Capacitance detection method and circuit

Abstract

The application provides a capacitance detection method and circuit applied to an electronic cigarette, comprising the following steps: obtaining first sampling data corresponding to the sum of a first parasitic capacitance and a sensor capacitance through a detection module; obtaining second sampling data corresponding to the sum of a second parasitic capacitance and the sensor capacitance through the detection module; obtaining third sampling data corresponding to the sum of the first parasitic capacitance and the second parasitic capacitance through the detection module; and calculating sampling data corresponding to the sensor capacitance according to the first sampling data, the second sampling data and the third sampling data, so that the influence of the first parasitic capacitance and the second parasitic capacitance on the capacitance detection result can be greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of electronic cigarette technology, and in particular to a capacitance detection method and circuit. Background Technology

[0002] Figure 1 This is a schematic diagram of a capacitance detection circuit in the prior art. (For example...) Figure 1 As shown, the capacitance detection circuit includes a TS module, a selector, and a sensor capacitor. The output terminal of the selector is connected to the TS module, and the input terminal of the selector is connected to the channel TS. One end of the parasitic capacitance C0 of the channel TS is grounded, and the other end of the parasitic capacitance C0 of the channel TS is connected to one end of the sensor capacitor C2. The other end of the sensor capacitor C2 is grounded.

[0003] Depend on Figure 1 The circuit diagram clearly shows that existing capacitance detection circuits use a single-ended detection method. In contrast, electronic cigarette sensors, using MEMS or electret condensers, utilize the varying pressure measured by the microphone to deform the internal thin film, resulting in a change in capacitance. A stable constant current source I is provided. CHG The capacitor (C0+C2) under test is charged and discharged. During the charging and discharging process, a constant voltage ΔV is set for comparison and switching, and the capacitance C and time T can be obtained. CHG Relationship such as 3. Through capacitor (C0+C2) and time T CHG By recording the charge / discharge cycle TCHG using the system clock, the corresponding value of the capacitor can be obtained. This value is called the capacitor sampling data.

[0004] The capacitance sampling data obtained by the TS module includes the sensor capacitance C2 and the parasitic capacitance C0 of the TS channel. Therefore, the system cannot distinguish whether the change in the sampling data is caused by a change in the parasitic capacitance C0 or a change in the sensor capacitance C2.

[0005] Therefore, it is necessary to provide a novel capacitance detection method and circuit to solve the above-mentioned problems existing in the prior art. Summary of the Invention

[0006] The purpose of this invention is to provide a capacitance detection method and circuit that reduces the influence of parasitic capacitance on the detection results.

[0007] To achieve the above objectives, the capacitance detection method of the present invention is applied to electronic cigarettes, comprising:

[0008] A capacitance detection circuit is provided, comprising a selection unit, a detection module, a first switch, a second switch, and a sensor capacitor. The output terminal of the selection unit is connected to the detection module. The first input terminal of the selection unit is connected to one end of the first switch and a first channel, and the other end of the first switch is grounded. The second input terminal of the selection unit is connected to one end of the second switch and a second channel, and the other end of the second switch is grounded. One end of the first parasitic capacitance of the first channel is connected to one end of the sensor capacitor, and the other end of the first parasitic capacitance of the first channel is grounded. One end of the second parasitic capacitance of the second channel is connected to the other end of the sensor capacitor, and the other end of the second parasitic capacitance of the second channel is grounded.

[0009] The detection module obtains the first sampling data corresponding to the sum of the first parasitic capacitance and the sensor capacitance.

[0010] The detection module obtains the second sampling data corresponding to the sum of the second parasitic capacitance and the sensor capacitance.

[0011] The detection module obtains the third sampling data corresponding to the sum of the first parasitic capacitance and the second parasitic capacitance;

[0012] The sampling data corresponding to the sensor capacitance is calculated based on the first sampling data, the second sampling data, and the third sampling data;

[0013] When acquiring the sampling data corresponding to the sensor capacitance multiple times, in the nth calculation of the sampling data corresponding to the sensor capacitance, only one of the first sampling data and the second sampling data, as well as the third sampling data, is reacquired, and the same first sampling data and the second sampling data are involved in the calculation at most twice.

[0014] Optionally, obtaining the first sampling data corresponding to the sum of the first parasitic capacitance and the sensor capacitance through the detection module includes:

[0015] When the first switch is turned off and the second switch is closed, the selection unit outputs the data from the first input terminal from the output terminal.

[0016] The sampling data acquired by the detection module is the first sampling data corresponding to the sum of the first parasitic capacitance and the sensor capacitance.

[0017] Optionally, obtaining the second sampling data corresponding to the sum of the second parasitic capacitance and the sensor capacitance through the detection module includes:

[0018] When the first switch is closed and the second switch is closed, the selection unit outputs the data from the second input terminal from the output terminal.

[0019] The sampling data acquired by the detection module is the second sampling data corresponding to the sum of the second parasitic capacitance and the sensor capacitance.

[0020] Optionally, obtaining the third sampling data corresponding to the sum of the first parasitic capacitance and the second parasitic capacitance through the detection module includes:

[0021] When the first switch is turned off and the second switch is turned off, the selection unit outputs the data from the first input terminal and the data from the second input terminal from the output terminal.

[0022] The sampling data acquired by the detection module is the third sampling data corresponding to the sum of the first parasitic capacitance and the second parasitic capacitance.

[0023] Optionally, the step of calculating the sampling data corresponding to the sensor capacitance based on the first sampling data, the second sampling data, and the third sampling data includes:

[0024] Calculate the sum of the first sampled data and the second sampled data, and then subtract the third sampled data to obtain an intermediate value;

[0025] Take half of the intermediate value to obtain the sampling data corresponding to the sensor capacitance.

[0026] Optionally, the capacitance detection method further includes converting the sampled data into capacitance values.

[0027] This invention also discloses a capacitance detection circuit for implementing a capacitance detection method, comprising a selection unit, a detection module, a first switch, a second switch, and a sensor capacitor. The output terminal of the selection unit is connected to the detection module. The first input terminal of the selection unit is connected to one end of the first switch and a first channel, and the other end of the first switch is grounded. The second input terminal of the selection unit is connected to one end of the second switch and a second channel, and the other end of the second switch is grounded. One end of the first parasitic capacitance of the first channel is connected to one end of the sensor capacitor, and the other end of the first parasitic capacitance of the first channel is grounded. One end of the second parasitic capacitance of the second channel is connected to the other end of the sensor capacitor, and the other end of the second parasitic capacitance of the second channel is grounded.

[0028] Optionally, the capacitance detection circuit further includes a main control unit, which is connected to the selection unit, the first switch, and the second switch, and is used to control the selection unit, the first switch, and the second switch.

[0029] The beneficial effects of the present invention are as follows: by obtaining the first sampling data corresponding to the sum of the first parasitic capacitance and the sensor capacitance through the detection module, obtaining the second sampling data corresponding to the sum of the second parasitic capacitance and the sensor capacitance through the detection module, obtaining the third sampling data corresponding to the sum of the first parasitic capacitance and the second parasitic capacitance through the detection module, and calculating the sampling data corresponding to the sensor capacitance based on the first sampling data, the second sampling data, and the third sampling data, the influence of the first parasitic capacitance and the second parasitic capacitance on the capacitance detection result can be greatly reduced. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of a capacitance detection circuit in the prior art;

[0031] Figure 2 This is a schematic diagram of the capacitance detection circuit in some embodiments of the present invention;

[0032] Figure 3 This is a flowchart of the capacitance detection method in some embodiments of the present invention;

[0033] Figure 4 This is a schematic diagram of the circuit for acquiring the first sampled data in some embodiments of the present invention;

[0034] Figure 5 This is a schematic diagram of the circuit for acquiring the second sampling data in some embodiments of the present invention;

[0035] Figure 6 This is a schematic diagram of the circuit for obtaining the third sampling data in some embodiments of the present invention;

[0036] Figure 7 This is a schematic diagram illustrating the changes in various capacitors during normal use of an electronic cigarette in some embodiments of the present invention. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art. The terms "comprising" and similar expressions used herein mean that the element or object preceding the word covers the element or object listed following the word and its equivalents, but do not exclude other elements or objects.

[0038] To address the problems existing in the prior art, embodiments of the present invention provide a capacitance detection circuit applied to electronic cigarettes. (Refer to...) Figure 2 The capacitance detection circuit includes a selection unit 101, a detection module 102, a first switch K1, a second switch K2, and a sensor capacitor C2. The output terminal of the selection unit 101 is connected to the detection module 102. The first input terminal of the selection unit 101 is connected to one end of the first switch K1 and the first channel TS0, and the other end of the first switch K1 is grounded. The second input terminal of the selection unit 101 is connected to one end of the second switch K2 and the second channel TS1, and the other end of the second switch K2 is grounded. One end of the first parasitic capacitance C0 of the first channel TS0 is connected to one end of the sensor capacitor C2, and the other end of the first parasitic capacitance C0 of the first channel TS0 is grounded. One end of the second parasitic capacitance C1 of the second channel TS1 is connected to the other end of the sensor capacitor C2, and the other end of the second parasitic capacitance C1 of the second channel TS1 is grounded.

[0039] Reference Figure 2 The capacitance detection circuit further includes a main control unit 103, which is connected to the selection unit 101, the first switch K1, and the second switch K2, and is used to control the selection unit 101, the first switch K1, and the second switch K2. The main control unit 103 is also connected to the detection module 102 and other functional modules, and is used to acquire the sampling data detected by the detection module 102 and control the other functional modules.

[0040] Figure 3 This is a flowchart of a capacitance detection method in some embodiments of the present invention. (Refer to...) Figure 3 The capacitance detection method is applied to electronic cigarettes and implemented through the capacitance detection circuit. The capacitance detection method includes the following steps:

[0041] S1: Obtain the first sampling data corresponding to the sum of the first parasitic capacitance and the sensor capacitance through the detection module;

[0042] S2: Obtain the second sampling data corresponding to the sum of the second parasitic capacitance and the sensor capacitance through the detection module;

[0043] S3: Obtain the third sampling data corresponding to the sum of the first parasitic capacitance and the second parasitic capacitance through the detection module;

[0044] S4: Calculate the sampling data corresponding to the sensor capacitance based on the first sampling data, the second sampling data, and the third sampling data;

[0045] In this method, when acquiring the sampling data corresponding to the sensor capacitance multiple times, in the nth calculation of the sampling data corresponding to the sensor capacitance, only one of the first and second sampling data, as well as the third sampling data, is reacquired, and the same first and second sampling data are involved in the calculation at most twice. For example: in the first calculation of the sampling data corresponding to the sensor capacitance, the first, second, and third sampling data are acquired, and then the sampling data corresponding to the sensor capacitance is calculated based on the first, second, and third sampling data; in the second calculation of the sampling data corresponding to the sensor capacitance, the third and first sampling data are reacquired, and the second sampling data obtained in the first calculation is combined to calculate the sampling data corresponding to the sensor capacitance; in the third calculation of the sampling data corresponding to the sensor capacitance, the third and second sampling data are reacquired, and the first sampling data obtained in the second calculation is combined to calculate the sampling data corresponding to the sensor capacitance; in the fourth calculation of the sampling data corresponding to the sensor capacitance, the third and first sampling data are reacquired, and the second sampling data obtained in the third calculation is combined to calculate the sampling data corresponding to the sensor capacitance, which can greatly improve the overall sampling rate of the sensor capacitance.

[0046] In some embodiments, obtaining the first sampling data corresponding to the sum of the first parasitic capacitance and the sensor capacitance through the detection module includes:

[0047] When the first switch K1 is turned off and the second switch K2 is closed, the selection unit 101 outputs the data from the first input terminal from the output terminal, such as... Figure 4 As shown;

[0048] The sampling data acquired by the detection module 102 is the first sampling data TS0 corresponding to the sum of the first parasitic capacitance C0 and the sensor capacitance C2.

[0049] In some embodiments, obtaining the second sampling data corresponding to the sum of the second parasitic capacitance and the sensor capacitance through the detection module includes:

[0050] When the first switch K1 is closed and the second switch K2 is closed, the selection unit 101 outputs the data from the second input terminal from the output terminal, such as... Figure 5 As shown;

[0051] The sampling data acquired by the detection module 102 is the second sampling data TS1 corresponding to the sum of the second parasitic capacitance C1 and the sensor capacitance C2.

[0052] In some embodiments, obtaining the third sampling data corresponding to the sum of the first parasitic capacitance and the second parasitic capacitance through the detection module includes:

[0053] When the first switch is turned off and the second switch is turned off, the selection unit outputs the data from the first input terminal and the data from the second input terminal from the output terminal, such as... Figure 6 As shown;

[0054] The sampling data acquired by the detection module 102 is the third sampling data TS0&TS1 corresponding to the sum of the first parasitic capacitance C0 and the second parasitic capacitance C1.

[0055] In some embodiments, calculating the sampling data corresponding to the sensor capacitance based on the first sampling data, the second sampling data, and the third sampling data includes:

[0056] Calculate the sum of the first sampled data TS0 and the second sampled data TS1, and then subtract the third sampled data TS0 & TS1 to obtain an intermediate value;

[0057] Take half of the intermediate value to obtain the sampling data corresponding to the sensor capacitance, which can be expressed by the formula (TS0+TS1-TS0&TS1) / 2.

[0058] In some embodiments, the capacitance detection method further includes converting the sampled data into capacitance values. The method for converting the sampled data into capacitance values ​​is common knowledge in the art and will not be described in detail here.

[0059] Figure 7 This is a schematic diagram illustrating the changes in various capacitors during normal use of an electronic cigarette in some embodiments of the present invention. (Refer to...) Figure 7 In the diagram, △TS0 represents the change in the first sampled data TS0, △TS1 represents the change in the second sampled data TS1, and △TS0&TS1 represents the change in the third sampled data TS0&TS1. The negative pressure change generated during normal use (normal inhalation) of the electronic cigarette only causes a change in the capacitance value of the sensor capacitor C2. At this time, the sampling results of the first parasitic capacitance C0 and the second parasitic capacitance C1 also cause a change in the sampling result of the capacitance value of the sensor capacitor C2. The sampling results of the third sampled data TS0&TS1 are only related to the first parasitic capacitance C0 and the second parasitic capacitance C1, and therefore will not change. Based on this condition, while the detection module acquires the sensor capacitance C2, by detecting the changes in the first sampled data TS0, the second sampled data TS1, and the third sampled data TS0&TS1, it is possible to confirm whether the capacitance change is caused by external coupling, thereby achieving stable capacitance value detection.

[0060] While embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations fall within the scope and spirit of the invention as set forth in the claims. Furthermore, the invention described herein may have other embodiments and can be implemented or carried out in various ways.

Claims

1. A capacitance detection method, applied to electronic cigarettes, characterized in that, include: A capacitance detection circuit is provided, comprising a selection unit, a detection module, a first switch, a second switch, and a sensor capacitor. The output terminal of the selection unit is connected to the detection module. The first input terminal of the selection unit is connected to one end of the first switch and a first channel, and the other end of the first switch is grounded. The second input terminal of the selection unit is connected to one end of the second switch and a second channel, and the other end of the second switch is grounded. One end of the first parasitic capacitance of the first channel is connected to one end of the sensor capacitor, and the other end of the first parasitic capacitance of the first channel is grounded. One end of the second parasitic capacitance of the second channel is connected to the other end of the sensor capacitor, and the other end of the second parasitic capacitance of the second channel is grounded. The detection module obtains the first sampling data corresponding to the sum of the first parasitic capacitance and the sensor capacitance. The detection module obtains the second sampling data corresponding to the sum of the second parasitic capacitance and the sensor capacitance. The detection module obtains the third sampling data corresponding to the sum of the first parasitic capacitance and the second parasitic capacitance; The sampling data corresponding to the sensor capacitance is calculated based on the first sampling data, the second sampling data, and the third sampling data; Specifically, when acquiring the sampling data corresponding to the sensor capacitance multiple times, in the nth calculation of the sampling data corresponding to the sensor capacitance, only one of the first sampling data and the second sampling data, as well as the third sampling data, is reacquired, and the same first sampling data and the same second sampling data are each involved in a maximum of two calculations.

2. The capacitance detection method according to claim 1, characterized in that, The step of obtaining the first sampling data corresponding to the sum of the first parasitic capacitance and the sensor capacitance through the detection module includes: When the first switch is turned off and the second switch is closed, the selection unit outputs the data from the first input terminal from the output terminal. The sampling data acquired by the detection module is the first sampling data corresponding to the sum of the first parasitic capacitance and the sensor capacitance.

3. The capacitance detection method according to claim 1, characterized in that, The step of obtaining the second sampling data corresponding to the sum of the second parasitic capacitance and the sensor capacitance through the detection module includes: When the first switch is closed and the second switch is closed, the selection unit outputs the data from the second input terminal from the output terminal. The sampling data acquired by the detection module is the second sampling data corresponding to the sum of the second parasitic capacitance and the sensor capacitance.

4. The capacitance detection method according to claim 1, characterized in that, The step of obtaining the third sampling data corresponding to the sum of the first parasitic capacitance and the second parasitic capacitance through the detection module includes: When the first switch is turned off and the second switch is turned off, the selection unit outputs the data from the first input terminal and the data from the second input terminal from the output terminal. The sampling data acquired by the detection module is the third sampling data corresponding to the sum of the first parasitic capacitance and the second parasitic capacitance.

5. The capacitance detection method according to claim 1, characterized in that, The step of calculating the sampling data corresponding to the sensor capacitance based on the first sampling data, the second sampling data, and the third sampling data includes: Calculate the sum of the first sampled data and the second sampled data, and then subtract the third sampled data to obtain an intermediate value; Take half of the intermediate value to obtain the sampling data corresponding to the sensor capacitance.

6. The capacitance detection method according to claim 1, characterized in that, Also includes: The sampled data is converted into capacitance values.

7. A capacitance detection circuit for implementing the capacitance detection method as described in any one of claims 1 to 6, characterized in that, The device includes a selection unit, a detection module, a first switch, a second switch, and a sensor capacitor. The output terminal of the selection unit is connected to the detection module. The first input terminal of the selection unit is connected to one end of the first switch and a first channel, and the other end of the first switch is grounded. The second input terminal of the selection unit is connected to one end of the second switch and a second channel, and the other end of the second switch is grounded. One end of the first parasitic capacitor of the first channel is connected to one end of the sensor capacitor, and the other end of the first parasitic capacitor of the first channel is grounded. One end of the second parasitic capacitor of the second channel is connected to the other end of the sensor capacitor, and the other end of the second parasitic capacitor of the second channel is grounded.

8. The capacitance detection circuit according to claim 7, characterized in that, It also includes a main control unit, which is connected to the selection unit, the first switch and the second switch, and is used to control the selection unit, the first switch and the second switch.

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