage are the same, and at this time the voltage magnitude is generally half of the power supply voltage. Figure 3 This is a schematic diagram illustrating the working principle of a temperature measurement circuit provided in an embodiment of this application; as shown below. Figure 3As shown, the first voltage generating circuit 1 and the second voltage generating circuit 2 respectively output a first voltage Vtemp1 with a positive temperature slope and a second voltage Vtemp2 with a negative temperature slope. The slope of Vtemp1 changing with temperature is "slop" (greater than 0), and the slope of Vtemp2 changing with temperature is "-slop" (less than 0). Therefore, at lower temperatures, when Vtemp1 is less than or equal to half of the power supply voltage, Vtemp2 is greater than Vtemp1, and the comparator cmp outputs cmp_out as logic low ("0"); at this time, the first switch S1 is closed, the second switch S2 is open, and the input signal of the amplifier OP is Vtemp = Vtemp1 (corresponding to...). Figure 3 The output line of the medium temperature sensor is located in the solid line section to the left of the vertical dashed line. As the temperature rises, Vtemp1 increases with a slope of slop. When Vtemp1 is greater than half the power supply voltage, Vtemp2 decreases with a slope of "-slop". At this time, Vtemp2 is less than Vtemp1, and the comparator cmp outputs cmp_out as a logic high ("1"). The first switch S1 opens, the second switch S2 closes, and the input of amplifier OP, Vtemp = Vtemp2 (corresponding to...). Figure 3 The output line of the medium temperature sensor is located in the solid line portion to the right of the vertical dashed line. Vts is... Figure 3 The solid line portion of the temperature sensor output line (Vts) outputs code[N-1:0] after analog-to-digital conversion.

[0042] The temperature sensor outputs code[N-1:0] to reflect Vts, which is generated by... Figure 3 It is known that Vts first increases and then decreases, so the output code[N-1:0] of the analog-to-digital converter (ADC) will have one code corresponding to two temperature points, which is not allowed. Therefore, the output code[N-1:0] of the ADC needs to be corrected. When Vtemp1 is less than or equal to half of the power supply voltage, the TD signal (the signal controlling the first switch S1) is logic "1", and the multiplexer MUX selects code2 to pass. At this time, code3 = code2 = 0, so the final output code is code[N:0] = 0 + Code[N-1:0]. When Vtemp1 is greater than half of the power supply voltage, the TD signal is logic "0", and the multiplexer MUX selects twice the code1 to pass. code1 is the binary code corresponding to 0.5*VDD / LSB (code1: the output code of the ADC when the input of the ADC is half of the power supply voltage, corresponding to...). Figure 3 (VDD / 2_code in the text). At this time, the output code of the temperature sensor is code[N:0]=2*code1-code[N-1:0].

[0043] As can be seen, by generating two voltages that change in opposite directions with equal rates of temperature change and comparing them, the output voltage (Vtemp1 or Vtemp2) at different temperature ranges can be selected as the input signal (Vtemp) for the next-stage circuit, thus obtaining a non-monotonic temperature voltage with positive and negative rates of change. When the two voltages that change in opposite directions with equal rates of temperature change (half of the power supply voltage) are used as the input of the analog-to-digital converter (ADC), the ADC output code1 is used as the slope correction code, making the final output code magnitude monotonic with temperature change, which facilitates the observation of temperature values.

[0044] The above example proposes a method for adaptive positive and negative voltage slope based on the temperature voltage (Vtemp) using ΔVBE, addressing the limitations imposed by the power supply voltage on the slope of temperature voltage change and the accuracy of temperature sensors in low-power supply voltage applications. In low-temperature applications, when the temperature voltage Vtemp is less than 0.5 times the power supply voltage, Vtemp exhibits a positive rate of change with temperature; when Vtemp is greater than 0.5 times the power supply voltage, it exhibits a negative rate of change with temperature. This avoids the temperature voltage Vtemp exceeding the power supply voltage as the temperature rises, thus preventing the slope of Vtemp from being limited by the power supply voltage and overcoming the accuracy limitation of CMOS temperature sensors imposed by the power supply voltage. This improves the accuracy of the temperature sensor. It should be noted that the above example is only one example provided in this application and does not limit other solutions of this application.

[0045] This application provides a temperature measurement circuit including a first voltage generation circuit, a second voltage generation circuit, and a conversion circuit. Both the first and second voltage generation circuits are connected to the object under test (AUT) to acquire its temperature and generate a corresponding voltage. Both circuits exhibit monotonic voltage changes. Specifically, the first voltage generated by the first voltage generation circuit changes positively with temperature (i.e., as temperature increases, the first voltage also increases); while the second voltage generated by the second voltage generation circuit changes negatively with temperature (i.e., as temperature increases, the second voltage decreases). The first and second voltage generation circuits are connected to the conversion circuit. The conversion circuit determines the AUT temperature based on the first voltage when the first voltage generated by the first voltage generation circuit is less than a first threshold, and determines the AUT temperature based on the second voltage when the second voltage generated by the second voltage generation circuit is less than a second threshold. Due to power supply voltage limitations, the measured temperature is inaccurate after the first and second voltages rise to a certain value. Therefore, this application only determines the corresponding temperature when the voltage value is less than the threshold, and uses a first voltage generation circuit with a positive correlation between voltage and temperature and a second voltage generation circuit with a negative correlation between voltage and temperature to ensure a sufficiently wide measured temperature range. Compared to traditional temperature measurement circuits with monotonic voltage changes, this application not only guarantees the temperature measurement range but also improves the accuracy of temperature measurement.

[0046] As mentioned in the above embodiments, this application achieves temperature detection of the object under test through a first voltage generating circuit, a second voltage generating circuit, and a conversion circuit, but the specific structure of the conversion circuit is not limited. This application provides a conversion circuit, specifically including: a first switch, a second switch, a control circuit, and an arithmetic unit. The first voltage generating circuit is connected to a first terminal of the first switch, the second voltage generating circuit is connected to a first terminal of the second switch, and the second terminals of the first and second switches are respectively connected to the arithmetic unit. The arithmetic unit receives a first voltage generated by the first voltage generating circuit after the first switch is closed, receives a second voltage generated by the second voltage generating circuit after the second switch is closed, and determines the temperature of the object under test based on the received voltage magnitude and the voltage generating circuit that generated the voltage. The control circuit is connected to the first voltage generating circuit, the second voltage generating circuit, the first switch, and the second switch, respectively. It is used to control the first switch to close when the first voltage generated by the first voltage generating circuit is less than a first threshold and to control the first switch to open when the first voltage is greater than the first threshold. It is also used to control the second switch to close when the second voltage generated by the second voltage generating circuit is less than a second threshold and to control the second switch to open when the second voltage is greater than the second threshold.

[0047] Generally, the first and second thresholds are set based on the power supply voltages of the first and second voltage generating circuits. In practical applications, the first and second voltages generated by the first and second voltage generating circuits typically have the same range and opposite slopes; that is, the first and second voltages are two symmetrical straight lines. (See reference [link to relevant documentation] for details.) Figure 3 At this point, the first threshold and the second threshold can be set to equal voltage values, specifically half of the power supply voltage, which can avoid overlapping calculations when calculating temperature using the first and second voltages.

[0048] The specific form of the control circuit mentioned above is not required; the control logic can be stored in a chip, and the above scheme can be implemented through the control chip. This application provides a preferred solution where the control circuit is specifically a comparator. The first terminal of the comparator's input is connected to a first voltage generation circuit to obtain a first voltage, and the second terminal of the comparator's input is connected to a second voltage generation circuit to obtain a second voltage. The output of the comparator is connected to a first switch and a second switch, respectively. The comparator is used to compare the first voltage and the second voltage to control the switch corresponding to the lower voltage to close. It can be seen that the comparator can ensure that the temperature is determined based on the lower portion of the first and second voltages. The circuit structure is simple, and there is no overlap in the temperature calculation using the first and second voltages.

[0049] In practical applications, the conversion circuit generally also includes components such as an amplifier circuit and an analog-to-digital converter (ADC). The input terminal of the amplifier circuit is connected to the second terminals of both the first and second switches, and its output terminal is connected to the operational unit to amplify the corresponding voltage signal. The specific structure of the amplifier circuit is not limited and can consist of an amplifier, a first resistor, and a second resistor. Correspondingly, the non-inverting input terminal of the amplifier is connected to the second terminals of both the first and second switches, and its output terminal is connected to the operational unit. The inverting input terminal of the amplifier is connected to the first terminals of both the first and second resistors, and the second terminal of the first resistor is connected to the output terminal of the amplifier. The second terminal of the second resistor is grounded. The input terminal of the ADC is connected to the output terminal of the amplifier, and its output terminal is connected to the operational unit to convert the received voltage signal into a digital signal. Amplifying the voltage signal through the amplifier circuit meets practical requirements, and then converting it into a digital signal through the ADC allows for the acquisition of the actual temperature value.

[0050] This application specifically employs two voltage generation circuits where the voltage changes with temperature exhibiting both positive and negative rates of change. Specifically, the correspondence between the first voltage and the second voltage and temperature is different: the first voltage increases with increasing temperature, while the second voltage decreases. Therefore, when determining the temperature based on these two voltages, it is necessary to determine the temperature level based on their respective correspondences and the actual voltage magnitude. This application provides a method whereby a conversion circuit determines the temperature of the object under test based on the corresponding voltages, including: when the first voltage generated by the first voltage generation circuit is less than a first threshold, converting the first voltage into a corresponding temperature value according to a first correspondence between the first voltage and temperature; and when the second voltage generated by the second voltage generation circuit is less than a second threshold, converting the second voltage into a corresponding temperature value according to a second correspondence between the second voltage and temperature. The specific conversion process can be referred to in the example of analog-to-digital converter output encoding described above, and will not be repeated here. The method provided in this application, which calculates temperature values ​​based on the respective correspondences between the first and second voltages and temperature, can improve the efficiency of temperature calculation.

[0051] This application proposes a method for implementing a CMOS-based adaptive temperature sensor circuit with positive and negative rate of change. This method can achieve a high rate of change with temperature over low or wide voltage ranges, avoiding the problem of reduced sensor accuracy caused by the lower limit of the power supply voltage (low voltage) limiting the rate of change of temperature voltage over wide voltage ranges in traditional solutions. A comparison is provided below between a traditional solution and an example solution from this application. The power supply voltage range is VLL (minimum) to VHH (maximum). In traditional solutions, to prevent Vts (which is monotonic) from exceeding the lower limit of the power supply voltage range VLL, the maximum value of Vts is typically designed as R2*VLL / (R1+R2). When R1 = R2, the slope of Vts in the temperature range of -40°C to 125°C is K1 = (0.5*VLL - Vn40°C) / 165. However, when applying the power supply voltage of VMM (VMM>VLL), the slope K2 of Vtemp remains K1 (it's limited, otherwise it wouldn't meet the requirements of VLL). In this case, when the reference voltage of the analog-to-digital converter (ADC) is the power supply voltage, the ADC's LSB = VMM / 2N. Therefore, the slope of the output code changing with temperature is Kc = LSB / K(code_num / ℃). Since VMM>VLL, increasing the power supply voltage increases LSB and Kc, thus reducing the sensor's accuracy. To meet the requirements of high-voltage applications, the lower limit of the power supply voltage range needs to be increased.

[0052] In the example scheme proposed in this application, there is no need to worry about the limitation of the lower limit of the power supply voltage range VLL on the rate of change of Vts with temperature when applying different power supply voltages. As analyzed above regarding traditional schemes, in wide power supply voltage applications, the accuracy of the temperature sensor is limited by the lower limit of the power supply voltage range as the power supply voltage increases. Therefore, in the scheme proposed in this application, the slope requirement of Vts (which is not monotonic) can be determined based on the upper limit of the power supply voltage range VHH (VHH>VMM>VLL), thus determining the rate of change of temperature voltage with temperature at the lower limit of the power supply voltage range: Kvtemp1=(0.5*VLL-Vn40C) / (Tm-40)=|Ktemp2|=(0.5*VLL-V125C) / (125-Tm). This allows determination of the temperature point Tm (the temperature point where VTemp1=Vtemp2). Thus, when meeting high-voltage applications, there is no need to increase the lower limit of the temperature range, thereby expanding the power supply voltage range. As can be seen, this application can meet the accuracy requirements in wide power supply voltage applications, and its performance is optimized compared to traditional solutions.

[0053] To address the aforementioned technical problems, this application provides a temperature sensor, including the temperature measurement circuit described in the above embodiments.

[0054] Since the embodiments of the temperature sensor section correspond to the embodiments of the temperature measurement circuit section, please refer to the description of the embodiments of the temperature measurement circuit section for the embodiments of the temperature sensor section, which will not be repeated here.

[0055] The temperature sensor provided in this embodiment corresponds to the temperature measurement circuit described above, and therefore has the same beneficial effects as the temperature measurement circuit described above.

[0056] Furthermore, the specific structure of the control circuit in the above embodiments is not limited, and may include a memory and a processor. The memory is used to store computer programs, and the processor is used to execute the computer programs to implement the steps mentioned in the above embodiments.

[0057] The processor may include one or more processing cores, such as a quad-core processor or an octa-core processor. The processor can be implemented using at least one of the following hardware forms: Digital Signal Processor (DSP), Field-Programmable Gate Array (FPGA), or Programmable Logic Array (PLA). The processor may also include a main processor and coprocessors. The main processor, also known as the Central Processing Unit (CPU), is used to process data in the wake-up state; the coprocessors are low-power processors used to process data in the standby state. In some embodiments, the processor may integrate a Graphics Processing Unit (GPU), which is responsible for rendering and drawing the content to be displayed on the screen. In some embodiments, the processor may also include an Artificial Intelligence (AI) processor, which handles computational operations related to machine learning.

[0058] The memory may include one or more computer-readable storage media, which may be non-transitory. The memory may also include high-speed random access memory and non-volatile memory, such as one or more disk storage devices or flash memory devices. In this embodiment, the memory is used to store at least the following computer program, which, after being loaded and executed by the processor, is capable of implementing the relevant steps disclosed in any of the foregoing embodiments. In addition, the resources stored in the memory may also include operating systems and data, and the storage method may be temporary or permanent storage. The operating system may include Windows, Unix, Linux, etc. The data may include, but is not limited to, the data involved in the above methods.

[0059] Finally, this application also provides an embodiment corresponding to a computer-readable storage medium. The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps described in the above method embodiments.

[0060] It is understood that if the methods in the above embodiments are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and executes all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0061] The computer-readable storage medium provided in this embodiment corresponds to the method described above, and therefore has the same beneficial effects as the method described above.

[0062] The temperature measurement circuit and temperature sensor provided in this application have been described in detail above. The various embodiments in the specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. It should be noted that those skilled in the art can make various improvements and modifications to this application without departing from the principles thereof, and these improvements and modifications also fall within the protection scope of the claims of this application.

[0063] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the aforementioned element.

Claims

1. A temperature measuring circuit, characterized in that, include: First voltage generating circuit, second voltage generating circuit, conversion circuit; Both the first voltage generating circuit and the second voltage generating circuit are connected to the object under test and are used to obtain the temperature of the object under test and generate a corresponding voltage; wherein, the first voltage generated by the first voltage generating circuit changes positively with temperature, and the second voltage generated by the second voltage generating circuit changes negatively with temperature. The first voltage generating circuit and the second voltage generating circuit are respectively connected to the conversion circuit. The conversion circuit determines the temperature of the object to be tested based on the first voltage when the first voltage generated by the first voltage generating circuit is less than a first threshold, and determines the temperature of the object to be tested based on the second voltage when the second voltage generated by the second voltage generating circuit is less than a second threshold.

2. The temperature measuring circuit according to claim 1, characterized in that, The conversion circuit includes: a first switch, a second switch, a control circuit, and an arithmetic unit; The first voltage generating circuit is connected to the first terminal of the first switch, the second voltage generating circuit is connected to the first terminal of the second switch, and the second terminals of the first and second switches are respectively connected to the arithmetic unit; wherein, the arithmetic unit receives the first voltage generated by the first voltage generating circuit after the first switch is closed, receives the second voltage generated by the second voltage generating circuit after the second switch is closed, and determines the temperature of the object to be measured based on the magnitude of the received voltage and the voltage generating circuit that generates the voltage; The control circuit is connected to the first voltage generating circuit, the second voltage generating circuit, the first switch, and the second switch respectively. It is used to control the first switch to close when the first voltage generated by the first voltage generating circuit is less than the first threshold, and to control the first switch to open when the first voltage is greater than the first threshold. It is also used to control the second switch to close when the second voltage generated by the second voltage generating circuit is less than the second threshold, and to control the second switch to open when the second voltage is greater than the second threshold.

3. The temperature measuring circuit according to claim 2, characterized in that, The first voltage generated by the first voltage generating circuit and the second voltage generated by the second voltage generating circuit have the same range; The control circuit includes: a comparator; The first terminal of the comparator input is connected to the first voltage generating circuit to obtain the first voltage, the second terminal of the comparator input is connected to the second voltage generating circuit to obtain the second voltage, and the output terminal of the comparator is connected to the first switch and the second switch respectively; the comparator is used to compare the first voltage and the second voltage to control the switch corresponding to the smaller voltage to close.

4. The temperature measuring circuit according to claim 3, characterized in that, The conversion circuit further includes: an amplifier circuit; The input terminal of the amplifier circuit is connected to the second terminal of the first switch and the second terminal of the second switch, respectively, and the output terminal of the amplifier circuit is connected to the arithmetic unit for amplifying the corresponding voltage signal.

5. The temperature measuring circuit according to claim 4, characterized in that, The amplifier circuit includes: an amplifier, a first resistor, and a second resistor; The non-inverting input terminal of the amplifier is connected to the second terminal of the first switch and the second terminal of the second switch, respectively, and the output terminal of the amplifier is connected to the arithmetic unit. The inverting input terminal of the amplifier is connected to the first terminal of the first resistor and the first terminal of the second resistor, respectively. The second terminal of the first resistor is connected to the output terminal of the amplifier, and the second terminal of the second resistor is grounded.

6. The temperature measuring circuit according to claim 5, characterized in that, The conversion circuit further includes: an analog-to-digital converter; The input terminal of the analog-to-digital converter is connected to the output terminal of the amplifier, and the output terminal of the analog-to-digital converter is connected to the arithmetic unit, used to convert the received voltage signal into a digital signal.

7. The temperature measuring circuit according to claim 1, characterized in that, The conversion circuit determines the temperature of the object under test based on the corresponding voltage, including: When the first voltage generated by the first voltage generating circuit is less than the first threshold, the first voltage is converted into a corresponding temperature value according to the first correspondence between the first voltage and temperature. When the second voltage generated by the second voltage generating circuit is less than the second threshold, the second voltage is converted into a corresponding temperature value according to the second correspondence between the second voltage and the temperature.

8. The temperature measuring circuit according to claim 7, characterized in that, The first threshold and the second threshold are set according to the power supply voltage of the first voltage generating circuit and the second voltage generating circuit.

9. The temperature measuring circuit according to claim 8, characterized in that, The first voltage generated by the first voltage generating circuit and the second voltage generating circuit have the same range; the first threshold is equal to the second threshold.

10. A temperature sensor, characterized in that, Includes the temperature measurement circuit according to any one of claims 1 to 9.

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