Linear optimization test method for semiconductor gas sensor

Abstract

The invention discloses a linearity optimization test method for a semiconductor gas sensor, which belongs to the technical field of gas detection, and specifically comprises the following steps: acquiring a working temperature interval [A, B] when the linearity of the sensor is greater than a set standard, and setting a plurality of test temperatures in a test environment to collect the internal temperature of the sensor in real time, for each test temperature, if the test temperature is smaller than A, the adjustable voltage output circuit is controlled to heat the sensor; if yes, the adjustable voltage output circuit is controlled to cool the sensor. Drawing a time-varying curve of the internal temperature of the sensor at any test temperature, and calculating the temperature variation speed corresponding to the test temperature; then calculating a corresponding balanced working voltage according to the temperature change speed, and taking the balanced working voltage as a working voltage of the adjustable voltage output circuit at the test temperature; according to the invention, targeted optimization of the gas sensor in different scenes is realized.

Description

Technical Field

[0001] The invention relates to the technical field of gas detection, and in particular to a linearity optimization test method for a semiconductor gas sensor. Background Art

[0002] Semiconductor gas sensors are devices that can convert gas concentrations into electrical signal outputs and are widely used in environmental monitoring, industrial production, family health and other fields. However, since the working characteristics of gas sensors are affected by multiple factors such as temperature, air pressure, and humidity, their performance often has certain nonlinearity, which brings certain problems to the accurate measurement of gas concentration.

[0003] In order to improve the measurement accuracy of semiconductor gas sensors, the existing technology mainly uses calibration methods to optimize the linearity of sensors. In the article "Study on the Influence of Dynamic Heating Voltage on the Linearity of SnO2 Gas Sensors", the effects of four different dynamic heating voltages, 3-5V sine wave, square wave, FM frequency modulation wave and AM amplitude modulation wave, on the linearity of SnO2 gas sensors were experimentally studied. The experimental results show that compared with the static heating method, the use of periodic dynamic heating voltage can effectively improve the linearity of SnO2 gas sensors. Compared with sine waves and square waves, the sensor can obtain better linearity under the action of FM frequency modulation waves and AM amplitude modulation waves, and the effect is best under the action of FM frequency modulation waves.

[0004] However, in the actual application of semiconductor gas sensors, the ambient temperature varies greatly in different application scenarios and seasons and does not remain at a constant temperature. Therefore, a fixed heating voltage cannot meet the heating needs of the sensor. The heating temperature needs to be adjusted according to changes in ambient temperature so that the operating temperature of the semiconductor gas sensor is always maintained within an appropriate range, thereby ensuring the stability of the sensor linearity. Summary of the invention

[0005] The purpose of the present invention is to provide a linearity optimization test method for semiconductor gas sensors to solve the following technical problems: In the actual application of semiconductor gas sensors, the ambient temperature varies greatly in different application scenarios and seasons and does not remain at a constant temperature. Therefore, a fixed heating voltage cannot meet the heating needs of the sensor. The heating temperature needs to be adjusted according to changes in ambient temperature so that the operating temperature of the semiconductor gas sensor is always maintained within an appropriate range, thereby ensuring the stability of the sensor linearity.

[0006] The purpose of the present invention can be achieved through the following technical solutions: A linearity optimization test method for a semiconductor gas sensor comprises the following steps: Obtain the operating temperature interval [A, B] when the linearity of the sensor is greater than the set standard, set n test temperatures T, n is a preset value, the test temperature is not within the operating temperature interval, and at any test temperature, collect the internal temperature t of the sensor in real time; For the i-th test temperature T i , i∈[1,n], if the test temperature is less than the interval temperature A, the adjustable voltage output circuit is controlled to heat the sensor. When the internal temperature t reaches A, the heating is suspended, and the sensor is continued to be heated after waiting for the set time. When the internal temperature reaches B, the heating is stopped; If the test temperature is greater than B, the adjustable voltage output circuit is controlled to cool the sensor. When the internal temperature t reaches B, the cooling is suspended, and the sensor is cooled again after the set time. When the internal temperature reaches A, the cooling is stopped. Draw a curve of the internal temperature of the sensor changing with time, obtain the slopes k1 and k2 when the internal temperature t passes through the A coordinate point and the B coordinate point respectively, convert the slopes into the corresponding temperature change rates v1 and v2, and calculate the balanced working voltages U1 and U2 of the adjustable voltage output circuit according to the temperature change rates. The calculation formula is: ; ; The unit of temperature change rate is Kelvin per second, ω is the preset correction coefficient, c is the specific heat capacity of the semiconductor material, m is the mass of the semiconductor material, and R is the resistance value of the semiconductor material at the current temperature; then for the i-th test temperature T i When the test temperature is lower than the interval temperature A, the operating voltage interval of the adjustable voltage output circuit is [U1, U2]; when the test temperature is higher than the interval temperature B, the operating voltage interval of the adjustable voltage output circuit is [U2, U1].

[0007] As a further solution of the present invention: the process of obtaining the slope is: Mark the time coordinate when the internal temperature of the sensor is A or B. After the adjustable voltage output circuit stops heating or cooling, monitor the curve of the internal temperature t of the sensor changing with time. When the internal temperature of the sensor reaches Aa or Bb, a and b are the test temperature thresholds. Get the time coordinate at this time, mark the slope of the line between the A coordinate point and the Aa coordinate point as k1, and mark the slope of the line between the B coordinate point and the Bb coordinate point as k2.

[0008] As a further solution of the present invention: at any test temperature, the operating temperature interval [A, B] is evenly divided into N temperature sub-intervals, N is a preset value, and the corresponding operating voltage interval of the adjustable voltage output circuit is also evenly divided into N voltage sub-intervals, the temperature sub-intervals correspond to the voltage sub-intervals in sequence, and when the internal temperature of the semiconductor is in any temperature sub-interval, the operating voltage of the adjustable voltage output circuit is set to the corresponding voltage sub-interval.

[0009] As a further solution of the present invention: N second test temperatures are set, and the second test temperatures correspond to humidity sub-intervals one by one. Whenever the second test temperature changes, the working voltage of the corresponding adjustable voltage output circuit is also adjusted to the corresponding voltage sub-interval, and the index of the test gas sample is also adjusted; the output gas index collected by the sensor at different second test temperatures is recorded, and the linearity R of the semiconductor sensor is calculated based on the actual gas index. 2 , the formula is: ; Among them, y i is the output gas index corresponding to any second test temperature, is the average value of the actual gas index, For any actual gas index corresponding to the second test temperature, when the calculated sensor linearity is lower than the set standard, the test temperature threshold is reduced and the test is performed again.

[0010] As a further solution of the present invention: when the test temperature is within [A, B], the internal temperature of the semiconductor is not collected, and the adjustable voltage output circuit stops working.

[0011] As a further solution of the present invention: the n test temperatures are selected as follows: On both sides of the operating temperature range [A, B], several test temperatures are selected at fixed intervals, and the number of test temperatures on both sides is equal.

[0012] As a further solution of the present invention: the internal temperature of the semiconductor is collected based on the internal temperature sensor of the STM32 chip, the sensor integrates ADC, the voltage value of the internal temperature sensor is read by the ADC, and converted into temperature by a formula.

[0013] As a further solution of the present invention: the adjustable voltage output circuit adjusts the power of the heater based on the microprocessor and the digital potentiometer to heat the sensor; the adjustable voltage output circuit cools the sensor by adjusting the reference voltage or the resistance value in the feedback loop.

[0014] As a further solution of the present invention: the waveform of the working voltage of the adjustable voltage output circuit is an FM amplitude modulation wave.

[0015] Beneficial effects of the present invention: The present invention places the sensor in different test temperatures and changes the internal temperature of the sensor by adjusting the adjustable voltage output circuit. When the internal temperature of the sensor passes through the upper and lower limits of the operating temperature range, the temperature transfer speed at this time is recorded by pausing, thereby obtaining the ambient temperature at this time and the heat transfer speed of the sensor surface, and then calculating the operating voltage of the adjustable voltage output circuit according to the heat transfer speed, so that no matter what the usage scenario is, the semiconductor sensor can always be in a suitable operating temperature range, and through cyclic testing, the measurement accuracy and stability of the sensor are gradually improved, thereby realizing the adaptability and versatility of the sensor in different application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be further described below in conjunction with the accompanying drawings.

[0017] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] See also Figure 1 As shown, the present invention is a linearity optimization test method for a semiconductor gas sensor, comprising the following steps: 1. Selection of test temperature and setting of internal temperature collection rules: Determine the operating temperature range: First, it is necessary to obtain the operating temperature range in which the sensor linearity is greater than the set standard, recorded as [A, B]. This range is the temperature range in which the sensor can maintain good linearity under normal working conditions, which is crucial to ensure the accuracy and reliability of the sensor output signal.

[0020] Test temperature setting: On both sides of the working temperature range [A, B], select several test temperatures at fixed intervals, and the number of test temperatures on both sides is equal, and a total of n test temperatures are set, where n is the preset value. These test temperatures are not within the working temperature range in order to simulate the performance of the sensor when it is beyond the normal working temperature range, so as to better optimize its linearity.

[0021] Internal temperature acquisition conditions: At any test temperature, the internal temperature t of the sensor is acquired in real time. However, when the ambient temperature is within the operating temperature range [A, B], the internal temperature of the semiconductor is not acquired, and the adjustable voltage output circuit stops working. This is because within this temperature range, the sensor itself can maintain good linearity without the need for additional temperature control and voltage adjustment.

[0022] 2. Temperature control operation process: For each test temperature T i , according to its relationship with the working temperature range, different temperature control strategies are adopted: Heating control: If the test temperature T i If it is less than the interval temperature A, it means that the current ambient temperature of the sensor is low and needs to be heated. The specific operation is to control the adjustable voltage output circuit to heat the sensor. When the internal temperature t reaches A, the heating is suspended. After waiting for the set time, the sensor is continued to be heated until the internal temperature reaches B, and then the heating is stopped. This ensures that the internal temperature of the sensor can be stably heated from a state below A to B, simulating the process of starting in a low temperature environment and heating to the normal operating temperature range.

[0023] Cooling control: If the test temperature T i If it is greater than the interval temperature B, it indicates that the ambient temperature of the sensor is too high and needs to be cooled. The operation method is to control the adjustable voltage output circuit to cool the sensor. When the internal temperature t reaches B, the cooling is suspended. After waiting for the set time, the sensor is cooled again until the internal temperature reaches A. The cooling is stopped. This process is to examine how the sensor reaches the normal operating temperature range by cooling in a high temperature environment, and the changes in its linearity during this process.

[0024] 3. Curve drawing and voltage calculation method: Curve drawing: During the entire temperature control process, draw a curve of the sensor's internal temperature changing over time. This curve can intuitively reflect how the sensor's internal temperature rises or falls over time at different test temperatures, as well as the temperature change trend when it reaches the boundary of the operating temperature range.

[0025] Slope acquisition: mark the time coordinate when the internal temperature of the sensor is A or B. After the adjustable voltage output circuit stops heating or cooling, monitor the curve of the internal temperature t of the sensor changing with time. When the internal temperature of the sensor reaches Aa or Bb, a and b are the test temperature thresholds. Get the time coordinate at this time, mark the slope of the line between the A coordinate point and the Aa coordinate point as k1, and mark the slope of the line between the B coordinate point and the Bb coordinate point as k2.

[0026] Temperature change rate and voltage calculation: According to the slope, the corresponding temperature change rates v1 and v2 are obtained. With the temperature change rate, the balanced operating voltages U1 and U2 of the adjustable voltage output circuit can be calculated according to the following calculation formula: ; ; The unit of temperature change rate is Kelvin per second, ω is the preset correction factor (used to fine-tune the calculation results according to the actual situation to be closer to the actual working scene), c is the specific heat capacity of the semiconductor material, m is the mass of the semiconductor material, and R is the resistance value of the semiconductor material at the current temperature. These parameters jointly determine the voltage that the adjustable voltage output circuit should output under different temperature change conditions, so that the internal temperature of the sensor can stably change as expected.

[0027] Working voltage range determination: For the i-th test temperature T i , according to its relationship with the operating temperature range, determine the operating voltage range of the adjustable voltage output circuit. When the test temperature is less than the interval temperature A, the operating voltage range of the adjustable voltage output circuit is [U1, U2]; when the test temperature is greater than the interval temperature B, the operating voltage range of the adjustable voltage output circuit is [U2, U1]. In this way, the voltage output range of the adjustable voltage output circuit can be accurately adjusted according to different test temperature scenarios, thereby optimizing the linearity of the sensor so that it can maintain good measurement performance under various ambient temperatures.

[0028] In the semiconductor gas sensor linearity optimization test method of the present invention, in order to more finely control the internal temperature of the sensor and then accurately adjust the working voltage of the adjustable voltage output circuit to optimize the linearity of the sensor, the following advanced partition control strategy is adopted: 1. Division of temperature sub-intervals and voltage sub-intervals: 1. Temperature sub-interval division: At any test temperature, the operating temperature interval [A, B] of the sensor is evenly divided into N temperature sub-intervals, where N is a pre-set positive integer value. This division method subdivides the operating temperature interval into multiple small temperature ranges, and each temperature sub-interval represents a specific change stage of the internal temperature of the sensor. For example, if the operating temperature interval is [20℃, 80℃], and N=5 is preset, the width of each temperature sub-interval is (80-20) / 5=12℃, and the temperature sub-intervals are [20℃, 32℃), [32℃, 44℃), [44℃, 56℃), [56℃, 68℃), and [68℃, 80℃]. This detailed division helps to more accurately monitor and control the changes in the internal temperature of the sensor.

[0029] 2. Voltage sub-interval division: At the same time, the corresponding operating voltage interval of the adjustable voltage output circuit is also evenly divided into N voltage sub-intervals. Similar to the temperature sub-interval, the voltage sub-interval division is also to subdivide the operating voltage range into multiple small voltage ranges, and each voltage sub-interval corresponds to a specific temperature sub-interval. For example, if the operating voltage interval of the adjustable voltage output circuit is [5V, 15V], and N=5 is also preset, the width of each voltage sub-interval is (15-5) / 5=2V, and the voltage sub-intervals are [5V, 7V), [7V, 9V), [9V, 11V), [11V, 13V), [13V, 15V].

[0030] 2. One-to-one correspondence between temperature sub-intervals and voltage sub-intervals and their applications: 1. Establishment of correspondence: The temperature sub-intervals correspond to the voltage sub-intervals in order. This means that each temperature sub-interval has a unique corresponding voltage sub-interval. This correspondence is pre-set and determined based on the characteristics of the sensor and experimental data. For example, the temperature sub-interval [20°C, 32°C) corresponds to the voltage sub-interval [5V, 7V), the temperature sub-interval [32°C, 44°C) corresponds to the voltage sub-interval [7V, 9V), and so on. This one-to-one correspondence provides a clear basis for voltage adjustment for precise control of the internal temperature of the sensor.

[0031] 2. Basis for setting the working voltage: When the internal temperature of the semiconductor is in any temperature sub-interval, according to the above correspondence, the working voltage of the adjustable voltage output circuit is set to the corresponding voltage sub-interval. The specific operation is: monitor the internal temperature of the sensor in real time. Once it is detected that the internal temperature enters a certain temperature sub-interval, immediately adjust the output voltage of the adjustable voltage output circuit so that it works in the voltage sub-interval corresponding to the temperature sub-interval. For example, when the internal temperature of the sensor rises from 30℃ to 35℃, that is, from the temperature sub-interval [20℃, 32℃) to [32℃, 44℃), the output voltage of the adjustable voltage output circuit will be adjusted from [5V, 7V) to [7V, 9V). In this way, it can ensure that the sensor can obtain the most suitable working voltage at different internal temperature stages, thereby optimizing its linearity and improving measurement accuracy and stability.

[0032] 3. Linearity verification and retesting: The present invention sets N second test temperatures, and these second test temperatures form a one-to-one correspondence with the pre-divided temperature sub-intervals. During the test process, whenever the second test temperature changes, the working voltage of the adjustable voltage output circuit matching it will automatically adjust to the corresponding voltage sub-interval, and at the same time, the index of the test gas sample will also be adjusted accordingly to ensure the accuracy and consistency of the test conditions.

[0033] At each second test temperature, the sensor will collect real-time gas index data. These data are recorded in detail for subsequent analysis. Based on these actual collected gas indicators, this method uses a specific calculation formula to evaluate the linearity R of the semiconductor sensor. 2 The formula is ; Among them, y i is the output gas index corresponding to any second test temperature, is the average value of the actual gas index, For any actual gas index corresponding to the second test temperature, when the calculated sensor linearity is lower than the set standard, the test temperature threshold is reduced and the test is performed again.

[0034] When the calculated sensor linearity is lower than the preset performance standard, the method will automatically trigger the temperature threshold adjustment mechanism. Specifically, the system will reduce the test temperature threshold, thereby improving the accuracy of the slope value and improving the linearity and measurement accuracy of the sensor over the full temperature range.

[0035] The semiconductor gas sensor linearity optimization test method of the present invention involves accurate acquisition of the internal temperature of the sensor and the design of an adjustable voltage output circuit: 1. Internal temperature collection technology: 1. Core components for acquisition: The internal temperature acquisition of the semiconductor is based on the internal temperature sensor of the STM32 chip. As a high-performance microcontroller, the STM32 chip integrates a variety of functional modules, including a high-precision temperature sensor. The temperature sensor can sense the temperature changes inside the chip and the sensor closely connected to it in real time, providing an accurate data basis for subsequent temperature control and linearity optimization.

[0036] 2. ADC integration and voltage reading: The sensor integrates ADC (analog-to-digital converter), which is a key component for digitalizing temperature acquisition. Through ADC, the analog voltage signal sensed by the internal temperature sensor can be accurately converted into a digital signal. During the acquisition process, the system will read the voltage value of the internal temperature sensor. This voltage value is a direct reflection of the temperature change, and its change pattern is closely related to the actual temperature inside the sensor.

[0037] 3. Temperature conversion formula: The voltage value read cannot directly represent the temperature. It needs to be converted through a pre-set formula to obtain an accurate temperature value. This formula is based on the characteristics of the temperature sensor and experimental calibration data, and can establish an accurate correspondence between the voltage value and the temperature value. For example, suppose the formula is T = aV + b, where T represents temperature, V represents voltage value, and a and b are coefficients determined according to the characteristics of the sensor. Through this formula, the system can quickly and accurately convert the collected voltage value into a temperature value, thereby grasping the temperature status inside the sensor in real time.

[0038] 2. Adjustable voltage output circuit design: 1. Heating control: The adjustable voltage output circuit adjusts the power of the heater based on the microprocessor and the digital potentiometer to heat the sensor. The microprocessor, as the control core of the entire circuit, can accurately control the resistance of the digital potentiometer according to the real-time data of the internal temperature of the sensor and the preset temperature control strategy. The change in the resistance of the digital potentiometer will directly affect the operating current of the heater, thereby changing the power output of the heater. When the sensor needs to be heated, the microprocessor will adjust the resistance of the digital potentiometer to gradually increase the power of the heater to increase the temperature inside the sensor until the predetermined temperature target is reached.

[0039] 2. Cooling control: Corresponding to the heating control, the adjustable voltage output circuit cools the sensor by adjusting the reference voltage or the resistance value in the feedback loop. During the cooling process, the microprocessor will fine-tune the reference voltage or the resistance value in the feedback loop according to the temperature feedback signal. This adjustment can change the gain characteristics of the circuit, thereby reducing the power output of the heater and reducing the internal temperature of the sensor. For example, by reducing the reference voltage, the power of the heater can be reduced, thereby reducing the heat generation and achieving the purpose of cooling; or by changing the resistance value in the feedback loop and adjusting the feedback coefficient of the circuit, fine control of the heater power can be achieved, thereby achieving a cooling effect.

[0040] 3. Working voltage waveform: The waveform of the working voltage of the adjustable voltage output circuit is an FM amplitude modulation wave. FM amplitude modulation wave is a special modulation waveform, which is characterized by a combination of frequency modulation and amplitude modulation. Under this waveform, the frequency of the working voltage will change with the change of the temperature control signal, and the amplitude of the voltage will also be modulated accordingly. The design of this amplitude modulation waveform enables the adjustable voltage output circuit to control the power of the heater more flexibly and efficiently, respond quickly to temperature change requirements, and achieve precise control of the internal temperature of the sensor. For example, when rapid heating is required, the frequency and amplitude of the FM amplitude modulation wave can be increased at the same time, so that the heater can quickly output a large amount of heat; when slow cooling is required, the frequency and amplitude can be gradually reduced, so that the power of the heater is steadily reduced to avoid drastic temperature fluctuations.

[0041] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A linearity optimization test method for a semiconductor gas sensor, characterized in that: The following steps are involved: Obtain the operating temperature interval [A, B] when the linearity of the sensor is greater than the set standard, set n test temperatures T, n is a preset value, the test temperature is not within the operating temperature interval, and at any test temperature, collect the internal temperature t of the sensor in real time; For the i-th test temperature T i , i∈[1,n], if the test temperature is less than the interval temperature A, the adjustable voltage output circuit is controlled to heat the sensor. When the internal temperature t reaches A, the heating is suspended, and the sensor is continued to be heated after waiting for the set time. When the internal temperature reaches B, the heating is stopped; If the test temperature is greater than B, the adjustable voltage output circuit is controlled to cool the sensor. When the internal temperature t reaches B, the cooling is suspended, and the sensor is cooled again after the set time. When the internal temperature reaches A, the cooling is stopped. Draw a curve of the internal temperature of the sensor changing with time, obtain the slopes k1 and k2 when the internal temperature t passes through the A coordinate point and the B coordinate point respectively, convert the slopes into the corresponding temperature change rates v1 and v2, and calculate the balanced working voltages U1 and U2 of the adjustable voltage output circuit according to the temperature change rates. The calculation formula is: ； ； The unit of temperature change rate is Kelvin per second, ω is the preset correction coefficient, c is the specific heat capacity of the semiconductor material, m is the mass of the semiconductor material, and R is the resistance value of the semiconductor material at the current temperature; then for the i-th test temperature T i When the test temperature is lower than the interval temperature A, the operating voltage interval of the adjustable voltage output circuit is [U1, U2]; when the test temperature is higher than the interval temperature B, the operating voltage interval of the adjustable voltage output circuit is [U2, U1].

2. A linearity optimization test method for a semiconductor gas sensor according to claim 1, characterized in that: The process of obtaining the slope is: Mark the time coordinate when the internal temperature of the sensor is A or B. After the adjustable voltage output circuit stops heating or cooling, monitor the curve of the internal temperature t of the sensor changing with time. When the internal temperature of the sensor reaches Aa or Bb, a and b are the test temperature thresholds. Get the time coordinate at this time, mark the slope of the line between the A coordinate point and the Aa coordinate point as k1, and mark the slope of the line between the B coordinate point and the Bb coordinate point as k2.

3. A linearity optimization test method for a semiconductor gas sensor according to claim 2, characterized in that: At any test temperature, the operating temperature interval [A, B] is evenly divided into N temperature sub-intervals, N is a preset value, and the corresponding operating voltage interval of the adjustable voltage output circuit is also evenly divided into N voltage sub-intervals. The temperature sub-intervals correspond to the voltage sub-intervals in sequence. When the internal temperature of the semiconductor is in any temperature sub-interval, the operating voltage of the adjustable voltage output circuit is set to the corresponding voltage sub-interval.

4. A linearity optimization test method for a semiconductor gas sensor according to claim 3, characterized in that: N second test temperatures are set, and the second test temperatures correspond to humidity sub-intervals one by one. Whenever the second test temperature changes, the working voltage of the corresponding adjustable voltage output circuit is also adjusted to the corresponding voltage sub-interval, and the index of the test gas sample is also adjusted; the real-time gas index collected by the sensor at different second test temperatures is recorded, and the linearity R of the semiconductor sensor is calculated based on the actual gas index. 2 , the formula is: ； Among them, y i is the output gas index corresponding to any second test temperature, is the average value of the actual gas index, For any actual gas index corresponding to the second test temperature, when the calculated sensor linearity is lower than the set standard, the test temperature threshold is reduced and the test is performed again.

5. The linearity optimization test method for semiconductor gas sensor according to claim 1, characterized in that: When the test temperature is within [A, B], the internal temperature of the semiconductor is not collected and the adjustable voltage output circuit stops working.

6. A linearity optimization test method for semiconductor gas sensors according to claim 1, characterized in that: The n test temperatures are selected as follows: On both sides of the operating temperature range [A, B], several test temperatures are selected at fixed intervals, and the number of test temperatures on both sides is equal.

7. A linearity optimization test method for semiconductor gas sensors according to claim 1, characterized in that: The internal temperature of the semiconductor is collected based on the internal temperature sensor of the STM32 chip. The sensor integrates an ADC, reads the voltage value of the internal temperature sensor through the ADC, and converts it into temperature through a formula.

8. A linearity optimization test method for a semiconductor gas sensor according to claim 1, characterized in that: The adjustable voltage output circuit adjusts the power of the heater based on the microprocessor and the digital potentiometer to heat the sensor; the adjustable voltage output circuit cools the sensor by adjusting the reference voltage or the resistance value in the feedback loop.

9. A linearity optimization test method for a semiconductor gas sensor according to claim 8, characterized in that: The waveform of the working voltage of the adjustable voltage output circuit is an FM amplitude modulation wave.

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