Device and Delivery System

Abstract

An apparatus is described that includes a resonant circuit and circuitry for applying one or more pulses to the resonant circuit, the resonant circuit including an inductive element and a capacitor, the inductive element including one or more at least partially exposed coils for heating the susceptor when the susceptor is disposed across and in electrical contact with the exposed coils.

Description

Technical Field

[0001] This specification relates to an induction heating configuration for use in an aerosol generating device. The aerosol generating device can be, for example, a tobacco heating product. Background

[0002] Smoking articles such as cigarettes and cigars generate tobacco smoke by burning tobacco during use. Attempts have been made to provide alternatives to these articles by creating products that release compounds without burning. For example, a tobacco heating device forms an aerosol by heating an aerosol-forming substance such as tobacco, heating rather than burning the substrate. The material can be, for example, tobacco or other non-tobacco products, and may or may not contain nicotine. Summary

[0003] In a first aspect, this specification describes an apparatus comprising a resonant circuit including an inductor and a capacitor, the inductor including one or more coils that are at least partially exposed, the inductor being for heating a susceptor when the susceptor is disposed across the exposed coil and in electrical contact with the exposed coil, and a circuit (e.g., a drive circuit or a control circuit) for applying one or more pulses to the resonant circuit. The coil may be made of gold or may have a gold tip.

[0004] The exposed coil of the inductor may be corrosion resistant.

[0005] One or more coils of the inductor may be formed by a printed circuit board. For example, the printed circuit board may be a multilayer printed circuit board, and the coils may be formed from different layers of the printed circuit board.

[0006] The induction element can include a conductive non-helical first portion that coincides with a first plane, a conductive non-helical second portion that coincides with a second plane spaced apart from the first plane, and a conductive connector that electrically connects the first portion to the second portion. The first portion may be a first partial ring, and the second portion may be a second partial ring.

[0007] In some exemplary embodiments, the induction element and the capacitor are connected in parallel. In some exemplary embodiments, the induction element and the capacitor are connected in series.

[0008] The circuit may be a self-oscillating drive circuit. Alternatively, the circuit includes an H-bridge drive circuit.

[0009] In a second aspect, the present specification describes a delivery system comprising an apparatus as described above with reference to the first aspect. The delivery system may be a non-combustible aerosol generating device.

[0010] The delivery system may be configured to receive a removable article containing an aerosol generating material. For example, the aerosol generating device of the delivery system may be configured to receive a removable article such that the susceptor physically contacts (such that the susceptor and the coil are electrically in contact) an exposed portion of one or more coils. The aerosol generating material may include, for example, an aerosol product substance and an aerosol forming material. The removable article can include a susceptor configuration. Further, in use, the susceptor configuration can be electrically in contact with one or more at least partially exposed coils of the induction element of the device.

Brief Description of the Drawings

[0011] Here, with reference to the following schematic diagrams, exemplary embodiments will be described by way of mere example.

Figure 1

Figure 2

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Figure 5

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Figure 7

Figure 8

Figure 9

Figure 10

[0012] As used herein, the term "aerosol delivery device" is intended to encompass a system for delivering a substance to a user and includes the following: · Non-combustible aerosol delivery systems that release compounds from aerosolizable materials without burning the aerosolizable materials, such as hybrid systems that generate aerosols using electronic cigarettes, tobacco heating products, and combinations of aerosolizable materials; and · Articles containing aerosolizable materials and configured to be used in one of these non-combustible aerosol delivery systems.

[0013] According to the present disclosure, a "flammable" aerosol delivery system is one in which the constituent aerosolizable material (or its constituents) of the aerosol delivery system is burned or combusted to facilitate delivery to the user.

[0014] According to the present disclosure, a "non-combustible" aerosol delivery system is one in which the aerosolizable material (or its components) of the aerosol delivery system does not burn, or is non-flammable, in order to facilitate delivery to the user.

[0015] In embodiments described herein, the delivery system is a non-combustible aerosol delivery system, such as a powered non-combustible aerosol delivery system.

[0016] In one embodiment, the non-combustible aerosol delivery system is an electronic cigarette, also known as a vapor inhalation device or an electronic nicotine delivery system (ENDS), but it should be noted that the presence of nicotine in the aerosolizable material is not a requirement.

[0017] In some embodiments, the non-combustible aerosol delivery system is an aerosol-generating material heating system, also known as a non-combustion heating system. An example of such a system is a tobacco heating system.

[0018] In one embodiment, the non-combustible aerosol delivery system is a hybrid system that uses a combination of aerosolizable materials to generate an aerosol, and one or more of the aerosolizable materials can be heated. Each of the aerosolizable materials may be in the form of, for example, a solid, liquid, or gel, and may or may not contain nicotine. In one embodiment, the hybrid system includes a liquid or gel aerosolizable material and a solid aerosolizable material. The solid aerosolizable material may include, for example, tobacco or non-tobacco products.

[0019] Typically, a non-combustible aerosol delivery system can comprise a non-combustible aerosol delivery device and an article for use with the non-combustible aerosol delivery system. However, it is contemplated that an article that itself provides means for powering the aerosol-generating components can itself form a non-combustible aerosol delivery system.

[0020] In one embodiment, the non-combustible aerosol providing device may include a power source and a controller. The power source may be a power source or a heat generating power source. In one embodiment, the heat generating power source includes a carbon substrate that can be energized to distribute power in the form of heat to an aerosolizable material or a heat transfer material in proximity to the heat generating power source. In one embodiment, a power source such as a heat generating power source is provided to an article so as to form non-combustible aerosol provision.

[0021] In one embodiment, an article for use with the non-combustible aerosol providing device may include an aerosolizable material, an aerosol generating component, an aerosol generating region, a mouthpiece, and / or a region for receiving the aerosolizable material.

[0022] In one embodiment, the aerosol generating component is a heater that can interact with the aerosolizable material to release one or more volatile substances from the aerosolizable material to form an aerosol.

[0023] In one embodiment, the aerosolizable material may include an active material, an aerosol-forming material, and optionally one or more functional materials. The active material may include nicotine (optionally contained in tobacco or tobacco derivatives), or one or more other non-olfactory physiologically active materials. A non-olfactory physiologically active material is a material contained in the aerosolizable material to achieve a physiological response other than olfactory perception. As used herein, an active substance may be a physiologically active material intended to achieve or enhance a physiological response. The active substance may be selected from, for example, dietary supplements, nootropics, and stimulants. The active substance may be naturally occurring or synthetically obtained. The active substance may include, for example, nicotine, caffeine, taurine, theine, vitamins such as B6 or B12 or C, melatonin, cannabinoids, or their constituents, derivatives or combinations. The active substance may include one or more constituents, derivatives or extracts of tobacco, cannabis or another plant. In one embodiment, the active substance is a legally acceptable recreational drug.

[0024] In some embodiments, the active substance includes nicotine. In some embodiments, the active substance includes caffeine, melatonin or vitamin B12.

[0025] The aerosol-forming material may include one or more of glycerin, glycerol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,3-butylene glycol, erythritol, meso-erythritol, ethyl vanillate, ethyl laurate, diethyl suberate, triethyl citrate, triacetin, diacetin mixture, benzyl benzoate, benzyl phenyl acetate, tributyrin, lauryl acetate, lauric acid, myristic acid, and propylene carbonate.

[0026] The one or more functional materials may include one or more of a flavorant, a carrier, a pH adjuster, a stabilizer and / or an antioxidant.

[0027] In one embodiment, an article for use with a non-combustible aerosol delivery device may include an aerosolizable material or a region for receiving an aerosolizable material. In one embodiment, an article for use with a non-combustible aerosol delivery device may include a mouthpiece. The region for receiving an aerosolizable material may be a storage region for storing the aerosolizable material. For example, the storage region may be a reservoir. In one embodiment, the region for receiving an aerosolizable material may be separate from or combined with an aerosol generation region.

[0028] The aerosolizable material, which may also be referred to herein as an aerosol generating material, is a material that can generate an aerosol when heated, irradiated, or energized by any other method, for example. The aerosolizable material may be in the form of a solid, liquid, or gel that may or may not contain nicotine and / or flavorants, for example.

[0029] The aerosol generating material may be an "amorphous solid". In some embodiments, the amorphous solid is a "monolithic solid". The aerosol generating material may be non-fibrous or fibrous. In some embodiments, the aerosol generating material may be a dry gel. The aerosol generating material may be a solid material that can hold some fluid such as a liquid therein. In some embodiments, the held fluid may be water (such as water absorbed from around the aerosol generating material), or the held fluid may be a solvent (such as when the aerosol generating material is formed from a slurry). In some embodiments, the solvent may be water.

[0030] The aerosolizable material may be present on a substrate. The substrate can be or can include, for example, paper, card, cardboard, thick paper, reconstituted aerosolizable material, plastic material, ceramic material, composite material, glass, metal, or metal alloy.

[0031] A consumable is an article that contains or consists of an aerosol - generating material, and part or all of which is intended to be consumed during use by a user. The consumable may include one or more other components such as an aerosol - generating material storage region, an aerosol - generating material transfer component, an aerosol - generating region, a housing, a wrapper, a mouthpiece, a filter, and / or an aerosol modifier. The consumable may also include an aerosol generator such as a heater that releases heat to generate an aerosol from the aerosol - generating material during use. The heater may include, for example, a combustible material or a material that can be heated by electrical conduction, or a susceptor.

[0032] An aerosol generator is a device configured to generate an aerosol from an aerosol - generating material. In some embodiments, the aerosol generator is a heater configured to supply thermal energy to the aerosol - generating material to release one or more volatile substances from the aerosol - generating material to form an aerosol. In some embodiments, the aerosol generator is configured to generate an aerosol from the aerosol - generating material without heating. For example, the aerosol generator may be configured to subject the aerosol - generating material to one or more of vibration, pressure increase, or electrostatic energy.

[0033] A susceptor is a material that can be heated by penetration by a fluctuating magnetic field such as an alternating magnetic field. The susceptor may be a conductive material, and as a result, penetration of the conductive material by the fluctuating magnetic field causes inductive heating of the heating material. The heating material may be a magnetic material, and as a result, penetration of the magnetic material by the fluctuating magnetic field causes magnetic hysteresis heating of the heating material. The susceptor may be both conductive and magnetic, and as a result, the susceptor can be heated by both heating mechanisms. A device configured to generate a fluctuating magnetic field is referred to herein as a magnetic field generator.

[0034] Figure 1 is a block diagram of a system, generally designated by reference numeral 200, according to an exemplary embodiment. System 200 includes a resonant circuit 201 (e.g., an LC resonant circuit), a control module 202, and a susceptor 203. The resonant circuit 201 may be a self-oscillating drive circuit.

[0035] The resonant circuit 201 can include an inductor and a capacitor connected in series or in parallel. The resonant circuit can be used to inductively heat the susceptor 203 to heat an aerosol-generating material. By heating the aerosol-generating material, an aerosol can be generated (as further described below).

[0036] The control module 202 provides a control signal (e.g., a drive signal) for the resonant circuit 201. For example, the control module 202 can provide a switching signal that switches the inductor of the resonant circuit 201 between a first state of charging and a second state of discharging. In such a configuration, the resonant circuit resonates, and charge flows from the inductor to the capacitor and back again. As further described below, other configurations for driving and controlling the resonant circuit are possible.

[0037] System 200 can be used with a wide variety of susceptor configurations. Some embodiments are described below by way of example. However, those skilled in the art will understand that other embodiments are possible.

[0038] The susceptor is a material that can be heated by penetration by a varying magnetic field, such as an alternating magnetic field. The heating material may be a conductive material, such that penetration of the conductive material by the varying magnetic field causes inductive heating of the heating material. The heating material may be a magnetic material, such that penetration of the magnetic material by the varying magnetic field causes magnetic hysteresis heating of the heating material. The heating material may be both conductive and magnetic, such that the heating material can be heated by both heating mechanisms.

[0039] Inductive heating is a process in which a conductive object is heated by passing a variable magnetic field through it. This process is explained by Faraday's law of induction and Ohm's law. An induction heater can comprise an electromagnet and a device for passing a variable current, such as an alternating current, through the electromagnet. When the electromagnet and the object to be heated are properly positioned relative to each other such that the resulting variable magnetic field generated by the electromagnet penetrates the object, one or more eddy currents are generated within the object. The object has a resistance to the flow of current. Thus, when such eddy currents are generated within the object, the flow of the eddy currents against the electrical resistance of the object causes heating of the object. This process is called Joule heating, Ohmic heating, or resistive heating. An object that can be inductively heated is known as a susceptor.

[0040] FIG. 2 is a block diagram of a circuit, generally designated by reference numeral 210, according to an exemplary embodiment. Circuit 210 is an exemplary implementation of the system 200 described above.

[0041] Circuit 210 comprises a control module 211, a transistor 212, an inductor 213, and a capacitor 214. The control module 211 and the transistor 212 are exemplary implementations of the control module 202 of the system 200. The parallel connection of the inductor 213 and the capacitor 214 is an exemplary implementation of the resonant circuit 201. Thus, the resonant circuit formed by the inductor 213 and the capacitor 214 can be used to inductively heat the susceptor 203 of the system 200.

[0042] The transistor 212 has a first state and a second state that depend on the output of the control module 211. In the first state, the transistor 212 is conductive such that a variable current generated from the voltage supply V DC flows through the inductor 213 (thereby charging the inductor). The voltage supply may be provided by a battery (e.g., the battery of the aerosol generating device).

[0043] In the second state, the first switching configuration is non-conductive such that the inductor 213 (charged in the first state) discharges and thereby charges the capacitor 214. If the switching configuration remains in the second state, the resonant circuit 211 resonates at a frequency given by the formula:

Number

[0044] FIG. 3 is a cross-sectional view of an inductor configuration generally designated by reference numeral 150 according to an exemplary embodiment.

[0045] FIG. 4 is a perspective view of the inductor 160 of the inductor configuration 150. The inductor 160 can be used to implement the inductor 213 of the resonant circuit described above (or the inductor of other exemplary embodiments described above), although alternative inductor configurations may be used.

[0046] The inductor configuration 150 includes an electrical insulation support 172 and an inductor 160. The support 172 has opposing first and second side surfaces 172a and 172b, and portions 162, 164 of the inductor 160 are on the first and second side surfaces 172a and 172b of the support 172, respectively.

[0047] More specifically, the inductor 160 is formed of a conductive element 160. The element 160 includes a conductive non-helical first portion 162 that coincides with a first plane P1 and a conductive non-helical second portion 164 that coincides with a second plane P2 spaced apart from the first plane P1. In this example, the second plane P2 is parallel to the first plane P1, but in other examples, this need not be the case. For example, the second plane P2 may be at an angle to the first plane P1, such as an angle of 20 degrees or less or 10 degrees or less or 5 degrees or less. The inductor 160 also includes a first conductive connector 163 that electrically connects the first portion 162 to the second portion 164. The first portion 162 is on a first side surface 172a of the support 172, and the second portion 164 is on a second side surface 172b of the support 172. The conductive connector 163 passes through the support 172 from the first side surface 172a to the second side surface 172b. The conductive connector 163 may have a plating (e.g., copper plating) structure on the surface of a through-hole provided in the support 172.

[0048] The support 172 can be made of any suitable electrically insulating material. In some examples, the support 172 includes a matrix (such as an epoxy resin, optionally with a filler such as ceramic added) and a reinforcing structure (such as a woven or non-woven material such as glass fiber or paper).

[0049] The inductor 160 can be made of any suitable conductive material. In some examples, the inductor 160 is made of copper.

[0050] In some examples, the inductor configuration 150 includes or is formed from a printed circuit board (PCB). In such examples, the support 172 is a non-conductive substrate of a PCB that can be formed from a material such as FR-4 glass epoxy impregnated with a phenolic resin or cotton paper, and the first portion 162 and the second portion 164 of the inductor 160 are tracks on the substrate. This facilitates the manufacture of the inductor configuration 150 and also allows the portions 162, 164 of the element 160 to be made thin and closely spaced, as will be described in more detail below.

[0051] In this example, the first portion 162 is the first partial loop 162, and the second portion 164 is the second partial loop 164. Further, in this example, each of the first portion 162 and the second portion 164 follows only a part of its respective circular path. Thus, the first portion or the first partial loop 162 is the first circular arc, and the second portion or the second partial loop 164 is the second circular arc. In other examples, the first portion 162 and the second portion 164 may follow a path other than circular, such as elliptical, polygonal, or irregular.

[0052] As can be best understood from further consideration of FIG. 3, when viewed in a direction orthogonal to the first plane P1, and thus in the direction of the axis B-B of the inductor 160, the first portion 162 and the second portion 164 extend in opposite rotational directions from the first conductive connector 163. For example, when viewing the inductor 160 of FIG. 3 in the direction of the axis B-B from left to right as depicted in FIG. 4, the first portion 162 of the inductor 160 extends in the counterclockwise direction from the connector 163, and the second portion 164 of the inductor 160 extends in the clockwise direction from the connector 163.

[0053] Also, in this example, when viewed in a direction orthogonal to the first plane P1, the first portion 162 or the first partial loop overlaps, although only partially, with the second portion 164 or the second partial loop. In this example, the first portion 162 and the second portion 164 together define approximately 1.75 turns about the axis B-B that is orthogonal to the first plane P1 and the second plane P2. In other examples, the number of turns may be other than 1.75, such as another number of turns that is at least 0.9. For example, the number of turns may be 0.9 to 1.5, or 1 to 1.25. In other examples, the number of turns may be less than 0.9, but a decrease in the number of turns per support 172 may lead to an increase in the axial length of the inductor assembly 150.

[0054] Furthermore, when viewed from a direction orthogonal to the first plane P1, the first portion 162 or the first partial ring and the second portion 164 or the second partial ring at least partially overlap the first conductive connector 163. This is facilitated by the inductor configuration 150 that includes (or more generally, is formed from) a PCB (or planar substrate layer). In particular, in such an example, the first conductive connector 163 takes the form of a "via" extending through the support 172. Even in an example where the inductor configuration 150 is not formed from a PCB, the connector 163 can still extend through the support 172. This overlapping configuration enables the inductor 160 to occupy a relatively small installation area when viewed in a direction orthogonal to the first plane P1, as compared to a comparative example where the first portion 162 and the second portion 164 are connected by a connector 163 spaced radially outward of the first portion 162 and the second portion 164. Furthermore, this overlapping configuration enables the width of the through-hole 152 to be increased as compared to a comparative example where the first portion 162 and the second portion 164 are connected by a connector 163 spaced radially inward of the first portion 162 and the second portion 164. Nevertheless, in some examples, the connector 163 may be located radially inward or radially outward of the first portion 162 and the second portion 164. This can be achieved by a connector 163 formed by a "through-via" extending through the support 172. Since through-vias can be formed after the PCB is manufactured, they tend to be formed at a lower cost than blind vias.

[0055] In this example, it should be noted that the inductor configuration 150 includes two additional supports 174, 176, and the element 160 includes two additional conductive non-helical portions 166, 168 that respectively coincide with two spaced-apart planes P3, P4 parallel to the first plane P1. In other examples, one or each of the spaced-apart planes P3, P4 may be at an angle with respect to the first plane P1, such as an angle of 20 degrees or less or 10 degrees or less or 5 degrees or less. The second conductive non-helical portion 164 and the third conductive non-helical portion 166 are on both sides of the second support 174 and are electrically connected by the second conductive connector 165. The third conductive non-helical portion 166 and the fourth conductive non-helical portion 168 are on both sides of the third support 176 and are electrically connected by the third conductive connector 167. The second conductive connector 165 and the third conductive connector 167 are offset in the rotational direction from the first conductive connector 163. In a configuration where the supports 172, 174, and 176 are formed as a PCB, the connectors 163, 167 may be formed as "blind vias", and the connector 165 may be formed as an "embedded via".

[0056] It should also be noted that the inductor 160 includes a first terminal 161 and a second terminal 169 at both ends of the inductor 160. These terminals are for passing current through the inductor 160 during use.

[0057] In this example, each of the planes P1 to P4 is a flat plane or a substantially flat plane. However, this does not necessarily apply to other examples.

[0058] The combination of the first conductive connector 163 and the first portion 162 and the second portion 164 of the conductive element 160 can be considered to be a spiral coil or close to it. In fact, the complete inductor 160 can be considered to be a spiral coil or close to it.

[0059] The inductor configuration 150 of the example shown in the figure has three supports 172, 174, 176 and an inductor 160 including four parts 162, 164, 166, 168, but this need not apply to other exemplary embodiments.

[0060] Figure 5 is a plan view of an inductor configuration, generally designated by reference numeral 220, according to an exemplary embodiment.

[0061] The inductor configuration 220 includes an inductor 222 having one or more coils 223 that are at least partially exposed. By way of example, the inductor 222 may be implemented using the inductor 160, and the exposed coil 223 may form part 162 of the inductor 160. However, other configurations are possible and will be apparent to those skilled in the art.

[0062] The inductor configuration 220 further includes a susceptor 224 disposed across the exposed coil 223 such that the susceptor is in electrical contact with the exposed coil 223 (and thus the inductor 222).

[0063] By way of example, the inductor 222 can be used to implement the inductor 213 of the system 210. The susceptor 224 may be the susceptor 203 of one of the susceptor configurations of the system 200, further described below.

[0064] The exposed coil 223 of the inductor 222 may be corrosion resistant, for example, the coil may be gold or have a gold tip.

[0065] The coil of the inductor 222 may be formed by a printed circuit board. The inductor 160 is one exemplary implementation of such an inductor, but alternative forms are possible.

[0066] Figure 6 shows an equivalent inductor circuit, generally designated by reference numeral 230, according to an exemplary embodiment.

[0067] The equivalent circuit 230 includes a series connection of inductors L3, L4, L5, and L6. The inductors L3 to L6 represent the inductance of the inductor 222. The equivalent circuit 230 further includes a parallel connection 232 including an inductor L7 and a resistor R4. The parallel connection 232 represents the susceptor 224.

[0068] The effect of placing the susceptor 224 across the exposed coil 223 of the inductor 222 is electrically represented by providing the susceptor in parallel with a part of the inductor 222. The susceptor 224 is in electrical contact with an exposed coil having some conceptual similarity to a voltage divider, resulting in inductive heating of the susceptor. The effect can be similar to that of a single-turn transformer.

[0069] A susceptor (such as the susceptor 224) can contact the exposed coil (such as the coil 223) of the inductor in many ways. As an example, System 1 described below provides a plurality of connection points between the susceptor and the exposed coil so that a plurality of heating zones are provided. This is one of many exemplary implementations of the principles described herein.

[0070] FIG. 7 is a side view of an aerosol providing system generally designated by reference numeral 1 according to an exemplary embodiment. The aerosol providing system 1 can use, for example, the principles of the system 200 for heating the susceptor of an aerosol delivery device.

[0071] The system 1 includes an aerosol providing device 100 and an article 10 including an aerosolizable material 11. The aerosolizable material 11 can be, for example, any of the types of aerosolizable materials described herein. In one example, the aerosol providing device 100 is a tobacco heating product (also known in the art as a tobacco heating device or a non-combustion heating device).

[0072] Thus, as described in detail above, the aerosol delivery device 100 can be configured to receive the removable article 10 such that the susceptor of the article 10 makes physical and electrical contact with the exposed portions of one or more coils of the inductor of the aerosol delivery device 100.

[0073] In some examples, the aerosolizable material 11 is a non-liquid material. In some examples, the aerosolizable material 11 is a gel. In some examples, the aerosolizable material 11 includes tobacco. However, in other examples, the aerosolizable material 11 may consist of tobacco, may consist substantially entirely of tobacco, may include tobacco and other aerosolizable materials, may include other aerosolizable materials, or may not include tobacco. In some examples, the aerosolizable material 11 may include a vapor or aerosol forming agent or a humectant such as glycerol, propylene glycol, triacetin or diethylene glycol. In some examples, the aerosolizable material 11 includes a reconstituted aerosolizable material such as reconstituted tobacco.

[0074] In some examples, the aerosolizable material 11 is generally cylindrical having a generally circular cross-section and a longitudinal axis. In other examples, the aerosolizable material 11 may have a different cross-sectional shape and / or may not be elongated.

[0075] The aerosolizable material 11 of the article 10 may have, for example, an axial length of from 8 mm to 120 mm. For example, the axial length of the aerosolizable material 11 may be greater than 9 mm, or 10 mm, or 15 mm, or 20 mm. For example, the axial length of the aerosolizable material 11 may be less than 100 mm, or 75 mm, or 50 mm, or 40 mm.

[0076] In some examples, the article 10 comprises a filter arrangement 12 for filtering aerosol or vapour released from the aerosolizable material 11 during use. Alternatively or additionally, the filter arrangement 12 may be for controlling the pressure drop across the length of the article 10. The filter arrangement 12 can comprise one or more filters. The filter arrangement 12 can be of any type used in the tobacco industry. For example, the filter can be made of cellulose acetate. In some examples, the filter arrangement 12 is generally cylindrical having a generally circular cross-section and a longitudinal axis. In other examples, the filter arrangement 12 may have a different cross-sectional shape and / or may not be elongated.

[0077] In some examples, the filter arrangement 12 abuts the longitudinal end of the aerosolizable material 11. In other examples, the filter arrangement 12 may be spaced from the aerosolizable material 11 by a gap and / or one or more additional components of the article 10, etc. In some examples, the filter arrangement 12 may include, for example, an additive or flavour source (such as an additive or flavourant-containing capsule or filament) held by the body of the filter material or between two bodies of the filter material.

[0078] The article 10 may also include a wrapper (not shown) wrapped around the aerosolizable material 11 and the filter assembly 12 to hold the filter assembly 12 against the aerosolizable material 11. The wrapper may be wrapped around the aerosolizable material 11 and the filter assembly 12 such that the free ends of the wrapper overlap each other. The wrapper may form part or all of the circumferential outer surface of the article 10. The wrapper can be made of any suitable material such as paper, card or reconstituted aerosolizable material (e.g., reconstituted tobacco). The paper may be tipping paper known in the art. The wrapper may also include an adhesive (not shown) that adheres the overlapping free ends of the wrapper to each other to help prevent separation of the overlapping free ends. In other examples, the adhesive may be omitted or the wrapper may take a form different from the form described. In other examples, the filter assembly 12 may be held against the aerosolizable material 11 by a connection other than the wrapper, such as an adhesive. In some examples, the filter assembly 12 may be omitted.

[0079] The aerosol delivery device 100 includes a heating zone 110 for receiving at least a portion of the article 10, an outlet 120 through which an aerosol can be delivered from the heating zone 110 to a user during use, and a heating device 130 for causing heating of the article 10 when the article 10 is at least partially located within the heating zone 110, thereby generating an aerosol. In some examples, the aerosol can be delivered from the heating zone 110 to the user through the article 10 itself rather than through any gaps adjacent to the article 10. Nevertheless, in such examples, the aerosol still passes through the outlet 120 even while moving within the article 10.

[0080] Device 100 can define at least one air inlet (not shown) that fluidly connects the heating zone 110 to the exterior of the device 100. A user can inhale the volatile components of an aerosolizable material by drawing the volatile components from the heating zone 110 through the article 10. When the volatile components are removed from the heating zone 110 and the article 10, air can be drawn into the heating zone 110 through the air inlet of the device 100.

[0081] In this example, the heating zone 110 extends along axis A-A and is sized and shaped to accommodate only a portion of the article 10. In this example, axis A-A is the central axis of the heating zone 110. Further, in this example, the heating zone 110 is elongated, such that axis A-A is the longitudinal axis A-A of the heating zone 110. The article 10 is at least partially insertable into the heating zone 110 through the outlet 120 and protrudes from the heating zone 110 through the outlet 120 during use. In other examples, the heating zone 110 may or may not be elongated and may be sized to receive the entire article 10. In some such examples, the device 100 can include a mouthpiece that is disposed to cover the outlet 120 and can draw an aerosol from the heating zone 110 and the article 10.

[0082] In this example, when the article 10 is at least partially located within the heating zone 110, different portions 11a - 11e of the aerosolizable material 11 are located at respective different positions 111 - 115 within the heating zone 110. In this example, these positions 111 - 115 are at respective different axial positions along the axis A - A of the heating zone 110. Further, in this example, since the heating zone 110 is elongated, the positions 111 - 115 can be considered to be at different positions spaced longitudinally along the length of the heating zone 110. In this example, the article 10 can be considered to include five such portions 11a - 11e of the aerosolizable material 11 located at the first position 111, the second position 112, the third position 113, the fourth position 114, and the fifth position 115, respectively. More specifically, the second position 112 is fluidly located between the first position 111 and the outlet 120, the third position 113 is fluidly located between the second position 112 and the outlet 120, the fourth position 114 is fluidly located between the third position 113 and the outlet 120, and the fifth position 115 is fluidly located between the fourth position 114 and the outlet 120.

[0083] The heating device 130 includes a plurality of heating units 140a - 140e, each of which can heat each of the portions 11a - 11e of the aerosolizable material 11 to a temperature sufficient to aerosolize its components when the article 10 is at least partially located within the heating zone 110. The plurality of heating units 140a - 140e may be axially aligned with each other along the axis A - A. Each of the portions 11a - 11e of the aerosolizable material 11 that can be heated in this way may have a length in the direction of the axis A - A of, for example, 1 millimeter to 20 millimeters, for example 2 millimeters to 10 millimeters, 3 millimeters to 8 millimeters, or 4 millimeters to 6 millimeters.

[0084] The heating device 130 in this example includes five heating units 140a to 140e, namely, a first heating unit 140a, a second heating unit 140b, a third heating unit 140c, a fourth heating unit 140d, and a fifth heating unit 140e. The heating units 140a to 140e are at different respective axial positions along the axis A-A of the heating zone 110. Further, in this example, since the heating zone 110 is elongated, the heating units 140a to 140e can be considered to be at different positions spaced longitudinally along the length of the heating zone 110. More specifically, the second heating unit 140b is located between the first heating unit 140a and the outlet 120, the third heating unit 140c is located between the second heating unit 140b and the outlet 120, the fourth heating unit 140d is located between the third heating unit 140c and the outlet 120, and the fifth heating unit 140e is located between the fourth heating unit 140d and the outlet 120. In other examples, the heating device 130 can include more than five or less than five heating units, for example, only four, only three, only two, or only one heating unit. The number of portions of the aerosolizable material 11 that can be heated by each heating unit can correspondingly vary.

[0085] The heating device 130 also includes a controller 135 configured to cause the heating units 140a-140e to operate and thereby cause heating of respective portions 11a-11e of the aerosolizable material 11 during use. In this example, the controller 135 is configured to operate the heating units 140a-140e independently of each other, such that the respective portions 11a-11e of the aerosolizable material 11 can be heated independently. This may be desirable to effect a progressive heating of the aerosolizable material 11 during use. Further, in examples where the portions 11a-11e of the aerosolizable material 11 have different respective forms or characteristics, such as different tobacco blends and / or different applied or inherent flavorants, the ability to independently heat the portions 11a-11e of the aerosolizable material 11 can enable heating of selected portions 11a-11e of the aerosolizable material 11 at different times during a use session to produce an aerosol having a predetermined characteristic that is time-dependent. Nevertheless, in some examples, the heating device 130 may be operable in one or more modes in which the controller 135 is configured to operate two or more of the heating units 140a-140e, such as all of the heating units 140a-140e, simultaneously during a use session.

[0086] In this example, the heating units 140a to 140e each include an induction heating unit configured to generate a respective variable magnetic field such as an alternating magnetic field. Therefore, the heating device 130 can be considered to include a magnetic field generator, and the controller 135 can be considered to be a device operable to pass a variable current through the inductor 150 of each heating unit 140a to 140e. Further, in this example, the device 100 includes a susceptor 190 configured to be heatable by penetration by a variable magnetic field, thereby heating the heating zone 110 and the article 10 therein during use. That is, portions of the susceptor 190 are heatable by penetration by respective variable magnetic fields, thereby causing heating of respective portions 11a to 11e of the aerosolizable material 11 at respective positions 111 to 115 within the heating zone 110.

[0087] In some examples, the susceptor 190 is made of or includes aluminum. However, in other examples, the susceptor 190 may include one or more materials selected from the group consisting of conductive materials, magnetic materials, and magnetoconductive materials. In some examples, the susceptor 190 may include a metal or a metal alloy. In some examples, the susceptor 190 may include one or more materials selected from the group consisting of aluminum, gold, iron, nickel, cobalt, conductive carbon, graphite, steel, plain carbon steel, mild steel, stainless steel, ferritic stainless steel, molybdenum, silicon carbide, copper, and bronze. In other examples, other materials may be used.

[0088] In some examples, such as examples where the susceptor 190 includes iron such as steel (e.g., mild steel or stainless steel) or aluminum, the susceptor 190 may include a coating to help avoid corrosion or oxidation of the susceptor 190 during use. Such coatings may include, for example, nickel plating, gold plating, or a coating of ceramic or an inert polymer.

[0089] In this example, susceptor 190 is tubular and surrounds heating zone 110. In fact, in this example, the inner surface of susceptor 190 partially delimits heating zone 110. The internal cross-sectional shape of susceptor 190 may be circular, or may be different shapes such as elliptical, polygonal or irregular. In other examples, susceptor 190 can take different forms such as a non-tubular structure that still partially surrounds heating zone 110, or a protruding structure such as a rod, pin or blade that penetrates heating zone 110. In some examples, susceptor 190 may be replaced by a plurality of susceptors, each of which is heatable by penetration by a respective one of the varying magnetic fields, thereby causing heating of each one of portions 11a - 11e of aerosolizable material 11. Each of the plurality of susceptors may, for example, be tubular, or may take one of the other forms described herein for susceptor 190. In yet another example, device 100 may not include susceptor 190, and article 10 may be heatable by penetration by a varying magnetic field, thereby causing heating of each of portions 11a - 11e of aerosolizable material 11, and may include one or more susceptors. Each of the one or more susceptors of article 10 can take any suitable form such as a structure wound around or otherwise surrounding aerosolizable material 11 (e.g., a metal foil such as aluminum foil), a structure disposed within aerosolizable material 11, or a group of particles or other elements mixed with aerosolizable material 11. In an example where device 100 does not include susceptor 190, susceptor 190 may be replaced by a heat-resistant tube that partially delimits heating zone 110. Such a heat-resistant tube can be made, for example, from polyetheretherketone (PEEK) or a ceramic material.

[0090] In this example, the heating device 130 includes a power source (not shown) and a user interface (not shown) for user operation of the device. The power source in this example is a rechargeable battery. In other examples, the power source may be other than a rechargeable battery, such as a non-rechargeable battery, a capacitor, a battery-capacitor hybrid, or a connection to a main power supply.

[0091] In this example, the controller 135 is electrically connected between the power source and the heating units 140a - 140e. In this example, the controller 135 is also electrically connected to the power source. More specifically, in this example, the controller 135 is for controlling the supply of power from the power source to the heating units 140a - 140e. In this example, the controller 135 includes an integrated circuit (IC) such as an IC on a printed circuit board (PCB). In other examples, the controller 135 can take different forms. The controller 135 is, in this example, operated by a user operation of the user interface. The user interface may include push buttons, toggle switches, dials, touchscreens, etc. In other examples, the user interface may be remote and may be wirelessly connected to the rest of the aerosol providing device 100 via Bluetooth (registered trademark) or the like.

[0092] In this example, by operating the user interface by the user, the controller 135 passes an alternating current through at least one inductor 150 of each of the heating units 140a - 140e. Thereby, an alternating magnetic field is generated in the inductor 150. The inductor 150 and the susceptor 190 are appropriately positioned relative to each other such that the alternating magnetic field generated by the inductor 150 penetrates the susceptor 190. When the susceptor 190 is conductive, this penetration generates one or more eddy currents in the susceptor 190. The flow of the eddy currents in the susceptor 190 against the electrical resistance of the susceptor 190 heats the susceptor 190 by Joule heating. When the susceptor 190 is magnetic, as the applied magnetic field changes, the orientation of the magnetic dipoles in the susceptor 190 changes, and heat is generated in the susceptor 190.

[0093] The device 100 can include a temperature sensor (not shown) for detecting the temperature of the heating chamber 110, the susceptor 190, or the article 10. The temperature sensor may be communicably connected to the controller 135. As a result, the controller 135 can monitor the respective temperatures of the heating chamber 110, the susceptor 190, or the article 10 based on the information output by the temperature sensor. In other examples, the temperature can be detected and monitored by measuring electrical characteristics of the system, such as changes in the current within the heating units 140a - 140e. Based on one or more signals received from the temperature sensor, the controller 135 can adjust the characteristics of the variable or alternating current as needed to ensure that the temperatures of the heating chamber 110, the susceptor 190, or the article 10 each remain within a predetermined temperature range. The characteristics can be, for example, amplitude or frequency or duty cycle. Within the predetermined temperature range, during use, the aerosolizable material 11 within the article 10 disposed within the heating chamber 110 is heated sufficiently to volatilize at least one component of the aerosolizable material 11 without burning the aerosolizable material 11.

[0094] Accordingly, the controller 135, and the device 100 as a whole, are configured to heat the aerosolizable material 11 to volatilize at least one component of the aerosolizable material 11 without burning the aerosolizable material 11. The temperature range can be from about 50°C to about 350°C, such as from about 100°C to about 300°C, or from about 150°C to about 280°C. In other examples, the temperature range may be outside of one of these ranges. In some examples, the upper limit of the temperature range may exceed 350°C. In some examples, the temperature sensor may be omitted.

[0095] In this example, the heating device 130 is configured to cause the heating of the first portion 11a of the aerosolizable material 11 to a temperature sufficient to aerosolize the components of the first portion 11a of the aerosolizable material 11 before or more rapidly than the heating of the second portion 11b of the aerosolizable material 11 during the heating session. More specifically, the controller 135 is configured to cause the operation of the first heating unit 140a and the second heating unit 140b so as to cause the heating of the first portion 11a of the aerosolizable material 11 before or more rapidly than the heating of the second portion 11b of the aerosolizable material 11 during the heating session. Accordingly, during the heating session, the location at which thermal energy is applied to the aerosolizable material 11 of the article 10 is initially relatively fluidly separated from the outlet 120 and the user and then moves towards the outlet 120. This provides the advantage that during the heating session an aerosol is generated from successive “fresh” portions of the aerosolizable material 11, which can result in a more satisfying sensory experience for the user that may be more similar to smoking a conventional combustible factory-made cigarette.

[0096] Further, in some examples, the controller 135 is configured to stop supplying power to the first heating unit 140a during at least a portion (or all) of the period in which the controller 135 is configured to cause the second heating unit 140b to operate. This provides the further advantage that the aerosol generated at a given portion of the aerosolizable material 11 does not need to pass through another portion of the previously heated aerosolizable material 11, which could otherwise negatively affect the aerosol. For example, an aerosol passing through previously heated or used aerosolizable material can introduce aerosol pickup components that create "dissonance" in the aerosol.

[0097] In some examples where the heating device 130 has three or more heating units, during a heating session, the heating device 130 may also be configured to cause heating of at least one further portion 11b-11e of the aerosolizable material 11 before or more rapidly than heating of yet further portions 11c-11e of the aerosolizable material 11 that are fluidly closer to the outlet 120, to a temperature sufficient to aerosolize the components of the further portion 11b-11e of the aerosolizable material 11. That is, the controller 135 may be configured to cause appropriate operation of the heating units to cause heating of at least one further portion 11b-11e of the aerosolizable material 11 before or more rapidly than heating of yet further portions 11c-11e of the aerosolizable material 11.

[0098] For a given duration of a heating session, the greater the number of heating units and associated parts of the aerosolizable material 11, the greater the opportunity to generate aerosol from the "fresh" or unused portion of the aerosolizable material 11 extending along a given axial length. Alternatively, for a given duration of heating each portion of the aerosolizable material 11, the greater the number of heating units and associated parts of the aerosolizable material 11, the longer the heating session can be. It should be understood that the duration for which an individual heating unit can be operated can be adjusted (e.g., reduced) to adjust (e.g., shorten) the overall heating session, and at the same time, the power supplied to the heating element can be adjusted (e.g., increased) to reach the operating temperature more quickly. A balance can be achieved among the number of heating units (which can determine the number of "fresh puffs"), the length of the overall session, and the achievable power supply (which can be determined by the characteristics of the power source).

[0099] As described above, a susceptor can be heated using an inductor that forms part of a parallel LC resonant circuit, and the susceptor physically (and electrically) contacts the exposed coil of the inductor. As will be further described below, several other configurations are possible.

[0100] FIG. 8 is a block diagram of a system generally designated by reference numeral 300 according to an exemplary embodiment.

[0101] System 300 includes a power source in the form of a direct current (DC) voltage supply 11, a switching configuration 13, a resonant circuit 14, a susceptor configuration 16, and a control circuit 18. The switching configuration 13 and the resonant circuit 14 may be coupled to each other in an inductive heating configuration 12 that can be used to heat the susceptor 16.

[0102] The resonant circuit 14 can include a capacitor and one or more inductive elements for inductively heating the susceptor configuration 16 to heat the aerosol-generating material. By heating the aerosol-generating material, an aerosol can be generated.

[0103] The switching configuration 13 can be enabled to generate an alternating current from the DC voltage supply 11 (under the control of the control circuit 18). The alternating current can flow through one or more inductive elements and can cause heating of the susceptor configuration 16. The switching configuration may comprise a plurality of transistors. Exemplary DC-AC converters include an H-bridge circuit or an inverter circuit, examples of which are described below.

[0104] System 300 has some similarities with the above-described system 200, but in system 300, the resonant circuit 14 can comprise an inductor and a capacitor connected in series, as will be further described below.

[0105] FIG. 9 is a block diagram of a circuit, generally designated by reference numeral 400, according to an exemplary embodiment. Circuit 400 is an exemplary implementation of the above-described system 300.

[0106] Circuit 400 comprises a positive terminal 67 and a negative (ground) terminal 68 (which are exemplary implementations of the DC voltage supply 11 of the above-described system 300). Circuit 400 comprises a switching configuration 64 (implementing the above-described switching configuration 13), and the switching configuration 64 comprises a bridge circuit (such as an H-bridge circuit, such as a FET H-bridge circuit). The switching configuration 64 comprises a first leg 64a and a second leg 64b, and the first leg 64a and the second leg 64b are coupled by a resonant circuit 69 (which implements the above-described resonant circuit 14). The first leg 64a comprises switches 65a and 65b, and the second leg 64b comprises switches 65c and 65d. The switches 65a, 65b, 65c and 65d may be transistors, such as field effect transistors (FETs), and may receive an input from a controller, such as the control circuit 18 of system 10.

[0107] The resonance circuit 69 includes a series connection of a capacitor 66 and an inductive element 63 such that the resonance circuit 69 can be an LC resonance circuit. The circuit 60 further shows a susceptor equivalent circuit 62 (which implements the susceptor configuration 16 thereby). The susceptor equivalent circuit 62 includes a resistive element and an inductive element that exhibit the electrical effects of the exemplary susceptor configuration 16. As described in detail above, the susceptor 16 can be disposed across (and in electrical contact with) the exposed coil of the inductor 63. (Thus, the susceptor 16 can be similar to the susceptor 224 described above.)

[0108] When a susceptor is present, the susceptor configuration 62 and the inductive element 63 can act as a transformer 61 (e.g., a single-winding transformer). The transformer 61 can generate a varying magnetic field such that when the circuit 60 receives power, the susceptor is heated. During the heating operation in which the susceptor configuration 16 is heated by an inductive configuration, the switching configuration 64 is driven (e.g., by the control circuit 18) such that each of the first and second branches is sequentially coupled so that an alternating current passes through the resonance circuit 69. The resonance circuit 69 has a resonance frequency that is partially based on the susceptor configuration 16, and the control circuit 18 can be configured to control the switching configuration 64 to switch at the resonance frequency or a frequency close to the resonance frequency. Driving the switching circuit at or near resonance helps to improve efficiency and reduces the energy lost in the switching elements (which causes unnecessary heating of the switching elements). In an example where an article 21 comprising an aluminum foil is heated, the switching configuration 64 can be driven at a frequency of about 2.5 MHz. However, in other implementations, the frequency can be, for example, anywhere from 500 kHz to 4 MHz.

[0109] As described above, there are many other circuit configurations that include an inductor forming part of a parallel LC resonance circuit that can be used to heat a susceptor, and the susceptor makes physical (and electrical) contact with the exposed coil of the inductor. As an example, FIG. 10 is a block diagram of a circuit, generally designated by reference numeral 500, according to an exemplary embodiment.

[0110] Circuit 500 includes a resonance circuit 550 for inductive heating of susceptor configuration 510. The resonance circuit 550 includes an inductive element 558 and a capacitor 556 connected in parallel (an exemplary implementation of the above-described resonance circuit 201).

[0111] The resonance circuit 550 includes a switching configuration Ml, M2 including a first transistor Ml and a second transistor M2 in this example. The first transistor M1 and the second transistor M2 each include respective first terminals G1, G2, second terminals D1, D2, and third terminals S1, S2. The second terminal D1 of the first transistor M1 and the second terminal D2 of the second transistor M2 are connected to both sides of a combination of the parallel inductive element 558 and the capacitor 556. The third terminal S1 of the first transistor M1 and the third terminal S2 of the second transistor M2 are each connected to ground 151. In circuit 500, both the first transistor M1 and the second transistor M2 are MOSFETs, the first terminals G1, G2 are gate terminals, the second terminals Dl, D2 are drain terminals, and the third terminals S1, S2 are source terminals. It will be understood that in an alternative example, other types of transistors may be used instead of the MOSFETs described above.

[0112] The resonance circuit 550 has an inductance L and a capacitance C. The inductance L of the resonance circuit 550 is provided by the inductive element 558 and may also be affected by the inductance of the susceptor configuration 510 arranged for inductive heating by the inductive element 558. As described above, in use, the susceptor configuration 510 can be provided across (and in electrical contact with) the exposed coil of the inductive element 558.

[0113] A DC supply voltage V1 is supplied to the resonant circuit 550. The positive terminal of the DC voltage supply V1 is connected to the resonant circuit 550 at the first point 559 and the second point 560. The negative terminal of the DC voltage supply V1 (not shown) is connected to ground 551 and thus, in this example, to the source terminals S of both the MOSFET M1 and the MOSFET M2. In the example, the DC supply voltage V1 can be supplied to the resonant circuit directly from a battery or via an intermediate element.

[0114] Thus, the resonant circuit 550 can be considered to be connected as an electrical bridge having an inductive element 558 and a capacitor 556 connected in parallel between two arms of the bridge. The resonant circuit 550 acts to produce the switching effect described below, whereby a variable current, for example an alternating current, is drawn through the inductive element 558 and thus an alternating magnetic field is created and the susceptor configuration 510 is heated. The first point 559 is connected to a first node A located on the first side of the parallel combination of the inductive element 558 and the capacitor 556. The second point 560 is connected to a second node B on the second side of the parallel combination of the inductive element 558 and the capacitor 556. The first choke inductor 561 is connected in series between the first point 559 and the first node A, and the second choke inductor 562 is connected in series between the second point 560 and the second node B. The first choke 561 and the second choke 562 act to remove the AC frequency entering the circuit from the first point 559 and the second point 560 respectively, but allow a DC current to be drawn through and flow through the inductor 558. The chokes 561 and 562 allow the voltages at A and B to oscillate with little or no visible effect at the first point 559 or the second point 160.

[0115] The resonant circuit 550 switches from a first state to a second state and back again. Thus, the resonant circuit 55 can be considered to be an oscillator circuit.

[0116] In the first state, · the voltage at node A is high; · The voltage of node B is low; · The first diode d1 is forward-biased; · The second MOSFET M2 is on; · The second diode d2 is reverse-biased; · The first MOSFET M1 is off.

[0117] From this point on, with the second MOSFET M2 on and the first MOSFET M1 off, current is drawn from the supply V1 through the first choke 561 and the inductive element 558. Due to the presence of the inductive choke 561, the voltage at node A oscillates freely. Since the inductive element 558 is in parallel with the capacitor 556, the voltage observed at node A follows a voltage with a half-sine wave voltage profile. The frequency of the voltage observed at node A is equal to the resonant frequency of the circuit 550.

[0118] The voltage at node A decreases sinusoidally over time from its maximum value towards zero as a result of energy attenuation at node A. The voltage at node B is kept low (because MOSFET M2 is on), and the inductor L is charged from the DC supply V1. MOSFET M2 is turned off when the voltage at node A becomes less than or equal to the gate threshold voltage of M2 + the forward-bias voltage of d2. When the voltage at node A finally reaches zero, MOSFET M2 is fully turned off.

[0119] At the same time, or immediately thereafter, the voltage of node B increases. This is caused by the resonant transfer of energy between the inductive element 558 and the capacitor 556. When the voltage of node B increases due to this resonant transfer of energy, the situation described above with respect to nodes A, B and MOSFETs M1, M2 is reversed. That is, as the voltage of A decreases towards zero, the drain voltage of M1 is reduced. The drain voltage of M1 is reduced until it no longer reverse-biases the second diode d2 and becomes forward-biased. Similarly, the voltage of node B rises to its maximum, and the first diode d1 switches from forward bias to reverse bias. When this occurs, the gate voltage of M1 is no longer coupled to the drain voltage of M2, and thus the gate voltage of M1 increases under the application of the gate supply voltage V2. Therefore, the first MOSFET M1 is switched to the on state because its gate-source voltage exceeds the switch-on threshold here. Here, since the gate terminal of M2 is connected to the low-voltage drain terminal of M1 via the forward-biased second diode d2, the gate voltage of M2 is low. Therefore, M2 is switched to the off state.

[0120] In summary, at this point, the circuit 150 is in the second state, · the voltage of node A is low; · the voltage of node B is high; · the first diode d1 is reverse-biased; · the second MOSFET M2 is off; · the second diode d2 is forward-biased; · the first MOSFET M1 is on.

[0121] At this point, a current is drawn from the supply voltage V1 through the second choke 562 to the inductive element 558. Therefore, the direction of the current has been reversed due to the switching operation of the resonant circuit 550. The resonant circuit 550 continues to switch between the first state and the second state.

[0122] In the steady operating state, energy is transferred between the electrostatic domain (i.e., in capacitor 556) and the magnetic domain (i.e., in inductor 558), and vice versa.

[0123] As described above, the resonant frequency of circuit 550 depends on the inductance L and capacitance C of circuit 550, which in turn depends on inductive element 558, capacitor 556, and further on susceptor configuration 510. That is, it can be considered that the resonant frequency changes as energy is transferred from the inductive element to the susceptor configuration.

[0124] The various embodiments described herein are presented only to assist in the understanding and teaching of the claimed features. These embodiments are provided only as representative samples of the embodiments and are not exhaustive and / or exclusive. The advantages, embodiments, examples, functions, features, structures, and / or other aspects described herein should not be considered as limitations on the scope of the invention defined by the claims or limitations on equivalents of the claims, and it should be understood that other embodiments can be utilized and modifications can be made without departing from the scope of the claimed invention. The various embodiments of the present invention can suitably include, consist of, or essentially consist of appropriate combinations of disclosed elements, components, features, parts, steps, means, etc. other than those specifically described herein. Further, the present disclosure can include other inventions that are not currently claimed but may be claimed in the future. [Item of Invention] [Item 1] A resonant circuit including an inductor and a capacitor, wherein the inductor includes one or more coils that are at least partially exposed, and the inductor is for heating the susceptor when the susceptor is disposed across the exposed coil and is in electrical contact with the exposed coil, a resonant circuit, and a circuit for applying one or more pulses to the resonant circuit; An apparatus comprising the same. [Item 2] The apparatus according to Item 1, wherein the exposed coil of the inductor is resistant to corrosion. [Item 3] The apparatus according to Item 1 or 2, wherein the coil is made of gold or the tip is made of gold. [Item 4] The apparatus according to any one of Items 1 to 3, wherein the one or more coils of the inductor are formed by a printed circuit board. [Item 5] The apparatus according to Item 4, wherein the printed circuit board is a multilayer printed circuit board, and the coil is formed from different layers of the printed circuit board. [Item 6] The apparatus according to any one of Items 1 to 5, wherein the inductor includes a conductive non-helical first portion that coincides with a first plane, a conductive non-helical second portion that coincides with a second plane spaced apart from the first plane, and a conductive connector that electrically connects the first portion to the second portion. [Item 7] The apparatus according to Item 6, wherein the first portion is a first partial ring and the second portion is a second partial ring. [Item 8] The apparatus according to any one of Items 1 to 7, wherein the inductor and the capacitor are connected in parallel. [Item 9] The apparatus according to any one of Items 1 to 7, wherein the inductor and the capacitor are connected in series. [Item 10] The apparatus according to any one of Items 1 to 9, wherein the circuit is a self-oscillation drive circuit. [Item 11] The apparatus according to any one of Items 1 to 9, wherein the circuit includes an H-bridge drive circuit. [Item 12] A delivery system comprising the apparatus according to any one of Items 1 to 11. [Item 13] The delivery system according to Item 12, configured to receive a removable article containing an aerosol-generating material. [Item 14] The delivery system according to Item 13, wherein the aerosol-generating material includes an aerosol product substance and an aerosol-forming material. [Item 15] The delivery system according to item 13 or 14, wherein the removable article includes a susceptor configuration. [Item 16] The delivery system according to item 15, wherein, in use, the susceptor configuration is in electrical contact with at least a partially exposed coil of the induction element of the device. [Item 17] The delivery system according to any one of items 12 to 16, wherein the delivery system is a non-combustible aerosol generating device.

Claims

1. A resonant circuit including an inductor and a capacitor, wherein the inductor includes one or more coils that are at least partially exposed, the inductor is configured such that a susceptor is disposed across the exposed coil and heats the susceptor when in electrical contact with the exposed coil, the resonant circuit; A circuit for applying one or more pulses to the resonant circuit; An apparatus comprising the above.

2. The apparatus according to claim 1, wherein the exposed coil of the inductor is resistant to corrosion.

3. The apparatus according to claim 1, wherein the coil is made of gold or has a gold tip.

4. The apparatus according to claim 1, wherein the one or more coils of the inductor are formed by a printed circuit board.

5. The apparatus according to claim 4, wherein the printed circuit board is a multilayer printed circuit board and the coils are formed from different layers of the printed circuit board.

6. The apparatus according to claim 1, wherein the inductor comprises a conductive non-helical first portion that coincides with a first plane, a conductive non-helical second portion that coincides with a second plane spaced apart from the first plane, and a conductive connector that electrically connects the first portion to the second portion.

7. The apparatus according to claim 6, wherein the first portion is a first partial ring and the second portion is a second partial ring.

8. The apparatus according to claim 1, wherein the inductor and the capacitor are connected in parallel.

9. The apparatus according to claim 1, wherein the inductor and the capacitor are connected in series.

10. The apparatus according to claim 1, wherein the circuit is a self-oscillating drive circuit.

11. The apparatus according to claim 1, wherein the circuit includes an H-bridge drive circuit.

12. A delivery system comprising the apparatus according to any one of claims 1 to 11.

13. The delivery system according to claim 12, configured to receive a removable article containing an aerosol-generating material.

14. The delivery system according to claim 13, wherein the aerosol-generating material includes an aerosol product substance and an aerosol-forming material.

15. The delivery system according to claim 13, wherein the removable article includes a susceptor configuration.

16. The delivery system according to claim 15, wherein in use, the susceptor configuration makes electrical contact with at least a portion of the one or more coils of the induction element of the device that is at least partially exposed. **Claim 17** The delivery system according to claim 12, wherein the delivery system is a non-combustible aerosol generating device.

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