State detection circuit for electronic cigarette, electronic cigarette

Abstract

The disclosed embodiment provides a state detection circuit and an electronic cigarette for an electronic cigarette, including: an oscillating unit, which is connected to a capacitive airflow sensor and generates a first periodic signal based on the capacitance value of the capacitive airflow sensor; a base value counter, which is connected to the oscillating unit and counts the first periodic signal for a preset first counting time to obtain a base value and store it; a real-time value counter, which is connected to the oscillating unit and counts the first periodic signal to obtain a real-time counting value, wherein the real-time counting value includes a detection value corresponding to a preset second counting time; a state judgment unit, which is respectively connected to the base value counter and the real-time value counter, and judges the state of the capacitive airflow sensor according to the base value and the detection value; wherein the second counting time is different from the first counting time. This solution enables the detection process to be only related to the capacitance change amount, and has nothing to do with the capacitance value itself, so it has a wider scope of application.

Description

Technical Field

[0001] The present disclosure relates to the technical field of electronic cigarettes, and in particular to a state detection circuit for electronic cigarettes and an electronic cigarette. Background Art

[0002] Compared with traditional cigarettes, e-cigarettes are more economical and significantly reduce the harm of secondhand smoke to others, and have gradually been widely accepted by the market.

[0003] Traditional disposable electronic cigarettes generally use a switch microphone (i.e., airflow sensor) to detect the smoking action. When there is a smoking action, under the action of negative air pressure, the positive and negative poles of the switch microphone are closed. After the control circuit detects that the positive and negative poles of the microphone are closed, it starts to drive the heating wire to heat up and produce smoke, thereby achieving the effect of automatically generating smoke when there is a smoking action.

[0004] In order to improve the sensitivity, that is, to drive the heating wire to generate smoke under very small suction force, the positive and negative poles of the switch microphone need to be very close. However, this will bring another problem, that is, under a slight vibration, the positive and negative poles of the switch microphone can also be closed, thereby triggering smoking by mistake. Long-term continuous false triggering of smoking actions will cause the e-cigarette to overheat, burn the plastic shell of the e-cigarette, and discharge the battery in vain, shortening the life of the e-cigarette. On the other hand, because it is difficult to accurately control the distance between the diaphragm and the fixed plate when producing the switch microphone, the sensitivity of traditional disposable e-cigarette products is too low and it is difficult to inhale.

[0005] In response to the above problems, some solutions have provided capacitive microphones, and by converting the capacitance value of the capacitive microphone into a comparison signal and comparing it with a set threshold, the heating wire driving circuit is controlled to be turned on and off according to the comparison result. Unfortunately, this solution generally has strict requirements on the capacitance value range of the microphone itself, that is, when a capacitor outside the capacitance range is used, the detection accuracy will be seriously affected. Therefore, the existing microphone detection solution has a small scope of application and low application value. Summary of the invention

[0006] In view of the above, in order to solve the problems of small application range and low detection accuracy of the existing electronic cigarette microphone detection circuit, the first aspect of the present disclosure provides a state detection circuit for an electronic cigarette, the circuit comprising: an oscillation unit, which is used to connect with a capacitive airflow sensor and generate a first periodic signal based on the capacitance value of the capacitive airflow sensor; a base value counter, which is connected to the oscillation unit and is used to count the first periodic signal for a preset first counting time to obtain and store a base value; a real-time value counter, which is connected to the oscillation unit and is used to count the first periodic signal to obtain a real-time counting value, wherein the real-time counting value includes a detection value corresponding to a preset second counting time; a state judgment unit, which is respectively connected to the base value counter and the real-time value counter, and is used to judge the state of the capacitive airflow sensor according to the base value and the detection value, wherein the state includes a triggered state and a non-triggered state; wherein the second counting time is different from the first counting time.

[0007] Preferably, the trigger state includes an inhalation state; the second counting time includes a third counting time, the third counting time is greater than the first counting time, and the detection value includes a first detection value; the real-time value counter is used to periodically count the first periodic signal to correspondingly obtain periodic real-time counting values, wherein the real-time counting value of each period includes a first detection value corresponding to the third counting time; the state judgment unit is used to periodically judge whether the capacitive airflow sensor is in the inhalation state based on the base value and the first detection value.

[0008] Preferably, the trigger state includes a blowing state; the second counting time includes a fourth counting time, the fourth counting time is less than the first counting time, and the detection value includes a second detection value; the real-time value counter is used to periodically count the first periodic signal to obtain periodic real-time counting values ​​accordingly, wherein the real-time counting value of each period includes a second detection value corresponding to the fourth counting time; the state judgment unit is used to periodically judge whether the capacitive airflow sensor is in the blowing state based on the base value and the second detection value.

[0009] Preferably, the state detection circuit further comprises a logic unit, which is respectively connected to the state judgment unit and the base value counter to determine an update method of the base value according to the state of the capacitive airflow sensor.

[0010] Preferably, the logic unit is used to count the duration of the trigger state; when the state judgment unit determines that the capacitive airflow sensor is in the trigger state, and the logic unit determines that the duration of the trigger state is greater than or equal to a preset threshold time, the logic unit outputs a reset signal to enable the base value counter to count the first periodic signal again for the first counting time to obtain a new base value and overwrite the original base value.

[0011] Preferably, the real-time value counter is also used to periodically count the first periodic signal to obtain periodic real-time count values ​​accordingly, wherein the real-time count value of each period includes an update reference value corresponding to the first counting time; the state detection circuit also includes a base value update judgment unit, which is respectively connected to the base value counter and the real-time value counter, and the base value update judgment unit is used to output an update request signal according to the base value and the update reference value; the logic unit is connected to the base value update judgment unit to determine whether to output an update signal according to the update request signal and the state of the capacitive airflow sensor.

[0012] Preferably, the update request signal includes a first update request signal, and the update signal includes a first update signal. When the logic unit continuously receives a preset threshold number of first update request signals and the state judgment unit determines that the capacitive airflow sensor is in a non-triggered state during this period, the logic unit outputs a first update signal to cause the base value counter to increase the base value by a preset first change amount; or, the update request signal includes a second update request signal, and the update signal includes a second update signal. When the logic unit continuously receives a preset threshold number of second update request signals and the state judgment unit determines that the capacitive airflow sensor is in a non-triggered state during this period, the logic unit outputs a second update signal to cause the base value counter to reduce the base value by a preset first change amount.

[0013] Preferably, the threshold number is greater than or equal to 2.

[0014] Preferably, the state detection circuit also includes a timing control unit, which is respectively connected to the base value counter, the real-time value counter and the state judgment unit, the timing control unit controls the base value counter to count the first counting time, the timing control unit outputs a counting start signal to trigger the real-time value counter to start counting, and the timing control unit also outputs a state detection signal to enable the state judgment unit to obtain the detection value currently output by the real-time value counter, and judge the state of the capacitive airflow sensor based on the detection value and the state detection signal.

[0015] Preferably, the state judgment unit includes a comparator and a state judgment subunit; one input end of the comparator is connected to the base value counter to receive the base value, and the other input end is connected to the real-time value counter to receive the real-time count value; one input end of the state judgment subunit is connected to the output end of the comparator, and the other input end of the state judgment subunit is connected to the timing control unit to receive the current output signal of the comparator in response to the state detection signal and judge the state of the capacitive airflow sensor based on the output signal and the state detection signal.

[0016] Preferably, the ratio of the difference between the second counting time and the first counting time to the first counting time is in the range of 0.01-0.1.

[0017] Preferably, the ratio of the difference between the second counting time and the first counting time to the first counting time is a preset value.

[0018] A second aspect of the present disclosure further provides an electronic cigarette, which includes the state detection circuit described in any one of the above items, and the oscillation unit of the state detection circuit is connected to the capacitive airflow sensor.

[0019] The beneficial effect of the state detection circuit in this embodiment is that by setting different counting times of the two counters and performing real-time counting value comparison, the state of the capacitive airflow sensor can be accurately detected, and the detection process is only related to the capacitance change amount, but not to the capacitance value itself, and the base value is obtained by counting, not by preset. Therefore, the scope of application is wider and the application value is higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

[0021] Figure 1 is a module structure diagram of a state detection circuit for an electronic cigarette provided by an embodiment of the present disclosure;

[0022] Figure 2 is a structural diagram of a capacitive airflow sensor involved in a state detection circuit provided in an embodiment of the present disclosure;

[0023] Figure 3 It is a timing diagram of a state detection circuit performing periodic state detection provided by an embodiment of the present disclosure;

[0024] Figure 4 It is a module structure diagram of another state detection circuit for an electronic cigarette provided by an embodiment of the present disclosure;

[0025] Figure 5is another timing diagram of a state detection circuit performing periodic state detection provided by an embodiment of the present disclosure;

[0026] Figure 6 It is a module structure diagram of an electronic cigarette 20 provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0027] In the following description, certain specific details are set forth in order to provide a thorough understanding of various embodiments of the present disclosure. However, it will be understood by those skilled in the art that the present disclosure may be practiced without these specific details.

[0028] In the description of the present disclosure, above, below, within, at least, etc. are understood to include the number itself. If there is a description of first or second, it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features. In addition, the connection referred to in the present disclosure should be interpreted in a broad sense, that is, electrical connection, that is, it is not limited to direct connection between devices, but also includes direct or indirect connection between devices, devices and units, and units and units.

[0029] The present disclosure provides a state detection circuit 10 for an electronic cigarette. For ease of understanding, the following is combined with Figure 1-Figure 5 , the circuit is described in detail.

[0030] like Figure 1As shown, the state detection circuit 10 of the electronic cigarette includes an oscillation unit 11, a base value counter 12, a real-time value counter 13 and a state judgment unit 14. The oscillation unit 11 is connected to the capacitive airflow sensor SW, and generates a first periodic signal CLK1 based on the capacitance value of the capacitive airflow sensor SW. The base value counter 12 is connected to the oscillation unit 11, and is used to receive the first periodic signal CLK1 and count the first periodic signal CLK1. The base value counter 12 counts the first periodic signal CK1 for a preset first counting time to obtain a base value C0 and store it. The real-time value counter 13 is connected to the oscillation unit 11, and is used to receive the first periodic signal CLK1 and count the first periodic signal CLK1 to obtain a real-time count value, wherein the real-time count value includes a detection value C1 corresponding to a preset second counting time T2. The state judgment unit 14 is connected to the base value counter 12 and the real-time value counter 13 respectively, and is used to receive the base value C0 and the detection value C1, and judge the state of the capacitive airflow sensor SW according to the base value C0 and the detection value C1, and the state includes a trigger state and a non-trigger state, wherein the second counting time T2 is different from the first counting time T1. In this embodiment, the capacitive airflow sensor is, for example, a capacitive microphone, a MEMS (Micro-Electro-Mechanical System), etc.

[0031] The inventors have found that since the capacitance value of the capacitive airflow sensor changes with the flow of the external airflow, the frequency of the first periodic signal CLK1 generated by the oscillation unit 11 also changes accordingly. Specifically, Figure 2As shown, compared with the standby state, when the electronic cigarette inhales, that is, the capacitive airflow sensor SW senses that the external airflow flows in the inhalation direction, the capacitance value of the capacitive airflow sensor SW increases, and the frequency of the first periodic signal CLK1 generated by the oscillation unit 11 decreases. When the electronic cigarette blows, that is, the capacitive airflow sensor SW senses that the external airflow flows in the blowing direction, the capacitance value decreases, and the frequency of the first periodic signal CLK1 generated by the oscillation unit 11 increases. The standby state refers to the state when the capacitive airflow sensor does not sense the flow of the external airflow. Therefore, compared with the standby state, when the electronic cigarette inhales or blows, the number of the first periodic signal CLK1 counted at the same time will change, that is, at the same counting time, the number of the first periodic signal CLK1 counted when blowing> the number of the first periodic signal CLK1 counted in the standby state> the number of the first periodic signal CLK1 counted when inhaling. Therefore, the technical concept of the state detection circuit 10 provided in this embodiment is: by cleverly setting two counters to count the first periodic signal CLK1 for different counting times, two count values ​​with a certain difference are obtained in the standby state, that is, the detection value C1 is greater than the base value C0, or the detection value C1 is less than the base value C0, at this time, the capacitive airflow sensor SW is in a non-triggered state, when the count value change caused by the change in the capacitance value of the capacitive airflow sensor is sufficient to make up for the original count difference, even if the detection value C1 is less than the base value C0, or the detection value C1 is greater than the base value C0, it is judged that the capacitive airflow sensor SW is in a triggered state at this time. Among them, the trigger state includes the inhalation state and the blowing state. When the capacitive airflow sensor SW is not in the inhalation state or the blowing state, it is considered to be in a non-triggered state. It can be understood that when the capacitive airflow sensor SW is detected to be in the inhalation state, and the duration of the inhalation state reaches the set time, it means that the user is smoking, and the heating element of the electronic cigarette is driven to work. When the capacitive airflow sensor SW is detected to be in the blowing state or the non-triggered state, it means that the user is not smoking, and the heating element of the electronic cigarette is not driven to work.

[0032] The beneficial effect of the state detection circuit 10 under this embodiment is that by setting different counting times of the two counters and comparing the count values, the state of the capacitive airflow sensor can be accurately detected, and the detection process is only related to the capacitance change amount, but not to the capacitance value itself, and the base value is obtained by counting, not by preset. Therefore, the scope of application is wider and the application value is higher.

[0033] In this embodiment, the state detection of the capacitive airflow sensor can be set to periodic detection. Figure 3As shown, when the second counting time T2 is greater than the first counting time T1, it indicates that the state detection to be performed is the inhalation state detection, and the second counting time T2 greater than the first counting time T1 is called the third counting time T21. After the power-on self-test reset, the base value counter 12 obtains and stores the base value C0 after counting the first periodic signal CLK1 for the first counting time T1. Thereafter, except for the power-on self-test reset or receiving the reset signal, the base value counter 12 no longer counts the first periodic signal CLK1. The real-time value counter 13 periodically counts the first periodic signal CLK1 to obtain a periodic real-time count value, that is, the real-time count value is cleared after each cycle of counting is completed, and the cycle is called the detection cycle T0. For each real-time count value of the detection cycle T0, it includes a first detection value C11 corresponding to the third counting time T21, wherein the third counting time T21 is the counting time within the cycle. The state judgment unit 14 compares the first detection value C11 obtained with the stored base value C0 in each detection cycle, thereby judging whether the capacitive airflow sensor SW is in the inhalation state, and outputting the inhalation state result signal SMOKE_ANSWER, the inhalation state result signal SMOKE_ANSWER including the first state signal SMOKE_ANSWER1 indicating that the capacitive airflow sensor SW is in the inhalation state, and the second state signal SMOKE_ANSWER2 indicating that the capacitive airflow sensor SW is not in the inhalation state. Specifically, the judgment process is explained below with reference to an example.

[0034] It is worth mentioning that the status detection is usually started after the base value counter 12 obtains the base value C0 after the power-on self-test reset. Therefore, in this embodiment, the starting time t2 of the first detection cycle T0(1) is later than the time t1 when the base value counter 12 obtains the base value C0.

[0035] Under normal power-on conditions, such as Figure 3 As shown, taking one of the detection cycles T0 as an example, assuming T21 / T1≈1.03;

[0036] Assume that the duration of a detection cycle is T0 = 1024 × CLK2,

[0037] T1=990×CLK2, where CLK2 represents one period of the reference periodic signal, and the period duration of the periodic signal is generally fixed;

[0038] Then T21 = 1020 × CLK2;

[0039] After the power-on self-check reset, the result of the base counter 12 counting the first cycle signal CLK1 for the first counting time T1 is the base value C0; within the detection cycle T0, the real-time count value corresponding to the third counting time T21 is the first detection value C11. Within the detection cycle T0, if the electronic cigarette is not inhaled, that is, the capacitance value of the capacitance airflow sensor SW hardly changes, then the first detection value C11 hardly changes. At this time, since T21 / T1≈1.03, then C11≈1.03*C0, that is, C0<C11. Since C11<C0 is not satisfied, the state judgment unit 14 judges that the capacitance airflow sensor SW is not in the inhalation state, and the state judgment unit 14 outputs the second state signal SMOKE_ANSWER2.

[0040] If the electronic cigarette inhales slightly (that is, the increase amplitude of the capacitance value does not exceed the preset threshold of "3%"), at this time C0≤C11<1.03*C0. Since C11<C0 is still not satisfied, the state judgment unit 14 still judges that the capacitance airflow sensor SW is not in the inhalation state, and the state judgment unit 14 still outputs the second state signal SMOKE_ANSWER2.

[0041] It is worth mentioning that defining the capacitance change of the capacitance airflow sensor less than a certain threshold as the non-trigger state is set to prevent false triggering. For example, during the transportation of the electronic cigarette or during the storage by the user, due to the change of air or environment, the electronic cigarette may be falsely triggered. Generally speaking, when the user inhales the electronic cigarette normally, the capacitance change of the capacitance airflow sensor will be greater than this threshold. In this embodiment, this threshold is set to 3%. Of course, in other embodiments of the present invention, those skilled in the art can also adjust the threshold according to needs, such as setting the threshold to 1%, 2%, 4%, 5%, etc.

[0042] If the electronic cigarette inhales normally (that is, the increase amplitude of the capacitance value exceeds the preset threshold of "3%"), at this time C11>C0. At this time, the state judgment unit 14 will judge that the capacitance airflow sensor SW is in the inhalation state, and the state judgment unit 14 outputs the first state signal SMOKE_ANSWER1.

[0043] Specifically, as Figure 1 shown, the state detection circuit 10 further includes a logic unit 15. The logic unit 15 is connected to the state judgment unit. When the logic unit 15 receives a preset number of first state signals SMOKE_ANSWER1, it outputs a drive signal SMOKE_EN to drive the heating element to work. In this embodiment, the preset number is 2, but it is not limited to this. In other embodiments of the present application, the number can also be 1, 3, 4, 5, etc.

[0044] When the second counting time T2 is less than the first counting time T1, it indicates that the state detection to be performed is the blowing state detection. The second counting time T2 that is less than the first counting time T1 is called the fourth counting time T22. As Figure 3 shown, for the real-time count value of each detection period T0, it includes a second detection value C12 corresponding to the fourth counting time T22. Among them, the fourth counting time T22 is the counting time within the period. The state judgment unit 14 compares the obtained second detection value C12 with the stored base value C0 in each detection period T0, so as to judge whether the capacitive airflow sensor SW is in the blowing state, and outputs a blowing state result signal BLOW_ANSWER. The blowing state result signal BLOW_ANSWER includes a third state signal BLOW_ANSWER1 indicating that the capacitive airflow sensor SW is in the blowing state, and a fourth state signal BLOW_ANSWER2 indicating that the capacitive airflow sensor SW is not in the blowing state. Specifically, the following combines examples to explain the judgment process.

[0045] Under normal power-on conditions, as Figure 3 shown, taking one detection period T0 as an example, assume that T22 / T1≈0.97; that is:

[0046] T0 = 1024×CLK2,

[0047] T1 = 990×CLK2,

[0048] T22 = 960×CLK2;

[0049] After power-on self-check reset, the result of the base value counter 12 counting the first cycle signal CLK1 for the first counting time T1 is the base value C0; within this detection period T0, the real-time count value corresponding to the fourth counting time T22 is called the second detection value C12. Within this detection period T0, if the electronic cigarette does not blow, that is, the capacitance value of the capacitive airflow sensor SW hardly changes, then the second detection value C12 hardly changes. At this time, since T22 / T1≈0.97, then C12≈0.97*C0, that is, C0 > C12. Since C12 > C0 is not satisfied, it is judged that the capacitive airflow sensor SW is not in the blowing state, and the state judgment unit 14 outputs the fourth state signal BLOW_ANSWER2.

[0050] If the electronic cigarette blows slightly (that is, the decrease amplitude of the capacitance value does not exceed the preset threshold "3%"), at this time 0.97*C0 ≤ C12 < C0. Since C12 > C0 is still not satisfied, it is still judged that the capacitive airflow sensor SW is not in the blowing state, and the state judgment unit 14 outputs the fourth state signal BLOW_ANSWER2.

[0051] It is worth mentioning that the capacitance change of the capacitive airflow sensor is defined as an untriggered state when it is less than a certain threshold value. This setting is to prevent false triggering, for example, during the transportation of the electronic cigarette or the storage of the user, the electronic cigarette is falsely triggered due to changes in the air or environment. Generally speaking, the capacitance change of the capacitive airflow sensor when the user blows air on the electronic cigarette will be greater than the threshold value. In this embodiment, the threshold value is set to 3%. Of course, in other embodiments of the present invention, those skilled in the art can also adjust the threshold value as needed, for example, setting the threshold value to 1%, 2%, 4%, 5%, etc.

[0052] If the electronic cigarette is blowing normally (ie the capacitance value decreases by more than the preset threshold value "3%"), C12>C0, and it is determined that the capacitive airflow sensor SW is in the blowing state, and the state judgment unit 14 outputs the third state signal BLOW_ANSWER1.

[0053] It should be noted that, in the state detection circuit of this embodiment, the ratio of the second counting time T2 to the first counting time T1 is not limited to the above values, that is, T21 / T1≈1.03, T22 / T1≈0.97, so that the ratio of the difference between the second counting time T2 and the first counting time T1 to the first counting time T1 is not limited to a fixed value of 0.03. Preferably, the range of the ratio of the difference between the second counting time T2 and the first counting time T1 to the first counting time T1 can be 0.01-0.1, for example, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, etc., and there can also be certain fluctuations, and it can also be set to a certain value according to actual needs.

[0054] Specifically, Figure 1As shown, the state detection circuit 10 provided in this embodiment may also include a counting control unit 17, which is respectively connected to the base value counter 12, the real-time value counter 13 and the state judgment unit 14. The counting control unit generates a base value counting control signal T_BASE and sends it to the base value counter 12 to control the base value counter 12 to count the first period signal CLK1 for the first counting time T1 to obtain the base value C0. The counting control unit 17 also generates a period control signal T_CONTROL and sends it to the real-time value counter 13 to control the periodic counting of the real-time value counter. Specifically, the period control signal T_CONTROL includes a period start signal T_START0, a zeroing end signal T_END0, and a counting start signal T_START1. The period start signal T_START0 is used to control the starting time of each detection period T0, and the zeroing end signal T_END0 is used to control the real-time value counter 13 to clear the count to facilitate the next detection period to count again. The counting start signal T_START1 is used to trigger the real-time value counter 13 to start counting in each detection period T0 to obtain the real-time count value. Figure 3 The counting start signal T_START1 and the cycle start signal T_START0 are the same signal. For each real-time count value of the detection cycle T0, it includes a first detection value C11 corresponding to the third counting time T21 and a second detection value C12 corresponding to the fourth counting time T22. The counting control unit 17 also generates a periodic state detection signal CHECK and sends it to the state judgment unit 14, so that the state judgment unit 14 obtains the detection value C1 currently output by the real-time value counter 13, and judges the state of the capacitive airflow sensor SW according to the output detection value C1 and the state detection signal CHECK.

[0055] Specifically, the status detection signal CHECK includes a suction detection signal SMOKE_CHECK and a blow detection signal BLOW_CHECK. Figure 1 and Figure 3As shown, the inhalation detection signal SMOKE_CHECK and the blowing detection signal BLOW_CHECK are periodically generated, and each inhalation detection signal SMOKE_CHECK and each blowing detection signal BLOW_CHECK can be a pulse signal. When the counting control unit 17 generates the inhalation detection signal SMOKE_CHECK at time t5, the state judgment unit 14 receives the inhalation detection signal SMOKE_CHECK. At this time, the state judgment unit 14 compares and judges the size of the count value currently output by the base value counter 12 and the real-time value counter 13. Since the time t5 from the generation time of the inhalation detection signal SMOKE_CHECK to the generation time t2 of the counting start signal T_START1 is the third counting time T21, the real-time value counter 13 is equal to the value of the real-time value counter 13. The real-time count value currently output by the counter 13 is the first detection value C11. At this time, the state judgment unit 14 judges whether the capacitive airflow sensor is in the inhalation state; when the counting control unit 17 generates the blowing detection signal BLOW_CHECK at time t3, the state judgment unit 14 receives the blowing detection signal BLOW_CHECK. At this time, the state judgment unit 14 compares and judges the base value and the real-time count value currently output by the real-time value counter 13. At this time, the state judgment unit 14 judges whether the capacitive airflow sensor is in the blowing state. Since the time t3 from the time t2 when the counting start signal T_START1 is generated to the fourth counting time T22, the count value currently output by the real-time value counter 13 is the second detection value C12.

[0056] Specifically, Figure 1As shown, the counting control unit 17 has a first output end for outputting an inhalation detection signal SMOKE_CHECK and a second output end for outputting a blow detection signal BLOW_CHECK. The state judgment unit 14 includes a comparator 141, a first state judgment subunit 142 and a second state judgment subunit 143. One input end of the comparator 141 is connected to the base value counter 12 to receive the base value C0, and the other input end is connected to the real-time value counter 13 to receive the real-time count value. One input end of the first state judgment subunit 142 is connected to the output end of the comparator 141, and the other input end is connected to the first output end of the counting control unit 17. The output end of the first state judgment subunit 142 is connected to the logic unit 15 for outputting the inhalation state result signal SMOKE_ANSWER. When the logic unit 15 receives the first state signal SMOKE_ANSWER1 for two consecutive detection cycles, the logic unit 15 outputs a drive signal SMOKE_EN to drive the heating element to work. One input end of the second state judgment subunit 143 is connected to the output end of the comparator 141, and the other input end is connected to the second output end of the counting control unit 17. The output end of the second state judgment subunit 143 is connected to the logic unit 15 for outputting the blowing state result signal BLOW_ANSWER. When the logic unit 15 receives the third state signal BLOW_ANSWER1 for two consecutive detection cycles, the logic unit 15 determines that the user is blowing back the electronic cigarette.

[0057] The following is an example to illustrate the periodic state detection process performed by the state detection circuit 10. Figure 3 As shown, when the first state judgment subunit 142 receives the inhalation detection signal SMOKE_CHECK at time t5, the first state judgment subunit 142 outputs the first state signal SMOKE_ANSWER1 or the second state signal SMOKE_ANSWER2 accordingly according to the high or low level of the output of the comparator 141 currently received. It can be understood that at this time, the two input terminals of the comparator 141 receive the base value C0 and the first detection value C11 respectively.

[0058] When the second state judgment subunit 143 receives the blowing detection signal BLOW_CHECK at time t3, the second state judgment subunit 143 outputs the third state signal BLOW_ANSWER1 or the fourth state signal BLOW_ANSWER2 accordingly according to the high or low level of the output of the comparator 141 currently received. It can be understood that at this time, the two input terminals of the comparator 141 receive the base value C0 and the second detection value C12 respectively.

[0059] Specifically, the suction detection signal SMOKE_CHECK and the blowing detection signal BLOW_CHECK may be pulse signals.

[0060] The beneficial effect of the state detection circuit 10 under the present embodiment is that, in addition to being able to accurately detect the state of the capacitive airflow sensor and improve the applicable range of the capacitance value, since the ratio of the second counting time to the first counting time in each detection cycle is equal, the capacitance value change corresponding to each detection of the inhalation state or the blowing state can be equal, thereby improving the stability of the state detection and effectively avoiding mis-inhalation.

[0061] In addition, in addition to normal power-on, electronic cigarettes also include abnormal power-on situations, that is, power-on by inhalation or power-on by blowing. It can be understood that the initial capacitance value corresponding to power-on by blowing or power-on by inhalation is different from that of normal power-on, and thus the base value C0 obtained by the first calculation is different from that of normal power-on, and will be larger or smaller, but the state judgment process and principle after power-on are exactly the same as those of the above-mentioned normal power-on situation. Therefore, when power-on by inhalation occurs (assuming that the capacitance value is larger than 3% when the base value C0 is recorded for the first time than that of normal power-on), according to the above-mentioned state detection circuit 10, after stopping inhalation, the state judgment unit will misjudge that the capacitive airflow sensor is in the blowing state, and after normal inhalation again (the capacitance value increases by more than 3%), it will detect that the blowing state has been exited. When the blowing power-on occurs (assuming that the capacitance value is more than 3% smaller than the normal power-on when the base value C0 is recorded for the first time), according to the above-mentioned state detection circuit 10, after stopping the blowing, the state judgment unit will misjudge that the capacitive airflow sensor is in the inhalation state, and after blowing normally again (the capacitance value decreases by more than 3%), it will detect the exit from the inhalation state. The detailed judgment process is exactly the same as the above-mentioned normal power-on, and will not be elaborated here. As a result, the electronic cigarette is inconsistent with the normal use condition, affecting the normal use of the user. In addition, the inventors also found that after multiple or long-lasting inhalations or blowing, the capacitance value of the capacitive airflow sensor SW may not be completely restored to the original value, which will cause the current base value to not accurately reflect the current capacitance value. Alternatively, under the influence of external environments such as wind speed and air pressure, the current base value may not accurately reflect the current capacitance value. In addition, in the case of the aforementioned inhalation power-on or blowing power-on, the base value C0 obtained by counting may not accurately reflect the current capacitance value. Therefore, in order to make the base value C0 accurately reflect the current capacitance value and adapt to various situations, as one of the preferred methods of the state detection circuit 10 provided in this embodiment, a base value update mechanism can be added.

[0062] Specifically, Figure 4 As shown, the logic unit 15 is also connected to the base value counter 12, and determines the updating method of the base value C0 according to the state of the capacitive airflow sensor SW.

[0063] It is understandable that, due to the situation of powering on by inhalation, powering on by blowing, or inhaling or blowing for too long, the current base value C0 cannot accurately reflect the current capacitance value. Therefore, for the above situation, as an example of the base value update mechanism. The logic unit 15 is also used to count the duration of the trigger state. When the state judgment unit 14 determines that the capacitive airflow sensor SW is in the trigger state, and the duration of the trigger state reaches the preset threshold time, the logic unit 15 controls the base value counter 12 to count the first counting time T1 again to obtain a new base value and overwrite the original base value C0.

[0064] Specifically, when the logic unit 15 receives the first state signal SMOKE_ANSWER1 and receives the first state signal SMOKE_ANSWER1 in two consecutive detection cycles T0, the logic unit 15 starts timing. If the logic unit 15 continues to receive the first state signal SMOKE_ANSWER1 in each detection cycle T0 during the period when the timing time reaches the first threshold time, the timing is reset when the timing time reaches the first threshold time, and the timing is restarted. If the logic unit 15 continues to receive the first state signal SMOKE_ANSWER1 in each detection cycle T0 during the period when the re-timing time reaches the third threshold time, the logic unit 15 generates a reset signal REPLACE_EN when the re-timing time reaches the third threshold time and sends it to the base value counter 12 and the counting control unit 17, so that the base value counter 12 counts the first cycle signal CLK1 again for the first counting time T1, obtains a new base value and overwrites the original base value C0, and this new base value is the base value C0 that can accurately reflect the current capacitance value. If the logic unit 15 receives the second state signal SMOKE_ANSWER2 or the third state signal BLOW_ANSWER1 before the first timing time reaches the first threshold time or the retiming time reaches the third threshold time, the reset signal REPLACE_EN is not generated, and the base value counter 12 does not re-count the first cycle signal CLK1 for the first counting time T1. If the first state signal SMOKE_ANSWER1 is still received after the retiming reaches the third threshold time, the above timing steps are repeated. In this embodiment, the sum of the first threshold time and the third threshold time is called the threshold time, and the first threshold time and the third threshold time can be equal or different, preferably equal. For example, the preset inhalation timeout is 10s, which is the first threshold time, and the countdown time is 10s, which is the third threshold time. If the inhalation state is judged to be timed out (i.e., more than 10s), a 10s countdown is performed. If the countdown ends and the inhalation state is not exited, a reset signal REPLACE_EN is sent to the base value counter 12 and the counting control unit 17, so that the base value counter 12 counts the first cycle signal CLK1 again for the first counting time T1, obtains a new base value and covers the original base value C0. If the inhalation does not time out or the inhalation state has been exited before the countdown ends, the base value C0 is not re-counted. In this example, the threshold time is equal to the inhalation timeout (10s) plus the countdown time (10s). It is worth mentioning that when the logic unit 15 receives the first state signal SMOKE_ANSWER1 for two consecutive detection cycles T0, a drive signal SMOKE_EN is generated to drive the heating element of the electronic cigarette to work.

[0065] Similarly, the logic unit 15 receives the third state signal BLOW_ANSWER1, and receives the third state signal BLOW_ANSWER1 in two consecutive detection cycles T0, and the logic unit 15 starts timing. If the logic unit 15 continues to receive the third state signal BLOW_ANSWER1 in each detection cycle T0 during the period when the re-timing time reaches the second threshold time, the logic unit 15 generates a reset signal REPLACE_EN when the timing time reaches the second threshold time and sends it to the base value counter 12 and the counting control unit 17, so that the base value counter 12 counts the first cycle signal CLK1 again for the first counting time T1, obtains a new base value and overwrites the original base value C0, and this new base value is the base value C0 that can accurately reflect the current capacitance value. If the logic unit 15 receives the first state signal SMOKE_ANSWER1 or the fourth state signal BLOW_ANSWER2 before the timing time reaches the second threshold time, the reset signal REPLACE_EN is not generated, and the base value counter 12 does not re-count the first cycle signal CLK1 for the first counting time T1. If the third state signal BLOW_ANSWER1 is still received after the timing reaches the second threshold time, the corresponding aforementioned timing steps are repeated. For example, the preset blowing timeout is 10s, and this 10 seconds is the second threshold time. If it is determined that the blowing state has timed out (i.e., more than 10s), a reset signal REPLACE_EN is sent to the base value counter 12 and the counting control unit 17, so that the base value counter 12 counts the first cycle signal CLK1 again for the first counting time T1, obtains a new base value and overwrites the original base value C0. If the blowing state has been exited before the blowing timeout, the base value C0 is not re-counted. In this example, the second threshold time is equal to the blowing timeout (10s).

[0066] As another example of a base value update mechanism. Figure 4 As shown, the state detection circuit 10 also includes a base value update judgment unit 16, which is connected to the base value counter 12 and the real-time value counter 13 respectively. Figure 5As shown, for each real-time count value of the detection period T0, it includes an updated reference value C2 corresponding to the first counting time T1, where the first counting time T1 is the counting time within the period. The base value update judgment unit 16 compares the obtained updated reference value C2 with the stored base value C0 in each detection period and outputs an update requirement signal SA. The update requirement signal SA includes a first update requirement signal SA1 indicating the increment requirement of the base value C0, where the base value C0 is less than the updated reference value C2 at this time, and a second update requirement signal SA2 indicating the decrement requirement of the base value C0, where the base value C0 is greater than the updated reference value C2 at this time. The base value update judgment unit 16 is also connected to the logic unit 15 to determine the update method of the base value according to the update requirement signal SA and the state of the capacitive airflow sensor.

[0067] It can be understood that since the counting times corresponding to the updated reference value C2 and the base value C0 are equal, that is, both are the first counting time T1, therefore, when there is no blowing and no inhalation, in an ideal situation (that is, the base value C0 can accurately reflect the current capacitance value), the updated reference value C2 is equal to the base value C0. On the contrary, due to factors such as environmental influence and detection accuracy influence, the base value update judgment unit 16 generally detects that the updated reference value C2 is not equal to the base value C0. Specifically, if C2 > C0, it means that the base value C0 is too small at this time, and the first update requirement signal SA1 indicating an increment adjustment is output. If C2 < C0, it means that the base value C0 is too large at this time, and the second update requirement signal SA2 indicating a decrement adjustment is output to instruct the logic unit 15 to adjust the base value in combination with the state of the capacitive airflow sensor.

[0068] Specifically, when the logic unit 15 continuously receives a preset threshold number of first update requirement signals SA1, and during this period the state judgment unit 14 determines that the capacitive airflow sensor is in a non-trigger state, the logic unit 15 sends a first update signal RENEW1_EN to the base value counter 12, so that the base value counter 12 increases the base value C0 by a preset first change amount. For example, the preset threshold number is 2, and the preset first change amount is 1. When the logic unit 15 receives the first update requirement signal SA1 output by the base value update judgment unit 16 in two consecutive detection periods, and does not receive the first status signal SMOKE_ANSWER1 or the third status signal BLOW_ANSWER1 during this period, that is, when the capacitive airflow sensor SW is not in the blowing state and the inhalation state, a first update signal RENEW1_EN is generated and sent to the base value counter 12, and the base value counter 12 performs a +1 update on the base value C0.

[0069] Similarly, when the logic unit 15 continuously receives the second update request signal SA2 of the preset threshold number, and during this period the state judgment unit 14 judges that the capacitive airflow sensor is in a non-trigger state, the logic unit 15 sends the second update signal RENEW2_EN to the base value counter 12, so that the base value counter 12 reduces the base value C0 by the preset first change amount. For example, the preset threshold number is 2, and the preset first change amount is 1. When the logic unit 15 receives the second update request signal SA2 output by the base value update judgment unit 16 in two consecutive detection cycles, and does not receive the first state signal SMOKE_ANSWER1 or the third state signal BLOW_ANSWER1 during this period, the second update signal RENEW2_EN is generated and sent to the base value counter 12, and the base value counter 12 performs a -1 update on the base value C0.

[0070] Preferably, in the state detection circuit 10 of this embodiment, the number of the above thresholds can be set to be more than two, which has the advantage of being able to effectively avoid errors and make the update of the base value C0 more accurate.

[0071] Specifically, Figure 4 As shown, the counting control unit 17 also has a third output terminal for outputting a base value update detection signal BASE_CHECK. The base value update judgment unit 16 includes a comparator 141 and a base value update judgment subunit 144. Among them, the comparator 141 of the base value update judgment unit 16 is shared with the state judgment unit to reduce costs. Of course, a separate comparator 141 that is not shared can also be set; one input terminal of the base value update judgment subunit 144 is connected to the output terminal of the comparator 141, and the other input terminal is connected to the third output terminal of the counting control unit 17. The output terminal of the base value update judgment subunit 144 is connected to the logic unit 15 for outputting an update request signal SA. In addition, as Figure 5 As shown, the base value update detection signal BASE_CHECK is generated periodically, and the interval between the generation time t4 of each base value update detection signal BASE_CHECK and the counting start time t2 of the current detection cycle T0 (1) is the first counting time T1.

[0072] When the base value update detection signal BASE_CHECK arrives, the base value update judgment subunit 144 outputs the first update request signal SA1 or the second update request signal SA2 accordingly according to the high or low level of the output of the comparator 141 currently received. It can be understood that at this time, the two input terminals of the comparator 141 receive the base value C0 and the update reference value C2 respectively.

[0073] Specifically, the base value update detection signal BASE_CHECK may be a pulse signal.

[0074] The beneficial effect of the state detection circuit 10 under this embodiment is that, on the one hand, by setting different counting times of the two counters and performing real-time count value comparison, the state of the capacitive airflow sensor can be accurately detected, and the detection process is only related to the capacitance change, and has nothing to do with the capacitance value itself. Moreover, the base value is obtained by counting, not by preset. Therefore, the scope of application is wider and the application value is higher. On the other hand, by setting a base value update mechanism, the capacitance value of the capacitive airflow sensor SW cannot be fully restored and the influence of the external environment can be effectively eliminated, ensuring that the base value accurately reflects the current capacitance value, so that the capacitance value change corresponding to the inhalation state or the blowing state is equal each time it is detected, ensuring the stability and accuracy of the state detection.

[0075] In addition, in this embodiment, see Figure 1 and Figure 4 , the counting control unit 17 itself generates a reference period signal, and each period CLK2 of the reference period signal is fixed, so that the counting control unit 17 can count the number of periods of the reference period signal to obtain different durations, such as obtaining a first counting time, a third counting time, and a fourth counting time. However, the present invention is not limited thereto. In other embodiments of the present invention, the counting control unit 17 is also electrically connected to the oscillation unit 11, and the oscillation unit 11 generates a reference period signal, and each period CLK2 of the reference period signal is fixed, so that the counting control unit 17 can count the number of periods of the received reference period signal to obtain different durations, such as obtaining a first counting time, a third counting time, and a fourth counting time.

[0076] The disclosed embodiment also provides an electronic cigarette 20, such as Figure 6 As shown, the electronic cigarette 20 includes a capacitive airflow sensor SW and a state detection circuit.

[0077] It should be noted that the state detection circuit included in the electronic cigarette 20 provided in this embodiment belongs to the same concept as the state detection circuit 10 provided in the above embodiment, and its specific circuit structure, implementation process and technical details in the embodiment are all applicable in the embodiment of the electronic cigarette 20, and the repeated parts will not be repeated.

[0078] It is understandable that the above-mentioned state detection circuit 10 can be directly set on the printed circuit board, or can be set as an integrated circuit chip installed on the printed circuit, or can be partially set on the printed circuit board and partially set as an integrated circuit chip installed on the printed circuit. The present disclosure does not limit this.

[0079] The beneficial effect of the electronic cigarette 20 under this embodiment is that, on the one hand, by setting different counting times of the two counters and performing real-time counting value comparison, the state of the capacitive airflow sensor can be accurately detected, and the detection process is only related to the capacitance change, and has nothing to do with the capacitance value itself. Moreover, the base value is obtained by counting, not by preset. Therefore, the scope of application is wider and the application value is higher. On the other hand, by setting a base value update mechanism, the capacitance value of the capacitive airflow sensor SW cannot be fully restored and the influence of the external environment can be effectively eliminated, ensuring that the base value accurately reflects the current capacitance value, so that the capacitance value change corresponding to each inhalation state or blowing state is equal, ensuring the stability and accuracy of state detection.

[0080] The various embodiments described above can be combined to provide further embodiments. Aspects of the embodiments can be modified, if necessary, to employ the concepts of the various patents, applications and publications to provide yet further embodiments.

[0081] In light of the above detailed description, these and other changes can be made to the embodiments. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and claims, but should be construed to include all possible embodiments, along with the full range of equivalents to which the claims are entitled. Accordingly, the claims are not limited by the present disclosure.

Claims

1. A state detection circuit for an electronic cigarette, characterized in that: include: an oscillating unit, which is used to be connected to the capacitive airflow sensor and generate a first periodic signal based on a capacitance value of the capacitive airflow sensor; A base value counter connected to the oscillation unit and used for counting the first periodic signal for a preset first counting time to obtain and store a base value; A real-time value counter connected to the oscillation unit and configured to count the first periodic signal to obtain a real-time count value, wherein the real-time count value includes a detection value corresponding to a preset second count time; A state judgment unit, which is connected to the base value counter and the real-time value counter respectively, and is used to judge the state of the capacitive airflow sensor according to the base value and the detection value, wherein the state includes a triggered state and a non-triggered state; Wherein, the second counting time is different from the first counting time; The trigger state includes an inhalation state; The second counting time includes a third counting time, the third counting time is greater than the first counting time, and the detection value includes a first detection value; The real-time value counter is used to periodically count the first periodic signal to correspondingly obtain a periodic real-time count value, wherein the real-time count value of each period includes a first detection value corresponding to the third counting time; The state determination unit is used to periodically determine whether the capacitive airflow sensor is in an inhalation state according to the base value and the first detection value.

2. A state detection circuit for an electronic cigarette, characterized in that: include: an oscillating unit, which is used to be connected to the capacitive airflow sensor and generate a first periodic signal based on a capacitance value of the capacitive airflow sensor; A base value counter connected to the oscillation unit and used for counting the first periodic signal for a preset first counting time to obtain and store a base value; A real-time value counter connected to the oscillation unit and configured to count the first periodic signal to obtain a real-time count value, wherein the real-time count value includes a detection value corresponding to a preset second count time; A state judgment unit, which is connected to the base value counter and the real-time value counter respectively, and is used to judge the state of the capacitive airflow sensor according to the base value and the detection value, wherein the state includes a triggered state and a non-triggered state; Wherein, the second counting time is different from the first counting time; The trigger state includes a blowing state; The second counting time includes a fourth counting time, the fourth counting time is less than the first counting time, and the detection value includes a second detection value; The real-time value counter is used to periodically count the first periodic signal to correspondingly obtain a periodic real-time count value, wherein the real-time count value of each period includes a second detection value corresponding to the fourth counting time; The state judgment unit is used to periodically judge whether the capacitive airflow sensor is in a blowing state according to the base value and the second detection value.

3. The state detection circuit according to any one of claims 1 to 2, characterized in that: The state detection circuit also includes a logic unit, which is connected to the state judgment unit and the base value counter respectively to determine the update method of the base value according to the state of the capacitive airflow sensor.

4. The state detection circuit according to claim 3, characterized in that: The logic unit is used to count the duration of the trigger state; When the state judgment unit determines that the capacitive airflow sensor is in a triggered state, and the logic unit determines that the duration of the trigger state is greater than or equal to a preset threshold time, the logic unit outputs a reset signal to enable the base value counter to count the first period signal for the first counting time again to obtain a new base value and overwrite the original base value.

5. The state detection circuit according to claim 3, characterized in that: The real-time value counter is further used to periodically count the first periodic signal to correspondingly obtain a periodic real-time count value, wherein the real-time count value of each period includes an update reference value corresponding to the first counting time; The state detection circuit further comprises a base value update judgment unit, which is connected to the base value counter and the real-time value counter respectively, and the base value update judgment unit is used to output an update demand signal according to the base value and the update reference value; The logic unit is connected to the base value update judgment unit to determine whether to output an update signal according to an update request signal and a state of the capacitive airflow sensor.

6. The state detection circuit according to claim 5, characterized in that: The update demand signal includes a first update demand signal, and the update signal includes a first update signal. When the logic unit continuously receives a preset threshold number of first update demand signals and the state judgment unit judges that the capacitive airflow sensor is in a non-trigger state during this period, the logic unit outputs the first update signal to make the base value counter increase the base value by a preset first change amount; or, The update request signal includes a second update request signal, and the update signal includes a second update signal. When the logic unit continuously receives a preset threshold number of second update request signals and the state judgment unit determines that the capacitive airflow sensor is in a non-triggered state during this period, the logic unit outputs a second update signal to cause the base value counter to reduce the base value by a preset first change amount.

7. The state detection circuit according to claim 6, characterized in that: The threshold number is greater than or equal to 2.

8. The state detection circuit according to claim 1 or 2, characterized in that: The state detection circuit also includes a timing control unit, which is respectively connected to the base value counter, the real-time value counter, and the state judgment unit. The timing control unit controls the base value counter to count the first counting time. The timing control unit outputs a counting start signal to trigger the real-time value counter to start counting. The timing control unit also outputs a state detection signal to enable the state judgment unit to obtain the detection value currently output by the real-time value counter, and judge the state of the capacitive airflow sensor based on the detection value and the state detection signal.

9. The state detection circuit according to claim 8, characterized in that: The state judgment unit includes a comparator and a state judgment subunit; one input end of the comparator is connected to the base value counter to receive the base value, and the other input end is connected to the real-time value counter to receive the real-time count value; one input end of the state judgment subunit is connected to the output end of the comparator, and the other input end of the state judgment subunit is connected to the timing control unit to receive the current output signal of the comparator in response to the state detection signal and judge the state of the capacitive airflow sensor based on the output signal and the state detection signal.

10. The state detection circuit according to any one of claims 1 to 2, characterized in that: The ratio of the difference between the second counting time and the first counting time to the first counting time is in the range of 0.01-0.

1.

11. The state detection circuit according to any one of claims 1 to 2, characterized in that: A ratio of a difference between the second counting time and the first counting time to the first counting time is a preset value.

12. An electronic cigarette, comprising a capacitive airflow sensor, characterized in that: It also includes the state detection circuit as described in any one of claims 1-11, and the oscillation unit of the state detection circuit is connected to the capacitive airflow sensor.

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