Airflow sensing device and electronic cigarette

Abstract

This invention relates to the field of electronic cigarette technology, specifically disclosing an airflow sensing device and an electronic cigarette. The airflow sensing device includes: an airflow sensor, a calibration module, a signal conversion module, a drive module, and a heating wire connected in sequence. The calibration module includes: an initial value control logic unit and a first operational amplifier. The signal conversion module includes: a transconductance amplifier, a voltage multiplier resistor, and a second operational amplifier. The drive module includes: multiple comparators and a current drive unit. When the capacitance of the airflow sensor changes according to the airflow variation, the transconductance amplifier converts the voltage difference between the voltage across the capacitor and the first reference voltage into a current signal. The voltage multiplier resistor converts the current signal into a voltage signal. Each comparator generates a different switching signal by comparing the voltage signal with the gear voltage. The current drive unit generates a drive current signal based on the switching signal to drive the heating wire.

Description

Technical Field

[0001] This invention relates to the field of electronic cigarette technology, specifically to an airflow sensing device and an electronic cigarette. Background Technology

[0002] Electronic cigarettes, as electronic products that mimic traditional cigarettes, are gaining popularity due to their similar smoke, taste, and feel. Current electronic cigarettes typically use airflow sensors to detect whether the user is smoking. The airflow sensor generates a control signal based on the amplitude of capacitance changes over a fixed period, and the level of this control signal controls the operation of the electronic cigarette's atomizer.

[0003] Since users don't maintain the same level of inhalation intensity throughout, the heating power of the heating coil inside the e-cigarette determines the amount of e-liquid vapor inhaled, and to a large extent, the user's smoking experience. For example, the amount of e-liquid vapor inhaled and the smoking experience will differ significantly depending on whether the heating coil has a power of 10 watts or 30 watts.

[0004] In existing technologies, the heating power of the heating wire needs to be manually adjusted by pressing mechanical buttons or rotating an adjustment dial. Users need to constantly press buttons or rotate the dial to increase or decrease the power. This manual adjustment method is not only inconvenient to operate, but also has poor adjustment accuracy, resulting in a poor overall user experience. Summary of the Invention

[0005] To address the aforementioned problems, the airflow sensing device and electronic cigarette of the present invention can automatically and adaptively adjust the power of the heating wire according to the user's smoking status.

[0006] The first aspect of the present invention provides an airflow sensing device, comprising: an airflow sensor, a calibration module, a signal conversion module, a driving module, and a heating wire connected in sequence; wherein, the calibration module includes an initial value control logic unit and a first operational amplifier; the signal conversion module includes a transconductance amplifier, a voltage multiplier resistor, and a second operational amplifier; and the driving module includes multiple comparators and a current driving unit.

[0007] When the capacitance of the airflow sensor changes according to the airflow variation, the transconductance amplifier converts the voltage difference between the voltage across the capacitor and the first reference voltage into a current signal. The voltage doubler resistor converts the current signal into a voltage signal. Each comparator generates a different switching signal by comparing the voltage signal with the gear voltage. The current drive unit generates a drive current signal based on the switching signal to drive the heating wire to work.

[0008] In one possible implementation, when the control channel of the initial value control logic unit is opened, the first operational amplifier charges the voltage across the capacitor in the airflow sensor to the first reference voltage.

[0009] When the control channel of the initial value control logic unit is closed, the amount of charge in the capacitor remains unchanged.

[0010] In one possible implementation, when the airflow sensing device is powered on, the initial value control logic unit controls the channel to open for a first preset duration.

[0011] In one possible implementation, when the duration for which the control channel of the initial value control logic unit is closed reaches a preset closing duration, the control channel of the initial value control logic unit is opened for a second preset duration.

[0012] In one possible implementation, when air is blown, the capacitance of the airflow sensor decreases and the voltage across the capacitor increases; otherwise, the capacitance of the airflow sensor increases and the voltage across the capacitor decreases.

[0013] In one possible implementation, when the voltage across the capacitor is less than the first reference voltage, the voltage signal is greater than the second reference voltage, and the smaller the voltage across the capacitor, the larger the voltage signal.

[0014] When the voltage across the capacitor is greater than or equal to the first reference voltage, the voltage signal is equal to the second reference voltage.

[0015] In one possible implementation, the gear voltage is greater than the second reference voltage.

[0016] In one possible implementation, the value of the drive current is proportional to the value of the voltage signal.

[0017] In one possible implementation, the input terminal of the initial value control logic unit is connected to the airflow sensor, the output terminal of the initial value control logic unit is connected to the inverting input terminal and the output terminal of the first operational amplifier, and the non-inverting input terminal of the first operational amplifier is connected to the first reference voltage; the first input terminal of the transconductance amplifier is connected to the first reference voltage, the second input terminal of the transconductance amplifier is connected to the airflow sensor, the output terminal of the transconductance amplifier is connected in series with the voltage multiplier resistor and then connected to the inverting input terminal and the output terminal of the second operational amplifier, and the non-inverting input terminal of the second operational amplifier is connected to the second reference voltage; the output terminal of the transconductance amplifier is also connected to the first input terminal of the plurality of comparators, the second input terminal of each comparator is connected to the corresponding range voltage, the output terminal of the comparator is connected to the input terminal of the current drive unit, and the output terminal of the current drive unit is connected to the heating wire.

[0018] A second aspect of the present invention provides an electronic cigarette, including any of the airflow sensing devices described above.

[0019] The beneficial effects of the above technical solution are as follows:

[0020] (1) The present invention can automatically and adaptively adjust the power of the heating wire according to the user’s smoking status.

[0021] (2) This invention detects and converts the voltage change on the output capacitor of the airflow sensor to output different power levels according to different airflow speed and direction, and controls the ignition and extinguishing state of the electronic cigarette, thereby achieving the effect of adjusting the amount of smoke according to the user's smoking intensity and optimizing the user experience.

[0022] (3) The present invention solves the defects of the prior art in that the mechanical adjustment is not accurate and the operation is cumbersome. It does not require the addition of a turntable and is smaller and lighter than the prior art.

[0023] (4) Compared with the prior art, the present invention can effectively reduce the energy consumption of electronic cigarettes and extend the service life of electronic cigarettes and batteries. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the airflow sensing device provided in an embodiment of the present invention. Detailed Implementation

[0025] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of the present invention by way of example, but should not be used to limit the scope of the present invention. That is, the present invention is not limited to the described preferred embodiments, and the scope of the present invention is defined by the claims.

[0026] In the description of this invention, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance; those skilled in the art can understand the specific meaning of the above terms in this invention as appropriate.

[0027] Figure 1 This is a schematic diagram of the airflow sensing device provided in an embodiment of the present invention, as shown below. Figure 1As shown, the present invention provides an airflow sensing device, comprising: an airflow sensor 1, a calibration module 2, a signal conversion module 3, a drive module 4, and a heating wire 5 connected in sequence; wherein, the calibration module 2 includes an initial value control logic unit 21 and a first operational amplifier 22; the signal conversion module 3 includes a transconductance amplifier 31, a voltage multiplier resistor 32, and a second operational amplifier 33; the drive module 4 includes multiple comparators 41 and a current drive unit 42.

[0028] The input terminal of the initial value control logic unit 21 is connected to the airflow sensor 1, and the output terminal of the initial value control logic unit 21 is connected to the inverting input terminal and the output terminal of the first operational amplifier 22. The non-inverting input terminal of the first operational amplifier 22 is connected to the first reference voltage. The first input terminal of the transconductance amplifier 31 is connected to the first reference voltage, and the second input terminal of the transconductance amplifier 31 is connected to the airflow sensor 1. The output terminal of the transconductance amplifier 31 is connected to the inverting input terminal and the output terminal of the second operational amplifier 33 after being connected in series with the voltage multiplier resistor 32. The non-inverting input terminal of the second operational amplifier 33 is connected to the second reference voltage. The output terminal of the transconductance amplifier 31 is also connected to the first input terminal of a plurality of comparators 41 respectively. The second input terminal of each comparator 41 is connected to the corresponding gear voltage. The output terminal of the comparator 41 is connected to the input terminal of the current drive unit 42, and the output terminal of the current drive unit 42 is connected to the heating wire 5.

[0029] The above describes the structure of the airflow sensing device provided by this invention. The following describes the working process of the airflow sensing device.

[0030] When the capacitance of the airflow sensor 1 changes according to the airflow change, the transconductance amplifier 31 converts the voltage difference between the voltage across the capacitor and the first reference voltage into a current signal, the voltage doubler resistor 32 converts the current signal into a voltage signal, each comparator 41 generates different switching signals by comparing the voltage signal and the gear voltage, and the current drive unit 42 generates a drive current signal according to the switching signal to drive the heating wire 5 to work.

[0031] In one possible implementation, when the control channel of the initial value control logic unit 21 is opened, the first operational amplifier 22 charges the voltage across the capacitor in the airflow sensor 1 to the first reference voltage.

[0032] When the control channel of the initial value control logic unit 21 is closed, the amount of charge in the capacitor remains unchanged.

[0033] In one possible implementation, when the airflow sensing device is powered on, the initial value control logic unit 21 controls the channel to open for a first preset duration.

[0034] In one example, upon power-up, the initial value control logic is activated for a period of time, such as 10ms, to charge the capacitor of the first operational amplifier 22 to the first reference voltage, and then is turned off.

[0035] In one possible implementation, when the duration for which the control channel of the initial value control logic unit 21 is closed reaches a preset closing duration, the control channel of the initial value control logic unit 21 is opened for a second preset duration.

[0036] In one example, when there is no smoking, the initial value control logic unit 21 will be turned on for a period of time every time, such as every 15 seconds, to recharge the capacitor, so as to ensure that the initial value charge of the capacitor is sufficient and stable under static conditions.

[0037] In one possible implementation, when air is blown, the capacitance of the airflow sensor 1 decreases and the voltage across the capacitor increases; otherwise, the capacitance of the airflow sensor 1 increases and the voltage across the capacitor decreases.

[0038] In one possible implementation, when the voltage across the capacitor is less than the first reference voltage, the voltage signal is greater than the second reference voltage, and the smaller the voltage across the capacitor, the larger the voltage signal.

[0039] When the voltage across the capacitor is greater than or equal to the first reference voltage, the voltage signal is equal to the second reference voltage.

[0040] In one possible implementation, the gear voltage is greater than the second reference voltage.

[0041] In one possible implementation, the value of the drive current is proportional to the value of the voltage signal.

[0042] In one example, the initial capacitance of the capacitor is C, the voltage difference across the capacitor is VSEN, the first reference voltage is VREF1, the second reference voltage is VREF2, the initial charge stored in the capacitor is C*VREF1, the gain of the transconductance amplifier 31 is Gm, and the current flowing through the voltage multiplier resistor 32 is I. CT =Gm*(VREF1-VSEN), where the resistance of the voltage multiplier resistor 32 is R.

[0043] When external air is drawn in, the capacitance C of airflow sensor 1 increases, and the voltage VSEN on airflow sensor 1 decreases. The smaller VSEN is, the lower the I... CT The larger the voltage signal VCTR, the larger the voltage signal VCTR. According to the working principle of the second operational amplifier 33 and the transconductance amplifier 31, VCTR = I CT *R+VREF2. When the voltage of the voltage signal VCTR satisfies the toggling condition of the comparator 41 of the drive unit, the drive unit will heat the heating wire 5 and successfully produce smoke.

[0044] Conversely, when air is blown from the outside, the capacitance C of the airflow sensor 1 decreases, and the voltage VSEN on the airflow sensor 1 increases. When VSEN is greater than VREF1, the transconductance amplifier 31 is not in its operating range, and the minimum value of VCTR is VREF2. That is to say, when air is blown from the outside, the value of VCTR is the same as when there is no change in airflow, which cannot make the comparator 41 of the drive unit effectively flip. This successfully solves the problem of not being able to smoke when blowing air from the outside, and meets the user experience of inhaling and exhaling smoke.

[0045] The present invention also sets a smoking threshold. When external air is inhaled, the capacitance C of the airflow sensor 1 increases, the voltage VSEN on the airflow sensor 1 decreases, and after passing through the transconductance amplifier 31, VCTR increases.

[0046] VTH0 to VTHN are multiple voltage levels of comparator 41, with values ​​increasing sequentially. When the value of VCTR is less than VTH0, it is considered an effect of natural wind on the airflow sensor 1, indicating a malfunction. The current drive unit 42 does not operate, the current on the heating wire 5 is zero, and the smoking conditions are not met. As the external smoking intensity continues to increase, VCTR continues to rise. When it exceeds one or more values ​​among VTH1 to VTHN, the corresponding level switch will open, increasing the current in the corresponding branch, allowing the current drive unit 42 to perform N-level changes. The increased current flowing through the heating wire 5 leads to increased heating power, ultimately enabling the output power of the heating wire 5 to change progressively with the smoking intensity.

[0047] The present invention also provides an electronic cigarette, including any of the above-described airflow sensing devices.

[0048] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An airflow sensing device, characterized in that, include: The airflow sensor, calibration module, signal conversion module, drive module, and heating wire are connected in sequence; wherein, the calibration module includes an initial value control logic unit and a first operational amplifier; the signal conversion module includes a transconductance amplifier, a voltage multiplier resistor, and a second operational amplifier; the drive module includes multiple comparators and a current drive unit; When the capacitance of the airflow sensor changes according to the airflow variation, the transconductance amplifier converts the voltage difference between the voltage across the capacitor and the first reference voltage into a current signal. The voltage multiplier resistor converts the current signal into a voltage signal. Each comparator generates a different switching signal by comparing the voltage signal with the gear voltage. The current drive unit generates a drive current signal based on the switching signal to drive the heating wire. When the initial value control logic unit opens the control channel, the first operational amplifier charges the voltage across the capacitor in the airflow sensor to the first reference voltage. When the control channel of the initial value control logic unit is closed, the amount of charge in the capacitor remains unchanged; When the voltage across the capacitor is less than the first reference voltage, the voltage signal is greater than the second reference voltage, and the smaller the voltage across the capacitor, the larger the voltage signal. When the voltage across the capacitor is greater than or equal to the first reference voltage, the voltage signal is equal to the second reference voltage; The voltage at the specified gear position is greater than the second reference voltage.

2. The airflow sensing device according to claim 1, characterized in that, When the airflow sensing device is powered on, the initial value control logic unit controls the channel to open for a first preset duration.

3. The airflow sensing device according to claim 1, characterized in that, When the control channel of the initial value control logic unit is closed for a preset closed duration, the control channel of the initial value control logic unit is opened for a second preset duration.

4. The airflow sensing device according to claim 1, characterized in that, When air is blown, the capacitance of the airflow sensor decreases and the voltage across the capacitor increases; otherwise, the capacitance of the airflow sensor increases and the voltage across the capacitor decreases.

5. The airflow sensing device according to claim 1, characterized in that, The value of the driving current is proportional to the value of the voltage signal.

6. The airflow sensing device according to claim 1, characterized in that, The input terminal of the initial value control logic unit is connected to the airflow sensor, and the output terminal of the initial value control logic unit is connected to the inverting input terminal and the output terminal of the first operational amplifier. The non-inverting input terminal of the first operational amplifier is connected to the first reference voltage. The first input terminal of the transconductance amplifier is connected to the first reference voltage, and the second input terminal of the transconductance amplifier is connected to the airflow sensor. The output terminal of the transconductance amplifier is connected to the inverting input terminal and the output terminal of the second operational amplifier after being connected in series with the voltage multiplier resistor. The non-inverting input terminal of the second operational amplifier is connected to the second reference voltage. The output terminal of the transconductance amplifier is also connected to the first input terminal of the plurality of comparators, and the second input terminal of each comparator is connected to the corresponding range voltage. The output terminal of the comparator is connected to the input terminal of the current drive unit, and the output terminal of the current drive unit is connected to the heating wire.

7. An electronic cigarette, characterized in that, Includes the airflow sensing device as described in any one of claims 1-6.

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