Temperature measuring circuit and temperature measuring device

Abstract

The utility model discloses a temperature measuring circuit and a temperature measuring device, and relates to the electronic circuit field, the temperature measuring circuit comprises a control module, a first temperature detection module and a second temperature detection module, the first temperature detection module comprises a first NTC unit and a first ADC detection unit, and the second temperature detection module comprises a second NTC unit and a second ADC detection unit. The second temperature detection module comprises a second NTC unit and a second ADC detection unit; the first NTC unit is connected with the control module, the second NTC unit is connected with the control module, the first ADC detection unit is connected with the first NTC unit, and the second ADC detection unit is connected with the second NTC unit. According to the utility model, the technical problem of low temperature detection reliability is solved.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of electronic circuits, and particularly to a temperature measurement circuit and a temperature measurement device. Background Art

[0002] As a commonly used temperature measurement instrument, a body temperature probe has been widely used in monitoring devices. Currently, most body temperature probes measure temperature through an NTC resistor. For example, the NTC is connected to an MCU chip, and the MCU measures the temperature by reading the voltage value of the NTC. During the process of measuring temperature through the MCU and the NTC, there may be situations such as NTC failures, but the MCU cannot detect whether the NTC for measuring temperature is faulty. When the NTC fails, the MCU still determines the measured temperature based on the faulty NTC, thereby affecting the reliability of temperature measurement.

[0003] The above content is only used to assist in understanding the technical solution of the embodiments of the present application, and does not represent an admission that the above content is prior art. Summary of the Utility Model

[0004] The main purpose of the present utility model is to provide a temperature measurement circuit and a temperature measurement device, aiming to solve the technical problem of low reliability of temperature detection.

[0005] To achieve the above object, the present utility model provides a temperature measurement circuit. The temperature measurement circuit includes a control module, a first temperature detection module, and a second temperature detection module. The first temperature detection module includes a first NTC unit and a first ADC detection unit, and the second temperature detection module includes a second NTC unit and a second ADC detection unit;

[0006] The first NTC unit is connected to the control module, the second NTC unit is connected to the control module, the first ADC detection unit is connected to the first NTC unit, and the second ADC detection unit is connected to the second NTC unit;

[0007] Both the first ADC detection unit and the second ADC detection unit are used to detect whether the ADC function of the control module is normal; the control module is used to detect the first voltage division value of the first NTC unit and the second voltage division value of the second NTC unit when the first NTC unit and the second NTC unit are turned on and the ADC function is normal. When the difference between the first voltage division value and the second voltage division value is greater than a preset difference threshold, the control module outputs an NTC abnormal signal.

[0008] In one embodiment, the first NTC unit includes a first pull-up resistor, a first NTC resistor, a first switching tube, a first protection resistor, and a second protection resistor;

[0009] The first end of the first pull-up resistor is connected to the power supply, the second end of the first pull-up resistor is connected to the first end of the first NTC resistor, the first end of the first NTC resistor is further connected to the first sampling interface of the control module, the second end of the first NTC resistor is connected to the source electrode of the first switching tube, the first ends of the first protection resistor and the second protection resistor are both connected to the gate electrode of the first switching tube, the second end of the first protection resistor is connected to the first interface of the control module, and the second end of the second protection resistor is grounded;

[0010] The control module is configured to control the first switching tube to conduct so as to control the first NTC resistor in the first NTC unit to conduct, and the control module is configured to control the first switching tube to cut off so as to control the first NTC resistor in the first NTC unit to cut off.

[0011] In one embodiment, the first ADC detection unit includes a first pull-down resistor, a second switching tube, a third protection resistor, and a fourth protection resistor;

[0012] The first end of the first NTC resistor and the first end of the first pull-down resistor are both connected to the second end of the first pull-up resistor, the second end of the first pull-down resistor is connected to the source electrode of the second switching tube, the gate electrode of the second switching tube is connected to the first end of the third protection resistor, the second end of the third protection resistor is connected to the second interface of the control module, the first end of the fourth protection resistor is connected to the gate electrode of the second switching tube, and the second end of the fourth protection resistor is grounded.

[0013] In one embodiment, the control module is configured to control the conduction and / or cut-off of the second switching tube; when the second switching tube is conducting and the first switching tube is cut off, the control module detects the third voltage division value of the first pull-down resistor; when the third voltage division value is greater than a preset first voltage division threshold and less than a preset second voltage division threshold, the control module outputs an ADC abnormal signal.

[0014] In one embodiment, the second NTC unit includes a second pull-up resistor, a second NTC resistor, a third switching tube, a fifth protection resistor, and a sixth protection resistor;

[0015] The first end of the second pull-up resistor is connected to the power supply, the second end of the second pull-up resistor is connected to the first end of the second NTC resistor, the first end of the second NTC resistor is connected to the second sampling interface of the control module, the second end of the second NTC resistor is connected to the source electrode of the third switching tube, the first ends of the fifth protection resistor and the sixth protection resistor are both connected to the gate electrode of the third switching tube, the second end of the fifth protection resistor is connected to the third interface of the control module, and the second end of the sixth protection resistor is grounded;

[0016] The control module is configured to control the third switching transistor to conduct, so as to control the second NTC resistor in the second NTC unit to conduct, and the control module is configured to control the third switching transistor to cut off, so as to control the second NTC resistor in the second NTC unit to cut off.

[0017] In one embodiment, the second ADC detection unit includes a second pull-down resistor, a fourth switching transistor, a seventh protection resistor, and an eighth protection resistor;

[0018] The first end of the second NTC resistor and the first end of the second pull-down resistor are both connected to the second end of the second pull-up resistor. The second end of the second pull-down resistor is connected to the source of the fourth switching transistor. The gate of the fourth switching transistor is connected to the first end of the seventh protection resistor. The second end of the seventh protection resistor is connected to the fourth interface of the control module. The first end of the eighth protection resistor is connected to the gate of the fourth switching transistor, and the second end of the eighth protection resistor is grounded.

[0019] In one embodiment, the control module is configured to control the conduction and / or cut-off of the fourth switching transistor. When the fourth switching transistor is conducting and the third switching transistor is cut off, the control module detects the fourth voltage division value of the second pull-down resistor. When the fourth voltage division value is greater than a preset first voltage threshold and less than a preset second voltage threshold, the control module outputs an ADC abnormal signal.

[0020] In one embodiment, when the first switching transistor and the third switching transistor are conducting and the second switching transistor and the third switching transistor are cut off, the control module detects the first sampling value of the first sampling interface and the second sampling value of the second sampling interface to detect the temperature.

[0021] In one embodiment, the first switching transistor, the second switching transistor, the third switching transistor, and the fourth switching transistor are all NMOS transistors.

[0022] In addition, to achieve the above object, the present invention further provides a temperature measurement device, and the temperature measurement device includes the temperature measurement circuit as described above.

[0023] One or more technical solutions proposed by the present utility model have at least the following technical effects: By providing a first temperature detection module and a second temperature detection module in the temperature measurement circuit, and the first temperature detection module includes a first NTC unit and a first ADC detection unit, the present utility model realizes detecting whether the ADC function of the control module is normal through the first ADC detection unit and the second ADC detection unit. Furthermore, when the ADC function of the control module is normal and the first NTC unit and the second NTC unit are conducting, the first voltage division value of the first NTC unit and the second voltage division value of the second NTC resistor can be detected, so that the voltage division values corresponding to the two NTC units can be detected. The control module can output an NTC abnormal signal when the difference between the first voltage division value and the second voltage division value is greater than a preset difference threshold, and further detect whether there is an abnormal NTC in the temperature measurement circuit, thereby facilitating avoiding temperature measurement in the case of NTC abnormality and improving the reliability of temperature detection. Description of the Drawings

[0024] The drawings herein are incorporated into the specification and constitute a part of this specification, showing embodiments that conform to the embodiments of the present application, and are used together with the specification to explain the principles of the embodiments of the present application.

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0026] Figure 1 Schematic circuit diagram of an embodiment of the temperature measurement circuit of the utility model;

[0027] Figure 2 Schematic circuit connection diagram of the first NTC unit in the temperature measurement circuit of the utility model;

[0028] Figure 3 Schematic circuit connection diagram of the first temperature detection module in the temperature measurement circuit of the utility model;

[0029] Figure 4 Schematic circuit connection diagram of an embodiment in the temperature measurement circuit of the utility model;

[0030] Figure 5 Schematic circuit connection diagram of an example in the temperature measurement circuit of the utility model.

[0031] The realization of the objectives, functional characteristics, and advantages of the embodiments of the present application will be further described with reference to the embodiments and the drawings.

[0032] Explanation of the reference numerals in the drawings:

[0033] 100, Control module; 200, First temperature detection module; 300, Second temperature detection module; 210, First NTC unit; 220, First ADC detection unit; 310, Second NTC unit; 320, Second ADC detection unit; Q1 - Q4, First to Fourth switching transistors; R1, First NTC resistor;

[0034] R2, First pull - up resistor; R3, First protection resistor; R4, Second protection resistor; R5, First pull - down resistor; R6 - R7, Third to Fourth protection resistors; R8, Second NTC resistor; R9, Second pull - up resistor; R10, Second pull - down resistor; R11 - R14, Fifth to Eighth protection resistors; R15, Third pull - up resistor; R16, Third NTC resistor; NTC1_DEC, First sampling interface; NTC2_DEC, Second sampling interface; NTC1_CTL, First interface; NTC1_ADJ, Second interface; NTC2_CTL, Third interface; NTC2_ADJ, Fourth interface. Specific embodiments

[0035] It should be understood that the specific embodiments described herein are only used to explain the technical solutions of the embodiments of the present application and are not used to limit the embodiments of the present application.

[0036] To better understand the technical solutions of the embodiments of the present application, the following will be described in detail in conjunction with the accompanying drawings of the specification and specific implementation manners.

[0037] Based on this, referring to Figure 1 , this embodiment provides a temperature - measuring circuit. Referring to Figure 1 , Figure 1 which is a connection schematic diagram of the temperature - measuring circuit of the embodiments of the present application.

[0038] The temperature - measuring circuit includes a control module 100, a first temperature detection module 200, and a second temperature detection module 300. The first temperature detection module includes a first NTC unit 210 and a first ADC detection unit 220. The second temperature detection module includes a second NTC unit 310 and a second ADC detection unit 320;

[0039] The first NTC unit 210 is connected to the control module 100, the second NTC unit 310 is connected to the control module 100, the first ADC detection unit 220 is connected to the first NTC unit 210, and the second ADC detection unit 230 is connected to the second NTC unit 310;

[0040] Both the first ADC detection unit 220 and the second ADC detection unit 230 are configured to detect whether the ADC function of the control module 100 is normal; the control module 100 is configured to detect a first divided voltage value of the first NTC unit 210 and a second divided voltage value of the second NTC unit 310 when the first NTC unit 210 and the second NTC unit 310 are turned on and the ADC function is normal. When the difference between the first divided voltage value and the second divided voltage value is greater than a preset difference threshold, the control module 100 outputs an NTC abnormal signal.

[0041] It should be noted that the control module 100 may be a control chip, such as an MCU. Both the first temperature detection module 200 and the second temperature detection module 300 can be used to detect temperature. The first temperature detection module 200 includes a first NTC unit 210 and a first ADC unit. The first NTC unit 210 is configured to detect temperature, and the first ADC unit is configured to detect whether the ADC function of the control module 100 is normal. Detecting whether the ADC function is normal may include detecting whether the analog signal detected by the first temperature detection unit received by the control module 100 is normal and whether the analog signal can be normally converted into a digital signal.

[0042] The second temperature detection module 300 includes a second NTC unit 310 and a second ADC unit. The second NTC unit 310 is configured to detect temperature, and the second ADC unit can also be used to detect whether the ADC function of the control module 100 is normal.

[0043] When the ADC function is normal, the first NTC unit 210 and the second NTC unit 310 can be controlled to conduct, and the first partial pressure value of the first NTC unit 210 and the second partial pressure value of the second NTC unit 310 are detected. The first partial pressure value refers to the voltage value of the first NTC unit 210 detected by the control module 100, and the second partial pressure value is the voltage value of the second NTC unit 310 detected by the control module 100. The first partial pressure value can reflect the temperature detected by the first NTC unit 210, and the second partial pressure value can also reflect the temperature detected by the second NTC unit 310. When the difference between the detected first partial pressure value and the second partial pressure value is too large, that is, greater than the preset difference threshold, it indicates that the temperature detected by the first temperature detection module 200 and the temperature detected by the second temperature detection module 300 are too different. The first temperature detection module 200 and the second temperature detection module 300 are in the same space, and the temperature in the same space is the same. When the detected temperature difference is too large, it indicates that there is an abnormal NTC. Therefore, in this embodiment, by detecting the first partial pressure value and the second partial pressure value when the ADC function is normal, whether there is a faulty NTC in the temperature measurement circuit can be detected. The preset difference threshold can be determined based on the actual situation, and this embodiment does not make specific limitations on this.

[0044] Further, referring to Figure 2 , the first NTC unit 210 includes a first pull-up resistor R2, a first NTC resistor R1, a first switching transistor Q1, a first protection resistor R3, and a second protection resistor R4;

[0045] The first end of the first pull-up resistor R2 is connected to the power supply, the second end of the first pull-up resistor R2 is connected to the first end of the first NTC resistor R1, the first end of the first NTC resistor R1 is also connected to the first sampling interface NTC1_DEC of the control module 100, the second end of the first NTC resistor R1 is connected to the source of the first switching transistor Q1, the first ends of the first protection resistor R3 and the second protection resistor R4 are both connected to the gate of the first switching transistor Q1, the second end of the first protection resistor R3 is connected to the first interface NTC1_CTL of the control module 100, and the second end of the second protection resistor R4 is grounded;

[0046] The control module 100 is used to control the first switching transistor Q1 to conduct to control the first NTC resistor R1 in the first NTC unit 210 to conduct, and the control module 100 is used to control the first switching transistor Q1 to cut off to control the first NTC resistor R1 in the first NTC unit 210 to cut off.

[0047] It should be noted that the first switching transistor Q1 is used to control the conduction or cutoff of the first NTC resistor R1. When the first switching transistor Q1 is conducting, the first NTC resistor R1 is conducting; when the first switching transistor Q1 is cutoff, the first NTC resistor R1 is cutoff. The control module 100 is used to control the conduction and / or cutoff of the first switching transistor Q1. The gate of the first switching transistor Q1 is connected to the first interface NTC1_CTL of the control module 100 through the first protection resistor R3. The control module 100 controls the conduction and / or cutoff of the first switching transistor Q1 through the first interface NTC1_CTL. The first interface NTC1_CTL is an IO port of the control module 100, and the voltage of the gate of the first switching transistor Q1 can be adjusted to conduct or cutoff the first switching transistor Q1.

[0048] In the case where the first switching transistor Q1 is conducting and the first ADC detection unit 220 is cutoff, the first pull-up resistor R2 and the first NTC resistor R1 in the first temperature detection module 200 form a voltage dividing circuit. The voltage value at the first end of the first NTC resistor R1 can be detected to obtain the first voltage division value. Both the first protection resistor R3 and the second protection resistor R4 are used to protect the first switching transistor Q1. For example, referring to Figure 2 , the first voltage division value is the voltage value between the first pull-up resistor R2 and the first NTC resistor R1.

[0049] Furthermore, referring to Figure 3 , the first ADC detection unit 220 includes a first pull-down resistor R5, a second switching transistor Q2, a third protection resistor R6, and a fourth protection resistor R7;

[0050] The second end of the first NTC resistor R1 and the first end of the first pull-down resistor R5 are both connected to the second end of the first pull-up resistor R2. The second end of the first pull-down resistor R5 is connected to the source of the second switching transistor Q2. The gate of the second switching transistor Q2 is connected to the first end of the third protection resistor R6. The second end of the third protection resistor R6 is connected to the second interface NTC1_ADJ of the control module 100. The first end of the fourth protection resistor R7 is connected to the gate of the second switching transistor Q2, and the second end of the fourth protection resistor R7 is grounded.

[0051] It should be noted that the cutoff of the first ADC detection unit 220 means that the second switching transistor Q2 of the first ADC detection unit 220 is cutoff. When the second switching transistor Q2 is cutoff, the first pull-down resistor R5 is not conducting; when the second switching transistor Q2 is cutoff, the first pull-down resistor R5 is conducting.

[0052] The second interface NTC1_ADJ is an IO port of the control module 100. The gate of the second switching transistor Q2 is connected to the second interface NTC1_ADJ of the control module 100 through a third protection resistor R6. The control module 100 can control the conduction and / or cut-off of the second switching transistor Q2. Both the third protection resistor R6 and the fourth protection resistor R7 are used to protect the third switching transistor Q3.

[0053] The first end of the first pull-down resistor R5 is connected to the second end of the first pull-up resistor R2, and also to the first end of the first NTC resistor R1. The first end of the first NTC resistor R1 is connected to the first sampling interface NTC1_DEC of the control module 100. The first end of the first pull-down resistor R5 is also equivalent to being connected to the first sampling interface NTC1_DEC of the control module 100. When the first switching transistor Q1 is cut off and the second switching transistor Q2 is conducting, the control module 100 can detect the voltage value at the first end of the first pull-down resistor R5 through the first sampling interface NTC1_DEC, that is, the third divided voltage value. For example, referring to Figure 3 , the third divided voltage value is the voltage value between the first pull-up resistor R2 and the first pull-down resistor R5.

[0054] Furthermore, the control module 100 is used to control the conduction and / or cut-off of the second switching transistor Q2. When the second switching transistor Q2 is conducting and the first switching transistor Q1 is cut off, the control module 100 detects the third divided voltage value of the first pull-down resistor R5. When the third divided voltage value is greater than a preset first divided voltage threshold and less than a preset second divided voltage threshold, the control module 100 outputs an ADC abnormal signal.

[0055] It should be noted that the control module 100 can also be used to control the conduction and / or cut-off of the first switching transistor Q1. The third divided voltage value is the voltage value at the first end of the first pull-down resistor R5. When the first switching transistor Q1 is cut off and the second switching transistor Q2 is conducting, the first NTC resistor R1 is not conducting, and the first pull-down resistor R5 is conducting. In the first temperature detection module 200, a voltage dividing circuit is formed by the first pull-up resistor R2 and the first pull-down resistor R5. What the control module 100 detects is the voltage value at the first end of the first pull-down resistor R5, that is, the third divided voltage value. The third divided voltage value can be expressed as: (R9 / (R9 + R10)) * VCC.

[0056] Since the first pull - down resistor R5 is a fixed resistor, when the first switching transistor Q1 is turned off and the second switching transistor Q2 is turned on, the third divided voltage value detected by the control module 100 should be a constant value, that is, the third divided voltage value should be less than or equal to the preset first divided voltage threshold and greater than or equal to the preset second divided voltage threshold. Since there may be certain errors during the process of detecting the voltage value of the first pull - down resistor R5, and the detected third divided voltage value may have certain fluctuations, when the detected third divided voltage value is less than or equal to the preset first divided voltage threshold and greater than or equal to the preset second divided voltage threshold, it can be considered that the detected third divided voltage value is normal. The normal third divided voltage value indicates that the ADC function of the control module 100 is normal. The normal ADC function may mean that the ADC detection circuit corresponding to the control module 100 in the first temperature detection module 200 is normal, that is, the first pull - up resistor R2 in the first temperature detection module 200 is normal.

[0057] In the case where the third divided voltage value is greater than the preset first divided voltage threshold and less than the preset second divided voltage threshold, it indicates that the detected third divided voltage value is abnormal. The control module 100 outputs an ADC abnormal signal, and the ADC abnormal signal is used to indicate that the ADC function of the control module 100 is abnormal, so as to indicate that there is an abnormality in the temperature measurement circuit and it is not suitable to use the temperature measurement circuit to detect the temperature.

[0058] In this embodiment, by setting the first switching transistor Q1 and the second switching transistor Q2 in the first temperature detection module 200, the third divided voltage value can be detected when the first switching transistor Q1 is turned off and the second switching transistor Q2 is turned on. Furthermore, it can be detected whether there is a fault in the ADC function corresponding to the control module 100, so as to detect the faults existing in the temperature measurement circuit and improve the reliability of temperature detection.

[0059] Further, in a feasible embodiment, referring to Figure 4 , the second NTC unit 310 includes a second pull - up resistor R9, a second NTC resistor R8, a third switching transistor Q3, a fifth protection resistor R11, and a sixth protection resistor R12;

[0060] The first end of the second pull - up resistor R9 is connected to the power supply, the second end of the second pull - up resistor R9 is connected to the first end of the second NTC resistor R8, the first end of the second NTC resistor R8 is connected to the second sampling interface NTC2_DEC of the control module 100, the second end of the second NTC resistor R8 is connected to the source of the third switching transistor Q3, the first ends of the fifth protection resistor R11 and the sixth protection resistor R12 are both connected to the gate of the third switching transistor Q3, the second end of the fifth protection resistor R11 is connected to the first interface NTC1_CTL of the control module 100, and the second end of the sixth protection resistor R12 is grounded;

[0061] The control module 100 is configured to control the third switching transistor Q3 to conduct, so as to control the second NTC resistor R8 in the second NTC unit 310 to conduct, and the control module 100 is configured to control the third switching transistor Q3 to cut off, so as to control the second NTC resistor R8 in the second NTC unit 310 to cut off.

[0062] It should be noted that the second temperature detection module 300 includes a second NTC unit 310 and a second ADC unit. The second NTC unit 310 is used to detect temperature, and the second ADC unit is used to detect whether the ADC function of the control module 100 is normal. Detecting whether the ADC function is normal may include detecting whether the analog signal detected by the second temperature detection unit received by the control module 100 is normal, and whether the analog signal can be normally converted into a digital signal.

[0063] The third switching transistor Q3 is used to control the conduction or cut-off of the second NTC resistor R8. When the third switching transistor Q3 conducts, the second NTC resistor R8 conducts. When the third switching transistor Q3 cuts off, the second NTC resistor R8 cuts off. The control module 100 is configured to control the conduction and / or cut-off of the third switching transistor Q3. The gate of the third switching transistor Q3 is connected to the third interface NTC2_CTL of the control module 100 through a fifth protection resistor R11. The control module 100 controls the conduction and / or cut-off of the third switching transistor Q3 through the third interface NTC2_CTL. The third interface NTC2_CTL is an IO port of the control module 100, and the voltage of the gate of the third switching transistor Q3 can be adjusted to conduct or cut off the third switching transistor Q3.

[0064] In the case where the third switching transistor Q3 conducts and the second ADC detection unit 230 cuts off, the second pull-up resistor R9 and the second NTC resistor R8 in the second temperature detection module 300 form a voltage dividing circuit. The voltage value of the first end of the second NTC resistor R8 can be detected to obtain a second voltage dividing value. The fifth protection resistor R11 and the sixth protection resistor R12 are both used to protect the first switching transistor Q1. For example, referring to Figure 4 , since Q2 does not conduct when detecting the second voltage dividing value, the second voltage dividing value is Figure 4 the voltage value between the second pull-up resistor R9 and the second NTC resistor R8 in

[0065] In a feasible embodiment, the second ADC detection unit 230 includes a second pull-down resistor R10, a fourth switching transistor Q4, a seventh protection resistor R13, and an eighth protection resistor R14;

[0066] The first end of the second NTC resistor R8 and the first end of the second pull-down resistor R10 are both connected to the second end of the second pull-up resistor R9. The second end of the second pull-down resistor R10 is connected to the source electrode of the fourth switching transistor Q4. The gate electrode of the fourth switching transistor Q4 is connected to the first end of the seventh protection resistor R13. The second end of the seventh protection resistor R13 is connected to the first interface NTC1_CTL of the control module 100. The first end of the eighth protection resistor R14 is connected to the gate electrode of the fourth switching transistor Q4. The second end of the eighth protection resistor R14 is grounded.

[0067] It should be noted that the cut-off of the second ADC detection unit 230 means that the fourth switching transistor Q4 of the second ADC detection unit 230 is cut off. When the fourth switching transistor Q4 is cut off, the second pull-down resistor R10 is not conducting. When the fourth switching transistor Q4 is cut off, the second pull-down resistor R10 is conducting.

[0068] The fourth interface NTC2_ADJ is an IO port of the control module 100. The gate electrode of the fourth switching transistor Q4 is connected to the fourth interface NTC2_ADJ of the control module 100 through the seventh protection resistor R13. The control module 100 can control the conduction and / or cut-off of the fourth switching transistor Q4. Both the seventh protection resistor R13 and the eighth protection resistor R14 are used to protect the fourth switching transistor Q4.

[0069] The first end of the second pull-down resistor R10 is connected to the second end of the second pull-up resistor R9 and also to the first end of the second NTC resistor R8. The first end of the second NTC resistor R8 is connected to the second sampling interface NTC2_DEC of the control module 100. The first end of the second pull-down resistor R10 is also equivalent to being connected to the second sampling interface NTC2_DEC of the control module 100. In the case where the third switching transistor Q3 is cut off and the fourth switching transistor Q4 is conducting, the control module 100 can detect the voltage value at the first end of the second pull-down resistor R10, that is, the fourth voltage division value, through the second sampling interface NTC2_DEC. Refer to Figure 4 that the fourth voltage division value is the voltage value between the second pull-up resistor R9 and the second pull-down resistor in the case where Q3 is not conducting.

[0070] In a feasible embodiment, the control module 100 is used to control the conduction and / or cut-off of the fourth switching transistor Q4. In the case where the fourth switching transistor Q4 is conducting and the third switching transistor Q3 is cut off, the control module 100 detects the fourth voltage division value of the second pull-down resistor R10. In the case where the fourth voltage division value is not equal to the preset voltage division value, the control module 100 outputs an ADC abnormal signal.

[0071] It should be noted that the control module 100 can also be used to control the conduction and / or cut-off of the second switching transistor Q2. The fourth voltage division value is the voltage value at the first end of the second pull-down resistor R10. When the third switching transistor Q3 is cut off and the fourth switching transistor Q4 is conducting, the second NTC resistor R8 is non-conducting and the second pull-down resistor R10 is conducting. In the second temperature detection module 300, the second pull-up resistor R9 and the second pull-down resistor R10 form a voltage division circuit. What the control module 100 detects is the voltage value at the first end of the second pull-down resistor R10, that is, the fourth voltage division value, and the fourth voltage division value can be expressed as: (R2 / (R2 + R5)) * VCC.

[0072] Since the second pull-down resistor R10 is a fixed resistor, when the third switching transistor Q3 is cut off and the fourth switching transistor Q4 is conducting, the fourth voltage division value detected by the control module 100 should be a constant value, that is, the fourth voltage division value should be less than or equal to the preset first voltage division threshold and greater than or equal to the preset second voltage division threshold. Since there may be certain errors during the process of detecting the voltage value of the second pull-down resistor R10 and the detected fourth voltage division value may have certain fluctuations, when the detected fourth voltage division value is less than or equal to the preset first voltage division threshold and greater than or equal to the preset second voltage division threshold, it can be considered that the detected fourth voltage division value is normal. The normal fourth voltage division value indicates that the ADC function of the control module 100 is normal. The normal ADC function may include that the ADC detection loop corresponding to the control module 100 in the second temperature detection module 300 is normal, that is, the second pull-up resistor R9 in the second temperature detection module 300 is normal.

[0073] When the fourth voltage division value is greater than the preset first voltage division threshold and less than the preset second voltage division threshold, it indicates that the detected fourth voltage division value is abnormal. The control module 100 outputs an ADC abnormal signal, and the ADC abnormal signal is used to indicate that the ADC function of the control module 100 is abnormal, so as to indicate that there is an abnormality in the temperature measurement circuit and it is not suitable to use the temperature measurement circuit to detect the temperature.

[0074] In this embodiment, by setting the third switching transistor Q3 and the fourth switching transistor Q4 in the second temperature detection module 300, the fourth voltage division value can be detected when the third switching transistor Q3 is cut off and the fourth switching transistor Q4 is conducting. Furthermore, it can be detected whether there is a fault in the ADC function corresponding to the control module 100, so as to detect the faults existing in the temperature measurement circuit and improve the reliability of temperature detection.

[0075] Further, in a feasible embodiment, when the first switching transistor Q1 and the third switching transistor Q3 are turned on and the second switching transistor Q2 and the fourth switching transistor Q4 are turned off, the control module 100 detects a first sampling value of the first sampling interface NTC1_DEC and a second sampling value of the second sampling interface NTC2_DEC to detect the temperature.

[0076] It should be noted that when the first switching transistor Q1 and the third switching transistor Q3 are turned on and the second switching transistor Q2 and the fourth switching transistor Q4 are turned off, it means that the first NTC resistor R1 and the second NTC resistor R8 are turned on, and the first pull-down resistor R5 and the second pull-down resistor R10 are not turned on. At this time, the temperature can be detected through the first NTC resistor R1 and the second NTC resistor R8. The first sampling value refers to the first temperature value, and the second sampling value refers to the second temperature value. The first sampling value is obtained by the control module 100 after analog-to-digital conversion of the voltage value detected at the first end of the first NTC, and the second sampling value is also obtained by the control module 100 after analog-to-digital conversion of the voltage value detected at the first end of the second NTC. In this embodiment, the average value of the first sampling value and the second sampling value can be used as the temperature value detected by the temperature measurement circuit to improve the accuracy of the temperature measurement circuit in detecting the temperature.

[0077] In a feasible embodiment, the first switching transistor Q1, the second switching transistor Q2, the third switching transistor Q3, and the fourth switching transistor Q4 are all NMOS transistors. For NMOS transistors, when the gate voltage (VGS) is less than the preset threshold voltage (Vth), the NMOS transistor is in the cut-off state; when the gate voltage (VGS) is greater than the preset threshold voltage (Vth), the NMOS transistor is turned on. Therefore, the conduction and cut-off of the NMOS transistor can be controlled by adjusting the gate voltage. In this embodiment, the first switching transistor Q1, the second switching transistor Q2, the third switching transistor Q3, and the fourth switching transistor Q4 are respectively connected to the first interface NTC1_CTL, the second interface NTC1_ADJ, the third interface NTC2_CTL, and the fourth interface NTC2_ADJ of the control module 100. Therefore, the control module 100 can respectively adjust the gate voltages of the first switching transistor Q1, the second switching transistor Q2, the third switching transistor Q3, and the fourth switching transistor Q4 to respectively control the conduction and / or cut-off of the first switching transistor Q1, the second switching transistor Q2, the third switching transistor Q3, and the fourth switching transistor Q4.

[0078] Further, reference can be made to Figure 4 and Figure 5 , Figure 5 a circuit for temperature detection using NTC in the prior art, Figure 5Only the temperature is detected through the third pull-up resistor R15 and the third NTC resistor R16, and the control module 100 cannot detect whether there is a fault in R16, so there is a problem of unreliable temperature detection. In this embodiment, by separately turning on and / or off the first switch tube Q1, the second switch tube Q2, the third switch tube Q3, and the fourth switch tube Q4, it is possible to detect whether the ADC function corresponding to the temperature measurement circuit is normal when the second switch tube Q2 and the fourth switch tube Q4 are turned on and the first switch tube Q1 and the third switch tube Q3 are turned off. Furthermore, when the ADC function is normal, the second switch tube Q2 and the fourth switch tube Q4 are turned off, and the first switch tube Q1 and the third switch tube Q3 are turned on, the first voltage division value and the second voltage division value are detected, and then whether there is an abnormal NTC in the temperature measurement circuit is detected, so that the fault of the NTC can be detected, and temperature detection can be avoided in the case of NTC fault, improving the reliability of temperature detection. And when there is no faulty NTC in the temperature measurement circuit and the ADC function is also normal, temperature detection can also be performed when the second switch tube Q2 and the fourth switch tube Q4 are turned off and the first switch tube Q1 and the third switch tube Q3 are turned on, thereby improving the accuracy of temperature detection.

[0079] The present invention also provides a temperature measurement device, which includes the temperature measurement circuit as described above. The structure of the temperature measurement circuit can refer to the above embodiments and will not be elaborated here. Naturally, since the temperature measurement device of this embodiment includes all the technical solutions of all the embodiments of the above temperature measurement device and the achieved technical effects are exactly the same, they will not be elaborated here.

[0080] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. A temperature measurement circuit, characterized in that: The temperature measurement circuit includes a control module, a first temperature detection module and a second temperature detection module, the first temperature detection module includes a first NTC unit and a first ADC detection unit, and the second temperature detection module includes a second NTC unit and a second ADC detection unit; The first NTC unit is connected to the control module, the second NTC unit is connected to the control module, the first ADC detection unit is connected to the first NTC unit, and the second ADC detection unit is connected to the second NTC unit; The first ADC detection unit and the second ADC detection unit are both used to detect whether the ADC function of the control module is normal; the control module is used to detect a first voltage division value of the first NTC unit and a second voltage division value of the second NTC unit when the first NTC unit and the second NTC unit are controlled to be turned on and the ADC function is normal, and when the difference between the first voltage division value and the second voltage division value is greater than a preset difference threshold, the control module outputs an NTC abnormality signal.

2. The temperature measuring circuit according to claim 1, characterized in that: The first NTC unit includes a first pull-up resistor, a first NTC resistor, a first switch tube, a first protection resistor and a second protection resistor; The first end of the first pull-up resistor is connected to a power supply, the second end of the first pull-up resistor is connected to the first end of the first NTC resistor, the first end of the first NTC resistor is also connected to the first sampling interface of the control module, the second end of the first NTC resistor is connected to the source of the first switch tube, the first end of the first protection resistor and the first end of the second protection resistor are both connected to the gate of the first switch tube, the second end of the first protection resistor is connected to the first interface of the control module, and the second end of the second protection resistor is grounded; The control module is used to control the first switch tube to be turned on to control the first NTC resistor in the first NTC unit to be turned on, and the control module is used to control the first switch tube to be turned off to control the first NTC resistor in the first NTC unit to be turned off.

3. The temperature measuring circuit according to claim 2, characterized in that: The first ADC detection unit includes a first pull-down resistor, a second switch tube, a third protection resistor and a fourth protection resistor; The first end of the first NTC resistor and the first end of the first pull-down resistor are both connected to the second end of the first pull-up resistor, the second end of the first pull-down resistor is connected to the source of the second switch tube, the gate of the second switch tube is connected to the first end of the third protection resistor, the second end of the third protection resistor is connected to the second interface of the control module, the first end of the fourth protection resistor is connected to the gate of the second switch tube, and the second end of the fourth protection resistor is grounded.

4. The temperature measuring circuit according to claim 3, characterized in that: The control module is used to control the conduction and / or cutoff of the second switch tube; when the second switch tube is turned on and the first switch tube is cut off, the control module detects the third voltage division value of the first pull-down resistor; when the third voltage division value is greater than a preset first voltage division threshold and less than a preset second voltage division threshold, the control module outputs an ADC abnormal signal.

5. The temperature measuring circuit according to claim 1, characterized in that: The second NTC unit includes a second pull-up resistor, a second NTC resistor, a third switch tube, a fifth protection resistor and a sixth protection resistor; A first end of the second pull-up resistor is connected to a power supply, a second end of the second pull-up resistor is connected to a first end of a second NTC resistor, a first end of the second NTC resistor is connected to a second sampling interface of a control module, a second end of the second NTC resistor is connected to a source of a third switch tube, a first end of a fifth protection resistor and a first end of a sixth protection resistor are both connected to a gate of the third switch tube, a second end of the fifth protection resistor is connected to a third interface of the control module, and a second end of the sixth protection resistor is grounded; The control module is used to control the third switch tube to be turned on to control the second NTC resistor in the second NTC unit to be turned on, and the control module is used to control the third switch tube to be turned off to control the second NTC resistor in the second NTC unit to be turned off.

6. The temperature measuring circuit according to claim 5, characterized in that: The second ADC detection unit includes a second pull-down resistor, a fourth switch tube, a seventh protection resistor and an eighth protection resistor; The first end of the second NTC resistor and the first end of the second pull-down resistor are both connected to the second end of the second pull-up resistor, the second end of the second pull-down resistor is connected to the source of the fourth switch tube, the gate of the fourth switch tube is connected to the first end of the seventh protection resistor, the second end of the seventh protection resistor is connected to the fourth interface of the control module, the first end of the eighth protection resistor is connected to the gate of the fourth switch tube, and the second end of the eighth protection resistor is grounded.

7. The temperature measuring circuit according to claim 6, characterized in that: The control module is used to control the conduction and / or cutoff of the fourth switch tube. When the fourth switch tube is turned on and the third switch tube is cut off, the control module detects the fourth voltage division value of the second pull-down resistor. When the fourth voltage division value presets a first voltage division threshold and is less than a preset second voltage division threshold, the control module outputs an ADC abnormal signal.

8. The temperature measuring circuit according to any one of claims 1 to 7, characterized in that: When the first switch tube and the third switch tube are turned on and the second switch tube and the third switch tube are turned off, the control module detects a first sampling value of the first sampling interface and a second sampling value of the second sampling interface to detect the temperature. 9 . The temperature measurement circuit according to claim 1 , wherein the first switch tube, the second switch tube, the third switch tube and the fourth switch tube are all NMOS tubes.

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

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