Method for operating an aerosol generator

Abstract

A method for operating an aerosol generator of an aerosol delivery device includes determining a resonant frequency f0 of one or more inductive elements and supplying an alternating current to the one or more inductive elements for a plurality of time cycles, each time cycle comprising one or more first periods T1 and one or more second periods T2. During the first periods T1, the one or more inductive elements are supplied with an alternating current at a first frequency f1, where 0.9≦f1 / f0≦1.1. During the second periods T2, the one or more inductive elements are supplied with an alternating current at a different second frequency f2, where (a) f2 / f0≦0.9 or (b) f2 / f0≧1.1. This approach is simpler to implement and requires fewer components in the electronic circuitry than turning off the alternating current during the second periods T2.

Description

[Technical Field]

[0001] The present invention relates to a method of operating an aerosol generator of an aerosol delivery device, an electronic circuit for an aerosol generator of an aerosol delivery device, an aerosol delivery device, an aerosol generation system, and a method of generating an aerosol. [Background technology]

[0002] Smoking articles, such as cigarettes and cigars, burn tobacco during use to produce tobacco smoke. As an alternative to these articles, attempts have been made to provide products that release compounds without combustion. Examples of such products include so-called "heat-and-burn" products or tobacco heating devices or products, which release compounds by heating a material without burning it. This material may be, for example, a tobacco product or other non-tobacco product, and may or may not contain nicotine.

[0003] An aerosol delivery device is known that comprises an aerosol generator, the aerosol generator comprising two induction coils.

[0004] It would be desirable to provide an improved method of operating an aerosol generator. Summary of the Invention

[0005] According to one aspect, there is provided a method of operating an aerosol generator of an aerosol delivery device, the method comprising: determining a resonant frequency f0 of one or more inductive elements; supplying an alternating current to the one or more inductive elements over a plurality of time cycles, each time cycle comprising one or more first time periods T1 and one or more second time periods T2; supplying the alternating current to the one or more inductive elements at a first frequency f1 during the one or more first time periods T1, where 0.9≦f1 / f0≦1.1; supplying the AC current to the one or more inductive elements at a different second frequency f2 during the one or more second time periods T2, where (a) f2 / f0≦0.9 or (b) f2 / f0≧1.1 and f2>0; Equipped with.

[0006] According to various embodiments, an aerosol generator of an aerosol delivery device is provided, which is configured to provide an alternating current to one or more inductive elements. For example, the inductive elements may comprise a coil or an induction coil. A resonant frequency f0 of the inductive elements may be determined. The aerosol generator may be energized for an extended period of time (which may be several minutes). This extended period may correspond to one use session. This extended period or the entire use session may be subdivided into multiple time cycles, each of which may last, for example, one second.

[0007] A time cycle can be further subdivided into multiple first periods T1 interleaved with multiple second periods T2. For example, a time cycle lasting one second can be subdivided into multiple 10 millisecond first periods T1, with subsequent multiple first periods T1 interleaved with multiple second periods T2, where the second periods T2 may also be 10 milliseconds long. It will of course be understood that the first period T1 can be longer or shorter than 10 milliseconds. Similarly, the second period T2 can be longer or shorter than 10 milliseconds.

[0008] Thus, by way of example only, a use session lasting, for example, 180 seconds can be considered to comprise 180 time cycles, each lasting 1 second. Each 1-second time cycle may be subdivided into, for example, 50 first periods T1 and 50 second periods T2. Each of the first and second periods T1, T2 may last 10 milliseconds.

[0009] According to various embodiments, the aerosol generator may be configured to provide alternating current to the inductive element during a respective first time period T1, during which the inductive element may be considered to be energized or in an on state, and during a subsequent second time period T2, the inductive element may be considered to be de-energized or in an off state.

[0010] During the first time period T1, the aerosol generator may be configured to supply an alternating current to the inductive element at a frequency f1 close to the determined resonant frequency f0 of the inductive element. In particular, the alternating current may be supplied at a frequency f1 within ±10% of the determined resonant frequency f0 of the inductive element. As a result of being driven at a frequency f1 close to the resonant frequency f0 of the inductive element, an efficient process is established. As a result, an induced current is suitably generated in a coil forming part of the inductive element or in a susceptor disposed in proximity to the induction coil, thereby heating the susceptor during each first time period T1.

[0011] In contrast, during the second time period T2, the aerosol generator is configured to supply an alternating current to the inductive element at a frequency f2 sufficiently lower or sufficiently higher than the determined resonant frequency f0 of the inductive element. In particular, the alternating current is supplied at a frequency f2 that is at least 10% lower or at least 10% higher than the determined resonant frequency f0 of the inductive element. As a result of being driven at a frequency f2 that is not close to the resonant frequency f0 of the inductive element, the drive frequency is inefficient, and the inductive element can be considered to be essentially in an off-state. As a result, substantially no induced current is generated in the coil forming part of the inductive element or in a susceptor disposed proximate to the inductive coil, and therefore the susceptor is not heated by the alternating current applied to the inductive element during the second time period T2.

[0012] It will be appreciated that the AC current is not turned off, i.e., the frequency f2 is not reduced to zero, during one or more second periods T2, but the frequency f2 is sufficiently far from the resonant frequency f0 of the inductive element so that substantially no current is induced in the susceptor located in close proximity to the inductive element, and therefore the susceptor does not heat during the second periods T2.

[0013] According to various embodiments, the approach of substantially applying an alternating current to the inductive element, where the frequency of the applied alternating current repeatedly switches between a first frequency f1 close to the resonant frequency f0 and a second frequency f2 far from the resonant frequency f0, has the advantage of being simpler to implement than the approach of turning off the alternating current during the second time period T2. Also, the tolerances of electronic components in the electronic circuit can be relaxed, and the process places less demand on the individual components in the electronic circuit. As a result, the lifetime of the electronic circuit can be extended due to fewer failures of individual electronic components, and the reliability of the electronic circuit can be improved.

[0014] According to various embodiments, the electronic circuitry of various embodiments and the approach of repeatedly switching the frequency of the AC current between a first frequency f1 close to the resonant frequency f0 and a second frequency f2 far from the resonant frequency f0, rather than repeatedly turning the AC current on and off, places fewer demands on the DC battery. As will be appreciated by those skilled in the art, according to various embodiments, a DC battery is configured to supply DC voltage to multiple H-bridge driver circuits, each connected to a current switching circuit including two dual MOSFETs. The driver circuits continuously change the direction of current supplied to the terminals of an inductive element (e.g., a coil or induction coil) at a relatively high frequency. As a result, the combination of the H-bridge driver circuits and the MOSFETs driven by the H-bridge driver circuits effectively generates an AC current from the DC battery. By way of example only, the generated AC current may have a frequency of approximately 2 MHz.

[0015] It will be appreciated that this approach, according to various embodiments, places less demand on the DC battery, thereby extending its life. In particular, this approach, according to various embodiments, involves rapidly switching the frequency of the applied AC current between a frequency f1 close to the resonant frequency f0 of the inductive element and a frequency f2 detuned from the resonant frequency f0.

[0016] It will therefore be appreciated that various embodiments do not cycle the DC battery on and off at high frequencies, as would occur if a pulsed DC signal were repeatedly supplied to an H-bridge driver circuit.

[0017] Various embodiments provide an aerosol generator in which an induction coil is driven by an alternating current whose frequency is repeatedly switched between a first frequency f1 close to the resonant frequency f0 and a second frequency f2 detuned from the resonant frequency f0. This approach of repeatedly switching the frequency of the applied current between a frequency f1 close to the resonant frequency f0 and a frequency f2 detuned from the resonant frequency f0, rather than turning the alternating current on and off, allows for more durable, simpler, and more power-efficient electronic circuitry, particularly reducing the demands on DC batteries.

[0018] An advantage of the disclosed approach is that the electronic circuit can be designed to utilize less power overall, even though the AC circuit is not turned off during the second time period T2. This is because the electronic circuit does not need to include components that require fast on / off of AC current. Instead, according to various embodiments, the AC current is repeatedly switched every few milliseconds between a frequency f1 close to the resonant frequency f0 and a frequency f2 far from the resonant frequency f0, but the frequency f2 is not zero.

[0019] Optionally, f0 is in the range of (i) <0.5 MHz, (ii) 0.5 to 1.0 MHz, (iii) 1.0 to 1.5 MHz, (iv) 1.5 to 2.0 MHz, (v) 2.0 to 2.5 MHz, (vi) 2.5 to 3.0 MHz, (vii) 3.0 to 3.5 MHz, (viii) 3.5 to 4.0 MHz, or (ix) >4.0 MHz.

[0020] Optionally, f1 is in the range of (i) <0.5 MHz, (ii) 0.5 to 1.0 MHz, (iii) 1.0 to 1.5 MHz, (iv) 1.5 to 2.0 MHz, (v) 2.0 to 2.5 MHz, (vi) 2.5 to 3.0 MHz, (vii) 3.0 to 3.5 MHz, (viii) 3.5 to 4.0 MHz, or (ix) >4.0 MHz.

[0021] Optionally, f2 is in the range of (i) <0.5 MHz, (ii) 0.5 to 1.0 MHz, (iii) 1.0 to 1.5 MHz, (iv) 1.5 to 2.0 MHz, (v) 2.0 to 2.5 MHz, (vi) 2.5 to 3.0 MHz, (vii) 3.0 to 3.5 MHz, (viii) 3.5 to 4.0 MHz, or (ix) >4.0 MHz.

[0022] Optionally, the one or more inductive elements comprise one or more inductive coils.

[0023] According to another aspect, there is provided an electronic circuit for an aerosol generator of an aerosol delivery device, the electronic circuit comprising: a circuit element configured to determine a resonant frequency f0 of the one or more inductive elements; a driver device for supplying alternating current to one or more inductive elements over a plurality of time cycles, each time cycle comprising one or more first periods T1 and one or more second periods T2; The driver device comprises: (i) in use, supplying an alternating current to one or more inductive elements at a first frequency f1 during one or more first time periods T1, where 0.9≦f1 / f0≦1.1; (ii) in use, supplying an alternating current to the one or more inductive elements at a different second frequency f2 during one or more second time periods T2, where (a) f2 / f0≦0.9 or (b) f2 / f0≧1.1 and f2>0; It is structured as follows.

[0024] Optionally, f0 is in the range of (i) <0.5 MHz, (ii) 0.5 to 1.0 MHz, (iii) 1.0 to 1.5 MHz, (iv) 1.5 to 2.0 MHz, (v) 2.0 to 2.5 MHz, (vi) 2.5 to 3.0 MHz, (vii) 3.0 to 3.5 MHz, (viii) 3.5 to 4.0 MHz, or (ix) >4.0 MHz.

[0025] Optionally, f1 is in the range of (i) <0.5 MHz, (ii) 0.5 to 1.0 MHz, (iii) 1.0 to 1.5 MHz, (iv) 1.5 to 2.0 MHz, (v) 2.0 to 2.5 MHz, (vi) 2.5 to 3.0 MHz, (vii) 3.0 to 3.5 MHz, (viii) 3.5 to 4.0 MHz, or (ix) >4.0 MHz.

[0026] Optionally, f2 is in the range of (i) <0.5 MHz, (ii) 0.5 to 1.0 MHz, (iii) 1.0 to 1.5 MHz, (iv) 1.5 to 2.0 MHz, (v) 2.0 to 2.5 MHz, (vi) 2.5 to 3.0 MHz, (vii) 3.0 to 3.5 MHz, (viii) 3.5 to 4.0 MHz, or (ix) >4.0 MHz.

[0027] Optionally, the one or more inductive elements comprise one or more inductive coils.

[0028] According to another aspect, there is provided an aerosol delivery device comprising the electronic circuit described above.

[0029] Optionally, the aerosol delivery device further comprises an aerosol generator.

[0030] Optionally, the aerosol generator comprises one or more directing elements.

[0031] Optionally, the one or more inductive elements comprise one or more inductive coils.

[0032] According to another aspect, there is provided an aerosol generating system, the aerosol generating system comprising: the aerosol delivery device described above; an aerosol-producing article comprising an aerosol-forming material; Equipped with.

[0033] According to another aspect, there is provided a method for generating an aerosol, the method comprising: providing an aerosol delivery device as described above; inserting an aerosol product article comprising an aerosol-forming material into an aerosol delivery device; energizing the aerosol delivery device to generate an aerosol from the aerosol-generating material; Equipped with. [Brief explanation of the drawings]

[0034] Various embodiments will now be described, by way of example only, and with reference to the accompanying drawings, in which:

[0035] [Figure 1] FIG. 1 illustrates the electronic circuitry of an aerosol delivery device with two induction coils, showing an aerosol product placed within the heating chamber of the aerosol delivery device. [Figure 2] A detailed diagram of a portion of the electronic circuitry of an aerosol delivery device according to various embodiments, in which two induction coils are each driven by an H-bridge configuration comprising two driver circuits, each configured to drive two MOSFETs. [Figure 3] 1 illustrates a method of operating an aerosol generator or aerosol delivery device according to various embodiments. [Figure 4] FIG. 2 is a schematic diagram illustrating an electronic circuit for an aerosol generator of an aerosol delivery device according to various embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0036] Induction heating is a process of heating an electrically conductive object (or susceptor) by electromagnetic induction. An induction heater can include an inductive element, such as one or more coils or an electromagnet (the coil may be part of the electromagnet), and a circuit for passing a varying current, e.g., an alternating current, through the one or more coils. The varying current in the coil generates a varying magnetic field. This magnetic field penetrates a susceptor appropriately positioned relative to the one or more coils, generating eddy currents within the susceptor. Because the susceptor has an electrical resistance to eddy currents, the flow of eddy currents across this resistance causes the susceptor to heat by Joule heating. If the susceptor contains a ferromagnetic material, such as iron, nickel, or cobalt, heat can also be generated by magnetic hysteresis losses in the susceptor. That is, heat can also be generated by magnetic dipoles in the magnetic material changing their orientation as a result of aligning with the varying magnetic field. Compared to heating by conduction, induction heating allows for rapid heating because heat is generated within the susceptor. Furthermore, since no physical contact is required between the induction heater and the susceptor, there is a high degree of freedom in construction and application.

[0037] An induction heater can be considered to comprise an RLC circuit in which resistance (R) provided by a resistor, inductance (L) provided by an inductive element (e.g., one or more coils or an electromagnet configured to inductively heat a susceptor), and capacitance (C) provided by a capacitor are connected in series. In some cases, the resistance is provided by ohmic resistance in the portion of the circuit connecting the inductor and capacitor, so the RLC circuit does not necessarily include a resistor itself. Such a circuit can be referred to, for example, as an LC circuit. Such a circuit can exhibit electrical resonance. Electrical resonance occurs at a particular resonant frequency when the imaginary parts of the impedances or admittances of two or more circuit elements have the same absolute value and opposite signs and therefore cancel each other out.

[0038] In an RLC or LC circuit, resonance occurs when the collapsing magnetic field of an inductor generates a current that charges a capacitor in its winding. The capacitor then discharges, providing the current that creates the magnetic field in the inductor. While the capacitor is charging, energy is stored in the electric field, and while current flows through the inductor, energy is stored in the magnetic field. Energy can be transferred from one side of the circuit to the other, which can be oscillatory in nature. When the circuit is driven at the resonant frequency, the series impedance of the inductor and capacitor is minimized and the circuit current is maximized. Therefore, driving an RLC or LC circuit at or near the resonant frequency can provide effective and / or efficient induction heating.

[0039] As will be appreciated by those skilled in the art, a transistor is a semiconductor device for switching electronic signals. A transistor typically has at least three terminals for connecting to an electronic circuit. A field effect transistor (FET) is a specific type of transistor that can vary the effective conductance of the transistor using the effect of an applied electric field.

[0040] A field effect transistor may comprise a body B, a source terminal S, a drain terminal D, and a gate terminal G. A field effect transistor comprises an active channel comprising a semiconductor through which charge carriers (e.g., electrons or holes) flow between the source S and the drain D. The conductivity of the channel, i.e., the conductivity between the drain D and source S terminals, is a function of the potential difference between the gate G and source S terminals (which may be generated, for example, by a potential applied to the gate terminal G).

[0041] One type of field effect transistor is the enhancement-mode FET, and it will be appreciated that in an enhancement-mode FET, when the voltage between the gate G and the source S is substantially zero, the FET is in an off state (i.e., a state that substantially prevents current from passing through), and when the voltage between the gate G and the source S is not substantially zero, the enhancement-mode FET switches to an on state (i.e., a state that substantially allows current to pass through).

[0042] An n-channel (or n-type) field-effect transistor (n-FET) is a field-effect transistor whose channel comprises an n-type semiconductor, where electrons are the majority carriers and holes are the minority carriers. For example, an n-type semiconductor can comprise an intrinsic semiconductor (e.g., silicon) doped with a donor impurity (e.g., phosphorus). In an n-channel FET, the drain terminal D is placed at a higher potential than the source terminal S (i.e., there is a positive drain-to-source voltage, or, in other words, there is a negative source-to-drain voltage). To turn on the n-channel FET (i.e., to allow current to flow), a switching potential higher than the potential of the source terminal S is applied to the gate terminal G.

[0043] A p-channel (or p-type) field-effect transistor (p-FET) is a field-effect transistor whose channel comprises a p-type semiconductor, where holes are the majority carriers and electrons are the minority carriers. For example, a p-type semiconductor can comprise an intrinsic semiconductor (e.g., silicon) doped with an acceptor impurity (e.g., boron). In a p-channel FET, the source terminal S is placed at a higher potential than the drain terminal D (i.e., there is a negative drain-to-source voltage, or in other words, there is a positive source-to-drain voltage). To turn on the p-channel FET (i.e., to allow current to flow), a switching potential lower than the potential of the source terminal S (and which may, for example, be higher than the potential of the drain terminal D) is applied to the gate terminal G.

[0044] A metal-oxide-semiconductor field-effect transistor (MOSFET) is a field-effect transistor in which the gate terminal G is electrically isolated from the semiconductor channel by an insulating layer. In some examples, the gate terminal G is a metal and the insulating layer is an oxide (e.g., silicon dioxide), hence the "metal-oxide-semiconductor." However, in other examples, the gate may be made of a material other than a metal (e.g., polysilicon) and the insulating layer may be made of a material other than an oxide (e.g., other dielectric materials). Nevertheless, such devices are typically referred to as metal-oxide-semiconductor field-effect transistors (MOSFETs), and the terms metal-oxide-semiconductor field-effect transistor or MOSFET as used herein should be understood to include such devices.

[0045] One type of MOSFET is the n-channel (or n-type) MOSFET, where the semiconductor is n-type. N-channel MOSFETs (n-MOSFETs) can be operated in the same manner as described above in connection with the n-channel FET. Another type of MOSFET is the p-channel (or p-type) MOSFET, where the semiconductor is p-type. P-channel MOSFETs (p-MOSFETs) can be operated in the same manner as described above in connection with the p-channel FET.

[0046] An n-MOSFET typically has a lower source-drain resistance than a p-MOSFET. It will be appreciated that an n-MOSFET generates less heat when it is in the on state (i.e., a state in which current flows) compared to a p-MOSFET. Therefore, an n-MOSFET wastes less energy during operation compared to a p-MOSFET. Furthermore, an n-MOSFET typically has a shorter switching time (i.e., the characteristic response time between changing the switching potential applied to the gate terminal G and the MOSFET changing whether or not current flows) compared to a p-MOSFET. This allows for higher switching speeds and improved switching control.

[0047] As described in detail below, an H-bridge is an electronic circuit that switches the polarity of a voltage applied to a load. In the context of an aerosol delivery device, an H-bridge circuit can be used to rapidly switch the direction of current flow through an inductor coil. It will be appreciated that the use of MOSFETs as high-speed switches allows the direction of current through the induction coil to be rapidly switched. As a result, applying a DC voltage to an H-bridge circuit including multiple MOSFETs can provide an electronic circuit that allows AC current to flow through the induction coil. According to various embodiments, the frequency of the AC current can be approximately 2 MHz.

[0048] As will be described in more detail below, the MOSFETs used in the H-bridge to supply AC current to the induction coil may, according to various embodiments, include enhancement-mode n-channel MOSFETs.

[0049] 1 is a schematic diagram of the electronic circuitry 106 of the aerosol delivery device 100. The aerosol delivery device 100 includes an aerosol generator that includes two induction heating elements 108, 109 and control electronics for energizing the heating elements 108, 109. The aerosol delivery device 100 may include a single induction heating element, or, as shown in FIG. 1, the aerosol delivery device 100 may include a first induction heating element 108 and a second induction heating element 109. The first induction heating element 108 may be configured to heat the first susceptor 110a, in use, and the second induction heating element may be configured to heat the second susceptor 110b, in use.

[0050] An aerosol product article 116 is shown inserted into the aerosol delivery device 100, and it is understood that the aerosol product article 116 includes an aerosol-forming material that, in use, is heated by the first and second susceptors 110 a, 110 b. It is understood that the first and second susceptors 110 a, 110 b are heated by inducing an electric current therein. The first and second susceptors 110 a, 110 b may include ferromagnetic portions, which may include metals such as iron, nickel, or cobalt. When an alternating current is applied to either or both of the first and second inductive elements 108, 109, the alternating current heats the corresponding first and / or second susceptors 110 a, 110 b by Joule heating and / or magnetic hysteresis heating. It is therefore understood that the electronic circuit 106 is configured to pass an alternating current through the first and second inductive elements 108, 109 and induce a corresponding current in the first and second susceptors 110a, 110b, causing the susceptors 110a, 110b to heat up, thereby heating the aerosol-generating material (provided as part of the aerosol product item 116).

[0051] A DC power supply 104 is provided, forming part of an electronic circuit 106. The DC power supply 104 may comprise a battery or a battery pack. The DC power supply 104 is configured to supply DC power to the electronic circuit 106. The electronic circuit 106 is electrically connected to first and second inductive elements 108, 109. Each inductive element 108, 109 may comprise, for example, an electromagnet including one or more coils or solenoids. The first and second inductive elements 108, 109 may be formed from copper wire. The electronic circuit 106 is configured to convert the DC current provided by the DC power supply 104 into AC current and supply it to the first and second inductive elements 108, 109. The electronic circuit 106 is configured to drive the first and second inductive elements 108, 109 at a relatively high frequency, for example, approximately 2 MHz.

[0052] The first and second susceptors 110 a, 110 b are positioned relative to the first and second induction heating elements 108, 109 to transfer inductive energy from the first and second induction heating elements 108, 109 to the first and second susceptors 110 a, 110 b. When an alternating current is applied to either or both of the first and second induction elements 108, 109, the alternating current heats the corresponding first and / or second susceptor 110 a, 110 b by Joule heating and / or magnetic hysteresis heating. The first and / or second susceptors 110 a, 110 b are positioned to heat an aerosol-forming material provided as part of the aerosol product article 116, for example, by conduction, convection, and / or radiation heating, to generate an aerosol during use.

[0053] According to various embodiments, the first and / or second susceptors 110a, 110b may form part of the aerosol delivery device 100. Also contemplated are embodiments in which the first and / or second susceptors 110a, 110b and the aerosol-generating material may be configured to form an integrated unit or consumable that may be inserted into and / or removed from the aerosol delivery device 100, and the integrated unit or consumable may be disposable. In some examples, the first and second inductive elements 108, 109 may be removable from the aerosol delivery device 100, for example, for replacement. The aerosol delivery device 100 may be handheld. The aerosol delivery device 100 may be configured to heat the aerosol-generating material to generate an aerosol for inhalation by a user.

[0054] It should be noted that the term "aerosol-forming material" as used herein includes materials that provide volatile components upon heating. These volatile components are typically provided in the form of a vapor or aerosol. The aerosol-forming material may be a non-tobacco-containing material or a tobacco-containing material. For example, the aerosol-forming material may be or contain tobacco. The aerosol-forming material may include, for example, one or more of whole tobacco, tobacco derivatives, expanded tobacco, reconstituted tobacco, tobacco extract, homogenized tobacco, or tobacco substitutes. The aerosol-forming material may be in the form of shredded tobacco, cut rag tobacco, extruded tobacco, reconstituted tobacco, reconstituted material, liquid, gel, gelled sheet, powder, or aggregate. The aerosol-forming material may also include other non-tobacco products. These non-tobacco products may or may not contain nicotine, depending on the product. The aerosol-forming material may also include one or more humectants, such as glycerol or propylene glycol.

[0055] Aerosol delivery device 100 may include a housing (not shown) configured to house DC battery 104, electronic circuitry 106, and first and second inductive elements 108, 109, and optionally first and second susceptors 110 a, 110 b. The housing may include a mouthpiece to allow generated aerosol to exit aerosol delivery device 100 during use.

[0056] In use, a user may activate the electronic circuitry 106, for example, by activating a button or via a puff detector (not shown), to apply alternating current to the first and second inductive elements 108, 109, thereby inductively heating the first and second susceptors 110a, 110b, which in turn heats the aerosol-generating material and generates an aerosol. The aerosol may be generated and mixed with air drawn in through an air inlet (not shown) of the aerosol delivery device 100. The aerosol and air mixture may then be directed toward the mouthpiece, from which the aerosol exits the aerosol delivery device 100 and may be inhaled by the user.

[0057] The aerosol-delivery device 100, which includes the electronic circuitry 106 and further includes first and second inductor elements 108, 109 coupled to the first and second susceptors 110a, 110b, may be configured to heat the aerosol-generating material to a temperature range to volatilize at least one component of the aerosol-generating material without burning the aerosol-generating material. For example, according to various embodiments, the aerosol-generating material may be heated to a temperature in the range of 50-100°C, 100-150°C, 150-200°C, 200-250°C, 250-300°C, or greater than 300°C.

[0058] According to various embodiments, the DC power source 104 (which may include a battery pack) may be connected to a driver device 124 for supplying electrical energy to the first and second inductive elements 108, 109 (which may include two coils). The driver device 124 may be connected to a positive terminal 126 of the battery pack 104, which provides a relatively high potential, and a negative terminal 128 of the battery pack 104, which provides a relatively low, zero, or negative potential, or ground GND. Thus, a voltage is developed across the driver device 124.

[0059] The driver device 124 includes a first full H-bridge driver circuit 142, 144 coupled to two dual MOSFETs 130, 132 for supplying alternating current to the first inductive element 108. The two dual MOSFETs 130, 132 may each include an enhancement mode n-channel MOSFET.

[0060] The driver device 124 further includes a second full H-bridge driver circuit 146, 148 coupled to two additional dual MOSFETs 134, 136 for supplying AC current to the second inductive element 109. The two additional dual MOSFETs 134, 136 may each comprise an enhancement mode n-channel MOSFET. Thus, the entire driver device may include eight MOSFETs 130, 132, 134, 136, which may comprise enhancement mode n-channel MOSFETs.

[0061] 2, the electronic circuit 106 may include a first full H-bridge including a pair of MOSFETs 130 connected to a first terminal of the first inductive element 108 (which are driven by a first H-bridge driver circuit 142) and a pair of MOSFETs 132 connected to a second terminal of the first inductive element 108 (which are driven by a second H-bridge driver circuit 144). The first inductive element 108 may include a first inductive coil 120.

[0062] A second full H-bridge is provided, which includes two MOSFETs 134 connected to a first terminal of the second inductive element 109 (which are driven by a third H-bridge driver circuit 146) and two MOSFETs 136 connected to a second terminal of the second inductive element 109 (which are driven by a fourth H-bridge driver circuit 148). The second inductive element 109 may include a second inductive coil 122.

[0063] Each pair of MOSFETs 130, 132, 134, 136 may be connected to a high potential VBAT or VBAT POWER+ and a negative potential POWER- or GND (shown in FIG. 1 but omitted in FIG. 2) of the battery pack 104. Referring to FIG. 1, a resistor 140 (e.g., 2 mΩ) may be provided in the connection line between the battery pack 104 and the pair of MOSFETs 130, 132, 134, 136.

[0064] 1 may include a first H-bridge driver circuit 142, a second H-bridge driver circuit 144, a third H-bridge driver circuit 146, and a fourth H-bridge driver circuit 148. The driver circuits 142, 144, 146, 148 are configured to drive each of the pairs of switching elements or MOSFETs 130, 132, 134, 136, i.e., to control each pair of MOSFETs 130, 132, 134, 136 to either a conducting or non-conducting state in order to redirect current between the terminals of the inductive elements 108, 109.

[0065] As shown in detail in Figure 2, the four driver circuits 142, 144, 146, 148 may be provided with a bias or supply voltage of, for example, 5V. The required value may vary depending on the particular driver. This supply voltage may be derived from a high potential VBAT POWER+ (Figure 1) or VBAT (Figure 2) from the battery pack 104, or may be derived via a buck-boost regulator or DC-DC converter 150 or other suitable regulator.

[0066] Aerosol delivery device 100 may be operated in a first, normal or standard mode of operation, and a second, or boost mode of operation. When aerosol delivery device 100 is operated in the second, or boost mode of operation, it may be desirable to increase the temperature of one or both of susceptors 110a, 110b, for example, to increase the temperature profile. In the second, or boost mode of operation, a DC voltage of 5 V may be supplied to driver circuits 142, 144, 146, 148.

[0067] In a first mode of operation, drivers 142, 144, 146, 148 may be supplied with a low voltage, for example 3.3V. This supply voltage may be derived from a buck-boost regulator or 5V from a DC-DC converter 150 via a voltage regulator 152. Voltage regulator 152 may comprise a low dropout (LDO) regulator.

[0068] The driver device 124 is thus configured to supply AC current from input DC current from the battery pack 104 to the coils 120, 122 or their corresponding LC circuits for driving the first and second inductive elements 108, 109 or the coils 120, 122 in use.

[0069] 1 , a central controller 154, such as a microcontroller unit (MCU), may be provided. The central controller 154 acts as a controller for the driver circuits 142, 144, 146, and 148. That is, the central controller 154 may be configured to control the circuits 142, 144, 146, and 148, for example, by providing pulse width modulated (PWM) signals to the driver circuits 142, 144, 146, and 148, which in turn control the dual MOSFETs 130, 132, 134, and 136.

[0070] The central controller 154 may be configured to set the frequency at which the dual MOSFETs 130, 132, 134, 136 are switched between conductive and non-conductive states, such that the central controller 154 is effectively configured to set the frequency of the alternating current applied to the inductive elements 108, 109.

[0071] According to various embodiments, the central controller 154 may be configured to determine a resonant frequency f of the inductive elements 108, 109. Additionally, the central controller 154 may be configured to supply an alternating current to the inductive elements 108, 109 at a first frequency f, for example, within 10% of the resonant frequency f. The central controller 154 may also be configured to supply an alternating current to the inductive elements 108, 109 at a second frequency f, for example, at least 10% below the resonant frequency f or at least 10% above the resonant frequency f.

[0072] The central controller 154 may also control various other functions and elements of the electronic circuit 106. For example, the central controller 154 may control the buck-boost regulator or DC-DC converter 150 and the voltage regulator 152 to supply either 5V (boost mode) or 3.3V (normal mode) to the driver circuits 142, 144, 146, 148.

[0073] 1, electronic circuit 106 may include battery charging circuit 156, which is connected to battery pack 104 at positive terminal 126 and may also be connected to ground GND. Battery charging circuit 156 may be connected to an interface 158, such as a USB interface, via, for example, positive connection line 160 for a high potential and a corresponding negative connection line 161. This allows, for example, a power plug to be connected to aerosol delivery device 100 to charge or recharge battery pack 104.

[0074] A USB temperature sensor 162, such as a negative temperature coefficient (NTC) temperature sensor, may be located on interface 158 and connected to central controller 154. USB temperature sensor 162 monitors the temperature of interface 158 and allows for controlled charging of battery 104. For example, charging may be interrupted if the temperature of interface 158 is determined to be above a maximum desired temperature threshold.

[0075] A data connection line 164 (e.g., a universal synchronous / asynchronous receiver-transmitter (USART) or other type of connection) may be provided between interface 158 and central controller 154, allowing data exchange between central controller 154 and an external device connected to aerosol delivery device 100 via interface 158, e.g., for controlling charging. Both data transfer directions are indicated in FIG. 1 by two arrowed lines: one from central controller 154 to interface 158 and one from interface 158 to central controller 154.

[0076] A debug connection line 166 (e.g., a serial wire debug (SWD) or other type of connection line) may be provided between interface 158 and central controller 154. Debug connection line 166 allows debugging of central controller 154 via an external device connected to aerosol delivery device 100 via interface 158. Both data transfer directions are indicated by two arrowed lines: one from central controller 154 to interface 158 and one from interface 158 to central controller 154.

[0077] The battery charging circuit 156 may be configured to supply power to the central controller 154 via power line 168. For example, the central controller 154 may be supplied with a voltage of 2.5 V. Any suitable type of voltage regulator 170 may be used to generate the required supply voltage for the central controller 154.

[0078] According to various embodiments, a battery temperature sensor 172 (e.g., an NTC temperature sensor) may be provided in the battery pack 104 and connected to the central controller 154. The battery temperature sensor 172 allows the temperature of the battery pack 104 to be monitored and charging of the battery pack 104 to be controlled. For example, charging may be interrupted if the battery pack 104 is determined to be excessively hot. Furthermore, normal operation of the aerosol delivery device 100 may be controlled based on the temperature of the battery pack 104.

[0079] Temperature sensors 174 (e.g., NTC temperature sensors) may be provided proximate the first and second inductive elements 108, 109 or the corresponding coils 120, 122 and connected to the central controller 154. According to various embodiments, thermocouple temperature sensors 176 may also be provided. In particular, each coil 120, 122 may be monitored by a separate thermocouple 176, and one or both thermocouples 176 may be connected to the central controller 154. A reference voltage Ref may be supplied to a first comparator 178 coupled to the temperature sensor 174. Similarly, the reference voltage Ref may be supplied to a second comparator 180 coupled to the thermocouple 180. These comparators 178, 180 may be provided to achieve a measurable voltage, thereby enabling monitoring of the temperature of the coils 120, 122 or the corresponding inductive elements 108, 109 and controlling their operation. For example, the operating frequency of the alternating current applied to the inductive elements 108, 109 can be altered, varied, increased, or decreased in response to the measured temperature of the inductive elements 108, 109 or coils 120, 122. For example, as will be appreciated by those skilled in the art, the resonant frequency f of the coils 120, 122 or inductive elements 108, 109 can change with temperature. For example, as the temperature of the inductive elements 108, 109 increases over time, the resonant frequency f of the inductive elements 108, 109 or coils 120, 122 can decrease over time.

[0080] The central controller 154 may be configured to measure the current supplied to the inductive elements 108, 109 or the coils 120, 122 by dual MOSFETs (switches) 130, 132, 134, 136. For example, a current sensing unit I_SENSE may be provided in a line connected between the MOSFETs 130, 132, 134, 136 and / or the H-bridge driver circuits 142, 144, 146, 148 and the negative terminal 128 of the resistor 140. An analog-to-digital converter (ADC) 182 may be used to convert the measured current into a digital voltage level and provide it to the central controller 154.

[0081] Indicator lights 184 (e.g., LEDs) may be provided to indicate one of several operational states of aerosol delivery device 100. LEDs 184 may comprise RGB LEDs, i.e., LEDs capable of providing illumination across the entire visible light spectrum or only a portion thereof. For example, LEDs 184 may be illuminated to display red, green, blue, white, and a variety of different shades. Indicator lights 184 may be powered via voltage regulator 152 and may be controlled by central controller 154. Indicator lights 184 may be provided as part of a user interface located on an exterior portion of aerosol delivery device 100.

[0082] Button or key 186 may be provided, for example, on the exterior housing of aerosol delivery device 100. Button or key 186 may be used to change the operating mode of aerosol delivery device 100, to turn power on or off, etc. Button or key 186 may be connected to central controller 154, which may receive a signal provided by operating button or key 186 and may, for example, perform a required operational change.

[0083] A haptic motor 188 or any other haptic feedback element may be provided. The haptic motor 188 may be powered by the battery pack 104 and controlled by the central controller 154, thereby allowing a user of the aerosol delivery device 100 to receive haptic feedback during use.

[0084] The central control unit 154 or its driver controller portion may be configured to control, via the driver unit 124, the frequency of the alternating current supplied to the coils 120, 122 or the LC circuits comprising these coils, and thus control the frequency of the alternating current flowing through the inductive elements 108, 109 or the coils 120, 122. The inductive elements 108, 109 or the corresponding coils 120, 122 may be operated in various modes of operation in which only one or both of the inductive elements 108, 109 are energized at any particular time.

[0085] As discussed above, the LC circuit may exhibit resonance. The central controller 154 or its driver controller portion may control the frequency of the AC current (i.e., the drive frequency) flowing through the coils or LC circuit to be at or near the resonant frequency of one or both of the coils 120, 122 or the LC circuit. For example, the drive frequency may be in the MHz range, e.g., 0.5 to 1.5 MHz (e.g., 1 MHz). In other embodiments, the drive frequency may be in the 1 to 2 MHz range. It will be understood that other frequencies may be used depending on the particular coils or LC circuits (and / or their components) and / or susceptors 110a, 110b used. For example, it will be understood that the resonant frequency f0 of the LC circuit depends on the inductance L of the coils 120, 122 and the capacitance C of the circuit, and thus may depend on the inductive elements 108, 109, the capacitor, and the susceptors 110a, 110b.

[0086] In use, when the central control unit 154 or its driver controller portion is activated, for example by a user, the central control unit 154 or its driver controller portion may control the driver unit 124 to pass an alternating current through one or more of the coils 120, 122 or the LC circuit, and thus through the inductive elements 108, 109, thereby causing inductive heating of the susceptors 110a, 110b. As the susceptors 110a, 110b heat, they may heat the aerosol-generating material that forms part of the aerosol product article 116, so that an aerosol may be generated for inhalation by the user.

[0087] Referring to FIG. 2, a portion of the electronic circuit 106 of the aerosol delivery device 100 of FIG. 1 is shown in more detail. As described with reference to FIG. 1, the driver apparatus may include an H-bridge configuration with two full H-bridges, one for each of the coils 120 and 122. Each full H-bridge includes four switching elements, which may include multiple transistors or pairs of MOSFETs 130, 132, 134, and 136. The four pairs of MOSFETs 130, 132, 134, and 136 may be implemented as two dual MOSFETs per full H-bridge. The dual MOSFETs 130, 132, 134, and 136 are shown in FIG. 2, with two pairs of MOSFETs 130, 132, 134, and 136 provided for each of the coils 120 and 122. Each pair of MOSFETs 130, 132, 134, 136 is connected to a high potential VBAT POWER+ or VBAT of the battery pack and a negative potential POWER- or GND (not shown here).

[0088] Thus, two half H-bridge drivers 142, 144; 146, 148 are provided for each full H-bridge or pair of dual MOSFETs 130, 132, 134, 136. The H-bridge drivers 142, 144; 146, 148 may be provided with a bias or supply voltage of, for example, 5V (e.g., in boost mode of operation) and a bias or supply voltage of, for example, 3.3V (e.g., in standard mode of operation), as described above.

[0089] 1, a central control unit such as the MCU 154 may function as a controller for the drivers 142, 144, 146, and 148; i.e., the MCU 154 may be configured to control the drivers 142, 144, 146, and 148 and provide clock signals to the drivers 142, 144, 146, and 148. For example, a first clock signal CLK1 may be provided to the first driver 142, and a second clock signal CLK2 may be provided to the second driver 144, where these drivers 142, 144 are configured to drive the pair of MOSFETs 130, 132 connected to the first coil 120. A third clock signal CLK3 may be provided to the third driver 146, and a fourth clock signal CLK4 may be provided to the fourth driver 148, where these drivers 146, 148 are configured to drive the pair of MOSFETs 134, 136 connected to the second coil 122.

[0090] A method of operating an aerosol generator of an aerosol delivery device 100 according to various embodiments will now be described in more detail with reference to Figure 3. The aerosol delivery device 100 comprises a control system configured to, in a first step 401, determine a resonant frequency f0 of one or more inductive elements 108, 109 forming part of the aerosol delivery device 100.

[0091] In a second step 402, the control system is configured to supply an alternating current to one or more inductive elements 108, 109 over a plurality of time cycles. Each time cycle may have, for example, a duration (e.g., one second). Each time cycle may further be considered to have a plurality of first periods T1 and a plurality of second periods T2 interleaved therebetween. In a third step 403, the control system is configured to supply an alternating current at a first frequency f1 to one or more inductive elements 108, 109 during each first period T1. The first frequency f1 is configured to be within 10% of the resonant frequency f0, i.e., 0.9≦f1 / f0≦1.1.

[0092] The control system may then, in a fourth step 404, supply an alternating current at a second, different frequency f2 to one or more inductive elements 108, 109 during each second time period T2. The second frequency f2 is different from the first frequency f1, and in particular is sufficiently different from the resonant frequency f0. For example, the second frequency f2 may be less than 90% of the resonant frequency f0, or the second frequency may be greater than 110% of the resonant frequency f0. In other words, according to various embodiments, either f2 / f0≦0.9 or f2 / f0≧1.1. It will be understood that the second frequency may be greater than zero, i.e., f2>0.

[0093] According to various embodiments, f0 may be in the ranges of (i) <0.5 MHz, (ii) 0.5-1.0 MHz, (iii) 1.0-1.5 MHz, (iv) 1.5-2.0 MHz, (v) 2.0-2.5 MHz, (vi) 2.5-3.0 MHz, (vii) 3.0-3.5 MHz, (viii) 3.5-4.0 MHz, or (ix) >4.0 MHz. For example, embodiments are contemplated in which f1 is in the ranges of (i) <0.5 MHz, (ii) 0.5-1.0 MHz, (iii) 1.0-1.5 MHz, (iv) 1.5-2.0 MHz, (v) 2.0-2.5 MHz, (vi) 2.5-3.0 MHz, (vii) 3.0-3.5 MHz, (viii) 3.5-4.0 MHz, or (ix) >4.0 MHz. Optionally, f2 may be in the range of (i) <0.5 MHz, (ii) 0.5-1.0 MHz, (iii) 1.0-1.5 MHz, (iv) 1.5-2.0 MHz, (v) 2.0-2.5 MHz, (vi) 2.5-3.0 MHz, (vii) 3.0-3.5 MHz, (viii) 3.5-4.0 MHz, or (ix) >4.0 MHz. One or more inductive elements 108, 109 may comprise one or more inductive coils 120, 122.

[0094] 1 and 2, according to various embodiments, an aerosol generator of an aerosol delivery device 100 is provided and may be configured to apply an alternating current to one or more inductive elements 108, 109 (e.g., coils or inductive coils 110a, 110b). A resonant frequency f0 of the inductive elements 108, 109 may be determined by an electronic circuit 106.

[0095] The aerosol generator may be energized for an extended period of time, even several minutes. For example, an aerosol product item 116 may be inserted into the aerosol delivery device 100 and a use session lasting 3-4 minutes may be initiated. Thus, a use session may last for several minutes, which may be subdivided into multiple time cycles, where a single cycle may last 1 second.

[0096] It will be appreciated that the duration of a single time cycle may be set to a convenient time depending on the clock signal provided to the electronic circuit 106. A time cycle may be further subdivided into multiple first periods T1 and multiple second periods T2 interleaved therebetween. For example, a time cycle lasting one second may be subdivided into multiple first periods T1 of 10 milliseconds, with multiple second periods T2 interleaved therebetween, where the second periods T2 may also have a length of 10 milliseconds. It will, of course, be appreciated that the first period T1 may be longer or shorter than 10 milliseconds. Similarly, the second period T2 may be longer or shorter than 10 milliseconds.

[0097] According to various embodiments, the aerosol generator may be configured to provide alternating current to the inductive elements 108, 109 during a first time period T1. During this time period, the inductive elements 108, 109 can be considered to be energized, or in an on state. During a subsequent second time period T2, the inductive elements 108, 109 can be considered to be de-energized, or in an off state.

[0098] During the first time period T1, the aerosol generator is configured to supply an alternating current to the inductive elements 108, 109 at a frequency f1 close to the determined resonant frequency f0 of the inductive elements 108, 109. In particular, the alternating current is supplied at a frequency f1 within ±10% of the determined resonant frequency f0 of the inductive elements 108, 109. As a result of being driven at a frequency f1 close to the resonant frequency f0 of the inductive elements 108, 109, an efficient process is established. As a result, an induced current is suitably generated in the susceptors 110a, 110b located in proximity to the coils or induction coils 120, 122 forming part of the inductive elements 108, 109, causing the susceptors 110a, 110b to heat up as a result.

[0099] In contrast, during the second time period T2, the aerosol generator is configured to supply an alternating current to the inductive elements 108, 109 at a frequency f2 sufficiently lower or higher than the determined resonant frequency f0 of the inductive elements 108, 109. In particular, the alternating current is supplied at a frequency f2 that is at least 10% lower or at least 10% higher than the determined resonant frequency f0 of the inductive elements 108, 109. As a result of being driven at a frequency that is not close to the resonant frequency f0 of the inductive elements 108, 109, the driving frequency is very inefficient, and the inductive elements 108, 109 can be considered to be essentially in an off state. As a result, substantially no induced current is generated in the susceptors 110a, 110b disposed adjacent to the coils or induction coils 120, 122 that form part of the inductive elements 108, 109, and the susceptors 110a, 110b are not heated by the alternating current applied to the inductive elements 108, 109.

[0100] It will be appreciated that during the one or more second time periods T2, the AC current is not turned off, i.e., the frequency f2 is not reduced to zero, but the frequency f2 is sufficiently far away from the resonant frequency f0 of the inductive elements 108, 109 so that substantially no current is induced in the susceptors 110a, 110b located in close proximity to the inductive elements 108, 109.

[0101] An advantage of the approach according to various embodiments, in which an AC current is substantially applied to the inductive elements 108, 109, and the frequency of the applied AC current repeatedly switches between a first frequency f1 close to the resonant frequency f0 and a second frequency f2 far from the resonant frequency f0, is that it is simpler to implement than an approach in which the AC current is turned off during the second time period T2. Furthermore, the tolerances of the electronic components in the electronic circuit 106 can be relaxed, and the process places less demands on the individual components in the electronic circuit 106. As a result, the lifetime of the electronic circuit 106 can be extended due to fewer failures of individual electronic components, and the reliability of the electronic circuit 106 can also be improved. As an additional advantage, even though the AC circuit is not turned off during the second time period T2, the entire electronic circuit 106 can be designed to utilize less power because the electronic circuit 106 does not need to include components that require fast turning off of the AC current. According to various embodiments, instead of fast turning off, the AC current is repeatedly switched every few milliseconds between a frequency f1 close to the resonant frequency f0 and a frequency f2 far from the resonant frequency f0.

[0102] It will be appreciated that an aerosol generator is thus provided in which the frequency at which induction coils 108, 109 are driven by an alternating current is repeatedly switched between a first frequency f1 close to the resonant frequency f0 and a second frequency f2 detuned from the resonant frequency f0. By switching the frequency to a frequency f2 detuned from the resonant frequency f0 instead of turning off the alternating current, it is possible to provide a more durable, simpler, and more power-efficient electronic circuit 106.

[0103] According to various embodiments, the electronic circuit 106 according to various embodiments and its approach of repeatedly switching between a first frequency f1 close to the resonant frequency f0 and a second frequency f2 far from the resonant frequency f0, rather than repeatedly turning the AC current on and off, places less demand on the DC battery 104. As will be appreciated by those skilled in the art, the DC battery 104 shown in FIG. 1 provides a DC voltage to H-bridge driver circuits 142, 144, 146, and 148 connected to pairs of MOSFETs 130, 132, 134, and 136, respectively. The H-bridge driver circuits 142, 144, 146, and 148 continuously change the direction of the current supplied to the terminals of the inductive elements 106, 108 (e.g., coils or induction coils 120, 122), thereby generating an AC current from the DC battery 104.

[0104] It will be appreciated that the approaches according to various embodiments place less demand on the DC battery 104, thus extending the life of the DC battery 104.

[0105] 4 is a diagram illustrating two components of an electronic circuit 501 for an aerosol generator of aerosol delivery device 100. According to various embodiments, a circuit element 502 is provided that is configured to determine a resonant frequency f of one or more inductive elements 108, 109. The electronic circuit also includes a driver unit 503.

[0106] According to various embodiments, the driver device 503 may be configured to supply an alternating current to the one or more inductive elements 108, 109 over a plurality of time cycles, each time cycle having one or more first periods T1 and one or more second periods T2. According to various embodiments, the driver device 503 is initially configured, in use, to supply an alternating current to the one or more inductive elements 108, 109 for the one or more first periods T1 at a first frequency f1, where 0.9≦f1 / f0≦1.1.

[0107] The driver device 503 may also be configured, in use, to supply an alternating current to the one or more inductive elements 108, 109 for one or more second time periods T2 at a second, different frequency f2, where (a) f2 / f0≦0.9, or (b) f2 / f0≧1.1 and f2>0. According to various embodiments, f0 may be in the ranges: (i) <0.5 MHz, (ii) 0.5-1.0 MHz, (iii) 1.0-1.5 MHz, (iv) 1.5-2.0 MHz, (v) 2.0-2.5 MHz, (vi) 2.5-3.0 MHz, (vii) 3.0-3.5 MHz, (viii) 3.5-4.0 MHz, or (ix) >4.0 MHz. Optionally, f1 may be in the range of (i) <0.5 MHz, (ii) 0.5-1.0 MHz, (iii) 1.0-1.5 MHz, (iv) 1.5-2.0 MHz, (v) 2.0-2.5 MHz, (vi) 2.5-3.0 MHz, (vii) 3.0-3.5 MHz, (viii) 3.5-4.0 MHz, or (ix) >4.0 MHz. Optionally, f2 may be in the range of (i) <0.5 MHz, (ii) 0.5-1.0 MHz, (iii) 1.0-1.5 MHz, (iv) 1.5-2.0 MHz, (v) 2.0-2.5 MHz, (vi) 2.5-3.0 MHz, (vii) 3.0-3.5 MHz, (viii) 3.5-4.0 MHz, or (ix) >4.0 MHz.

[0108] To address various problems and advance the art, this disclosure presents various embodiments by way of example. The advantages and features of this disclosure are merely those of representative embodiments and are not exhaustive and / or exclusive. They are presented solely for the purpose of understanding and teaching the claimed invention. The advantages, embodiments, examples, functions, features, structures, and / or other aspects of this disclosure should not be construed as limiting the disclosure as defined by the claims or to the equivalents of the claims; other embodiments may be utilized, and changes may be made without departing from the spirit of the claims. Various embodiments may suitably comprise, have, or essentially comprise various combinations of elements, components, features, portions, steps, means, etc., not specifically described herein, and thus it is understood that features of the dependent claims may be combined with features of the independent claims in combinations other than those explicitly recited in the claims. This disclosure may include other inventions not currently claimed but that may be claimed in the future.

Claims

1. 1. A method of operating an aerosol generator of an aerosol delivery device, comprising: determining a resonant frequency f0 of one or more inductive elements; supplying an alternating current to the one or more inductive elements for a plurality of time cycles, each time cycle comprising one or more first time periods T1 and one or more second time periods T2; supplying the alternating current to the one or more inductive elements at a first frequency f1 during the one or more first time periods T1, where 0.9≦f1 / f0≦1.1; supplying the AC current to the one or more inductive elements at a different second frequency f2 during the one or more second time periods T2, wherein (a) f2 / f0≦0.9 or (b) f2 / f0≧1.1 and f2>0; A method for providing

2. 2. The method of claim 1, wherein f is in the range of: (i) < 0.5 MHz, (ii) 0.5 to 1.0 MHz, (iii) 1.0 to 1.5 MHz, (iv) 1.5 to 2.0 MHz, (v) 2.0 to 2.5 MHz, (vi) 2.5 to 3.0 MHz, (vii) 3.0 to 3.5 MHz, (viii) 3.5 to 4.0 MHz, or (ix) > 4.0 MHz.

3. 3. The method of claim 1, wherein f1 is within the range of: (i) < 0.5 MHz, (ii) 0.5 to 1.0 MHz, (iii) 1.0 to 1.5 MHz, (iv) 1.5 to 2.0 MHz, (v) 2.0 to 2.5 MHz, (vi) 2.5 to 3.0 MHz, (vii) 3.0 to 3.5 MHz, (viii) 3.5 to 4.0 MHz, or (ix) > 4.0 MHz.

4. 4. The method of claim 1, 2, or 3, wherein f2 is within the range of: (i) < 0.5 MHz, (ii) 0.5 to 1.0 MHz, (iii) 1.0 to 1.5 MHz, (iv) 1.5 to 2.0 MHz, (v) 2.0 to 2.5 MHz, (vi) 2.5 to 3.0 MHz, (vii) 3.0 to 3.5 MHz, (viii) 3.5 to 4.0 MHz, or (ix) > 4.0 MHz.

5. The method of any one of claims 1 to 4, wherein the one or more inductive elements comprise one or more inductive coils.

6. 1. An electronic circuit for an aerosol generator of an aerosol delivery device, comprising: a circuit element configured to determine a resonant frequency f of the one or more inductive elements; a driver device for supplying an alternating current to the one or more inductive elements over a plurality of time cycles, each time cycle comprising one or more first periods T1 and one or more second periods T2; wherein the driver device (i) in use, supplying said alternating current to said one or more inductive elements at a first frequency f1 during said one or more first time periods T1, wherein 0.9≦f1 / f0≦1.1; (ii) in use, supplying said alternating current to said one or more inductive elements at a different second frequency f2 during said one or more second time periods T2, wherein (a) f2 / f0≦0.9 or (b) f2 / f0≧1.1 and f2>0; An electronic circuit configured as follows.

7. 7. The electronic circuit of claim 6, wherein f0 is within the range of: (i) < 0.5 MHz, (ii) 0.5 to 1.0 MHz, (iii) 1.0 to 1.5 MHz, (iv) 1.5 to 2.0 MHz, (v) 2.0 to 2.5 MHz, (vi) 2.5 to 3.0 MHz, (vii) 3.0 to 3.5 MHz, (viii) 3.5 to 4.0 MHz, or (ix) > 4.0 MHz.

8. 8. The electronic circuit according to claim 6, wherein f1 is within the range of (i) < 0.5 MHz, (ii) 0.5 to 1.0 MHz, (iii) 1.0 to 1.5 MHz, (iv) 1.5 to 2.0 MHz, (v) 2.0 to 2.5 MHz, (vi) 2.5 to 3.0 MHz, (vii) 3.0 to 3.5 MHz, (viii) 3.5 to 4.0 MHz, or (ix) > 4.0 MHz.

9. 9. The electronic circuit of claim 6, 7, or 8, wherein f2 is within the range of: (i) < 0.5 MHz, (ii) 0.5 to 1.0 MHz, (iii) 1.0 to 1.5 MHz, (iv) 1.5 to 2.0 MHz, (v) 2.0 to 2.5 MHz, (vi) 2.5 to 3.0 MHz, (vii) 3.0 to 3.5 MHz, (viii) 3.5 to 4.0 MHz, or (ix) > 4.0 MHz.

10. The electronic circuit of any one of claims 6 to 9, wherein the one or more inductive elements comprise one or more inductive coils.

11. An aerosol delivery device comprising the electronic circuit of any one of claims 6 to 10.

12. 12. The aerosol delivery device of claim 11, further comprising an aerosol generator.

13. The aerosol delivery device of claim 12 , wherein the aerosol generator comprises one or more directing elements.

14. 14. The aerosol delivery device of claim 13, wherein the one or more inductive elements comprise one or more inductive coils.

15. An aerosol delivery device according to any one of claims 11 to 14; an aerosol-producing article comprising an aerosol-forming material; An aerosol generating system comprising:

16. 1. A method for generating an aerosol, comprising: Providing an aerosol delivery device according to any one of claims 11 to 14; inserting an aerosol product article comprising an aerosol-forming material into the aerosol delivery device; energizing the aerosol delivery device to generate an aerosol from the aerosol-forming material; A method for providing

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