Temperature measurement circuit and temperature sensor

Abstract

The present disclosure relates to a temperature measurement circuit and a temperature sensor. The temperature measurement circuit comprises a temperature sampling circuit configured to output a first electrical parameter, a second electrical parameter and a reference electrical parameter, the first electrical parameter being negatively correlated with a temperature to be measured, and the second electrical parameter being positively correlated with the temperature to be measured; a first metering circuit coupled to the temperature sampling circuit, configured to output a first frequency signal according to the first electrical parameter and the second electrical parameter, and output first metering information according to the first frequency signal; and a second metering circuit coupled to the temperature sampling circuit, configured to output a second frequency signal according to the first electrical parameter and the reference electrical parameter, and output second metering information according to the second frequency signal; wherein the first metering information and the second metering information are used to determine the temperature to be measured, and the first frequency signal has a lower correlation degree with the temperature to be measured than the second frequency signal. Since the temperature to be measured can accurately reflect the actual temperature, the accuracy of temperature measurement is improved.

Description

Technical Field

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

[0002] Temperature sensors, which convert the physical quantity of temperature into a temperature signal, have a wide range of applications in industrial production, household appliances, and environmental monitoring. However, temperature sensors suffer from low measurement accuracy during temperature measurement. Summary of the Invention

[0003] To address the aforementioned technical problems, this disclosure provides a temperature measuring circuit and a temperature sensor.

[0004] According to a first aspect of this disclosure, a temperature measuring circuit is provided, the temperature measuring circuit comprising:

[0005] A temperature sampling circuit is used to output a first electrical parameter, a second electrical parameter, and a reference electrical parameter. The first electrical parameter is negatively correlated with the temperature to be measured, and the second electrical parameter is positively correlated with the temperature to be measured.

[0006] A first metering circuit, coupled to the temperature sampling circuit, is used to output a first frequency signal based on the first electrical parameter and the second electrical parameter, and to output first metering information based on the first frequency signal.

[0007] The second metering circuit is coupled to the temperature sampling circuit and is used to output a second frequency signal according to the first electrical parameter and the reference electrical parameter, and to output second metering information according to the second frequency signal.

[0008] The first measurement information and the second measurement information are used to determine the temperature to be measured, and the correlation between the first frequency signal and the temperature to be measured is lower than the correlation between the second frequency signal and the temperature to be measured.

[0009] According to some embodiments of this disclosure, the first metering circuit includes:

[0010] A first relaxation oscillation circuit, coupled to the temperature sampling circuit, is used to output the first frequency signal based on the first electrical parameter and the second electrical parameter.

[0011] The second metering circuit includes:

[0012] The second relaxation oscillation circuit, coupled to the temperature sampling circuit, is used to output the second frequency signal based on the first electrical parameter and the reference electrical parameter.

[0013] According to some embodiments of this disclosure, the temperature sampling circuit includes:

[0014] A bandgap reference circuit includes a first node that outputs a first voltage and a second node that outputs a second voltage. The first voltage and the second voltage are used as the first electrical parameter. The first node is coupled to the first voltage input terminal of the first relaxation oscillation circuit and the first voltage input terminal of the second relaxation oscillation circuit. The second node is coupled to the second voltage input terminal of the first relaxation oscillation circuit and the second voltage input terminal of the second relaxation oscillation circuit.

[0015] A first current generating circuit is coupled to the current input terminals of the bandgap reference circuit and the first relaxation oscillation circuit, and is used to generate a first current, which serves as the second electrical parameter.

[0016] The second current generating circuit is coupled to the current input terminals of both the bandgap reference circuit and the second relaxation oscillation circuit, and is used to generate a second current, which serves as the reference electrical parameter.

[0017] According to some embodiments of this disclosure, the bandgap reference circuit includes:

[0018] A first transistor, wherein a first terminal of the first transistor is used to couple to a power supply;

[0019] A first resistor, wherein a first end of the first resistor is coupled to a second end of the first transistor to form a third node;

[0020] The second resistor has its first end coupled to the second end of the first resistor to form a fourth node;

[0021] A third resistor, the first end of which is coupled to the third node;

[0022] The first temperature sensing transistor has a first terminal coupled to the second terminal of the second resistor to form the first node. The second terminal and the control terminal of the first temperature sensing transistor are both used to be coupled to a common terminal.

[0023] The second temperature sensing transistor has its first terminal coupled to the second terminal of the third resistor to form the second node. Both the second terminal and the control terminal of the second temperature sensing transistor are used to be coupled to the common terminal.

[0024] A first amplifier, wherein a first input terminal of the first amplifier is coupled to the fourth node, a second input terminal of the first amplifier is coupled to the second node, and an output terminal of the first amplifier is coupled to the control terminal of the first transistor.

[0025] According to some embodiments of this disclosure, the first current generating circuit includes:

[0026] The second transistor is coupled between the power supply and the common terminal, and the control terminal of the second transistor is coupled to the control terminal of the first transistor and the output terminal of the first amplifier.

[0027] A first current mirror circuit, wherein the input side of the first current mirror circuit is coupled between the second transistor and the common terminal, and the output side of the first current mirror circuit is coupled to the current input terminal of the first relaxation oscillation circuit.

[0028] According to some embodiments of this disclosure, the second current generating circuit includes:

[0029] A second amplifier, wherein the first input terminal of the second amplifier is coupled to the third node;

[0030] The third transistor has a first terminal for coupling to the power supply, a second terminal for coupling to the second input terminal of the second amplifier, and a control terminal for coupling to the output terminal of the second amplifier.

[0031] The fourth resistor has its first end coupled to both the second end of the third transistor and the second input terminal of the second amplifier, and its second end is used to be coupled to the common terminal.

[0032] The second current mirror circuit has its input side coupled between the power supply and the third transistor, and its output side coupled to the current input terminal of the second relaxation oscillation circuit.

[0033] According to some embodiments of this disclosure, the first relaxation oscillation circuit includes:

[0034] A first charging and discharging circuit, coupled to the first current generating circuit, is used to charge and discharge the first capacitor of the first charging and discharging circuit according to the first current.

[0035] A first comparison circuit is coupled to the first charging and discharging circuit, the first node, and the second node, and is used to output a first comparison signal based on the voltage of the first capacitor, the first voltage, and the second voltage.

[0036] A first trigger circuit, coupled to both the first charge / discharge circuit and the first comparator circuit, is used to output the first frequency signal based on the first comparison signal and control the first charge / discharge circuit; and / or,

[0037] The second relaxation oscillation circuit includes:

[0038] The second charging and discharging circuit is coupled to the second current generating circuit and is used to charge and discharge the second capacitor of the second charging and discharging circuit according to the second current.

[0039] The second comparison circuit is coupled to the second charging and discharging circuit, the first node, and the second node, and is used to output a second comparison signal based on the voltage of the second capacitor, the first voltage, and the second voltage.

[0040] The second trigger circuit is coupled to both the second charge / discharge circuit and the second comparison circuit. It is used to output the second frequency signal according to the second comparison signal and control the second charge / discharge circuit.

[0041] According to some embodiments of this disclosure, the first metering circuit includes:

[0042] A first counter is used to count the periods of the first frequency signal;

[0043] The second metering circuit includes:

[0044] The second counter is used to count the period of the second frequency signal;

[0045] Wherein, the first counter and the second counter stop counting in response to a stop counting trigger signal and output the first measurement information and the second measurement information; or,

[0046] When the second metering information output by the second counter meets the first preset condition, the first counter stops counting and outputs the first metering information; or,

[0047] When the first metering information output by the first counter meets the second preset condition, the second counter stops counting and outputs the second metering information.

[0048] According to some embodiments of this disclosure, the first counter is an adder counter, the second counter is a subtractor counter, and the first preset condition includes the second measurement information being 0.

[0049] According to a second aspect of this disclosure, a temperature sensor is provided, including the temperature measurement circuit described above.

[0050] In the temperature measuring circuit and temperature sensor disclosed herein, the temperature measuring circuit includes a temperature sampling circuit, a first metering circuit, and a second metering circuit, all of which are coupled to each other. The temperature sampling circuit outputs a first electrical parameter negatively correlated with the measured temperature, a second electrical parameter positively correlated with the measured temperature, and a reference electrical parameter unrelated to the measured temperature. The first metering circuit outputs a first frequency signal with low correlation to the measured temperature based on the first and second electrical parameters, and outputs a first metering parameter based on the first frequency signal. The second metering circuit generates a second frequency signal with high correlation to the measured temperature based on the first electrical parameter and the reference electrical parameter, and outputs a second metering parameter based on the second frequency signal. Because the first frequency signal has low sensitivity to the measured temperature while the second frequency signal has high sensitivity, the measured temperature determined based on the first metering information for the first frequency signal and the second metering information for the second frequency signal can accurately reflect the actual temperature, thereby improving the accuracy of temperature measurement.

[0051] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory, and do not limit this document. Attached Figure Description

[0052] The accompanying drawings, which form part of this document, are used to provide a further understanding of the document. The illustrative embodiments and descriptions herein are used to explain the document and do not constitute an undue limitation thereof. In the drawings:

[0053] Figure 1 This is a schematic diagram of the structure of a temperature measuring circuit shown in an exemplary embodiment of the present disclosure;

[0054] Figure 2 This is a schematic diagram of the structure of a temperature measuring circuit shown in another exemplary embodiment of this disclosure;

[0055] Figure 3 This is a schematic diagram of the structure of a temperature sampling circuit shown in an exemplary embodiment of the present disclosure;

[0056] Figure 4a This is a schematic diagram of the structure of a first current mirror circuit shown in an exemplary embodiment of this disclosure;

[0057] Figure 4b This is a schematic diagram of the structure of a second current mirror circuit shown in an exemplary embodiment of this disclosure;

[0058] Figure 5a This is a structural flowchart of a first relaxation oscillator circuit illustrated in an exemplary embodiment of the present disclosure;

[0059] Figure 5b This is a structural flowchart of a second relaxation oscillator circuit illustrated in an exemplary embodiment of the present disclosure;

[0060] Figure 6a This is a structural flowchart of a first relaxation oscillator circuit illustrated in another exemplary embodiment of this disclosure;

[0061] Figure 6b This is a flowchart illustrating the structure of a second relaxation oscillator circuit as shown in another exemplary embodiment of this disclosure;

[0062] Figure 7a This is a schematic diagram of the structure of a temperature measuring circuit shown in another exemplary embodiment of this disclosure;

[0063] Figure 7b This is a schematic diagram of the structure of a temperature measuring circuit shown in another exemplary embodiment of this disclosure.

[0064] In the picture:

[0065] 10. Temperature sampling circuit; 11. Bandgap reference circuit; 12. First current generation circuit; 13. Second current generation circuit; 20. First metering circuit; 21. First relaxation oscillation circuit; 22. First counter; 30. Second metering circuit; 31. Second relaxation oscillation circuit; 32. Second counter; 40. Temperature output circuit; 121. First current mirror circuit; 131. Second current mirror circuit; 211. First charge / discharge circuit; 212. First comparator circuit; 213. First trigger circuit; 311. Second charge / discharge circuit; 312. Second comparator circuit; 313. Second trigger circuit; N1. First node; N2. Second node; N3. Third node; N4. Fourth node; N5. Fifth node; N6. Sixth node; N7. Seventh node; N8. Eighth node; M1. First transistor; M2. Second transistor; M3. Third transistor Q1, First temperature sensing transistor; Q2, Second temperature sensing transistor; T1, First mirror transistor; T2, Second mirror transistor; T3, Third mirror transistor; T4, Fourth mirror transistor; T5, Fifth mirror transistor; T6, Sixth mirror transistor; T7, Seventh mirror transistor; T8, Eighth mirror transistor; T9, Ninth mirror transistor; T10, Tenth mirror transistor; S1, First switching unit; S2, Second switching unit; S3, Third switching unit; S4, Fourth switching unit; C1, First capacitor; C2, Second capacitor; R1, First resistor; R2, Second resistor; R3, Third resistor; R4, Fourth resistor; OP1, First amplifier; OP2, Second amplifier; CMP1, First comparator; CMP2, Second comparator; FF1, First flip-flop; FF2, Second flip-flop; VDD, Power supply; GND, Common terminal. Detailed Implementation

[0066] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this disclosure can be arbitrarily combined with each other. It should also be understood that the term "and / or" as used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0067] Temperature sensors, which convert the physical quantity of temperature into a temperature signal, have a wide range of applications in industrial production, household appliances, and environmental monitoring. There are many types of temperature sensors, mainly including traditional discrete temperature sensors, analog temperature sensors, and digital temperature sensors. Traditional discrete temperature sensors primarily utilize thermistors and thermistors to measure temperature. Although their structure is simple, their stability is relatively low. Analog temperature sensors mainly measure temperature based on temperature sensing devices and integrated circuits, featuring high accuracy, small error, and high resolution. Digital temperature sensors are mainly based on the temperature characteristics of field-effect transistors and bipolar transistors, and their outputs are mostly temperature-related current, frequency, period, etc. Compared to analog temperature sensors, digital temperature sensors have a simpler structure and smaller size.

[0068] Digital temperature sensors convert temperature into an analog signal, using an analog-to-digital converter to convert the analog signal back into a digital signal. This type of digital temperature sensor has a relatively complex structure, high power consumption, and low measurement accuracy. Digital temperature sensors can also convert temperature into a time-domain quantity and quantize it for output. This type of digital temperature sensor is affected by the power supply voltage, resulting in low measurement accuracy.

[0069] Based on this, this disclosure provides a temperature measuring circuit that generates frequency signals with different degrees of correlation to the temperature to be measured by using electrical parameters that are negatively correlated, positively correlated, or uncorrelated with the temperature to be measured. The circuit then determines the temperature to be measured based on the metrological information output from these frequency signals with varying degrees of correlation. Since different frequency signals have different sensitivities to the temperature to be measured, the temperature determined based on the metrological information can accurately reflect the actual temperature, thereby improving the accuracy of temperature measurement.

[0070] An exemplary embodiment of this disclosure provides a temperature measuring circuit, such as Figure 1As shown, the temperature measuring circuit includes a temperature sampling circuit 10, a first metering circuit 20, and a second metering circuit 30. The temperature sampling circuit 10 outputs a first electrical parameter, a second electrical parameter, and a reference electrical parameter. The first electrical parameter is negatively correlated with the measured temperature, the second electrical parameter is positively correlated with the measured temperature, and the reference electrical parameter is an electrical parameter unrelated to the measured temperature. The first metering circuit 20 is coupled to the temperature sampling circuit 10 and outputs a first frequency signal based on the first and second electrical parameters, and outputs first metering information based on the first frequency signal. The second metering circuit 30 is coupled to the temperature sampling circuit 10 and outputs second metering information based on the first electrical parameter and the reference electrical parameter. The first and second metering information are used to determine the measured temperature, and the correlation between the first frequency signal and the measured temperature is lower than the correlation between the second frequency signal and the measured temperature.

[0071] In the temperature measuring circuit and temperature sensor disclosed herein, the temperature measuring circuit includes a temperature sampling circuit, a first metering circuit, and a second metering circuit, all of which are coupled to each other. The temperature sampling circuit outputs a first electrical parameter negatively correlated with the measured temperature, a second electrical parameter positively correlated with the measured temperature, and a reference electrical parameter unrelated to the measured temperature. The first metering circuit outputs a first frequency signal with low correlation to the measured temperature based on the first and second electrical parameters, and outputs a first metering parameter based on the first frequency signal. The second metering circuit generates a second frequency signal with high correlation to the measured temperature based on the first electrical parameter and the reference electrical parameter, and outputs a second metering parameter based on the second frequency signal. Because the first frequency signal has low sensitivity to the measured temperature while the second frequency signal has high sensitivity, the measured temperature determined based on the first metering information for the first frequency signal and the second metering information for the second frequency signal can accurately reflect the actual temperature, thereby improving the accuracy of temperature measurement.

[0072] For example, a negative correlation between the first electrical parameter and the measured temperature means that the first electrical parameter decreases as the measured temperature increases. A positive correlation between the second electrical parameter and the measured temperature means that the second electrical parameter increases as the measured temperature increases. An indifference between the reference electrical parameter and the measured temperature means that the reference electrical parameter does not change with the measured temperature. The first electrical parameter, the second electrical parameter, and the reference electrical parameter may include parameters such as voltage and current.

[0073] For example, a low correlation between the first frequency signal and the measured temperature means that the first frequency signal changes little with the measured temperature. Alternatively, ideally, the first frequency signal does not change with temperature. A high correlation between the second frequency signal and the measured temperature means that the second frequency signal changes significantly with the measured temperature.

[0074] In one embodiment, such as Figure 2As shown, the first metering circuit 20 includes a first relaxation oscillation circuit 21. The first relaxation oscillation circuit 21 is coupled to the temperature sampling circuit 10 and is used to output a first frequency signal based on a first electrical parameter and a second electrical parameter. The second metering circuit 30 includes a second relaxation oscillation circuit 31. The second relaxation oscillation circuit 31 is coupled to the temperature sampling circuit 10 and is used to output a second frequency signal based on the first electrical parameter and a reference electrical parameter. The first and second frequency signals are periodic square wave signals. The period of the first frequency signal has a low correlation with the measured temperature, while the period of the second frequency signal has a high correlation with the measured temperature.

[0075] In this embodiment, the first relaxation oscillation circuit enables the second electrical parameter to oscillate within the range of the first electrical parameter to generate a first frequency signal. Since the first electrical parameter is negatively correlated with the measured temperature and the second electrical parameter is positively correlated with the measured temperature, the first and second electrical parameters can eliminate the influence of the measured temperature, resulting in a low correlation between the first frequency signal and the measured temperature. The second relaxation oscillation circuit enables the reference electrical parameter to oscillate within the range of the first electrical parameter to generate a second frequency signal. Since the first electrical parameter is negatively correlated with the measured temperature and the reference electrical parameter is unrelated to the measured temperature, the reference electrical parameter cannot eliminate the influence of the measured temperature, resulting in a high correlation between the second frequency signal and the measured temperature. By using two relaxation oscillation circuits, the first electrical parameter, the second electrical parameter, and the reference electrical parameter can be processed, outputting frequency signals with different correlations to the measured temperature to determine measurement information, thereby reducing the complexity of the measurement circuit structure.

[0076] For example, the first electrical parameter includes a first voltage V. EB1 Second voltage V EB2 First voltage V EB1 Second voltage V EB2 The difference is positively correlated with the temperature to be measured. In the first relaxation oscillation circuit 21 and the second relaxation oscillation circuit 31, the first voltage V is used. EB1 Second voltage V EB2 The difference is processed for the second electrical parameter and the reference electrical parameter, respectively. Therefore, due to the first voltage V EB1 Second voltage V EB2 The difference between the two electrical parameters and the second electrical parameter are both positively correlated with the temperature to be measured. After passing through the first relaxation oscillation circuit 21, the influence of the temperature to be measured on the signal is eliminated, resulting in a low correlation between the period of the first frequency signal and the temperature to be measured.

[0077] In one embodiment, the temperature sampling circuit 10 includes a bandgap reference circuit 11, a first current generation circuit 12, and a second current generation circuit 13. The bandgap reference circuit 11 includes an output first voltage V. EB1 The first node N1 and the output second voltage V EB2 The second node N2, the first voltage VEB1 Second voltage V EB2 As the first electrical parameter, the first node N1 is coupled to both the first voltage input terminal of the first relaxation oscillation circuit 21 and the first voltage input terminal of the second relaxation oscillation circuit 31, and the second node N2 is coupled to both the second voltage input terminals of the first relaxation oscillation circuit 21 and the second voltage input terminal of the second relaxation oscillation circuit 31. The first current generation circuit 12 is coupled to both the bandgap reference circuit 11 and the current input terminal of the first relaxation oscillation circuit 21, and is used to generate the first current I. r First current I r As a second electrical parameter, the second current generation circuit 13 is coupled to the current input terminals of both the bandgap reference circuit 11 and the second relaxation oscillation circuit 31, and is used to generate the second current I. C The second current I C Used as a reference electrical parameter.

[0078] In this embodiment, the temperature sampling circuit includes a bandgap reference circuit, a first current generation circuit, and a second current generation circuit. The bandgap reference circuit outputs a first electrical parameter, the first current generation circuit outputs a second electrical parameter, and the second current generation circuit outputs a reference electrical parameter. Since the first relaxation oscillation circuit and the second relaxation oscillation circuit each require two voltages as the upper and lower limits of oscillation and one current for oscillation, the first and second voltages are used as the upper and lower limits of oscillation, and the first and second currents are used for oscillation respectively. By generating the first electrical parameter, the second electrical parameter, and the reference electrical parameter through the bandgap reference circuit, the first current generation circuit, and the second current generation circuit, the complexity of the temperature sampling circuit is reduced.

[0079] It is understandable that, in addition to using the second current generation circuit 13 to output the reference electrical parameters, reference electrical parameters that are independent of the temperature to be measured can also be directly used from the device or equipment where the temperature measuring circuit is located. Alternatively, a circuit with the same function can be used to output the reference electrical parameters.

[0080] In one embodiment, such as Figure 3As shown, the bandgap reference circuit 11 includes a first transistor M1, a first temperature-sensing transistor Q1, a second temperature-sensing transistor Q2, a first resistor R1, a second resistor R2, a third resistor R3, and a first amplifier OP1. The first terminal of the first transistor M1 is coupled to the power supply VDD. The first terminal of the first resistor R1 is coupled to the second terminal of the first transistor M1 to form a third node N3. The first terminal of the second resistor R2 is coupled to the second terminal of the first resistor R1 to form a fourth node N4. The first terminal of the third resistor R3 is coupled to the third node N3. The first terminal of the first temperature-sensing transistor Q1 is coupled to the second terminal of the second resistor R2 to form a first node N1, and its second terminal and control terminal are both coupled to the common terminal GND. The first terminal of the second temperature-sensing transistor Q2 is coupled to the second terminal of the third resistor R3 to form a second node N2, and its second terminal and control terminal are both coupled to the common terminal GND. The first input terminal of the first amplifier OP1 is coupled to the fourth node N4, its second input terminal is coupled to the second node N2, and its output terminal is coupled to the control terminal of the first transistor M1.

[0081] In this embodiment, since the forward voltage drop of the first and second temperature-sensing transistors decreases with increasing temperature, and the voltages at their first terminals are different and negatively correlated with the temperature, they can be used as the first electrical parameter. By constructing a bandgap reference circuit using multiple transistors, multiple resistors, and an amplifier, the accuracy of the first electrical parameter is high, and the complexity of the bandgap reference circuit structure is reduced. Simultaneously, since the bandgap reference circuit can output a voltage at a third node independent of the temperature, this voltage can be converted and used as the second current, thereby reducing the complexity of the temperature sensing circuit structure.

[0082] It is understandable that the structure of the bandgap reference circuit 11 is not limited to the structure described above, and can also be other structures capable of outputting the first voltage V. EB1 Second voltage V EB2 The circuit structure for the voltage of the third node N3. In addition to using the bandgap reference circuit 11 to output the first electrical parameter, other circuits containing temperature-sensing transistors can also be used to output the first electrical parameter.

[0083] For example, the first temperature sensing transistor Q1 and the second temperature sensing transistor Q2 are PNP bipolar transistors.

[0084] For example, in addition to using a first current I r As the second electrical parameter and using the second current I C In addition to using the voltage difference across the second resistor R2 as a reference electrical parameter, the voltage at the third node N3 can also be used as a reference electrical parameter.

[0085] In one embodiment, reference continues to be made to Figure 3The first current generating circuit 12 includes a second transistor M2 and a first current mirror circuit 121. The second transistor M2 is coupled between the power supply VDD and the common terminal GND, and its control terminal is coupled to the control terminal of the first transistor M1 and the output terminal of the first amplifier OP1. The input side of the first current mirror circuit 121 is coupled between the second transistor M2 and the common terminal GND, and its output side is coupled to the current input terminal of the first relaxation oscillation circuit 21.

[0086] In this embodiment, since only a second transistor is needed to output the first current, the complexity of the temperature sampling circuit structure is reduced. The first current can be mirrored to the first metering circuit via the first current mirror circuit to stably transmit the second electrical parameter, which is positively correlated with the measured temperature, thereby improving the accuracy of temperature measurement.

[0087] For example, in addition to using the second transistor M2 to obtain the first current I r Alternatively, a voltage-to-current conversion circuit can be used to convert the voltage difference ΔV between the fourth node N4 and the first node N1. EB The conversion is performed to obtain the first current I. r .

[0088] In one embodiment, the second current generation circuit 13 includes a second amplifier OP2, a third transistor M3, a fourth resistor R4, and a second current mirror circuit 131. The first input terminal of the second amplifier OP2 is coupled to a third node N3. The first terminal of the third transistor M3 is coupled to the power supply VDD, the second terminal is coupled to the second input terminal of the second amplifier OP2, and the control terminal is coupled to the output terminal of the second amplifier OP2. The first terminal of the fourth resistor R4 is coupled to both the second terminal of the third transistor M3 and the second input terminal of the second amplifier OP2, and the second terminal is coupled to the common terminal GND. The input side of the second current mirror circuit 131 is coupled between the power supply VDD and the third transistor M3, and the output side is coupled to the current input terminal of the second relaxation oscillation circuit 31.

[0089] In this embodiment, a voltage-to-current conversion circuit is constructed using a second amplifier, a third transistor, and a fourth resistor. The second current is the value of the voltage at the third node converted by the fourth resistor, and the second current can accurately reflect the magnitude of the voltage at the third node. Because the voltage-to-current conversion circuit has a simple structure, the complexity of the temperature sampling circuit is reduced. The second current mirror circuit can mirror the second current to the second metering circuit to stably transmit reference electrical parameters independent of the measured temperature, thereby improving the accuracy of temperature measurement.

[0090] For example, the first transistor M1 and the second transistor M2 are P-type field-effect transistors, and the third transistor M3 is an NPN-type field-effect transistor.

[0091] For example, the mirror ratio of the first current mirror circuit 121 and the second current mirror circuit 131 is 1, but it can also be a positive number such as 2, 3, or 4.

[0092] For example, when the first metering circuit 20 is applied to the first current I r The required number of mirrors is two, and the second metering circuit 30 is for the second current I. C When two current mirrors are required, the first current mirror circuit 121 and the second current mirror circuit 131 can be configured as follows: Figure 4a and Figure 4b As shown. Reference Figure 4a The first current mirror circuit 121 includes a first mirror transistor T1, a second mirror transistor T2, a third mirror transistor T3, a fourth mirror transistor T4, and a fifth mirror transistor T5. The first mirror transistor T1 is coupled between the second transistor T2 and the common terminal GND, and its control terminal is coupled to the first terminal to form a fifth node N5. The first terminal of the second mirror transistor T2 is coupled to the power supply VDD, and its second terminal is coupled to the control terminal to form a sixth node N6. The first terminal of the third mirror transistor T3 is coupled to the sixth node N6, its second terminal is coupled to the common terminal GND, and its control terminal is coupled to the fifth node N5. The first terminal of the fourth mirror transistor T4 is coupled to the power supply VDD, its second terminal is coupled to the first metering circuit 20, and its control terminal is coupled to the sixth node N6. The first terminal of the fifth mirror transistor T5 is coupled to the first metering circuit 20, its second terminal is coupled to the common terminal GND, and its control terminal is coupled to the fifth node N5.

[0093] refer to Figure 4b The second current mirror circuit 131 includes a sixth mirror transistor T6, a seventh mirror transistor T7, an eighth mirror transistor T8, a ninth mirror transistor T9, and a tenth mirror transistor T10. The sixth mirror transistor T6 is coupled between the power supply VDD and the third transistor M3, and its control terminal is coupled to its second terminal to form a seventh node N7. The first terminal of the seventh mirror transistor T7 is coupled to the power supply VDD, and its control terminal is coupled to the seventh node N7. The first terminal of the eighth mirror transistor T8 is coupled to the second terminal of the seventh mirror transistor T7, and the second terminal is coupled to the common terminal GND. Its control terminal is coupled to its first terminal to form an eighth node N8. The first terminal of the ninth mirror transistor T9 is coupled to the power supply VDD, and its second terminal is coupled to the second metering circuit 30. Its control terminal is coupled to the seventh node N7. The first terminal of the tenth mirror transistor T10 is coupled to the second metering circuit 30, and its second terminal is coupled to the common terminal GND. Its control terminal is coupled to the eighth node N8.

[0094] In one embodiment, such as Figure 5aAs shown, the first relaxation oscillation circuit 21 includes a first charging / discharging circuit 211, a first comparison circuit 212, and a first trigger circuit 213. The first charging / discharging circuit 211 is coupled to the first current generation circuit 12 and is used to generate current based on a first current I. r The first capacitor of the first charge / discharge circuit 211 is charged and discharged. The first comparator circuit 212 is coupled to the first charge / discharge circuit 211, the first node N1, and the second node N2, and is used to charge and discharge the first capacitor based on the voltage V and the first voltage V. EB1 Second voltage V EB2 Output a first comparison signal. The first trigger circuit 213 is coupled to the first charge / discharge circuit 211 and the first comparison circuit 212, and is used to output a first frequency signal according to the first comparison signal and control the first charge / discharge circuit 211.

[0095] In this embodiment, a first charging and discharging circuit charges and discharges a first capacitor with a first current, causing the voltage of the first capacitor to oscillate between a first voltage and a second voltage, with the oscillation frequency related to the magnitude of the first current. A first comparison circuit compares the voltage of the first capacitor with the first and second voltages, outputting a first comparison signal with a frequency related to the first current. A first trigger circuit latches the first comparison signal, outputting a first frequency signal, which controls the first charging and discharging circuit to charge and discharge the first capacitor. Since the first and second voltages are negatively correlated with the measured temperature, and the first current is positively correlated with the measured temperature, the first frequency signal formed after charging and discharging the first capacitor with the first current, comparing, and latching has a low correlation with the measured temperature. By processing the first and second electrical parameters using the first charging and discharging circuit, the first comparison circuit, and the first trigger circuit, a first frequency signal with low correlation to the measured temperature is obtained, reducing the complexity of the first relaxation oscillation circuit structure. Simultaneously, because the output first frequency signal has low correlation with the measured temperature, it can be used to accurately determine the measured temperature, thereby improving the accuracy of temperature measurement.

[0096] In one embodiment, the reference electrical parameters are as follows: Figure 5b As shown, the second relaxation oscillation circuit 31 includes a second charging / discharging circuit 311, a second comparison circuit 312, and a second trigger circuit 313. The second charging / discharging circuit 311 is coupled to the second current generation circuit 13 and is used to generate current based on the second current I. C The second capacitor of the second charge / discharge circuit 311 is charged and discharged. The second comparator circuit 312 is coupled to the second charge / discharge circuit 311, the first node N1, and the second node N2, and is used to charge and discharge the second capacitor based on the voltage of the second capacitor and the first voltage V. EB1 Second voltage V EB2The second comparison signal is output. The second trigger circuit 313 is coupled to the second charge / discharge circuit 311 and the second comparison circuit 312, and is used to output a second frequency signal according to the second comparison signal and control the second charge / discharge circuit 311.

[0097] In this embodiment, a second charging and discharging circuit charges and discharges a second capacitor with a second current, causing the voltage of the second capacitor to oscillate between a first voltage and a second voltage, with the oscillation frequency related to the magnitude of the second current. A second comparison circuit compares the voltage of the second capacitor with the first and second voltages, outputting a second comparison signal with a frequency related to the second current. A second trigger circuit latches the second comparison signal, outputting a second frequency signal, which controls the second charging and discharging circuit to charge and discharge the second capacitor. Since the first and second voltages are negatively correlated with the temperature to be measured, and the second current is independent of the temperature to be measured, the second frequency signal formed after charging and discharging the second capacitor with the second current, comparing, and latching it has a high correlation with the temperature to be measured. By processing the first electrical parameter and the reference electrical parameter using the second charging and discharging circuit, the second comparison circuit, and the second trigger circuit, a second frequency signal with a high correlation to the temperature to be measured is obtained, reducing the complexity of the second relaxation oscillation circuit structure. Simultaneously, because the output second frequency signal has a high correlation with the temperature to be measured, it can be used to accurately determine the temperature, thereby improving the accuracy of temperature measurement.

[0098] For example, such as Figure 4a and 6a As shown, the first charging / discharging circuit 211 includes a first switching unit S1, a second switching unit S2, and a first capacitor C1. The first terminal of the first switching unit S1 is coupled to the second terminal of the fourth mirror transistor T4. The first terminal of the second switching unit S2 is coupled to the second terminal of the first switching unit S1, and its second terminal is coupled to the first terminal of the fifth mirror transistor T5. The first terminal of the first capacitor C1 is coupled between the first switching unit S1 and the second switching unit S2, and its second terminal is coupled to the common terminal GND. The first comparison circuit 212 includes a first comparator CMP1 and a second comparator CMP2. The first input terminal of the first comparator CMP1 is coupled to the second node N2, and its second input terminal is coupled to the first terminal of the first capacitor C1. The first input terminal of the second comparator CMP2 is coupled to the first terminal of the first capacitor C1, and its second input terminal is coupled to the first node N1. The first trigger circuit 213 includes a first trigger FF1. The first input terminal of the first flip-flop FF1 is coupled to the output terminal of the first comparator CMP1, the second input terminal is coupled to the output terminal of the second comparator CMP2, the first output terminal is coupled to the control terminal of the first switching unit S1, and the second output terminal is coupled to the control terminal of the second switching unit S2.

[0099] For example, such as Figure 4b and6b As shown, the second charging / discharging circuit 311 includes a third switching unit S3, a fourth switching unit S4, and a second capacitor C2. The first terminal of the third switching unit S3 is coupled to the second terminal of the ninth mirror transistor T9. The first terminal of the fourth switching unit S4 is coupled to the second terminal of the third switching unit S3, and its second terminal is coupled to the first terminal of the tenth mirror transistor T10. The first terminal of the second capacitor C2 is coupled between the third switching unit S3 and the fourth switching unit S4, and its second terminal is coupled to the common terminal GND. The second comparison circuit 312 includes a third comparator CMP3 and a fourth comparator CMP4. The first input terminal of the third comparator CMP3 is coupled to the second node N2, and its second input terminal is coupled to the first terminal of the second capacitor C2. The first input terminal of the fourth comparator CMP4 is coupled to the first terminal of the second capacitor C2, and its second input terminal is coupled to the first node N1. The second trigger circuit 313 includes a second trigger FF2. The first input terminal of the second flip-flop FF2 is coupled to the output terminal of the third comparator CMP3, the second input terminal is coupled to the output terminal of the fourth comparator CMP4, the first output terminal is coupled to the control terminal of the third switching unit S3, and the second output terminal is coupled to the control terminal of the fourth switching unit S4.

[0100] For example, the first flip-flop FF1 and the second flip-flop FF2 can be RS flip-flops. The first input terminal of the first flip-flop FF1 and the first input terminal of the second flip-flop FF2 are reset terminals R, the second input terminals of the first flip-flop FF1 and the second input terminals of the second flip-flop FF2 are set terminals S, the first output terminal of the first flip-flop FF1 and the first output terminal of the second flip-flop FF2 are non-inverting output terminals Q, and the second output terminals of the first flip-flop FF1 and the second output terminals of the second flip-flop FF2 are inverting output terminals.

[0101] It is understandable that the first flip-flop FF1 and the second flip-flop FF2 can be RS flip-flops, JK flip-flops, D flip-flops, etc.

[0102] In one embodiment, such as Figure 2 As shown, the first metering circuit 20 further includes a first counter 22. The first counter 22 is coupled to the first relaxation oscillation circuit 21 and is used to count the period of the first frequency signal. The second metering circuit 30 further includes a second counter 32. The second counter 32 is coupled to the second relaxation oscillation circuit 31 and is used to count the period of the second frequency signal.

[0103] In this embodiment, since the period of the first frequency signal has a low correlation with the temperature to be measured, the first counter counts the first frequency signal, and the magnitude of the count indirectly reflects the level of the temperature to be measured. Since the period of the second frequency signal has a high correlation with the temperature to be measured, the second counter counts the second frequency signal, and the magnitude of the count directly reflects the level of the temperature to be measured. By using two counters to count the periods of two frequency signals with different correlations to the temperature to be measured, the temperature to be measured is determined, thereby reducing the complexity of the metering circuit structure.

[0104] For example, the first output or the second output of the first flip-flop FF1 is coupled to the first counter 22. The first output or the second output of the second flip-flop FF2 is coupled to the second counter 32.

[0105] In one embodiment, the first counter 22 and the second counter 32 stop counting in response to a stop counting trigger signal and output first measurement information and second measurement information. The temperature to be measured is determined based on the first measurement information and the second measurement information.

[0106] In this embodiment, the first and second counters start and stop counting simultaneously to output the first and second measurement information, respectively, ensuring that the total measurement time is the same. Within this equal time, the temperature to be measured can be determined based on the first and second measurement information, thereby improving the accuracy of temperature measurement.

[0107] In one embodiment, when the second metering information output by the second counter 32 meets the first preset condition, the first counter 22 stops counting and outputs the first metering information.

[0108] In this embodiment, since the period of the second frequency signal is highly correlated with the temperature to be measured, when the second measurement information output by the second counter meets the first preset condition, the magnitude of the second measurement information can reflect the magnitude of the temperature to be measured. Since the period of the first frequency signal remains almost constant with the temperature to be measured, the first counter outputs the first measurement information when the second measurement information meets the first preset condition, and the magnitude of the first measurement information can reflect the level of the temperature to be measured. Because different frequency signals have different sensitivities to the temperature to be measured, the temperature to be measured determined based on the measurement information can accurately reflect the actual temperature, thereby improving the accuracy of temperature measurement.

[0109] In one embodiment, the first counter 22 is an adder counter, and the second counter 32 is a subtractor counter, with the first counter 22 and the second counter 32 coupled together. When the second measurement information of the second counter 32 decreases from the preset measurement information to 0, the second measurement information satisfies the first preset condition. The second counter 32 sends a stop counting trigger signal to the first counter 22, causing the first counter 22 to stop counting, and the measurement information output by the first counter 22 is the first measurement information. Based on the first measurement information, the temperature to be measured can be determined. The relationship between the first measurement information, the preset measurement information, the first frequency signal, and the second frequency signal is as follows: n = m × tc / tr. Wherein, n is the first measurement information, m is the preset measurement information, tr is the period of the first frequency signal, and tc is the period of the second frequency signal. At this time, the first measurement information is positively correlated with the temperature to be measured.

[0110] In this embodiment, since the second counter is a subtraction counter, when the second measurement information of the second counter decreases from the preset measurement information to 0, a trigger signal can be automatically issued to stop the first counter from counting. Because no additional trigger signal is required, the complexity of the metering circuit structure is reduced.

[0111] It is understandable that, in addition to the first counter 22 being an adder and the second counter 32 being a subtractor, both the first counter 22 and the second counter 32 could also be subtractors.

[0112] In one embodiment, when the first measurement information output by the first counter meets the second preset condition, the second counter stops counting and outputs the second measurement information.

[0113] In this embodiment, since the period of the first frequency signal has low correlation with the temperature to be measured, when the first measurement information output by the first counter meets the second preset condition, the magnitude of the first measurement information can reflect the reference time. Since the period of the second frequency signal varies greatly with the temperature to be measured, when the first measurement information meets the second preset condition, the second counter is determined to output the second measurement information, and the magnitude of the second measurement information can reflect the level of the temperature to be measured. Because different frequency signals have different sensitivities to the temperature to be measured, the temperature to be measured determined based on the measurement information can accurately reflect the actual temperature, thereby improving the accuracy of temperature measurement.

[0114] In one embodiment, the first counter 22 is a subtraction counter, and the second counter 32 is an addition counter, with the first counter 22 and the second counter 32 coupled together. When the first measurement information of the first counter 22 decreases from a preset measurement information to 0, the first measurement information satisfies a second preset condition. The first counter 22 sends a stop-counting trigger signal to the second counter 32, causing the second counter 32 to stop counting, and the measurement information output by the second counter 32 is the second measurement information. Based on the second measurement information, the temperature to be measured can be determined.

[0115] For example, the first measurement information may include the first count value of the first counter 22, the second measurement information may include the second count value of the second counter 32, and the preset measurement information may be a pre-designed value.

[0116] In one embodiment, such as Figure 7a As shown, the temperature measuring circuit also includes a temperature output circuit 40. When the temperature to be measured is determined based on the first measurement information, the temperature output circuit 40 is coupled to the first counter 22 and is used to output the temperature to be measured based on the first measurement information.

[0117] In this embodiment, the temperature output circuit can process the highly accurate first measurement information to obtain the temperature to be measured, thereby improving the accuracy of temperature measurement.

[0118] For example, when the temperature to be measured is output based on the first measurement information, the temperature output circuit 40 can multiply the first measurement information by the temperature conversion coefficient to obtain the temperature change, and then superimpose the temperature change with the reference temperature to obtain the temperature to be measured. That is, the temperature output circuit 40 may include multiplication circuits and addition circuits, or it may include a microcontroller. After obtaining the temperature to be measured, the temperature output circuit 40 can display the temperature. That is, the temperature output circuit 40 may include a display circuit. The temperature conversion coefficient is related to the preset measurement information.

[0119] In one embodiment, such as Figure 7b As shown, when the temperature to be measured is determined based on the first measurement information and the second measurement information, the temperature output circuit 40 is coupled to both the first counter 22 and the second counter 32, and is used to output the temperature to be measured based on the first measurement information and the second measurement information.

[0120] In this embodiment, the temperature output circuit can process the first measurement information with high accuracy to obtain the temperature to be measured, thereby improving the accuracy of temperature measurement.

[0121] For example, when the temperature to be measured is output based on the first measurement information and the second measurement information, the temperature output circuit 40 can multiply the second measurement information by a preset conversion coefficient to obtain a temperature conversion coefficient, multiply the first measurement information by the temperature conversion coefficient to obtain a temperature change, and superimpose the temperature change with a reference temperature to obtain the temperature to be measured. That is, the temperature output circuit 40 may include multiplication circuits and addition circuits, or it may include a microcontroller.

[0122] This disclosure also provides a temperature sensor, which includes the temperature measurement circuit as described in any of the above embodiments.

[0123] The above-described contents can be implemented individually or in various combinations, and all such variations are within the scope of this disclosure.

[0124] This disclosure is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (devices), and computer program products according to embodiments of this disclosure. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create a machine for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0125] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0126] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0127] In this disclosure, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase “comprising…” does not exclude the presence of additional identical elements in the article or device that includes said element.

[0128] Although preferred embodiments of the present disclosure have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this disclosure.

[0129] Obviously, those skilled in the art can make various modifications and variations to this disclosure without departing from its spirit and scope. Therefore, if such modifications and variations fall within the scope of the claims of this disclosure and their equivalents, the intent of this disclosure also includes these modifications and variations.

Claims

1. A temperature measuring circuit, characterized in that, The temperature measuring circuit includes: A temperature sampling circuit is used to output a first electrical parameter, a second electrical parameter, and a reference electrical parameter. The first electrical parameter is negatively correlated with the temperature to be measured, the second electrical parameter is positively correlated with the temperature to be measured, and the reference electrical parameter is independent of the temperature to be measured. A first metering circuit, coupled to the temperature sampling circuit, is used to output a first frequency signal based on the first electrical parameter and the second electrical parameter, and to output first metering information based on the first frequency signal. The second metering circuit is coupled to the temperature sampling circuit and is used to output a second frequency signal according to the first electrical parameter and the reference electrical parameter, and to output second metering information according to the second frequency signal. Wherein, the first measurement information and the second measurement information are used to determine the temperature to be measured, and the correlation between the first frequency signal and the temperature to be measured is lower than the correlation between the second frequency signal and the temperature to be measured; The first metering circuit includes: A first relaxation oscillation circuit, coupled to the temperature sampling circuit, is used to output the first frequency signal based on the first electrical parameter and the second electrical parameter. The second metering circuit includes: The second relaxation oscillation circuit is coupled to the temperature sampling circuit and is used to output the second frequency signal according to the first electrical parameter and the reference electrical parameter. The temperature sampling circuit includes: A bandgap reference circuit includes a first node that outputs a first voltage and a second node that outputs a second voltage. The first voltage and the second voltage serve as a first electrical parameter. The difference between the first voltage and the second voltage is positively correlated with the temperature to be measured. The first node is coupled to the first voltage input terminal of both the first relaxation oscillation circuit and the second relaxation oscillation circuit. The second node is coupled to the second voltage input terminal of both the first relaxation oscillation circuit and the second relaxation oscillation circuit. The first relaxation oscillation circuit and the second relaxation oscillation circuit use the difference to process the second electrical parameter and the reference electrical parameter, respectively. A first current generating circuit is coupled to the current input terminals of the bandgap reference circuit and the first relaxation oscillation circuit, and is used to generate a first current, which serves as the second electrical parameter. The second current generating circuit is coupled to the current input terminals of both the bandgap reference circuit and the second relaxation oscillation circuit, and is used to generate a second current, which serves as the reference electrical parameter.

2. The temperature measuring circuit according to claim 1, characterized in that, The bandgap reference circuit includes: A first transistor, wherein a first terminal of the first transistor is used to couple to a power supply; A first resistor, wherein a first end of the first resistor is coupled to a second end of the first transistor to form a third node; The second resistor has its first end coupled to the second end of the first resistor to form a fourth node; A third resistor, the first end of which is coupled to the third node; The first temperature sensing transistor has a first terminal coupled to the second terminal of the second resistor to form the first node. The second terminal and the control terminal of the first temperature sensing transistor are both used to be coupled to a common terminal. The second temperature sensing transistor has its first terminal coupled to the second terminal of the third resistor to form the second node. Both the second terminal and the control terminal of the second temperature sensing transistor are used to be coupled to the common terminal. A first amplifier, wherein a first input terminal of the first amplifier is coupled to the fourth node, a second input terminal of the first amplifier is coupled to the second node, and an output terminal of the first amplifier is coupled to the control terminal of the first transistor.

3. The temperature measuring circuit according to claim 2, characterized in that, The first current generating circuit includes: The second transistor is coupled between the power supply and the common terminal, and the control terminal of the second transistor is coupled to the control terminal of the first transistor and the output terminal of the first amplifier. A first current mirror circuit, wherein the input side of the first current mirror circuit is coupled between the second transistor and the common terminal, and the output side of the first current mirror circuit is coupled to the current input terminal of the first relaxation oscillation circuit.

4. The temperature measuring circuit according to claim 2, characterized in that, The second current generating circuit includes: A second amplifier, wherein the first input terminal of the second amplifier is coupled to the third node; The third transistor has a first terminal for coupling to the power supply, a second terminal for coupling to the second input terminal of the second amplifier, and a control terminal for coupling to the output terminal of the second amplifier. The fourth resistor has its first end coupled to both the second end of the third transistor and the second input terminal of the second amplifier, and its second end is used to be coupled to the common terminal. The second current mirror circuit has its input side coupled between the power supply and the third transistor, and its output side coupled to the current input terminal of the second relaxation oscillation circuit.

5. The temperature measuring circuit according to any one of claims 1 to 4, characterized in that, The first relaxation oscillation circuit includes: A first charging and discharging circuit, coupled to the first current generating circuit, is used to charge and discharge the first capacitor of the first charging and discharging circuit according to the first current. A first comparison circuit is coupled to the first charging and discharging circuit, the first node, and the second node, and is used to output a first comparison signal based on the voltage of the first capacitor, the first voltage, and the second voltage. A first trigger circuit, coupled to both the first charge / discharge circuit and the first comparator circuit, is used to output the first frequency signal based on the first comparison signal and control the first charge / discharge circuit; and / or, The second relaxation oscillation circuit includes: The second charging and discharging circuit is coupled to the second current generating circuit and is used to charge and discharge the second capacitor of the second charging and discharging circuit according to the second current. The second comparison circuit is coupled to the second charging and discharging circuit, the first node, and the second node, and is used to output a second comparison signal based on the voltage of the second capacitor, the first voltage, and the second voltage. The second trigger circuit is coupled to both the second charge / discharge circuit and the second comparison circuit. It is used to output the second frequency signal according to the second comparison signal and control the second charge / discharge circuit.

6. The temperature measuring circuit according to any one of claims 1 to 4, characterized in that, The first metering circuit includes: A first counter is used to count the periods of the first frequency signal; The second metering circuit includes: The second counter is used to count the period of the second frequency signal; Wherein, the first counter and the second counter stop counting in response to a stop counting trigger signal and output the first measurement information and the second measurement information; or, When the second metering information output by the second counter meets the first preset condition, the first counter stops counting and outputs the first metering information; or, When the first metering information output by the first counter meets the second preset condition, the second counter stops counting and outputs the second metering information.

7. The temperature measuring circuit according to claim 6, characterized in that, The first counter is an adder counter, the second counter is a subtractor counter, and the first preset condition includes the second measurement information being 0.

8. A temperature sensor, characterized in that, Includes the temperature measuring circuit as described in any one of claims 1 to 7.

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