Temperature sampling circuit, sampling method and vehicle
By introducing auxiliary voltage divider resistors and control switches into the temperature sampling circuit, combined with filtering and current limiting capacitors, the problem of limited measurement accuracy and range caused by the nonlinearity of NTC thermistors is solved, and stable and reliable measurement over a wide temperature range is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA FAW CO LTD
- Filing Date
- 2025-12-12
- Publication Date
- 2026-05-12
AI Technical Summary
In existing temperature sampling circuits, the resistance of NTC thermistors exhibits a non-linear relationship with temperature, which limits the measurement accuracy and range, making it difficult to maintain stability over a wide range.
A combination of main voltage divider resistors, auxiliary voltage divider resistors, and control switches is used. The control switch controls the connection and disconnection of the auxiliary voltage divider resistors to adapt to the measurement requirements of different temperature ranges. Combined with filter capacitors and current-limiting resistors, voltage sampling is stabilized.
It achieves stability and adaptability in maintaining measurement accuracy over a wide temperature range, and improves the measurement range and reliability of the temperature sampling circuit.
Smart Images
Figure CN122016072A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of vehicle technology, specifically to a temperature sampling circuit, sampling method, and vehicle. Background Technology
[0002] In existing technologies, NTC thermistors are widely used in temperature measurement due to their low cost and fast response speed. However, the non-linear relationship between the resistance of NTC thermistors and temperature limits the wide range and high accuracy of the entire measurement system. Current temperature sampling circuits typically use a fixed voltage divider resistor connected in series with the NTC thermistor to form a voltage divider, and sampling is performed at the voltage divider point. Research has shown that this circuit method yields varying sampling accuracy across different temperature ranges, thus limiting the overall measurement temperature range to maintain a certain level of accuracy. Therefore, improving the measurement range of the entire sampling circuit while maintaining stable measurement accuracy is a pressing technical problem that needs to be addressed in the industry. Summary of the Invention
[0003] This invention provides a temperature sampling circuit, sampling method, and vehicle to address the problem of how to improve the measurement range of the entire sampling circuit and maintain the stability of measurement accuracy, at least providing a beneficial option or creating conditions.
[0004] This invention provides a temperature sampling circuit, comprising: a main voltage divider resistor, an auxiliary voltage divider resistor, an NTC thermistor, a control switch, a power supply voltage node, a ground node, a sampling node, a control interface, and a sampling interface; The power supply voltage node is connected to one end of the main voltage divider resistor and one end of the control switch; the control terminal of the control switch is connected to the control interface, and the control interface is connected to an external control module. The other end of the control switch is connected to one end of the auxiliary voltage divider resistor; the other end of the main voltage divider resistor is connected to one end of the NTC thermistor, the other end of the auxiliary voltage divider resistor, and the sampling node; the sampling node is connected to an external acquisition module through the sampling interface; the other end of the NTC thermistor is connected to the ground node.
[0005] Furthermore, the temperature sampling circuit also includes an oscillation suppression resistor, which is connected in series between the control terminal of the control switch and the control interface.
[0006] Furthermore, the temperature sampling circuit also includes a current-limiting resistor, which is connected in series between the sampling node and the sampling interface.
[0007] Furthermore, the temperature sampling circuit also includes a first filter capacitor, one end of which is connected to the sampling node, and the other end of which is connected to the ground node.
[0008] Furthermore, the temperature sampling circuit also includes a second filter capacitor, one end of which is connected to the sampling interface, and the other end of which is connected to the ground node.
[0009] Furthermore, the control switch is an NMOS transistor, the gate of which is connected to the control interface, the source of which is connected to the power supply voltage node, and the drain of which is connected to one end of the auxiliary voltage divider resistor.
[0010] Furthermore, the value of the first filter capacitor is in the nanofarad range.
[0011] Furthermore, the value of the second filter capacitor is in the nanofarad range.
[0012] On the other hand, a temperature sampling method is provided, which is applied to the temperature sampling circuit in any one of the above technical solutions. The temperature sampling method includes: when it is determined that the current temperature is in a set high temperature range, turning on the control switch to connect the auxiliary voltage divider resistor; after determining that the auxiliary voltage divider resistor is connected, collecting temperature data through the sampling node. When the current temperature is determined to be within the set low temperature range, the control switch is turned off, causing the auxiliary voltage divider resistor to disconnect. After the auxiliary voltage divider resistor is disconnected, temperature data is collected through the sampling node.
[0013] On the other hand, a vehicle is provided that integrates a temperature sampling circuit as described in any of the above-mentioned technical solutions.
[0014] This invention has at least the following beneficial effects: By adding an auxiliary voltage divider resistor and a control switch, and using the control switch to control whether the auxiliary voltage divider resistor is connected or not, the entire temperature sampling circuit can adapt to different temperature changes while ensuring acquisition accuracy. This results in a wider measurement temperature range and more reliable results. Furthermore, this invention also provides a corresponding sampling method and vehicle. The beneficial effects of the sampling method and vehicle are similar to those of the system and will not be repeated here. This invention is primarily applicable to the field of vehicle technology. Attached Figure Description
[0015] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the technical solutions of the present invention, and do not constitute a limitation on the technical solutions of the present invention.
[0016] Figure 1 This is a schematic diagram of the circuit structure of a temperature sampling circuit; Figure 2 This is a specific component block diagram of a temperature sampling circuit; Figure 3 This is a schematic diagram of the circuit structure of a temperature sampling circuit in the prior art. Detailed Implementation
[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0018] It should be noted that although functional modules are divided in the system diagram and the logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the system or the order in the flowchart. The terms "first," "second," etc., in the specification, claims, and the aforementioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.
[0019] Before providing a detailed description of the embodiments of this application, some of the nouns and terms involved in the embodiments of this application will be explained first. The nouns and terms involved in the embodiments of this application are subject to the following interpretations.
[0020] An NTC thermistor is an electronic component whose resistance is highly sensitive to temperature changes.
[0021] In vehicle-related technologies, how to improve the measurement range of the entire sampling circuit and maintain the stability of measurement accuracy are technical issues that urgently need to be studied in the industry.
[0022] refer to Figure 3 , Figure 3 This is a schematic diagram of the circuit structure of a temperature sampling circuit in the prior art.
[0023] In existing related technologies, the overall temperature sampling circuit structure typically uses a fixed voltage divider resistor R6 and a thermistor R7 (NTC) connected in series to form a voltage divider, with the ADC module of the MCU main control chip sampling at the voltage divider point AN. Research has revealed limitations of this approach, including: 1. Limited measurement accuracy: Due to the limited selection of fixed resistor values, the accuracy of the entire measurement system is limited by the nonlinear characteristics of the NTC thermistor. The rate of resistance change of the NTC thermistor varies across different temperature ranges; the resistance is high and the rate of change is high in the low-temperature region, while it is low and the change is gradual in the high-temperature region. Therefore, good measurement resolution can only be obtained within a fixed temperature range. 2. Limited measurement range: Since a single fixed-value voltage divider resistor cannot simultaneously optimize the measurement accuracy of the NTC thermistor in both high-temperature and low-temperature regions, some applications often choose a compromise voltage divider resistor value to cover a wider measurement range, thus limiting the measurement range. 3. Limited response speed.
[0024] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the circuit structure of a temperature sampling circuit.
[0025] To address the problems in the prior art, this application discloses a temperature sampling circuit, including: a main voltage divider resistor R1, an auxiliary voltage divider resistor R2, an NTC thermistor R5, a control switch Q1, a power supply voltage node V1, a ground node, a sampling node A, a control interface MCU_GPIO, and a sampling interface MCU_AN.
[0026] The power supply voltage node V1 is connected to one end of the main voltage divider resistor R1 and one end of the switch side of the control switch Q1. The control terminal of the control switch Q1 is connected to the control interface MCU_GPIO, which is connected to an external control module. The other end of the switch side of the control switch Q1 is connected to one end of the auxiliary voltage divider resistor R2. The other end of the main voltage divider resistor R1 is connected to one end of the NTC thermistor R5, the other end of the auxiliary voltage divider resistor R2, and the sampling node A.
[0027] The sampling node A is connected to an external acquisition module through the sampling interface MCU_AN; the other end of the NTC thermistor R5 is connected to the ground node.
[0028] In actual operation, the power supply voltage node V1 is connected to an external power supply voltage, and the ground node is connected to an external ground terminal. The control interface MCU_GPIO can be connected to an external control module, typically an automotive-grade control chip. The sampling interface MCU_AN can be connected to an external sampling module, typically an automotive-grade sampling chip. In some embodiments, the control chip and sampling chip can be integrated into a single automotive-grade chip. In this case, the control interface MCU_GPIO is connected to the control terminal of the integrated chip, and the sampling interface MCU_AN is connected to the ADC port of the integrated chip.
[0029] refer to Figure 2 , Figure 2 This is a flowchart of the temperature sampling method.
[0030] To more clearly illustrate the working principle of the temperature sampling circuit of this application, the following description focuses on the temperature sampling method. This application also provides a corresponding temperature sampling method based on the temperature sampling circuit. Specifically, the temperature sampling method includes: when it is determined that the current temperature is within a set high temperature range, turning on the control switch Q1 to connect the auxiliary voltage divider resistor R2; after confirming that the auxiliary voltage divider resistor R2 is connected, collecting temperature data through sampling node A.
[0031] When the current temperature is determined to be within the set low temperature range, the control switch Q1 is turned off, causing the auxiliary voltage divider resistor R2 to disconnect. After the auxiliary voltage divider resistor R2 is disconnected, temperature data is collected through sampling node A.
[0032] It should be noted that the setting of the high temperature range and the low temperature range is related to the specific circuit component parameters. Therefore, in actual operation, the high temperature range and the low temperature range are preset.
[0033] At lower temperatures, the NTC thermistor R5 has a large resistance. With the same temperature change, the resistance is large and the rate of change is large. The voltage difference obtained after voltage division calculation far exceeds the sampling module's acquisition accuracy. At this time, the external control module's pin outputs a low level through the control interface MCU_GPIO, and the control switch Q1 is in the off state. The auxiliary voltage divider resistor R2 is not connected to the circuit; only the main voltage divider resistor R1 acts as the voltage divider resistor, dividing the voltage with the NTC thermistor R5. The voltage is then sampled at sampling node A through the sampling interface MCU_AN.
[0034] At higher temperatures, the NTC thermistor R5 has a smaller resistance. Under the same temperature change, the resistance is small and the rate of change is small, resulting in a very small sampled voltage after voltage division calculation, which is lower than the acquisition accuracy of the sampling module. At this time, the pin of the external control module outputs a high level through the control interface MCU_GPIO, and the control switch Q1 is in the conducting state. At this time, the auxiliary voltage divider resistor R2 is connected in parallel with the main voltage divider resistor R1 to obtain a voltage divider resistor with a smaller resistance value. This voltage is then divided by the NTC thermistor R5, and the voltage is sampled at sampling node A through the sampling interface MCU_AN.
[0035] The calculation of the parameters for the main voltage divider resistor R1 and the auxiliary voltage divider resistor R2 needs to be determined based on the sampling accuracy. The calculation method is as follows: assuming the sampling module's acquisition accuracy is... If the bit is 1, then the voltage that 1 LSB can recognize is: .
[0036] Assuming the minimum temperature change to be detected is the resistance of the NTC thermistor R5, which is... Change to The sampling voltage difference is: .
[0037] Research revealed that at lower temperatures, specifically in the low-temperature range, the NTC thermistor R5 exhibits a larger resistance. With the same temperature change, the larger resistance and the greater rate of change result in a sampling voltage difference calculated using voltage divider techniques, far exceeding the acquisition accuracy of the sampling module.
[0038] That is, it manifests as: At this point, there is no need to connect the auxiliary voltage divider resistor R2; the acquisition accuracy is sufficient to sample the current temperature.
[0039] Research revealed that at higher temperatures, specifically in the high-temperature range, the NTC thermistor R5 has a smaller resistance. Under the same temperature change, the resistance is small and the rate of change is small, resulting in a very small sampling voltage obtained after voltage division calculation, which is lower than the acquisition accuracy of the sampling module.
[0040] That is, it manifests as: At this point, an auxiliary voltage divider resistor R2 needs to be connected to ensure the accuracy of the current temperature sampling.
[0041] in, This represents the voltage at the supply voltage node V1. This represents the resistance value of the main voltage divider resistor R1. This represents the resistance value of the NTC thermistor R5 before the change. This is expressed as the resistance value of the NTC thermistor R5 after the change.
[0042] This invention adds an auxiliary voltage divider resistor R2 and a control switch Q1. The control switch Q1 controls whether the auxiliary voltage divider resistor R2 is connected or not, allowing the entire temperature sampling circuit to adapt to different temperature variations while maintaining acquisition accuracy. This results in a wider measurement temperature range and more reliable results.
[0043] To ensure reliable control of the control switch Q1, in some further embodiments, the temperature sampling circuit also includes an oscillation suppression resistor R3, which is connected in series between the control terminal of the control switch Q1 and the control interface MCU_GPIO. The oscillation suppression resistor R3 allows the control signal to act more stably on the control switch Q1, suppressing oscillations in the circuit. The resistance value of the oscillation suppression resistor R3 is typically selected to be tens to one hundred ohms.
[0044] To prevent the acquisition module from being damaged by high voltage or high current during sampling, in some further embodiments, the temperature sampling circuit also includes a current-limiting resistor R4, which is connected in series between sampling node A and sampling interface MCU_AN. Generally, the current-limiting resistor R4 has a relatively large resistance value, which can be determined according to the specific parameters of the acquisition module.
[0045] To ensure voltage stability at sampling node A and avoid interference, in some further embodiments, the temperature sampling circuit also includes a first filter capacitor C1. One end of the first filter capacitor C1 is connected to sampling node A, and the other end is connected to the ground node. Generally, the capacitance value of the first filter capacitor C1 is on the order of nanofarads.
[0046] To ensure voltage stability at the sampling interface MCU_AN and avoid interference, in some further embodiments, the temperature sampling circuit also includes a second filter capacitor C2. One end of the second filter capacitor C2 is connected to the sampling interface MCU_AN, and the other end is connected to ground. Generally, the capacitance value of the second filter capacitor C2 is on the order of nanofarads.
[0047] The control switch Q1 can be an NMOS transistor, PMOS transistor, bipolar diode, or relay. Its main function is to connect and disconnect the auxiliary voltage divider resistor R2. In some further specific embodiments, the control switch Q1 is an NMOS transistor, the gate of which is connected to the control interface MCU_GPIO, the source of which is connected to the power supply voltage node V1, and the drain of which is connected to one end of the auxiliary voltage divider resistor R2.
[0048] On the other hand, the present invention also provides a vehicle that integrates a temperature sampling circuit according to any one of the above specific embodiments.
[0049] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatuses.
[0050] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.
[0051] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, apparatuses, or units, and may be electrical, mechanical, or other forms.
[0052] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.
[0053] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.
[0054] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.
[0055] Although the description of this application has been quite detailed and particularly focused on several of the described embodiments, it is not intended to limit itself to any of these details or embodiments or any particular embodiment. Rather, it should be considered as effectively covering the intended scope of this application by referring to the appended claims and taking into account the prior art, which provides for a broad possible interpretation of these claims. Furthermore, the foregoing description of this application with respect to embodiments foreseeable by the inventors is intended to provide a useful description, and non-substantial modifications to this application that have not yet been foreseen may still represent equivalent modifications.
[0056] It should be noted that in all specific embodiments of this application, when processing data related to user identity or characteristics, such as user information, user behavior data, user historical data, and user location information, user permission or consent is obtained first. Furthermore, the collection, use, and processing of this data comply with relevant laws, regulations, and standards. In addition, when embodiments of this application require access to sensitive personal information of users, separate permission or consent from the user is obtained through pop-ups or redirection to confirmation pages. Only after obtaining the user's separate permission or consent is the necessary user-related data required for the proper functioning of these embodiments acquired.
Claims
1. A temperature sampling circuit, characterized in that, include: Main voltage divider resistor, auxiliary voltage divider resistor, NTC thermistor, control switch, power supply voltage node, ground node, sampling node, control interface and sampling interface; The power supply voltage node is connected to one end of the main voltage divider resistor and one end of the control switch; the control terminal of the control switch is connected to the control interface, and the control interface is connected to an external control module. The other end of the control switch is connected to one end of the auxiliary voltage divider resistor; the other end of the main voltage divider resistor is connected to one end of the NTC thermistor, the other end of the auxiliary voltage divider resistor, and the sampling node; the sampling node is connected to an external acquisition module through the sampling interface; the other end of the NTC thermistor is connected to the ground node.
2. The temperature sampling circuit according to claim 1, characterized in that, It also includes an oscillation suppression resistor, which is connected in series between the control terminal of the control switch and the control interface.
3. The temperature sampling circuit according to claim 1, characterized in that, It also includes a current-limiting resistor, which is connected in series between the sampling node and the sampling interface.
4. A temperature sampling circuit according to claim 1, characterized in that, It also includes a first filter capacitor, one end of which is connected to the sampling node and the other end of which is connected to the ground node.
5. A temperature sampling circuit according to claim 1, characterized in that, It also includes a second filter capacitor, one end of which is connected to the sampling interface and the other end of which is connected to the ground node.
6. A temperature sampling circuit according to claim 1, characterized in that, The control switch is an NMOS transistor. The gate of the NMOS transistor is connected to the control interface, the source of the NMOS transistor is connected to the power supply voltage node, and the drain of the NMOS transistor is connected to one end of the auxiliary voltage divider resistor.
7. A temperature sampling circuit according to claim 4, characterized in that, The value of the first filter capacitor is in the nanofarad range.
8. A temperature sampling circuit according to claim 5, characterized in that, The value of the second filter capacitor is in the nanofarad range.
9. A temperature sampling method, characterized in that, The temperature sampling method is applied in the temperature sampling circuit according to any one of claims 1 to 8. The temperature sampling method includes: when it is determined that the current temperature is in a set high temperature range, turning on the control switch to connect the auxiliary voltage divider resistor; after determining that the auxiliary voltage divider resistor is connected, collecting temperature data through the sampling node. When the current temperature is determined to be within the set low temperature range, the control switch is turned off, causing the auxiliary voltage divider resistor to disconnect. After the auxiliary voltage divider resistor is disconnected, temperature data is collected through the sampling node.
10. A vehicle, characterized in that, The vehicle integrates a temperature sampling circuit as described in any one of claims 1 to 8.