Temperature-compensated humidity segmented calibration circuit with reusable computing unit

Abstract

This invention discloses a temperature-compensated humidity segmented calibration circuit with a reusable computing unit, comprising: a process control module, a high-precision analog-to-digital converter (ADC), an internal memory, and a reusable computing unit; the process control module is connected to the ADC and the internal memory module, and the ADC and the internal memory module are respectively connected to the reusable computing unit; the ADC is responsible for accurately acquiring temperature and humidity signals in the environment and converting analog signals into digital signals; the internal memory uses non-volatile memory to store calibration coefficients obtained through extensive experiments and data analysis. These coefficients are meticulously classified and stored for different temperature ranges and humidity measurement ranges, providing accurate parameter support for the calibration process; the reusable computing unit is the core of the entire circuit, undertaking the key calculation tasks for temperature and humidity calibration.

Description

Technical Field

[0001] This invention relates to the field of sensor signal processing technology, and specifically to a temperature-compensated humidity segmented calibration circuit. Background Technology

[0002] Accurate humidity measurement is crucial in numerous fields, including industrial manufacturing, environmental monitoring, medical equipment, and smart homes. As a key component for acquiring humidity data, the accuracy of humidity sensors directly impacts product quality, environmental comfort, and equipment operational stability. However, fluctuations in ambient temperature have always been a major interference factor affecting the accuracy of humidity sensor measurements. For example, for common capacitive humidity sensors, temperature changes alter the physical properties of their sensitive elements, causing changes in capacitance and leading to measurement deviations. Studies have shown that when temperature fluctuations are within ±10℃, the measurement error of humidity sensors can reach as high as ±5%RH, which significantly limits the application of humidity sensors in scenarios with stringent accuracy requirements.

[0003] To overcome the influence of temperature on humidity measurement and improve its accuracy, temperature compensation and segmented calibration of humidity sensors are essential. Temperature compensation aims to eliminate the errors added to humidity measurement results due to temperature variations, while segmented calibration performs more detailed calibration operations based on the differences in sensor characteristics within different humidity ranges, thereby comprehensively improving the accuracy of humidity measurement.

[0004] Traditional humidity calibration circuits typically employ multiple independent computing units to perform temperature compensation and segmented calibration functions separately. This design has several drawbacks. Firstly, each independent computing unit requires its own operational logic circuits, storage units, and other hardware resources, resulting in significant waste of hardware resources, a substantial increase in circuit cost, and higher overall power consumption. Secondly, the combination of multiple independent computing units leads to an extremely complex circuit structure, undoubtedly increasing the difficulty of circuit design, debugging, and subsequent maintenance. Furthermore, the complex circuit structure is more susceptible to noise interference, further reducing system stability and reliability. Therefore, developing a humidity calibration circuit and its implementation method that effectively integrates temperature compensation and segmented calibration functions, significantly reduces hardware resource consumption, and lowers circuit complexity and cost, has urgent practical needs and significant application value. Summary of the Invention

[0005] The present invention proposes a temperature-compensated humidity segmented calibration circuit with a reusable computing unit, which can at least solve one of the technical problems in the background art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A temperature-compensated humidity segmented calibration circuit with a reusable computing unit includes: a process control module, a high-precision analog-to-digital converter (ADC), an internal memory, and a reusable computing unit. The process control module is connected to the high-precision analog-to-digital converter (ADC) and the internal storage module, and the high-precision analog-to-digital converter (ADC) and the internal storage module are respectively connected to the reusable computing unit. The high-precision analog-to-digital converter (ADC) is responsible for accurately acquiring temperature and humidity signals from the environment and converting analog signals into digital signals for subsequent processing. The internal memory uses non-volatile memory to store calibration coefficients obtained through extensive experiments and data analysis. These coefficients are meticulously categorized and stored for different temperature ranges and humidity measurement ranges, providing accurate parameter support for the calibration process. The reusable computing unit is the core of the entire circuit, undertaking the critical calculation tasks of temperature and humidity calibration.

[0007] Furthermore, the reusable computing unit of the present invention includes: selector one, selector two, selector three, register one, register two, register three, and adder; The output of selector one is connected to the data input of register one, where input a is connected to the output of register one, and another input b is connected to the output of register two. The selection control terminal ctrl is controlled by the internal state machine of the system. The output of register one is connected to the control terminal of selector two and the control terminal of selector three (ctrl), and the clock signal input is connected to the internal system clock. The output of selector 2 is connected to the data input of register 2, one input terminal b is connected to the output of register 2, and the other input terminal a is connected to the data output of the internal memory. The output of selector 3 is connected to the data input of register 3, one input terminal b is connected to the output of register 3, and the other input terminal a is connected to the data output of the internal memory. The output of register 3 is connected to the adder, and the clock signal input is connected to the internal system clock. The output of register 2 is connected to the adder, and the clock signal input is connected to the internal system clock.

[0008] Furthermore, the data calibration formula for the reusable computing unit of the present invention is as follows: (1) In the formula, a and b are the endpoint values ​​of the temperature or humidity segments, x is the value before calibration, and y is the intermediate or final value during calibration.

[0009] Furthermore, the reusable computing unit of the present invention performs data calibration by including the following steps: S1. Data Acquisition: The temperature and humidity in the environment are sampled by a high-precision analog-to-digital converter (ADC) to obtain the raw temperature data T0 and humidity data RH0. S2, Temperature positioning: Substitute the original temperature data T0 into x in formula (1), and substitute a and b into the corresponding temperature coefficients stored in the internal memory. After calculation, the temperature positioning data T1 is obtained. S3. Humidity positioning: Substitute RH0 into x in formula (1), and substitute a and b into the humidity coefficient in the internal memory to calculate the humidity positioning data RH1. S4. Humidity calibration under temperature compensation: Based on the temperature location data T1, determine the humidity curves at two adjacent temperature points tL and tH; At temperature tL, two boundary values ​​are determined based on humidity location data RH1. These two boundary values ​​are substituted into a and b in formula (1) to calculate the humidity result RH2 at tL. At temperature tH, two boundary values ​​are obtained based on RH1. Substituting a and b, the humidity result RH3 at temperature tH is calculated. The actual temperature is between tL and tH, and the humidity result at the actual temperature is between RH2 and RH3. Taking RH2 and RH3 as a and b, the formula (1) is used again for calculation, and finally the accurate humidity result RH after temperature compensation and segmented calibration at the current temperature is obtained. S5. Final temperature calibration: Based on T1, obtain the two adjacent temperature boundary values, substitute them into a and b in formula (1), and calculate the more accurate actual temperature T.

[0010] As can be seen from the above technical solution, this invention utilizes a combination of shift registers and adders to calculate linear formulas, thus constructing a reusable computing unit. Based on the data collected by the temperature sensing circuit, the high-order bits of the result calculated by the reusable computing unit are used for partitioning and positioning, selecting two adjacent humidity change curves at different temperatures and obtaining a temperature reference value. Based on the data collected by the humidity sensing circuit, two adjacent humidity value points are selected from the humidity change curves at different temperatures using the result calculated by the reusable computing unit. Based on these two humidity values, a humidity reference value is calculated by the reusable computing unit; that is, each humidity curve has one humidity reference value. Using the two humidity reference values ​​as nodes, the slope and intercept are obtained. Combined with the temperature reference value, a humidity calibration value is calculated by the reusable computing unit.

[0011] All coefficients in the calculation process are adjustable, allowing for flexible adjustment of the compensation direction and magnitude, facilitating testing and calibration during chip manufacturing. Compared to existing technologies, this invention eliminates the need for a host computer for digital processing and complex digital compensation circuits. It innovatively combines algorithms with a single computing unit to complete temperature compensation and humidity segmented calibration calculations, significantly reducing hardware resource consumption and lowering circuit costs. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the temperature-compensated humidity segmented calibration circuit structure of the reusable computing unit of the present invention; Figure 2 This is a schematic diagram of the reusable computing unit circuit of the present invention; Figure 3 This is the core of the reusable computing unit of the present invention; Figure 4 This is a flowchart illustrating the calibration process of the reusable computing unit of this invention. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0014] like Figure 1 As shown, the temperature-compensated humidity segmented calibration circuit with reusable computing unit described in this embodiment includes: a process control module, a high-precision analog-to-digital converter (ADC), an internal memory, and a reusable computing unit. The process control module is connected to the high-precision analog-to-digital converter (ADC) and the internal storage module, and the high-precision analog-to-digital converter (ADC) and the internal storage module are respectively connected to the reusable computing unit. The high-precision analog-to-digital converter (ADC) is responsible for accurately acquiring temperature and humidity signals from the environment and converting analog signals into digital signals for subsequent processing. For internal memory, non-volatile memory, such as electrically erasable programmable read-only memory (EEPROM), is recommended. It is used to store calibration coefficients obtained through extensive experiments and data analysis. These coefficients are meticulously categorized and stored for different temperature ranges and humidity measurement ranges, providing accurate parameter support for the calibration process. The reusable computing unit is the core of the entire circuit, undertaking the critical calculation tasks of temperature and humidity calibration.

[0015] Among them, such as Figure 2As shown, the reusable computing unit includes selector 1, selector 2, selector 3, register 1, register 2, register 3, and adder; The output of selector one is connected to the data input of register one, where input a is connected to the output of register one, and another input b is connected to the output of register two. The selection control terminal ctrl is controlled by the internal state machine of the system. The output of register one is connected to the control terminal of selector two and the control terminal of selector three (ctrl), and the clock signal input is connected to the internal system clock. The output of selector 2 is connected to the data input of register 2, one input terminal b is connected to the output of register 2, and the other input terminal a is connected to the data output of the internal memory. The output of selector 3 is connected to the data input of register 3, one input terminal b is connected to the output of register 3, and the other input terminal a is connected to the data output of the internal memory. The output of register 3 is connected to the adder, and the clock signal input is connected to the internal system clock. The output of register 2 is connected to the adder, and the clock signal input is connected to the internal system clock.

[0016] like Figure 3 As shown, the calibration formula upon which the reusable computing unit is based is: (1); In the formula, a and b are the endpoint values ​​of the temperature or humidity segments, x is the value before calibration, and y is the intermediate or final value during calibration.

[0017] Because this formula involves multiplication and addition operations, it occupies a relatively large area in hardware circuit implementation. However, since this calculation unit is frequently used during temperature or humidity calibration, reusing the same calculation unit can greatly reduce the overall area of ​​the calibration calculation circuit and effectively reduce hardware costs.

[0018] Its calibration process is as follows Figure 4 As shown, the specific process is as follows: S1. Data Acquisition: The temperature and humidity in the environment are sampled by a high-precision analog-to-digital converter (ADC) to obtain the raw temperature data T0 and humidity data RH0. S2, Temperature positioning: Substitute the original temperature data T0 into x in the above formula (1), and substitute a and b into the corresponding temperature coefficients stored in the internal storage module. After calculation, the temperature positioning data T1 is obtained. S3, Humidity positioning: Substitute RH0 into x in formula (1), and substitute a and b into the humidity coefficient in the internal storage module to calculate the humidity positioning data RH1; S4. Humidity calibration under temperature compensation: Because humidity is affected by temperature, the humidity curves are different at different temperatures. Based on the temperature location data T1, the humidity curves at two adjacent temperature points tL and tH are determined. At temperature tL, two boundary values ​​are determined based on the humidity location data RH1. These two boundary values ​​are substituted into a and b in formula (1) to calculate the humidity result RH2 at tL. Similarly, at temperature tH, two boundary values ​​are obtained based on RH1. These are substituted into a and b to calculate the humidity result RH3 at tH. Since the actual temperature is between tL and tH, the humidity result at the actual temperature should be between RH2 and RH3. Taking RH2 and RH3 as a and b, we use formula (1) again to calculate and finally obtain the accurate humidity result RH at the current temperature after temperature compensation and segmented calibration. S5. Final temperature calibration: Based on T1, obtain the two adjacent temperature boundary values, substitute them into a and b in formula (1), and calculate the more accurate actual temperature T.

[0019] After the calibration process is complete, the calibrated temperature and humidity data can be transmitted through the chip's communication system.

[0020] In summary, the core of the humidity segmentation calibration algorithm of this invention is a linear formula, which is calculated using a combination of shift registers and adders. Based on the data collected by the temperature sensing circuit, the high-order bits of the result calculated by the reusable computing unit are used for partitioning and positioning, selecting two adjacent humidity change curves at different temperatures and obtaining temperature reference values. Based on the data collected by the humidity sensing circuit, two adjacent humidity value points are selected from the humidity change curves at different temperatures using the result calculated by the reusable computing unit. Based on these two humidity values, a humidity reference value is calculated by the reusable computing unit; that is, each humidity curve has one humidity reference value. Using the two humidity reference values ​​as nodes, the slope and intercept are obtained. Combined with the temperature reference value, the humidity calibration value is calculated by the reusable computing unit. After obtaining the temperature reference value, two adjacent temperature values ​​are selected in the memory using this value. Similarly, using the same computing unit, the slope and intercept are obtained from these two temperature values ​​as nodes, and combined with the temperature reference value, the temperature calibration value is calculated.

[0021] All coefficients in the calculation process are adjustable, allowing for flexible adjustment of the compensation direction and magnitude, facilitating testing and calibration during chip manufacturing. Compared to existing technologies, this invention eliminates the need for a host computer for digital processing and complex digital compensation circuits. It innovatively combines algorithms with a single computing unit to complete temperature compensation and humidity segmented calibration calculations, significantly reducing hardware resource consumption and lowering circuit costs.

[0022] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0023] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0024] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A temperature-compensated humidity segmented calibration circuit with a reusable computing unit, characterized in that, include: The system includes a process control module, an analog-to-digital converter (ADC), internal memory, and a reusable computing unit. The process control module is connected to the high-precision analog-to-digital converter (ADC) and the internal storage module, and the high-precision analog-to-digital converter (ADC) and the internal storage module are respectively connected to the reusable computing unit. The analog-to-digital converter (ADC) is responsible for accurately acquiring temperature and humidity signals from the environment and converting analog signals into digital signals for subsequent processing. The internal memory uses non-volatile memory to store calibration coefficients obtained through extensive experiments and data analysis. These coefficients are meticulously categorized and stored for different temperature ranges and humidity measurement ranges, providing accurate parameter support for the calibration process. Reusable computing units are used for data calibration; Data calibration includes temperature calibration and humidity calibration; The reusable computing unit includes: selector 1, selector 2, selector 3, register 1, register 2, register 3, and adder; The output of selector one is connected to the data input of register one, where input a is connected to the output of register one, and another input b is connected to the output of register two. The selection control terminal ctrl is controlled by the internal state machine of the system. The output of register one is connected to the control terminal of selector two and the control terminal of selector three (ctrl), and the clock signal input is connected to the internal system clock. The output of selector 2 is connected to the data input of register 2, one input terminal b is connected to the output of register 2, and the other input terminal a is connected to the data output of the internal memory. The output of selector 3 is connected to the data input of register 3, one input terminal b is connected to the output of register 3, and the other input terminal a is connected to the data output of the internal memory. The output of register 3 is connected to the adder, and the clock signal input is connected to the internal system clock. The output of register 2 is connected to the adder, and the clock signal input is connected to the internal system clock.

2. The temperature-compensated humidity segmented calibration circuit with a reusable computing unit according to claim 1, characterized in that, The formula for data calibration using reusable computing units is: ；（1） In the formula, a and b are the endpoint values ​​of the temperature or humidity segments, x is the value before calibration, and y is the intermediate or final value during calibration.

3. The temperature-compensated humidity segmented calibration circuit with a reusable computing unit according to claim 2, characterized in that: Data calibration using reusable computing units includes the following steps: S1. Data Acquisition: The temperature and humidity in the environment are sampled by a high-precision analog-to-digital converter (ADC) to obtain the raw temperature data T0 and humidity data RH0. S2, Temperature positioning: Substitute the original temperature data T0 into x in formula (1), and substitute a and b into the corresponding temperature coefficients stored in the internal storage module. After calculation, the temperature positioning data T1 is obtained. S3, Humidity positioning: Substitute RH0 into x in formula (1), and substitute a and b into the humidity coefficient in the internal storage module to calculate the humidity positioning data RH1; S4. Humidity calibration under temperature compensation: Based on the temperature location data T1, determine the humidity curves at two adjacent temperature points tL and tH; At temperature tL, two boundary values ​​are determined based on humidity location data RH1. These two boundary values ​​are substituted into a and b in formula (1) to calculate the humidity result RH2 at tL. At temperature tH, two boundary values ​​are obtained based on RH1. Substituting a and b, the humidity result RH3 at temperature tH is calculated. The actual temperature is between tL and tH, and the humidity result at the actual temperature is between RH2 and RH3. Taking RH2 and RH3 as a and b, we use formula (1) again to calculate and finally obtain the accurate humidity result RH at the current temperature after temperature compensation and segmented calibration. S5. Final temperature calibration: Based on T1, obtain the two adjacent temperature boundary values, substitute them into a and b in formula (1), and calculate the more accurate actual temperature T.

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