Trimming method and trimming circuit for airflow sensor

Abstract

The invention provides a trimming method for an airflow sensor, and the method is characterized in that the method comprises the steps: applying air pressure Pmin to the airflow sensor; judging whether the airflow sensor is started or not, and if yes, storing the air pressure value P when the airflow sensor is started to the starting air pressure of the airflow sensor; otherwise, continuing to apply the higher pressure Pmax; judging whether the opening air pressure P of the airflow sensor is within a target air pressure range 'P1-P2' or not; and if the opening air pressure P of the airflow sensor is not within the target air pressure range 'P1-P2', trimming and calibrating the airflow sensor until the opening air pressure P of the airflow sensor is within the target air pressure range 'P1-P2'. The method is used for solving the problem that the starting threshold value of the microphone capacitor does not conform to the product design target, so that the sensitivity of different microphone capacitors in the same batch to the externally applied air pressure response is kept consistent.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of sensors, and particularly relates to a trimming method and trimming circuit for an airflow sensor. BACKGROUND

[0002] A conventional airflow sensor, i.e., a microphone, is composed of a variable capacitor and a control circuit. The variable capacitor is also called a microphone capacitor. The capacitance of the microphone capacitor changes with the change of an externally applied air pressure. When the change of the capacitance reaches an opening threshold, the control circuit starts to work.

[0003] However, due to material or production process errors, the sensitivity of different microphone capacitors in the same batch to the externally applied air pressure is different, that is, the opening threshold of the microphone capacitors in the same batch is different, and even the opening threshold of some microphone capacitors deviates from the design target, resulting in the need for different externally applied air pressures when different products are used by users. In other words, the externally applied air pressure for opening the microphone is too large or too small, which affects the user experience.

[0004] Therefore, the application provides a microphone calibration method to solve the problem that the opening threshold of the microphone capacitor does not meet the product design target, so that the sensitivity of different microphone capacitors in the same batch to the externally applied air pressure is consistent. In other words, the externally applied air pressure for opening different microphone capacitors in the same batch is consistent. SUMMARY

[0005] According to a first aspect of the embodiments of the application, a trimming method for an airflow sensor is provided, characterized in that the method comprises:

[0006] applying an air pressure P min to the airflow sensor;

[0007] determining whether the airflow sensor is opened. If yes, storing the air pressure value P 开 of the airflow sensor when the airflow sensor is opened as the opening air pressure of the airflow sensor; otherwise, continuing to apply a larger air pressure P max ;

[0008] determining whether the opening air pressure P 开 of the airflow sensor falls within a target air pressure range

P1-P2

[0009] if the opening air pressure P 开 of the airflow sensor does not fall within the target air pressure range

P1-P2

P1-P2

[0010] In another implementation of the invention, the airflow sensor is adjusted and calibrated until the opening air pressure P of the airflow sensor is reached. 开 Falling within the target pressure range [P1-P2] also includes:

[0011] Apply air pressure P again to the adjusted airflow sensor min ;

[0012] Determine whether the adjusted airflow sensor is turned on. If so, store the air pressure value P when the airflow sensor is turned on. 开 The air pressure is adjusted to the activation pressure of the airflow sensor; otherwise, a higher atmospheric pressure P is applied. max ;

[0013] Determine the opening pressure P of the airflow sensor 开 Does it fall within the target pressure range [P1-P2]?

[0014] If the opening pressure P of the airflow sensor 开 If the airflow pressure does not fall within the target air pressure range [P1-P2], the airflow sensor should be adjusted and calibrated until the opening air pressure P of the airflow sensor is reached. 开 It falls within the target air pressure range [P1-P2].

[0015] In another implementation of the present invention, the airflow sensor is adjusted and calibrated, including:

[0016] Determine the opening pressure P of the airflow sensor 开 If the air pressure exceeds the maximum value P2 of the target air pressure range, then lower the activation threshold S of the airflow sensor. th The opening threshold S th The opening air pressure P is mentioned. 开 The following describes the operating frequency of the airflow sensor.

[0017] In another implementation of the present invention, the airflow sensor is adjusted and calibrated, including:

[0018] Determine the opening pressure P of the airflow sensor 开 If the air pressure is less than the minimum value P1 of the target air pressure range, then increase the opening threshold S of the airflow sensor. th The opening threshold S th It is the frequency at which the airflow sensor operates under the specified opening air pressure.

[0019] In another implementation of the present invention, a method for adjusting an airflow sensor is characterized in that the amount by which the opening threshold of the airflow sensor is reduced or increased is a preset fixed value.

[0020] In another implementation of the present application, the method for calibrating the air flow sensor further comprises:

[0021] calculating the difference between the opening air pressure of the air flow sensor and a target air pressure, the target air pressure being any value within the target air pressure range, and according to the difference, applying the successive approximation method to lower the opening threshold of the air flow sensor so that the opening air pressure approaches the target air pressure.

[0022] In another implementation of the present application, the method for calibrating the air flow sensor further comprises:

[0023] calculating the difference between the opening air pressure of the air flow sensor and a target air pressure, the target air pressure being any value within the target air pressure range, and according to the difference, applying the successive approximation method to lower the opening threshold of the air flow sensor so that the opening air pressure approaches the target air pressure.

[0024] According to a second aspect of the embodiments of the present application, a calibration circuit for an air flow sensor is provided, comprising:

[0025] a first judging module for judging whether the air flow sensor is opened;

[0026] a first storage module connected to the first judging module, for storing the air pressure value when the air flow sensor is opened and outputting the air pressure value as the opening air pressure of the air flow sensor when the first judging module judges that the air flow sensor is opened;

[0027] a second judging module connected to the first storage module, for judging whether the opening air pressure falls within a target air pressure range and outputting the judging result, the target air pressure range being a preset range;

[0028] a first calibration module connected to the second judging module, for calibrating the air flow sensor when the second judging module judges that the opening air pressure of the air flow sensor does not fall within the target air pressure range.

[0029] In another implementation of the present application, the calibration circuit for the air flow sensor further comprises that the first calibration module comprises a comparator and a calculator, the comparator is used for comparing the opening air pressure with the maximum value of the target air pressure range, and when the opening air pressure is greater than the maximum value of the target air pressure range, the comparator drives the calculator to calculate the difference between the opening air pressure and the target air pressure, and according to the difference, the opening threshold of the air flow sensor is calibrated so that the opening air pressure of the air flow sensor falls within the target air pressure range, the opening threshold being the frequency at which the air flow sensor works at the opening air pressure.

[0030] In another implementation of the present invention, a trimming circuit for an airflow sensor is characterized in that the calculator in the first trimming module includes a subtractor, and when the opening air pressure is greater than the maximum value of the target air pressure range, the comparator drives the subtractor in the calculator to reduce the opening threshold of the airflow sensor.

[0031] In another implementation of the present invention, a tuning circuit for an airflow sensor is characterized in that the first tuning module includes a comparator and a calculator. The comparator is used to compare the opening air pressure with the minimum value of the target air pressure range. When the opening air pressure is less than the minimum value of the target air pressure range, the comparator drives the calculator to calculate the difference between the opening air pressure and the target air pressure, and tunes the opening threshold of the airflow sensor according to the difference, so that the opening air pressure of the airflow sensor falls within the target air pressure range. The opening threshold is the frequency at which the airflow sensor operates under the opening air pressure.

[0032] In another implementation of the present invention, a trimming circuit for an airflow sensor is characterized in that the calculator in the first trimming module includes an adder, and when the opening air pressure is less than the minimum value of the target air pressure range, the comparator drives the adder in the calculator to increase the opening threshold of the airflow sensor.

[0033] In another implementation of the invention, the subtractor is a subtractor with successive approximation functionality.

[0034] In another implementation of the invention, the adder is an adder with successive approximation functionality.

[0035] In the solution of this invention embodiment, the opening threshold of the microphone capacitor is kept within the design target range by adjustment, so that the user experience is consistent. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0037] Figure 1 This is a schematic diagram of the structure of an airflow sensor;

[0038] Figure 2 A schematic diagram illustrating the application of test air pressure;

[0039] Figure 3 This is a flowchart of a tuning process for an airflow sensor.

[0040] Figure 4 is another flowchart for adjusting the airflow sensor;

[0041] Figure 5 is a structural block diagram of an adjusting circuit for the airflow sensor;

[0042] Figure 6 is another structural block diagram of an adjusting circuit for the airflow sensor;

[0043] Figure 7 is still another structural block diagram of an adjusting circuit for the airflow sensor;

[0044] Figure 8 is still another structural block diagram of an adjusting circuit for the airflow sensor. DETAILED DESCRIPTION

[0045] In order to make personnel in the art better understand the technical solutions in the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings of the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art should belong to the scope of protection of the present application.

[0046] As shown in Figure 1 , an airflow sensor 101, i.e., a microphone, comprises a shell 101, a ventilation mesh film 102, a metal sheet 103, a control chip 104, and a PCB board 105. The metal sheet is an upper plate of a variable capacitor, and a control circuit is arranged in the control chip. In other words, the microphone can be regarded as a combination of the variable capacitor composed of the metal sheet and the control circuit in the control chip.

[0047] Generally, as shown in Figure 2 , when testing the microphone, an external air pressure needs to be applied. The pressure value of the applied air pressure is gradually increased from P min to P max . It should be noted that P min to P max is the air pressure range that can be adjusted in the technical solutions provided in the present application. The present application does not make any limitation on the way of applying the external air pressure. It can be linear pressure increase as shown in Figure 2 , or stepwise pressure increase, which is not specifically limited in the present application.

[0048] The specific solutions provided in the present application will be described below in conjunction with Figure 3 .

[0049] an air pressure Pmin ;

[0050] For example, an initial air pressure of 200 kPa is applied to the airflow sensor 101.

[0051] Determine whether the airflow sensor is turned on; if so, store the air pressure value P when the airflow sensor is turned on. 开 The air pressure is adjusted to the activation pressure of the airflow sensor; otherwise, a higher atmospheric pressure P is applied. max ;

[0052] For example, it is determined whether the airflow sensor 101 is turned on at an initial air pressure of 200 kPa.

[0053] Determine the opening pressure P of the airflow sensor 开 Does it fall within the target pressure range [P1-P2]?

[0054] If the opening pressure P of the airflow sensor 开 If the airflow pressure does not fall within the target air pressure range [P1-P2], the airflow sensor should be adjusted and calibrated until the opening air pressure P of the airflow sensor is reached. 开 It falls within the target air pressure range [P1-P2].

[0055] For example, if the airflow sensor 101 is turned on at an initial air pressure of 200 kPa, then the P value of the airflow sensor 101 is recorded. 开 It is 200 kPa;

[0056] For example, if the airflow sensor 101 is not activated at an initial air pressure of 200 kPa, the air pressure is increased, for example, to 230 kPa, at which point the airflow sensor 101 activates, and the reading of the airflow sensor 101 is recorded.

[0057] P 开 It is 230 kPa. Determine the opening pressure P of the airflow sensor 101. 开 That is, 230 kPa. Determine whether 230 kPa is within the preset target air pressure range [220 kPa, 280 kPa]. At this time, the opening air pressure of the airflow sensor 101 is within the preset target air pressure range.

[0058] For example, if the airflow sensor 101 is not activated at an initial air pressure of 200 kPa, the air pressure is increased, for example, to 300 kPa, at which point the airflow sensor 101 activates, and the P value of the airflow sensor 101 is recorded. 开is 300kpa. At this time, it is judged whether 300kpa is in the preset target air pressure range 【220kpa, 280kpa】. At this time, the opening air pressure of the airflow sensor 101 is not in the preset target air pressure range, at this time, the airflow sensor 101 is calibrated, so that the P 开 of the airflow sensor 101 is in the target air pressure range 【220kpa, 280kpa】.

[0059] Further, the airflow sensor after adjustment is applied to the air pressure P min again.

[0060] Exemplarily, if the initial air pressure 200kpa is applied to the airflow sensor 101 again;

[0061] If the airflow sensor is opened, the air pressure value P 开 of the airflow sensor when the airflow sensor is opened is stored to the opening air pressure of the airflow sensor; otherwise, a larger air pressure P max is continuously applied.

[0062] Exemplarily, if the airflow sensor 101 is not opened, when the air pressure is continuously increased to 240kpa, the airflow sensor 101 is opened, and the P 开 of the airflow sensor 101 is recorded as 240kpa.

[0063] It is judged whether the opening air pressure P 开 of the airflow sensor falls within the target air pressure range

P1-P2

[0064] Exemplarily, the P 开 of the airflow sensor 101 is 240kpa, which is in the target air pressure range 【220kpa, 280kpa】.

[0065] If the opening air pressure P 开 of the airflow sensor does not fall within the target air pressure range

P1-P2

P1-P2

[0066] Exemplarily, if the airflow sensor 101 is opened after the initial air pressure 200kpa is applied again, the P 开 of the airflow sensor 101 is 200kpa, which is not in the target air pressure range 【220kpa, 280kpa】, the airflow sensor 101 is calibrated until the P 开 of the airflow sensor 101 is in the target air pressure range 【220kpa, 280kpa】.

[0067] Further, determine the activation pressure P of the airflow sensor. 开 If the air pressure exceeds the maximum value P2 of the target air pressure range, then lower the activation threshold S of the airflow sensor. th The opening threshold S th The opening air pressure P is mentioned. 开 The following describes the operating frequency of the airflow sensor.

[0068] For example, P of airflow sensor 101 开 It is 300 kPa, the P of the airflow sensor 101 开 If the air pressure exceeds the maximum value of 280 kPa within the target air pressure range [220 kPa, 280 kPa], then the activation threshold S of the airflow sensor 101 needs to be lowered. th That is, reduce the opening pressure P of the airflow sensor 101. 开 The operating frequency of the airflow sensor at 300 kPa.

[0069] Furthermore, the activation pressure P of the airflow sensor is determined. 开 If the air pressure is less than the minimum value P1 of the target air pressure range, then increase the opening threshold S of the airflow sensor. th The opening threshold S th It is the frequency at which the airflow sensor operates under the specified opening air pressure.

[0070] For example, P of airflow sensor 101 开 It is 210 kPa, the P of the airflow sensor 101 开 If the air pressure is less than the minimum value of 220 kPa within the target air pressure range [220 kPa, 280 kPa], then the opening threshold S of the airflow sensor 101 needs to be increased. th That is, increase the opening pressure P of the airflow sensor 101. 开 The operating frequency of the airflow sensor at 210 kPa.

[0071] Furthermore, the amount by which the opening threshold of the airflow sensor is reduced or increased is a preset fixed value.

[0072] For example, the opening pressure P of the airflow sensor 101 is adjusted in fixed steps of 10 kPa each time. 开 The operating frequency of the airflow sensor at 300 kPa.

[0073] In other examples, the opening pressure P of the airflow sensor 101 is adjusted in fixed steps of 10 kPa each time. 开 The operating frequency of the airflow sensor at 210 kPa.

[0074] Further, the difference between the opening air pressure of the airflow sensor and the target air pressure, which is any value within the target air pressure range, is calculated. According to the difference, the opening threshold of the airflow sensor is lowered by using the successive approximation method, so that the opening air pressure approaches the target air pressure.

[0075] For example, the opening air pressure P 开 300kpa and any value within the target 【220kpa, 280kpa】 range, such as 260kpa. The difference between 300kpa and 260kpa is 40kpa, and the opening threshold of the airflow sensor 101 under the excess 40kpa is lowered by using the successive approximation method, so that the opening air pressure P 开 of the airflow sensor 101 approaches 260kpa.

[0076] Further, the opening threshold of the airflow sensor 101 under the excess 60kpa can be lowered, and then the opening air pressure P 开 of the airflow sensor 101 is tested. 开 If the opening air pressure P 开 of the airflow sensor 101 is 220kpa at this time, the opening threshold of the airflow sensor 101 under the excess 40kpa is raised, and then the opening air pressure P 开 of the airflow sensor 101 is tested. 开 If the opening air pressure P 开 of the airflow sensor 101 is 270kpa at this time, the opening threshold of the airflow sensor 101 under the excess 20kpa is lowered, and so on, until the opening air pressure P 开 of the airflow sensor 101 approaches the target air pressure 260kpa.

[0077] Alternatively, the difference between the opening air pressure of the airflow sensor and the target air pressure, which is any value within the target air pressure range, is calculated. According to the difference, the opening threshold of the airflow sensor is raised by using the successive approximation method, so that the opening air pressure approaches the target air pressure.

[0078] For example, the opening air pressure P 开 of the airflow sensor 101 is 210kpa and any value within the target 【220kpa, 280kpa】 range, such as 260kpa. The difference between 210kpa and 260kpa is 50kpa, and the opening threshold of the airflow sensor 101 under the excess 50kpa is lowered by using the successive approximation method, so that the opening air pressure P 开 of the airflow sensor 101 approaches 260kpa.

[0079] Further, the opening threshold of the airflow sensor 101 under the excess 50kpa can be raised, and then the opening air pressure P开 If the opening air pressure P of the air flow sensor 101 at this time is 280 kPa, the opening threshold of the air flow sensor 101 under the excess of 40 kPa is increased, and then the opening air pressure P of the air flow sensor 101 is tested. 开 If the opening air pressure P of the air flow sensor 101 at this time is 280 kPa, the opening threshold of the air flow sensor 101 under the excess of 40 kPa is increased, and then the opening air pressure P of the air flow sensor 101 is tested. 开 If the opening air pressure P of the air flow sensor 101 at this time is 270 kPa, the opening threshold of the air flow sensor 101 under the excess of 20 kPa is increased, and so on until the opening air pressure P of the air flow sensor 101 approaches the target air pressure 260 kPa. 开 If the opening air pressure P of the air flow sensor 101 at this time is 270 kPa, the opening threshold of the air flow sensor 101 under the excess of 20 kPa is increased, and so on until the opening air pressure P of the air flow sensor 101 approaches the target air pressure 260 kPa. 开 If the opening air pressure P of the air flow sensor 101 at this time is 270 kPa, the opening threshold of the air flow sensor 101 under the excess of 20 kPa is increased, and so on until the opening air pressure P of the air flow sensor 101 approaches the target air pressure 260 kPa.

[0080] In addition, as shown in the figure, the application also provides a tuning circuit for an air flow sensor, comprising: Figure 5 A judgment module 501 is configured to judge whether the air flow sensor 101 is opened or not.

[0081] A storage module 502 is connected to the judgment module 501, and when the judgment module 501 judges that the air flow sensor 101 is opened, the storage module 502 stores the air pressure value when the air flow sensor 101 is opened and outputs it as the opening air pressure of the air flow sensor 101. For example, the opening air pressure of the air flow sensor 101 is 300 kPa.

[0082] A judgment module 503 is connected to the storage module 502, and judges whether the opening air pressure of the air flow sensor 101 falls within the target air pressure range or not, and outputs the judgment result. The target air pressure range is a preset range. For example, the target air pressure range is 【220 kPa, 280 kPa】.

[0083] A tuning module 504 is connected to the judgment module 503, and when the judgment module 503 judges that the opening air pressure of the air flow sensor 101 does not fall within the target air pressure range, the tuning module 504 tunes and calibrates the opening air pressure of the air flow sensor 101.

[0084] Further, as shown in the figure, the application also provides another tuning circuit for an air flow sensor, which is different from the above-mentioned tuning circuit in that the tuning module 604 in this embodiment comprises a comparator 6041 and a calculator 6042.

[0085] The comparator 6041 is configured to compare the opening air pressure with the maximum value of the target air pressure range, and when the opening air pressure is greater than the maximum value of the target air pressure range, the comparator 6041 drives the calculator 6042 to calculate the difference between the opening air pressure and the target air pressure, and according to the difference, tunes the opening threshold of the air flow sensor 101 so that the opening air pressure of the air flow sensor 101 falls within the target air pressure range. The opening threshold is the frequency at which the air flow sensor 101 works under the opening air pressure. Figure 6 Figure 5 The comparator 6041 is configured to compare the opening air pressure with the maximum value of the target air pressure range, and when the opening air pressure is greater than the maximum value of the target air pressure range, the comparator 6041 drives the calculator 6042 to calculate the difference between the opening air pressure and the target air pressure, and according to the difference, tunes the opening threshold of the air flow sensor 101 so that the opening air pressure of the air flow sensor 101 falls within the target air pressure range. The opening threshold is the frequency at which the air flow sensor 101 works under the opening air pressure.

[0086] ​The adjustment process is consistent with the foregoing, and will not be repeated again.

[0087] Further, as shown in Figure 7 The application further provides another adjustment circuit for the airflow sensor, which is different from the adjustment circuit shown in Figure 6 The calculator in the adjustment module 704 includes a subtracter 7042, and when the opening air pressure is greater than the maximum value of the target air pressure range, the comparator 7041 drives the subtracter 7042 to reduce the opening threshold of the airflow sensor 101.

[0088] The adjustment process is consistent with the foregoing, and will not be repeated again.

[0089] Further, as shown in Figure 8 The application further provides another adjustment circuit for the airflow sensor, which is different from the adjustment circuit shown in Figure 7 The calculator in the adjustment module 804 includes an adder 8042, and when the opening air pressure is less than the minimum value of the target air pressure range, the comparator 8041 drives the adder 8042 to increase the opening threshold of the airflow sensor 101.

[0090] The adjustment process is consistent with the foregoing, and will not be repeated again.

[0091] Further, the subtracter is a subtracter with a function of successive approximation, and the adder is an adder with a function of successive approximation, which are not limited in the application.

[0092] In addition, it should be noted that the information related to the user (including but not limited to user equipment information, user personal information, etc.) and data (including but not limited to sample data for training the model, data for analysis, stored data, displayed data, etc.) involved in the embodiments of the application are all information and data authorized by the user or authorized by all parties, and the collection, use and processing of the related data need to comply with relevant regulations and standards, and provide corresponding operation entrances for the user to select authorization or refusal.

[0093] It should be noted that, according to the needs of implementation, each component / step described in the embodiments of the application can be split into more components / steps, or two or more components / steps or part of the operation of the components / steps can be combined into a new component / step to achieve the purpose of the embodiments of the application.

[0094] The above-described methods according to embodiments of the present application can be implemented in hardware, firmware, or software, or any combination thereof, and can be stored in a recording medium such as CD-ROM, RAM, floppy disk, hard disk, or magneto-optical disk, or be downloaded by network from a remote recording medium or non-transitory machine-readable medium originally stored in a local recording medium and then stored in a local recording medium, so that the methods described herein can be stored in a recording medium on which such software is stored using a general-use computer, a special-purpose processor, or programmable or special-purpose hardware such as an Application Specific Integrated Circuit (ASIC) or a Field Programmable Gate Array (FPGA). It can be appreciated that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component (e.g., Random Access Memory (RAM), Read-Only Memory (ROM), flash memory, etc.) that can store or receive software or computer code when the software or computer code is accessed and executed by the computer, the processor, or the hardware, to implement the methods described herein. Furthermore, when a general-use computer accesses code for implementing the methods shown herein, the execution of the code will convert the general-use computer into a special-purpose computer for executing the methods shown herein.

[0095] Those skilled in the art can appreciate that the units and method steps of the examples described in connection with the embodiments disclosed herein can be realized in electronic hardware, or in a combination of computer software and electronic hardware. Whether the functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. A person skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the embodiments of the present application.

[0096] The above embodiments are only used to illustrate but not limit the embodiments of the present application, and a person of ordinary skill in the art can make various changes and modifications without departing from the spirit and scope of the embodiments of the present application, therefore all equivalent technical solutions belong to the scope of the embodiments of the present application, and the patent protection scope of the embodiments of the present application should be defined by the claims.

Claims

1. A trimming method for an air flow sensor, characterized by, comprising: applying air pressure P to the airflow sensor min ; determining whether the airflow sensor is open, if yes, storing the air pressure value P when the airflow sensor is open 开 to the opening air pressure of the airflow sensor; otherwise, continuing to apply greater air pressure P max ; determining whether the opening air pressure P of the air flow sensor falls within a target air pressure range 【P1-P2】 开 whether falls within a target air pressure range 【P1-P2】; If the opening air pressure P of the airflow sensor 开 not falling within the target air pressure range 【P1-P2】, the airflow sensor is adjusted and calibrated until the opening air pressure P of the airflow sensor 开 falls within the target air pressure range 【P1-P2】.

2. The trim method for an airflow sensor of claim 1, wherein, The airflow sensor is trim calibrated until the opening air pressure P 开 Falls within the target air pressure range 【P1-P2】 also includes: applying air pressure P to the airflow sensor again min ; determining whether the airflow sensor is turned on after the adjustment, and if so, storing the air pressure value P when the airflow sensor is turned on 开 the turning-on air pressure of the airflow sensor; otherwise, continuing to apply a greater air pressure P max ; determining whether the opening air pressure P of the air flow sensor falls within a target air pressure range 【P1-P2】 开 whether falls within a target air pressure range 【P1-P2】; If the opening air pressure P of the airflow sensor 开 not in the target air pressure range 【P1-P2】, the airflow sensor is adjusted and calibrated until the opening air pressure P of the airflow sensor 开 falls in the target air pressure range 【P1-P2】.

3. The trim method for an air flow sensor according to claim 1 or 2, characterized by, adjusting and calibrating the airflow sensor, comprising: determining whether the opening air pressure P of the airflow sensor is greater than the maximum value P2 of the target air pressure range, and if so, lowering the opening threshold S of the airflow sensor 开 determining whether the opening air pressure P of the airflow sensor is greater than the maximum value P2 of the target air pressure range, and if so, lowering the opening threshold S of the airflow sensor th , the opening threshold S th is the frequency at which the airflow sensor operates below the opening air pressure P 开 .

4. The trim method for an airflow sensor according to claim 1 or 2, characterized by, adjusting and calibrating the airflow sensor, comprising: determining whether the opening air pressure P of the airflow sensor is less than the minimum value P1 of the target air pressure range, and if so, increasing the opening threshold value S of the airflow sensor 开 determining whether the opening air pressure P of the airflow sensor is less than the minimum value P1 of the target air pressure range, and if so, increasing the opening threshold value S of the airflow sensor th th is the frequency at which the airflow sensor operates at the opening air pressure.​ 5. A trim method for an airflow sensor according to claim 3 or 4, characterized in that, The decrease or increase of the opening threshold of the airflow sensor is a preset fixed value.

6. The trim method for an airflow sensor of claim 3, wherein, Further comprising: Calculate the difference between the opening air pressure of the airflow sensor and the target air pressure, and the target air pressure is any value in the target air pressure range. According to the difference, the opening threshold of the airflow sensor is lowered by using the successive approximation method, so that the opening air pressure approaches the target air pressure.

7. The trim method for an airflow sensor of claim 4, wherein, Further comprising: Calculate the difference between the opening air pressure of the airflow sensor and the target air pressure, and the target air pressure is any value in the target air pressure range. According to the difference, the opening threshold of the airflow sensor is lowered by using the successive approximation method, so that the opening air pressure approaches the target air pressure.

8. A trim circuit for an airflow sensor, characterized by comprising: The first judgment module judges whether the airflow sensor is opened or not; The first storage module is connected to the first judgment module, and when the first judgment module judges that the airflow sensor is opened, the air pressure value when the airflow sensor is opened is stored and output as the opening air pressure of the airflow sensor; The second judgment module is connected to the first storage module, judges whether the opening air pressure falls within the target air pressure range, and outputs the judgment result, and the target air pressure range is a preset range; The first adjustment module is connected to the second judgment module, and when the second judgment module judges that the opening air pressure of the airflow sensor does not fall within the target air pressure range, the airflow sensor is adjusted and calibrated.

9. The adjustment circuit for the airflow sensor according to claim 8, wherein The first adjustment module comprises a comparator and a calculator, the comparator is used to compare the opening air pressure with the maximum value of the target air pressure range, and when the opening air pressure is greater than the maximum value of the target air pressure range, the comparator drives the calculator to calculate the difference between the opening air pressure and the target air pressure, and adjusts the opening threshold of the airflow sensor according to the difference, so that the opening air pressure of the airflow sensor falls within the target air pressure range, and the opening threshold is the frequency at which the airflow sensor works at the opening air pressure.

10. The adjustment circuit for the airflow sensor according to claim 9, wherein The calculator in the first adjustment module comprises a subtracter, and when the opening air pressure is greater than the maximum value of the target air pressure range, the comparator drives the subtracter in the calculator to lower the opening threshold of the airflow sensor.

11. The adjustment circuit for the airflow sensor according to claim 8, wherein The first trim module includes a comparator and a calculator, the comparator is used to compare the opening air pressure with the minimum value of the target air pressure range, when the opening air pressure is less than the minimum value of the target air pressure range, the comparator drives the calculator to calculate the difference between the opening air pressure and the target air pressure, and according to the difference, the opening threshold of the airflow sensor is trimmed, so that the opening air pressure of the airflow sensor falls within the target air pressure range, and the opening threshold is the frequency at which the airflow sensor works at the opening air pressure.

12. The trim circuit for the airflow sensor according to claim 11, wherein, The calculator in the first trim module includes an adder, when the opening air pressure is less than the minimum value of the target air pressure range, the comparator drives the adder in the calculator to increase the opening threshold of the airflow sensor.

13. The trim circuit for an air flow sensor of claim 10, wherein, The subtractor is a subtractor with a function of successive approximation.

14. The trim circuit for an air flow sensor of claim 12, wherein, The adder is an adder with a function of successive approximation.

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