Patent Description:
Recently, there has been a need for an alternative to general cigarettes. For example, there is growing demand for an aerosol generating device that generates an aerosol by heating an aerosol generating material in a cigarette or a liquid storage, instead of combusting a cigarette. <CIT> relates to an aerosol generating device in which a variety of feedback is provided through recognition of a user's puff.

Such an aerosol generating device has to accurately detect a user's puff to adjust a heating profile and to count the number of remaining puffs, but aerosol generating devices of the related art have a problem in that the user's puff may not be accurately detected.

An aerosol generating device needs to accurately detect a user's puff to adjust a heating profile and to count the number of remaining puffs.

The technical problem of the present disclosure is not limited to the above-described problem, and other technical problems may be inferred from the following examples.

According to an aspect of the present disclosure, an aerosol generating device includes a heater that heats an aerosol generating substrate, a temperature sensor that detects a temperature of the heater, and a controller that controls power supplied to the heater through a power signal such that the heater is heated within a preset temperature range, filters the power signal, and detects a user's puff based on the filtered power signal.

An aerosol generating device according to the present disclosure may detect a user's puff with only a power signal without a separate puff sensor.

In addition, when a filter is applied to a power signal, there is an advantage in that a filtered power signal is easily compared with a preset threshold.

In addition, an aerosol generating device sets a bandwidth of a filter by considering an average puff time of a user, and thus, a user's puff may be more accurately detected.

The effects of the present disclosure are not limited to the above-described effects, and undescribed effects will be clearly understood by those skilled in the art from the present specification and the accompanying drawings.

According to an aspect of the present disclosure, an aerosol generating device includes a heater that heats an aerosol generating substrate, a temperature sensor that detects a temperature of the heater, and a controller configured to control power supplied to the heater through a power signal such that the heater is heated within a preset temperature range, filter the power signal, and detect a user's puff based on the filtered power signal.

In addition, the power signal may be a pulse width modulation signal.

In addition, the controller may increase a duty value of the pulse width modulation signal in response to a decrease in temperature of the heater.

In addition, the controller may include a band-pass filter configured to filter the power signal.

In addition, a center frequency of the band-pass filter may be set based on an average puff time of a user.

In addition, the average puff time may be <NUM> seconds.

In addition, a center frequency of the band-pass filter may be <NUM>, a lower cutoff frequency may be <NUM>, and higher cutoff frequency may be <NUM>.

In addition, the band-pass filter may include a first low-pass filter and a second low-pass filter.

In addition, a first cutoff frequency of the first low-pass filter may be <NUM>, and a second cutoff frequency of the second low-pass filter may be <NUM>.

In addition, the controller may include the filtered power signal with a preset threshold and determine that the user's puff has occurred based on the filtered power signal being greater than or equal to the threshold.

With respect to the terms in the various embodiments, the general terms which are currently and widely used are selected in consideration of functions of structural elements in the various embodiments of the present disclosure. However, meanings of the terms can be changed according to intention, a judicial precedence, the appearance of a new technology, and the like.

The term "cigarette" (i.e., when used alone without "general," "traditional," or "combustive") may refer to any article which has a shape similar to a traditional combustive cigarette. This cigarette may contain an aerosol generating material that generates aerosols by operation (e.g., heating) of an aerosol generating device.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings.

Referring to <FIG>, the aerosol generating device <NUM> may include a battery <NUM>, a controller <NUM>, and a heater <NUM>. Referring to <FIG>, the aerosol generating device <NUM> may further include a vaporizer <NUM>. Also, the cigarette <NUM> may be inserted into an inner space of the aerosol generating device <NUM>.

Also, <FIG> illustrate that the aerosol generating device <NUM> includes the heater <NUM>. However, as necessary, the heater <NUM> may be omitted.

When the cigarette <NUM> is inserted into the aerosol generating device <NUM>, the aerosol generating device <NUM> may operate the heater <NUM> and/or the vaporizer <NUM> to generate an aerosol from the cigarette <NUM> and/or the vaporizer <NUM>. The aerosol generated by the heater <NUM> and/or the vaporizer <NUM> is delivered to a user by passing through the cigarette <NUM>.

According to necessity, even when the cigarette <NUM> is not inserted into the aerosol generating device <NUM>, the aerosol generating device <NUM> may heat the heater <NUM>.

The vaporizer <NUM> may generate an aerosol by heating a liquid composition and the generated aerosol may pass through the cigarette <NUM> to be delivered to a user. In other words, the aerosol generated via the vaporizer <NUM> may move along an air flow passage of the aerosol generating device <NUM> and the air flow passage may be configured such that the aerosol generated via the vaporizer <NUM> passes through the cigarette <NUM> to be delivered to the user.

The liquid storage may be detachable from the vaporizer <NUM> or may be formed integrally with the vaporizer <NUM>.

In addition, the heating element may include a conductive filament such as nichrome wire and may be wound around the liquid delivery element. As a result, an aerosol may be generated.

The aerosol generating device <NUM> may further include general-purpose components in addition to the battery <NUM>, the controller <NUM>, the heater <NUM>, and the vaporizer <NUM>. For example, the aerosol generating device <NUM> may include a display capable of outputting visual information and/or a motor for outputting haptic information. Also, the aerosol generating device <NUM> may include at least one sensor (e.g., a puff detecting sensor, a temperature detecting sensor, a cigarette insertion detecting sensor, etc.). Also, the aerosol generating device <NUM> may be formed as a structure where, even when the cigarette <NUM> is inserted into the aerosol generating device <NUM>, external air may be introduced or internal air may be discharged.

The cigarette <NUM> may be similar as a general combustive cigarette. For example, the cigarette <NUM> may be divided into a first portion including an aerosol generating material and a second portion including a filter, etc. Alternatively, the second portion of the cigarette <NUM> may also include an aerosol generating material. For example, an aerosol generating material made in the form of granules or capsules may be inserted into the second portion.

For example, the external air may flow into at least one air passage formed in the aerosol generating device <NUM>. For example, the opening and closing and/or a size of the air passage formed in the aerosol generating device <NUM> may be adjusted by the user. Accordingly, the amount of smoke and a smoking impression may be adjusted by the user. As another example, the external air may flow into the cigarette <NUM> through at least one hole formed in a surface of the cigarette <NUM>.

<FIG> illustrates an example of a cigarette.

Referring to <FIG>, the cigarette <NUM> may include a tobacco rod <NUM> and a filter rod <NUM>. The first portion <NUM> described above with reference to <FIG> may include the tobacco rod <NUM>, and the second portion <NUM> may include the filter rod <NUM>.

<FIG> illustrates that the filter rod <NUM> includes a single segment. However, the filter rod <NUM> is not limited thereto. In other words, the filter rod <NUM> may include a plurality of segments. For example, the filter rod <NUM> may include a first segment configured to cool an aerosol and a second segment configured to filter a certain component included in the aerosol. Also, according to necessity, the filter rod <NUM> may further include at least one segment configured to perform other functions.

The cigarette <NUM> may be packaged by at least one wrapper <NUM>. The wrapper <NUM> may have at least one hole through which external air may be introduced or internal air may be discharged. For example, the cigarette <NUM> may be packaged by one wrapper. As another example, the cigarette <NUM> may be double-packaged by at least two wrappers <NUM>. For example, the tobacco rod <NUM> may be packaged by a first wrapper <NUM>, and the filter rod <NUM> may be packaged by wrappers <NUM>, <NUM>, and <NUM>. Then, the entire cigarette <NUM> may be packaged by another wrapper <NUM>. When the filter rod <NUM> includes a plurality of segments, each segment may be packaged individually by wrappers <NUM>, <NUM>, and <NUM>.

Also, the tobacco rod <NUM> may be made out of pipe tobacco, which is formed of tiny bits cut from a tobacco sheet.

Referring to <FIG>, the cigarette <NUM> may further include a front-end plug <NUM>. The front-end plug <NUM> may be located on a side of the tobacco rod <NUM>, the side not facing the filter rod <NUM>. The front-end plug <NUM> may prevent the tobacco rod <NUM> from falling out and prevent a liquefied aerosol from flowing into the aerosol generating device <NUM> from the tobacco rod <NUM>, during smoking.

The filter rod <NUM> may include a first segment <NUM> and second segment <NUM>. Here, the first segment <NUM> can correspond to a first segment of a filter rod <NUM> of <FIG>, and the second segment <NUM> can correspond to a third segment of a filter rod <NUM> of <FIG>.

The diameter and total length of the cigarette <NUM> can correspond to the diameter and total length of the cigarette <NUM> of <FIG>. For example, the length of the front-end plug <NUM> may be about <NUM>, the length of the tobacco rod <NUM> may be about <NUM>, the length of the first segment <NUM> may be about <NUM>, and the length of the second segment <NUM> may be about <NUM>, but it is not limited to this.

The cigarette <NUM> may be packaged by at least one wrapper <NUM>. The wrapper <NUM> may have at least one hole through which external air may be introduced or internal air may be discharged. For example, the front-end plug33 may be packaged by a first wrapper <NUM>, and the tobacco rod <NUM> may be packaged by a second wrapper <NUM>, and the first segment <NUM> may be packaged by a third wrapper <NUM>, and the second segment <NUM> may be packaged by a fourth wrapper <NUM>. Also, the entire cigarette <NUM> may be packaged by a fifth wrapper <NUM>.

Also, the fifth wrapper <NUM> may have at least one hole <NUM>. For example, the hole <NUM> may be formed in an area surrounding the tobacco rod <NUM>, but is not limited thereto. The hole <NUM> may serve to transfer heat formed by the heater <NUM> shown in <FIG> to the inside of the tobacco rod <NUM>.

Also, the second segment <NUM> may include at least one capsule <NUM>.

<FIG> is a block diagram of an aerosol generating device according to an embodiment.

Referring to <FIG>, an aerosol generating device <NUM> may include a memory <NUM>, a temperature sensor <NUM>, a battery <NUM>, a heater <NUM>, a user interface <NUM>, and a controller <NUM>. The battery <NUM> of <FIG> may correspond to the battery <NUM> of <FIG>, and the heater <NUM> of <FIG> may correspond to the heater <NUM> of <FIG>. Therefore, redundant descriptions thereof are omitted.

The heater <NUM> may heat an aerosol generating substrate. The aerosol generating substrate may be the cigarette <NUM> of <FIG>.

The temperature sensor <NUM> may detect a temperature of the heater <NUM>. In one embodiment, the temperature sensor <NUM> may detect the temperature of the heater <NUM> in real time, convert temperature information into a digital signal, and output the digital signal. The temperature sensor <NUM> may transmit the digital signal to the controller <NUM>.

The controller <NUM> may include a pulse width modulator <NUM>, a monitor <NUM>, a filter <NUM>, and a puff determination unit <NUM>.

The controller <NUM> may control power supplied to the heater <NUM> through a power signal. The power signal may be a pulse width modulation (PWM) signal. The power signal in the form of PWM may be output by the pulse width modulator <NUM>.

The pulse width modulator <NUM> may control the power supplied from the battery <NUM> to the heater <NUM> by modulating a duty (i.e., by adjusting a duty ratio) of a DC pulse. In one embodiment, the pulse width modulator <NUM> may include a switching element and may modulate the duty of the DC pulse by adjusting an opening/closing cycle or an opening/closing ratio of the switching element.

The controller <NUM> may receive temperature information from the temperature sensor <NUM> and control the power supplied to the heater <NUM> based on the temperature information. The controller <NUM> may control the power supplied to the heater <NUM> such that a temperature of the heater <NUM> is within a preset temperature range. For example, the controller <NUM> may control the power supplied to the heater <NUM> such that the temperature of the heater <NUM> is heated in a range of <NUM> to <NUM>. However, the preset range is not limited to the above-described example and may be appropriately set by considering a vaporization temperature of the aerosol generating substrate.

In addition, when a user puffs, external air may flow into the heater <NUM>. Accordingly, the temperature of the heater <NUM> may be reduced. The controller <NUM> may increase a duty value of a power signal to compensate for a decrease in temperature of the heater <NUM>. In other words, when the temperature of the heater <NUM> is decreased by a user's puff, the controller <NUM> may increase the duty value of the power signal such that the temperature of the heater <NUM> is within a preset range.

The controller <NUM> may detect the user's puff based on the increased duty ratio. Specifically, the monitor <NUM> may monitor a power signal output from the pulse width modulator <NUM>. The monitor <NUM> may transmit the monitored power signal to the filter <NUM>.

The filter <NUM> may perform band-pass filtering on the power signal. To this end, the filter <NUM> may include a band-pass filter (BPF). The BPF may be a digital filter.

The filter <NUM> may filter the power signal through band-pass filtering, thereby removing a decrease tendency (which may be expressed as an envelope) of the power signal over time and may output a deviation value of the power signal over time.

The BPF may include a first low-pass filter 663a (see <FIG>) and a second low-pass filter 663b (see <FIG>). A calculation amount of a low-pass filter (LPF) is less than a calculation amount of a high-pass filter (HPF), and thus, when a BPF is embodied with LPFs, a filter calculation speed may be significantly increased.

In addition, a transfer function of the LPF may be as follows.

In Equation <NUM>, H(s) is a transfer function, and τ is a time constant of a LPF. The transfer function is a ratio of an output signal Y(s) to an input signal X(s), and thus, Equation <NUM> may be represented as follows.

In addition, when an S-domain is converted into a time domain in Equation <NUM>, Equation <NUM> may be obtained.

Here, when a derivative term is represented in the form of a difference of a discrete signal, Equation <NUM> may be obtained.

Therefore, when a sample time is ts, a discrete output signal yn for a discrete input signal xn may be represented as follows.

In Equation <NUM>, a cutoff frequency of the LPF may be determined by a time constant τ The first LPF 663a may filter a power signal by using a first time constant τ1, and, the second LPF 663b may filter the power signal by using a second time constant τ2.

A power signal of a preset band may be obtained by subtracting a power signal passing through the second LPF 663b from a power signal passing through the first LPF 663a. In this case, a center frequency may be determined based on an average puff time of a user. In one embodiment, the center frequency may be set based on an average puff time of a general user as stipulated by the Health Canada. For example, an average puff time of a user may be <NUM> seconds.

The controller <NUM> may convert an average puff time of a user into a frequency. Accordingly, the average puff time may be converted into an average puff frequency. For example, when the average puff time is <NUM> seconds, the average puff frequency may be converted to <NUM> according to an experiment.

The controller <NUM> may set the average puff frequency as a center frequency of a BPF. For example, when an average puff time of a user is <NUM> seconds, the center frequency may be set to <NUM>.

The controller <NUM> may set a puff recognition time based on the average puff time of the user. For example, when the average puff time of the user is <NUM> seconds, the controller <NUM> may set <NUM> second to <NUM> seconds as the puff recognition time.

The controller <NUM> may convert the puff recognition time into a frequency. The puff recognition time may mean a time for effectively recognizing the user's puff. Accordingly, the puff recognition time may be converted into a puff recognition frequency. For example, when the puff recognition time is <NUM> second to <NUM> seconds, the puff recognition frequency may be set to <NUM>/<NUM> (about <NUM>) Hz to <NUM> according to an experiment.

The controller <NUM> may set a lower cutoff frequency and a higher cutoff frequency of a BPF based on the puff recognition frequency. For example, when the puff recognition frequency is <NUM>/<NUM> (about <NUM>) Hz to <NUM>, the controller <NUM> may set the lower cutoff frequency to <NUM>/<NUM> (<NUM>) Hz and set the higher cutoff frequency to <NUM>.

The filter <NUM> may transmit the filtered power signal to the puff determination unit <NUM>. The puff determination unit <NUM> may detect a user's puff based on the filtered power signal.

The puff determination unit <NUM> may compare the filtered power signal with a preset threshold. In addition, the puff determination unit <NUM> may determine the filtered power signal greater than or equal to the preset threshold as the user's puff. A threshold may be set based on an average value of the maximum value and the minimum value of the power signal or the filtered power signal in each puff period but is not limited thereto, and any value between the maximum value and the minimum value of the filtered power signal may be selected as the threshold.

The user interface <NUM> may provide information on a state of the aerosol generating device <NUM> to a user. The user interface <NUM> may include various interfaces such as a display or a lamp that outputs visual information, a motor that outputs tactile information, a speaker that outputs sound information, a terminal for data communication with an input/output (I/O) interface (for example, a button or a touch screen) that receives information input from a user or outputs information to the user or for receiving charging power, and a communication interfacing module for performing wireless communication (for example, WI-FI, WI-FI Direct, Bluetooth, near-field communication (NFC), or so on) with an external device.

According to embodiments, the aerosol generating device <NUM> may selectively include only some of the examples of the various user interfaces <NUM> described above.

The memory <NUM> is hardware that stores various types of data processed in the aerosol generating device <NUM> and may store data processed by the controller <NUM> and data to be processed thereby. The memory <NUM> may include various types of memories such as random access memory (RAM) such as dynamic random access memory (DRAM) or static random access memory (SRAM), read-only memory (ROM), and electrically erasable programmable read-only memory (EEPROM).

In addition, an internal structure of the aerosol generating device <NUM> is not limited to the structure illustrated in <FIG>. Those skilled in the art relating to the present embodiment will be appreciate that some of the hardware configurations illustrated in <FIG> may be omitted or a new configuration may be added thereto depending on the design of the aerosol generating device <NUM>.

<FIG> is a view illustrating a power control method according to a heater temperature.

<FIG> illustrates a temperature sensing value <NUM> of the temperature sensor <NUM> and a power signal <NUM> of the controller <NUM>. In <FIG>, an x-axis denotes a time, and a y-axis denotes a duty and a temperature. In <FIG>, a duty value is plotted with a scale factor of four for comparison with the temperature sensing value <NUM>.

Referring to <FIG>, the controller <NUM> may control power supplied to the heater <NUM> such that a temperature of the heater <NUM> is within a preset temperature range. For example, the controller <NUM> may control the power supplied to the heater <NUM> such that the temperature of the heater <NUM> is heated within a range of <NUM> to <NUM>. However, the preset temperature range is not limited to the above-described example and may be appropriately set by considering vaporization temperature of the aerosol generating substrate.

When a user puffs, external air may flow into the heater <NUM>. Accordingly, the temperature of the heater <NUM> may be decreased, and the controller <NUM> may increase a duty value of the power signal <NUM> to compensate for the decrease in temperature of the heater <NUM>. In other words, when the temperature of the heater <NUM> is decreased by the user's puff, the controller <NUM> may increase the duty value of the power signal <NUM> such that the temperature of the heater <NUM> is within the preset temperature range.

The controller <NUM> may detect the user's puff based on the increased duty value (i.e., based on the increased duty ratio).

In addition, the power signal <NUM> of <FIG> has a small difference between the maximum value and the minimum value of the duty in one period of the puff. In addition, the power signal <NUM> of <FIG> has a large variation of the maximum values of duties in each puff period. Accordingly, the controller <NUM> may not use a fixed threshold to detect a user's puff. Instead, the controller <NUM> may set different thresholds Dth1, Dth2,. in each puff period. In this case, there is a problem that a rapid puff detection may not be made due to an increase in calculation amount of the controller <NUM>. In addition, there is a problem that the controller <NUM> may not accurately detect the user's puff because a difference between the maximum value and the minimum value of the duty is small within one period of the puff.

In order to solve these problems, an embodiment may adopt a digital filter and detects a user's puff based on the power signal to which the digital filter is applied.

<FIG> illustrates a frequency-converted power signal, <FIG> is a diagram illustrating a method of operating a BPF, <FIG> illustrate a method of implementing the BPF, and <FIG> is a diagram illustrating a method of comparing a filtered power signal and a preset threshold.

Referring to <FIG>, the controller <NUM> may convert the power signal <NUM> in a time domain into a power signal <NUM> in a frequency domain. For example, the controller <NUM> may convert the power signal <NUM> in a time domain into the power signal <NUM> in a frequency domain by using a Fourier Transform (FT), a Fast Fourier Transform (FFT), a Discrete Fourier Transform (DFT), and so on. However, the method of converting a frequency domain is not limited to the above-described examples.

In <FIG>, the filter <NUM> may band-pass-filter the power signal <NUM> in the frequency domain. To this end, the filter <NUM> may include a BPF <NUM>.

A center frequency fo of the BPF <NUM> may be set based on an average puff time of a user. For example, when the average puff time of the user is <NUM> seconds, the center frequency fo may be set to <NUM> according to an experiment.

A lower cutoff frequency fL and a higher cutoff frequency fH of the BPF <NUM> may be set based on a preset puff recognition time. For example, when the average puff time of the user is <NUM> seconds, the puff recognition time may be set to <NUM> to <NUM> seconds. In addition, when the puff recognition time is <NUM> second to <NUM> seconds, the lower cutoff frequency may be set to <NUM>/<NUM> (<NUM>) Hz, and the higher cutoff frequency may be set to <NUM>. Accordingly, a bandwidth BW of the BPF <NUM> may be set to <NUM>/<NUM> (<NUM>) Hz.

The BPF <NUM> may include the first LPF 663a and the second LPF 663b as illustrated in <FIG>.

Specifically, the filter <NUM> may include the first LPF 663a and the second LPF 663b. Unlike <FIG>, pass gains of the first LPF 663a and the second LPF 663b may be the same.

The first LPF 663a may remove frequencies higher than or equal to a first cutoff frequency fc1. The second LPF 663b may remove frequencies higher than or equal to a second cutoff frequency fc2. A difference between the first cutoff frequency fc1 and the second cutoff frequency fc2 may correspond to the bandwidth BW of the BPF <NUM>.

The first LPF 663a may output a first filtering signal Y1 by filtering a power signal. The second LPF 663b may output a second filtering signal Y2 by filtering a power signal.

The filter <NUM> may output a third filtering signal Y3 by subtracting the second filtering signal Y2 from the first filtering signal Y1. The third filtering signal Y3 may be a band-pass-filtered power signal.

In this case, since the BPF is embodied using only LPFs, a filter calculation speed may be remarkably increased.

<FIG> shows an example of a time domain signal corresponding to the band-pass-filtered power signal Y3.

Unlike <FIG>, a filtered power signal <NUM> of <FIG> has a large difference between a maximum value and a minimum value of a duty within one period of a puff. In addition, the filtered power signal <NUM> of <FIG> has a small variation of maximum values of duties obtained in each puff period. Accordingly, the controller <NUM> may use a fixed threshold value Dth to detect a user's puff. In addition, since there is the large difference between the maximum value and the minimum value of the duty within one period of a puff, the controller <NUM> may accurately detect the user's puff.

The puff determination unit <NUM> may compare the filtered power signal with the preset threshold Dth, and determine that a user's puff has occurred when the filtered power signal is greater than or equal to the preset threshold.

<FIG> is a flowchart illustrating an operating method of an aerosol generating device according to an embodiment.

Referring to <FIG>, in step S1210, the controller <NUM> may control power supplied to the heater <NUM> through a power signal to heat a temperature of the heater <NUM> within a preset range.

The power signal may be a pulse width modulation signal. The controller <NUM> may control power supplied from the battery <NUM> to the heater <NUM> by modulating a duty of a DC pulse. In one embodiment, the pulse width modulator <NUM> may include a switching element and may modulate the duty of the DC pulse by adjusting an opening/closing cycle or an opening/closing ratio of the switching element.

The controller <NUM> may receive temperature information from the temperature sensor <NUM> and control the power supplied to the heater <NUM> based on the temperature information. The controller <NUM> may control the power supplied to the heater <NUM> such that a temperature of the heater <NUM> is within a preset temperature range.

In step S1220, the controller <NUM> may filter a power signal.

The controller <NUM> may band-pass-filter the power signal. To this end, the controller <NUM> may include a BPF. The BPF may be a digital filter.

A center frequency of the controller <NUM> may be set based on an average puff time of a user. For example, when the average puff time of the user is <NUM> seconds, and the center frequency may be set to <NUM> according to an experiment.

The controller <NUM> may set a lower cutoff frequency and a higher cutoff frequency of the BPF based on a preset puff recognition time. For example, when the average puff time of the user is <NUM> seconds, the puff recognition time may be set to <NUM> second to <NUM> seconds. In addition, when the puff recognition time is <NUM> second to <NUM> seconds, the lower cutoff frequency may be set to <NUM>/<NUM> (<NUM>) Hz, and the higher cutoff frequency may be set to <NUM> according to an experiment. Accordingly, the bandwidth BW of the BPF <NUM> may be set to <NUM>/<NUM> (<NUM>) Hz.

In step S1230, the controller <NUM> may detect a user's puff based on the filtered power signal.

The controller <NUM> may detect the user's puff based on a fixed threshold. The controller <NUM> may determine that the user's puff has occurred when the filtered power signal is greater than or equal to a preset threshold.

The controller <NUM> may count the user's puff. In addition, the controller <NUM> may control internal components of the aerosol generating device <NUM> based on the counted number of the user's puffs. For example, the controller <NUM> may display the number of remaining puffs via the user interface <NUM>. However, this is only an example, and the operation of the controller <NUM> based on the user's puff is not limited thereto.

<FIG> is a diagram illustrating the method of detecting the puff.

Referring to <FIG>, in step S1310, the controller <NUM> may compare the filtered power signal with the preset threshold.

In step S1320, the controller <NUM> may determine that the user's puff has occurred when the filtered power signal is greater than or equal to a threshold. As aforementioned, since the filtered power signal according to the embodiments has a large difference between a maximum value and a minimum value of a duty within one period of a puff, the controller <NUM> may accurately detect the user's puff.

Claim 1:
An aerosol generating device (<NUM>, <NUM>) comprising:
a heater (<NUM>, <NUM>) configured to heat an aerosol generating substrate (<NUM>);
a temperature sensor (<NUM>) configured to detect a temperature of the heater (<NUM>, <NUM>); and
a controller (<NUM>, <NUM>) configured to control power supplied to the heater (<NUM>, <NUM>) through a power signal such that the heater (<NUM>, <NUM>) is heated within a preset temperature range, filter the power signal, and detect a user's puff based on the filtered power signal.