EP4611480A1

EP4611480A1 - Aerosol provision device

Info

Publication number: EP4611480A1
Application number: EP24160868.6A
Authority: EP
Inventors: Damyn Musgrave; Neil MCCARAGHER; Karl JESSEL
Original assignee: Nicoventures Trading Ltd
Current assignee: Nicoventures Trading Ltd
Priority date: 2024-03-01
Filing date: 2024-03-01
Publication date: 2025-09-03
Also published as: WO2025180898A1

Abstract

An aerosol provision device and method of operating such a device. The device comprises a heating arrangement configured to heat an aerosol generating material, comprising a heating element comprising a semiconductor material, and first and second electrical connectors connecting the heating element to a power supply, for supplying power to and causing heating of the heating element. During heating, a temperature of the heating element is determined based on a voltage drop measured between the first electrical connector and the heating element.

Description

Technical Field

The present disclosure relates to an aerosol provision device, an aerosol provision system, and a method of controlling an aerosol provision device.

Background

Smoking articles such as cigarettes, cigars and the like burn tobacco during use to create tobacco smoke. Attempts have been made to provide alternatives to these articles by creating products that release compounds without combusting. Examples of such products are so-called "heat not burn" products or tobacco heating devices or products, which release compounds by heating, but not burning, material. The material may be, for example, tobacco or other non-tobacco products, which may or may not contain nicotine.

Summary

From a first aspect, there is provided an aerosol provision device comprising a heating arrangement configured to heat an aerosol generating material, comprising:

a heating element comprising a semiconductor material;
a first electrical connector and a second electrical connector connecting the heating element to a power supply, for supplying power to and causing heating of the heating element; and
a temperature monitoring circuit configured to determine a temperature of the heating element based on a voltage drop measured between the first electrical connector and the heating element.

In embodiments, the first electrical connector comprises a metal which contacts the semiconductor material of the heating element to form a Schottky barrier.
In embodiments, the heating element substantially consists of semiconductor material (which may or may not be doped).
In embodiments, the semiconductor material comprises at least one of: silicon carbide or gallium nitride.
In embodiments, the voltage drop is measured between the first electrical connector, and a third electrical connector that contacts the heating element.
In embodiments, the aerosol provision device is configured so that substantially no power is provided to the heating element via the third electrical connector.
In embodiments, the third electrical connector contacts the heating element closer to the first electrical connector than to the second electrical connector.
In embodiments, the temperature monitoring circuit is configured to determine the temperature of a first region of the heating element adjacent the first electrical connector.
In embodiments, the aerosol provision device has a mouth end and a distal end, and the first electrical connector contacts the heating element closer towards the mouth end of the aerosol provision device than the second electrical connector.
In embodiments, the temperature monitoring circuit is configured to determine the temperature of the heating element by comparing the measured voltage drop against information representative of a relationship between voltage drop and temperature for the heating element.
In embodiments, the temperature monitoring circuit is configured to determine the temperature of the heating element based on the measured voltage drop, and based on one or more of: the amount of power supplied by the power supply; and the direction of current flow through the heating element.
In embodiments, the aerosol provision device is configured to:

during a heating cycle, provide a first amount of power from the power supply to the heating element, and then provide a second different amount of power to the heating element; and/or
during a heating cycle, cause current to flow in the heating element in a first direction, and then cause current to flow in a second different direction.

In embodiments, the aerosol provision device is configured to:

during a heating cycle, alternate between two or more different amounts of power supplied from the power source to the heating element; and/or
during a heating cycle, alternate between causing current to flow through the heating element in a first direction and a second opposite direction.

In embodiments, the temperature monitoring circuit is configured to determine the temperature of the heating element based on a voltage drop measured between the second electrical connector and the heating element (when power is supplied).
In embodiments, the aerosol provision device comprises an article receiving portion for receiving, in use, an article comprising an aerosol generating material, wherein the heating element is configured to heat an article received within the article receiving portion.
In embodiments, the heating element is hollow and is configured to receive an article.
From another aspect, there is provided an aerosol provision system comprising the aerosol provision device disclosed herein (and having any of the features described herein, for example but not limited to the above embodiments), and an article comprising an aerosol generating medium.
From another aspect, there is provided a method of controlling a heating arrangement of an aerosol provision device,
the heating arrangement comprising a heating element comprising a semiconductor material, and a power supply electrically connected to the heating element by a first electrical connector and a second electrical connector, the method comprising:
when providing power to the first electrical connector and the second electrical connector of the electrical connectors to cause heating of the heating element, measuring a voltage drop between the first electrical connector and the heating element, and determining a temperature of the heating element based on the measured voltage drop.
The aerosol provision device controlled by the method may have any of the features described herein, for example but not limited to the above embodiments.
In embodiments, the method comprises determining the temperature of the heating element based on the voltage drop measured when a first amount of power is supplied to the heating element, and based on the voltage drop measured when a second different amount of power is supplied to the heating element.
In embodiments, the determination of the temperature of the heating element is based on (accounts for) the amount of power supplied to the heating element.
In embodiments, the method comprises determining the temperature of the heating element based on the voltage drop measured when current is caused to flow in the heating element in a first direction, and based on the voltage drop measured when current is caused to flow in the heating element in a second opposite direction.
In embodiments, the determination of the temperature of the heating is based on (accounts for) the direction in which current caused to flow in the heating element.
In embodiments, the method comprises altering (varying) the amount power supplied to the heating element and/or the direction in which current is caused to flow in the heating element; and
updating the determination of temperature based on the altered amount of power and/or based on the altered direction of current flow.
In embodiments, the method comprises determining the temperature of the heating element based on the voltage drop measured between the first electrical connector and the heating element, and based on a voltage drop measured between the second electrical connector and the heating element.
Whilst various aspects and embodiments disclosed herein use the voltage drop measured between the first electrical connector and the heating element to determine a temperature of the heating element, the voltage drop could alternatively or additionally be used for other purposes if desired.
For example, and in embodiments, the voltage drop between the first electrical connector and the heating element may be used (by a processing circuit) to identify a condition of (associated with) the aerosol provision device. The condition may be, for example a fault, for example being any one or more of: a faulty connection between the electrical connector and the heating element; damage to the device; a fault associated with insertion of an article into the device. The condition (e.g. fault) identified may be indicated to a user, for example, via a user interface of the aerosol provision device (e.g. screen, LED, or other haptic feedback such as vibration), or via a user interface of another electronic device (e.g. portable electronic device, e.g. mobile phone, tablet or wearable device).
Thus, in another aspect, there is provided an aerosol provision device comprising a heating arrangement configured to heat an aerosol generating material, comprising:

a heating element comprising a semiconductor material;
a first electrical connector and a second electrical connector connecting the heating element to a power supply, for supplying power to and causing heating of the heating element; and
a voltage drop measuring circuit configured to measure a voltage drop between the first electrical connector and the heating element;
optionally comprising a processing circuit configured to determine a condition of the aerosol provision device based on the measured voltage drop.

In embodiments, the voltage drop measuring circuit is (also) configured to measure a voltage drop between the second electrical connector and the heating element. In such embodiments, the processing circuit may be configured to determine the condition of the aerosol provision device based (additionally or alternatively) on the measured voltage drop between the second electrical connector and the heating element.
The aerosol provision device may comprise any of the features described herein (such as, for example, in any of the embodiments above, and the description below).
In another aspect, there is provided a method of controlling a heating arrangement of an aerosol provision device,
the heating arrangement comprising a heating element comprising a semiconductor material, and a power supply electrically connected to the heating element by a first electrical connector and a second electrical connector, the method comprising:
when providing power to the first electrical connector and the second electrical connector of the electrical connectors to cause heating of the heating element, measuring a voltage drop between the first electrical connector and the heating element, and optionally determining a condition of the aerosol provision device based on the measured voltage drop.
The aerosol provision device and method of control may comprise any of the features described herein (such as, for example, in any of the embodiments above, and the description below).
In embodiments, the method comprises measuring the voltage drop when a first amount of power is supplied to the heating element, and when a second different amount of power is supplied to the heating element.
In embodiments, the condition is determined based on (accounting for) the amount of power supplied to the heating element.
In embodiments, the method comprises determining the condition based on the voltage drop measured when a first amount of power is supplied to the heating element, and based on the voltage drop measured when a second different amount of power is supplied to the heating element.
In embodiments, the method comprises measuring the voltage drop when current is caused to flow in the heating element in a first direction, and when current is caused to flow in the heating element in a second opposite direction.
In embodiments, the condition is determined based on (accounting) for the direction in which current caused to flow in the heating element.
In embodiments, the method comprises determining the condition based on the voltage drop measured when current is caused to flow in the heating element in a first direction, and based on the voltage drop measured when current is caused to flow in the heating element in a second opposite direction.
In embodiments, the method comprises measuring the voltage drop between the first electrical connector and the heating element, and measuring the voltage drop between the second electrical connector and the heating element.
In embodiments, the method comprises determining the condition based on the voltage drop measured between the first electrical connector and the heating element, and based on a voltage drop measured between the second electrical connector and the heating element.

Brief Description of the Drawings

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

Fig. 1 shows an aerosol provision system according to an embodiment of the present disclosure;
Figs. 2A and 2B show heating arrangements according to embodiments of the present disclosure;
Fig. 3A shows a test heating arrangement, with Figs. 3B-3E showing data for measured voltage drops;
Fig. 4 illustrates schematically changes in power supplied during a heating cycle in embodiments of the present disclosure;
Fig. 5 is a flowchart showing steps for determining the temperature of a heating element in embodiments of the present disclosure;
Figs. 6A to 6C show further heating arrangements according to embodiments of the present disclosure.

Detailed description

Aspects and features of certain examples and embodiments are discussed or described herein. Some aspects and features of certain examples and embodiments may be implemented conventionally and these are not discussed or described in detail in the interests of brevity. It will thus be appreciated that aspects and features of apparatus and methods discussed herein which are not described in detail may be implemented in accordance with conventional techniques for implementing such aspects and features.
The present disclosure relates to an aerosol provision device configured to heat an aerosol generating material, an aerosol provision system (comprising the aerosol provision device, and an article comprising an aerosol generating medium), and a method of controlling an aerosol provision device.
In some embodiments, the aerosol provision system is an electronic cigarette, also known as a vaping device or electronic nicotine delivery system (END), although it is noted that the presence of nicotine in the aerosol generating material is not a requirement.
In embodiments, the aerosol provision device is configured for heating, but not burning or combusting, an aerosol-generating material. Thus, the aerosol provision system is in embodiments a "non-combustible" aerosol provision system (sometimes referred to as "an aerosol provision system" or a "heat-not-burn" system). In embodiments, the aerosol provision device is a tobacco heating device. The aerosol provision device could alternatively or additionally heat any other suitable and desired aerosol-generating material that is capable of generating aerosol.
In embodiments, the aerosol provision device comprises a power source (e.g. an energy storage device) and a controller. The power source may be configured to provide power to the heating element of the aerosol provision device. The controller may control the provision of power to the heating element, for example, as will be described in more detail below.
The aerosol provision device may comprise any other suitable and desired features that an aerosol provision device typically comprises, such as any one or more of: a housing, a mouthpiece, and a filter.
The aerosol-generating material is a material that is capable of generating aerosol, for example when heated, irradiated or energized in any other way. Aerosol-generating material may, for example, be in the form of a solid, liquid or semi-solid (such as a gel) (or combinations thereof) which may or may not contain an active substance and/or flavourants.
The aerosol-generating material (which may be heated by aerosol provision device to generating aerosol) may include any plant based material, such as tobacco-containing material and may, for example, include one or more of tobacco, tobacco derivatives, expanded tobacco, reconstituted tobacco or tobacco substitutes.
The aerosol-generating material alternatively or additionally may include other, non-tobacco, products, which, depending on the product, may or may not contain nicotine (and so, for example, could be substantially free from botanical material, for example being substantially tobacco free).
The aerosol-generating material may for example be in the form of a solid, a liquid, a gel, a wax or the like. The aerosol-generating material may for example also be a combination or a blend of materials. The aerosol-generating material may also be known as "smokable material".
The aerosol-generating material may comprise a binder and an aerosol former. Optionally, an active and/or filler may also be present. Optionally, a solvent, such as water, is also present and one or more other components of the aerosol-generating material may or may not be soluble in the solvent.
The aerosol-generating material may comprise or be an "amorphous solid". The amorphous solid may be a "monolithic solid". In some embodiments, the amorphous solid may be a dried gel. The amorphous solid is a solid material that may retain some fluid, such as liquid, within it. In some embodiments, the aerosol-generating material may, for example, comprise from about 50wt%, 60wt% or 70wt% of amorphous solid, to about 90wt%, 95wt% or 100wt% of amorphous solid.
The aerosol-generating material may comprise an aerosol-generating film. The aerosol-generating film may comprise or be a sheet, which may optionally be shredded to form a shredded sheet. The aerosol-generating sheet or shredded sheet may be substantially tobacco free.
In embodiments, the aerosol generating device is configured to receive a consumable article (sometimes referred to as an "article") comprising the aerosol generating material for heating. The aerosol provision device may accordingly be configured receive an article within an article receiving portion, and to power the heating element to heat an article received within an article receiving portion.
An "article" in this context is a component that includes or contains in use the aerosol generating material, which is heated to volatilise the aerosol generating material, and optionally other components in use. A user may insert the article into the aerosol generating device before it is heated to produce an aerosol, which the user subsequently inhales. The article may be, for example, of a predetermined or specific size that is configured to be placed within a heating chamber of the device which is sized to receive the article.
In embodiments, an article for use with the aerosol provision device may comprise an aerosol-generating material, and any one or more of: an aerosol-generating material storage area, an aerosol-generating material transfer component, an aerosol generator, an aerosol generation area, a housing, a wrapper, a filter, a mouthpiece, and/or an aerosol-modifying agent.
Fig. 1 shows a schematic view of an aerosol provision system 102 according to an embodiment of the present disclosure. The aerosol provision system 102 comprises an aerosol provision device 100, in accordance with an embodiment of the invention, together with an article 120 comprising an aerosol generating material.
The aerosol provision device 100 shown in Fig. 1 comprises an article receiving portion 110 which is configured to receive the article 120 when the aerosol provision device 100 is in use. The article receiving portion 110 may be in the form of a cavity or chamber within the aerosol provision device 100 for receiving the article 120 therein. It will be appreciated, however, that the article receiving portion 110 may take any suitable form that is capable of receiving the article 110.
As depicted, the article 120 may be separate to (e.g. separable or removable from) the aerosol provision device 100, and may comprise one or more electrical connectors which correspond with one or more electrical connectors of the article receiving portion 110, enabling a circuit of the aerosol provision device 100 to detect when the article 120 is inserted into the article receiving portion 110. The article 120 comprises an aerosol generating material, which when heated will produce an aerosol which can be inhaled by a user of the aerosol provision system 102. As set out above, the aerosol generating material may comprise any suitable material.
The aerosol provision device 100 includes a heating arrangement 125, which is configured to heat the article 120 when received within the article receiving portion 110. The heating arrangement comprises a heating element 130 configured to heat up when power is supplied thereto by way of a first electrical connector 131 and a second electrical connector 132 connected to a power supply 150. Thus, as used herein, the term "heating element" may be understood as corresponding to that element which generates heat when power is supplied to it, for example to heat an article inserted into the aerosol generating device.
In embodiments, the heating element 130 defines at least part of the article receiving portion 110. In this way, when an article 120 is inserted into the article receiving portion 110 heat is transferred from the heating element 130 to the article 120. In embodiments, the heating element 130 is configured to directly contact the article when inserted.
The heating element 130 may be, and in embodiments is, hollow and adapted to receive an article 120 therein. Fig. 2A shows an example hollow heating element 130.
The hollow shape of the heating element 130 could be constant in cross sectional area along its longitudinal axis L, for example as shown in Fig. 2A. Alternatively, the cross-sectional area could vary along the longitudinal axis L in either a continuous or discontinuous manner, for example tapering towards a proximal (mouth) end 135 of the heating element 130 (so that the cross-sectional area narrows as an article is inserted), for example as shown in Fig. 6A.
In the embodiment shown in Fig. 2A, the hollow heating element 130 is tubular (cylindrical). However, the configuration of a hollow heating element 130 naturally extends to other shaped configurations. For example, the heating element 130 may be arranged as a hollow prism, such as a quadrilateral or hexagonal prism (so that the cross section of the tubular heating arrangement a polygon, such as a quadrilateral or a hexagon).
The shape of the heating element may accordingly be any suitable and desired shape for receiving an article.
The heating element could be formed of a single (continuous) piece, for example as shown in Fig. 2A. The heating element could alternatively be formed of (comprise) plural pieces, which could for example be adjacent and contact one another, or could be separated relative to each another. Each piece could be heated by applying current to a respective first electrical connector and second electrical connector for that piece. For example, the heating element could comprise one or more hollow pieces positioned along the longitudinal direction L of the heating element, for example as shown in Fig. 2C.
Whilst various of the figures show a heating element which is hollow, into which an article can be inserted, the heating element could alternatively comprise one or more pieces which are not hollow, e.g. which are planar. For example Fig. 2B shows a heating element formed of a planar piece. Each piece could be placed along (e.g. arranged so as to define) a side of the article receiving portion 110, or multiple sides of the article receiving portion 110.
In embodiments, the heating element 130 (whether provided as a single piece, or plural pieces) may have substantially the same length as the length L1 of the article receiving portion 110, for example as shown in Fig. 1.
Whilst various possible formats for the heating element are discussed above and shown in the figures, any suitable and desired size and shape of heating element could be used, for transferring heat to an aerosol generating material (which aerosol generating material could be provided within an article, or in any other suitable and desired way). As will be appreciated, the skilled person is capable of implementing a variety of configurations for the heating element consistent with the present disclosure.
The aerosol provision device 100 comprises a power supply (power source) 150. The heating element 130 is connected to the power supply 150 by (at least) a first electrical connector 131 and a second electrical connector 132.
The power source 150 may comprise, for example, at least one of: a battery (which may be single use or be rechargeable), a rechargeable capacitor (e.g. a rechargeable super capacitor), a rechargeable solid-state battery (SSB), a rechargeable lithium-ion battery (LiB) or the like, a hermetically sealed battery, a pouch cell battery or some combination thereof. The power source 150 may be charged by plugging a power supply into the aerosol provision device 100, or the power source 150 may be replaceable, e.g. in the form of a replaceable battery.
The aerosol provision device 100 may also comprise a controller 160 (control circuit) for controlling the provision of power from the power source 150 to the heating element 130, for example as will be described in more detail below. The controller (control circuit) 160 may also perform any other suitable and desired control of the aerosol provision device, for example controlling a user interface (e.g. display screen, LED(s), or other haptic feedback means such for providing vibration), or responding to user input (e.g. via a display screen, button or other interaction with the aerosol provision device).
The aerosol provision device 100 also comprises a voltage drop measuring circuit 165, configured to measure a voltage drop between the first electrical connector 131 and the heating element 130 (and optionally between the second electrical connector 132 and the heating element 130).
The voltage drop measured between the first electrical connector 131 and the heating element 130 is in embodiments used to determine a temperature of the heating element. Thus, in embodiments, the aerosol provision device 100 also comprises a temperature monitoring circuit 170, configured to determine a temperature of the heating element based on a voltage drop between the first electrical connector 131 and the heating element, for example as will be described in more detail below.
The voltage drop measured between the first electrical connector 131 and the heating element 130 could also be, and in embodiments is, used to determine (e.g. by a processing circuit, e.g. the control circuit 170) a condition associated with the aerosol provision device, such as a fault, for example any one or more of: a faulty connection between the electrical connector and the heating element; damage to the device; a fault associated with insertion of an article into the device.
In embodiments, the voltage drop between the first electrical connector and the heating element is measured between the first electrical connector 131, and a third electrical connector 132 that contacts the heating element 130, wherein the third electrical connector is in embodiments provided (only) for the purposes of measuring the voltage drop (and not for supplying power to cause heating of the heating element). As will be discussed in more detail below, the third electrical connector 137 may be positioned in the vicinity of the first electrical connector 131 so that the voltage drop measured is indicative of a voltage drop across the junction between the first electrical connector 131 and the heating element 130.
The connection between the power source 150, the electrical connectors 131, 132, 137, the control circuit 160, the voltage monitoring circuit 165, and the temperature monitoring circuit 170 is not shown in the figures, however these components could be electrically connected in any suitable and desired way.
Various other components may be included in the aerosol provision device 100, such as an activation switch or button, and any other components common to aerosol provision devices. However, for the sake of brevity, these components are not discussed here. Notwithstanding this, the skilled person would readily appreciate, if necessary, how to utilise some or all of these components when implementing the present invention.
According to the present disclosure, the heating element comprises a semiconductor material.
The Applicant has recognised that semiconductor material can be used to generate heat resistively by causing current to flow through it (by providing power to the semiconductor material via electrical connectors 131, 132), so that a semiconductor material can advantageously be used in the heating element 130 of an aerosol generating device 100 to generate heat. The heating element comprising the semiconductor material may thus be considered to form a resistive heating element.
The Applicant has furthermore found that, due to a barrier effect (potential energy difference) arising between the semiconductor material of the heating element and the first electrical connector 131, a voltage drop exists between the first electrical connector 131 and the heating element 130 which surprisingly varies as the temperature of the heating element changes. The Applicant has recognised that this voltage drop between the first electrical connector and the heating element can be used to determine the temperature of the heating element (among other possible uses).
Thus, in accordance with the present disclosure, there is provided an aerosol provision device comprising a heating arrangement configured to heat an aerosol generating material, comprising a heating element comprising a semiconductor material, a first electrical connector and a second electrical connector connecting the heating element to a power supply, for supplying power to and causing heating of the heating element, and a temperature monitoring circuit configured to determine a temperature of the heating element based on a voltage drop measured between the first electrical connector and the heating element.
In this broad aspect, the labelling of the electrical connectors as "first" and "second" is notional, and the voltage drop between either (or both) of the electrical connectors and the heating element could be measured and used to determine the temperature of the heating element.
By way of example only, and to illustrate the concepts described herein, example data relating to changes in voltage drop with temperature is shown in Figs. 3B to 3E, as obtained using the example test set-up shown in Fig. 3A.
In the test set-up, a heating arrangement was constructed using a heating element 130 having a tubular shape (as illustrated in Fig. 2A for example), the heating element formed of silicon carbide (SiC) semiconductor material. A first electrical connector 131 and second electrical connector 132 formed of metal were provided at the longitudinal ends of the heating element, via which power was supplied to the heating element to cause the heating element to heat up. The heating element tested was of a suitable size for incorporation into an aerosol provision device.
The heating arrangement was tested with first and second electrical connectors 131, 132 formed of nickel (see graphs 3B and 3C), and also with first and second electrical connectors 131, 132 formed of copper (see graphs 3D and 3E).
The power supply used was a "constant current" source configured to deliver a selected magnitude (and direction) of current. In this example, current was supplied in a direction such that the first electrical connector 131 formed a positive junction, and the second electrical connector 132 formed a negative junction.
A thermocouple 140 was connected to the heating element 130, approximately midway between the first and second electrical connectors 131, 132 (in the middle of the heating element), for measuring a temperature of the heating element.
Graphs 3B to 3E show various voltage drops as the magnitude of the supplied current was varied.
In the graphs, the voltage drop labelled as "Positive Junction" is the voltage drop between the first (positive) electrical connector 131 and the heating element (as measured between the first electrical connector 131 and a third electrical connector 137 positioned near the first electrical connector).
The voltage drop labelled as "Negative Junction" is the voltage drop between the second (negative) electrical connector 132 and the heating element (as measured between the second electrical connector 132 and a fourth electrical connector 138 positioned near the second electrical connector).
The voltage drop labelled as "Tube" is the voltage drop across the heating element (as measured between the first electrical connector 131 and the second electrical connector 132).
Graphs 3B and 3C show these voltage drops for various supplied currents at the point when, during the heating of the heating element, the temperature of the heating element (as measured by the thermocouple 140) reached 30 degrees Celsius, and 100 degrees Celsius respectively, when using nickel first and second electrical connectors. Similarly, graphs 3D and 3E show voltage drops when the temperature of the heating element was 30 degrees Celsius, and 100 degrees Celsius respectively, when using copper first and second electrical connectors.
As can be seen from each of the graphs, the voltage drop across the tube (labelled "Tube") follows the usual linear relationship for a restive element V=IR (voltage equals current multiplied by resistance). The voltage drop across the tube substantially did not change with changing temperature.
In comparison, the voltage drop between the first electrical connector and the heating element (labelled "positive junction") changes (and in particular decreases) with increasing temperature of the heating element. For example, comparing graphs 3B and 3C, the voltage drop between the first electrical connector and the heating element, for a supplied current of 20 Amps, is approximately 2V at 30 degrees Celsius, compared to approximately 1.75V at 100 degrees Celsius.
Similarly, the voltage drop between the second electrical connector and the heating element (labelled "negative junction") changes (and in particular decreases) with increasing temperature.
The Applicant believes that this change in voltage drop between the first electrical connector and the heating element (and similarly between the first electrical connector and the heating element) with temperature is likely due to changes in barrier effects between the semiconductor material of the heating element and the electrical connectors (in the example shown, the barrier effect being a Schottky barrier formed between each metal electrical connector and the semiconductor material of the heating element).
The Applicant has recognised that (as illustrated in the example data), when using a semiconductor heating element, since the voltage drop between the first electrical connector and the heating element (and equally between the second electrical connector and the heating element) varies with temperature, measurements of this voltage drop can advantageously be used to determine the temperature of the heating element.
Thus, in accordance with the present disclosure there is provided an aerosol provision device comprising a heating arrangement configured to heat an aerosol generating material, comprising a heating element comprising a semiconductor material, a first electrical connector and a second electrical connector connecting the heating element to a power supply for supplying power to and causing heating of the heating element, a temperature monitoring circuit configured to determine a temperature of the heating element based on a voltage drop measured between the first electrical connector and the heating element.
In embodiments, the determination of the temperature of the heating element is additionally or alternatively based on a voltage drop measured between the second electrical connector 132 and the heating element 130.
As can be seen from the data in figures 3B to 3D, the voltage drop at the first and second electrical connectors differs from one another. The Applicant believes this is due to differences in barrier effects at the positive and negative junctions with the heating element. Using both the voltage drop between the second electrical connector and the heating element, and the voltage drop between the first electrical connector and the heating element, may help to improve the accuracy of the determined temperature (or any other condition of the aerosol provision device determined based on the voltage drop(s)).
Thus, in embodiments, the determination of temperature (for example at a given time in a usage (heating) cycle) accounts for both the voltage drop measured between the first electrical connector 131 and the heating element 130, and the voltage drop measured between the second electrical connector 132 and the heating element 130. This could be done, for example, by comparing (e.g. averaging) a temperature determination based on the voltage drop measured across the first electrical connector, and a temperature determination based on the voltage drop measured across the first electrical connector.
In embodiments, the first electrical connector 131 comprises (in embodiments consists of) a metal, and forms a Schottky barrier with the semiconductor material of the heating element 130.
In embodiments where the voltage drop between the second electrical connector 132 and the heating element is used to determine the temperature of the heating element, then the second electrical connector 131 may comprise (in embodiments consist of) a metal, and form a Schottky barrier with the semiconductor material of the heating element 130.
Any suitable and desired metal could be used for one or more of (e.g. both of) the electrical connectors, such as one or more of (or combinations of): nickel, copper, molybdenum, platinum, chromium, tungsten, and aluminium. Other materials capable of forming a Schottky Diode with a semiconductor material (and which could be used one or more of (e.g. both of) the electrical connectors) include metal silicides, such as palladium silicide and platinum silicide
The first electrical connector 131 and heating element 130 (and/or the second electrical connector 131 and heating element 130) are in embodiments configured so that the metal of the electrical connector (directly) contacts the semiconductor material of the heating element.
This could be achieved in any suitable and desired way. For example, and in embodiments, the heating element 130 may be formed substantially of (consist of) semiconductor material (which may or may not be doped). Alternatively, the heating element could comprise semiconductor material in combination with one or more materials which are not semiconductors, provided that at least some semiconductor material contacts the metal of the first electrical connector.
Thus, the heating element 130 could comprise, in addition to semiconductor material, one or more other materials (which are not semiconductor materials), for example one or more materials conventionally used in resistive heating elements (for example a metal, metal alloy, a ceramic material, or other suitable and desired material). For example, a piece of semiconductor material could be placed in contact with the first electrical connector (and/or second electrical connector) to form a Schottky barrier (whereas one or more other (conductive) materials are provided elsewhere in the heating element, e.g. between the semiconductor material). In this regard, the electrical connectors could (each) interface with semiconductor material which is coupled (at least in part) with a cheaper conductive material in between..
In the examples shown in Figs. 3A to 3E, the heating element 130 is formed of silicon carbide (SiC) semiconductor material. Another semiconductor material which could be used is gallium nitride. Other semiconductors could be used for this purpose, however, if desired.
In embodiments, the heating element comprises a semiconductor material comprising silicon carbide and/or gallium nitride.
The semiconductor material may be doped. For example, in embodiments where the semiconductor material comprises silicon carbide, it may be doped with nitrogen or phosphorous, in order to make a n-type semiconductor. Alternatively, the silicon carbide could be doped with beryllium, boron, aluminium or gallium to form a p-type semiconductor. The doping could be tailored to provide a suitable voltage drop between the first electrical connector and the heating element which varies with temperature.
In embodiments, the semiconductor material is doped at least in a region 180 adjacent the first electrical connector 131 (in embodiments where the voltage drop between the first electrical connector 131 and the heating element 130 is to be used to determine the temperature of the heating element), as illustrated for example in Fig. 6B. It would be possible to vary the doping of the heating element 130 between the first and second electrical connectors 131, 132, so that an amount and/or type of dopant material differs in a region adjacent the first electrical connector compared to a region adjacent the second electrical connector (for example to tailor the relationship between voltage drop at each connector, and temperature), and in embodiments this is done.
The heating element used in examples Figs. 3A to 3E has a tubular (cylindrical shape). However, the heating element could have any suitable and desired shape, as may be desired to providing heat an aerosol generating material, such as any of the shapes discussed above.
The first and second electrical connectors 131, 132, could be provided at any suitable and desired position on the heating element, and may have any suitable and desired size and shape, as may be appropriate for transferring power from the power supply to the heating element to cause heating of the heating element.
In embodiments, the first electrical connector 131 is positioned closer to a mouth end 135 of the heating element 130 (closer towards a mouth end of the aerosol provision device) compared to the second electrical connector 132. In embodiments the first and second electrical connectors are positioned at (for example outwards from) the distal ends 135, 136 of the heating element 130, for example as shown in Figs. 2A to C, Fig. 3A and Figs. 6A to B. This may allow current to flow along the entire length of the heating element 130 when power is provided to the first and second electrical connectors.
Alternatively, the electrical connectors 131, 132 could instead be positioned near (for example, inwards of) the distal ends of the heating element. The electrical connectors 131, 132 could equally be placed at any other suitable and desired location on the heating element.
It is also noted that whilst Figs. 2A to C, Fig. 3A and Figs. 6A to B show electrical connectors 131, 132 which (entirely) cover an end of, or encircle, the heating element, this is not necessary and any other suitable and desired shape of electrical connector could be used. By way of example, Fig. 6C illustrates an electrical connector 132 which only partially covers (does not entirely cover) the end of the heating element.
In embodiments, the voltage drop between the first electrical connector 131 and the heating element 130 is measured between the first electrical connector 131 and a third electrical connector 137 that contacts the heating element.
The third electrical connector 137 may be used only for the purpose of measuring the voltage drop between the first electrical connector 131 and the heating element 130, and so is not used (in embodiments is not configured) for supplying power to cause heating of the heating element. Thus, in embodiments, the aerosol provision device is configured so that substantially no power is provided to the heating element via the third electrical connector 137.
The third electrical connector 137 may be positioned at any suitable and desired location for measuring the voltage drop between the first electrical connector 131 and the heating element 130.
In embodiments, the third electrical connector 137 is configured so that the voltage drop between the first electrical connector 131 and the third electrical connector 137 is indicative of (substantially corresponds to) the voltage drop across the junction between first electrical connector 131 and the heating element 130.
Thus, in embodiments, the third electrical connector 137 contacts the heating element at a position between the first electrical connector 131 and the second electrical connector 132, in embodiments contacting the heating element closer to the first electrical connector 131 than to the second electrical connector 132. In embodiments, the third electrical connector 137 contacts the heating element in the vicinity of (near) the first electrical connector 131 (as is the case for example in the figures shown). In embodiments, the distance between the third electrical connector 137 and the first electrical connector 131 is at most 3 cm, or at most 2 cm, or at most 1cm, or at most 0.5 cm.
By providing the third electrical connector 137 in the vicinity of the first electrical connector 131, the voltage drop measured between the third electrical connector 137 and the first electrical connector 131 is likely to better represent the temperature dependent voltage drop cause by barrier effects (e.g. Schottky barrier), and less likely to be contaminated or affected by effects elsewhere in the heating element.
In embodiments where a voltage drop is (additionally or alternatively) measured between the second electrical connector 132 and the heating element 130, this voltage drop could be measured between the second electrical connector 132 and the third electrical connector 137. Alternatively, and in embodiments, the voltage drop between the second electrical connector 132 and the heating element 130 is measured between the second electrical connector 132 and a fourth electrical connector 138 that contacts the heating element and is in embodiments provided only for the purpose of (only configured for) measuring the voltage drop (and not for supplying power to cause heating of the heating element).
The fourth electrical connector 138 may be configured so that the voltage drop between the second electrical connector 132 and the fourth electrical connector 138 is indicative of (substantially corresponds to) the voltage drop across the junction between second electrical connector 132 and the heating element 130. As such, the fourth electrical connector 138 may contact the heating element between the first electrical connector 131 and the second electrical connector 132, in embodiments contacting the heating element closer to the second electrical connector 132 than to the first electrical connector 131. In embodiments, the fourth electrical connector 138 contacts the heating element in the vicinity of (near) the second electrical connector 132, in embodiments such that a distance between the fourth electrical connector 138 and the second electrical connector 132 is at most 3 cm, or at most 2 cm, or at most 1cm, or at most 0.5 cm. By providing the fourth electrical connector 138 in the vicinity of the second electrical connector 132, the voltage drop measured between the fourth electrical connector 138 and the second electrical connector 132 is likely to better represent the temperature dependent voltage drop cause by barrier effects (e.g. Schottky barrier), and less likely to be contaminated or affected by effects elsewhere in the heating element.
Whilst heating arrangements are described above as comprising a 'first' and 'second' electrical connector for providing power to, it would be possible to provide more than two electrical connectors for supplying power to the heating element (and in embodiments this is done). In such embodiments, the control circuit 160 may be configured to select a pair of electrical connectors (a notional 'first' and 'second' electrical connector) for providing power to, and causing current to flow between, in embodiments to selectively heat a region of the heating element between the selected pair of electrical connectors (and to change which pair of electrical connectors which are selected to change the region of the heating element which is heated). In such embodiments, the temperature monitoring circuit 160 will determine a temperature of the heating element based on the voltage drop between the selected 'first' (and/or the 'second') electrical connector and the heating element. Thus, the voltage drop may be measured between the selected 'first' (and/or the 'second') electrical connector and the heating element 130. The voltage drop may be measured between the selected 'first' (and/or the 'second') electrical connector and another electrical connector (for example provided for the purposes of monitoring voltage, and positioned in the vicinity of the 'first' or 'second' electrical connector respectively).
The temperature of the heating element 130 which is determined (by the temperature monitoring circuit 170) may be a temperature at any suitable and desired location of the heating element.
It may be the case that the heating element heats uniformly when power is supplied to the first and second electrical connectors 131, 132 (so that the temperature is the same throughout the entire heating element), or the heating element may not heat uniformly (so that one or more regions of the heating element heat faster (and are hotter) than one or more other regions of the heating element).
In any case, the relationship between temperature at a given (particular, e.g. selected) position on the heating element and the voltage drop between the first electrical connector 131 and the heating element (and/or the voltage drop between the second electrical connector 132 and the heating element) can be determined (for example, being known in advance for the particular aerosol provision device, based on its particular configuration of heating element 130 and electrical connectors 131, 132, for example based on calibration data).
In embodiments (where the heating element does not heat uniformly), the temperature which is determined (by the temperature monitoring circuit 170) is a temperature for a position on the heating element between the first and second electrical connectors 131, 132. In this way, the temperature may be indicative of the temperature of the region through which current flows when power is supplied to the first and second electrical connectors 131, 132.
In embodiments (where the heating element does not heat uniformly), the temperature which is determined is a temperature of a first region "a" adjacent the (proximal) mouth end 135 of the heating element. Thus, in embodiments, the temperature which is determined corresponds to a position on the heating element that is within a first region "a" adjacent the mouth end 135 of the heating element. By monitoring (and controlling) the temperature near the mouth end of the heating element, it may be possible to better control the provision of a first puff of aerosol to a user of the device.
As noted above, in embodiments, the first electrical connector 131 is provided adjacent the mouth end 135 of the heating element. Accordingly, the first region "a" for which temperature is determined may be a region adjacent the first electrical connector 131.
The first region "a" is in embodiments a region extending up to at most 25%, or up to at most 10%, of the length L2 of the heating element 130 away from the mouth end 135 (and/or away from the first electrical connector 131). The first region "a" is in embodiments a region extending up to at most 3 cm from mouth end 135 (and/or from the electrical connector 131), in embodiments or up to at most 2cm, in embodiments up to at most 1 cm. An example first region "a" for which temperature may be determined is shown in Figs 2A and B, and Figs. 6A and B.
It may be the case the region "a" (which is in the vicinity of the first electrical connector 131), for which temperature may be determined, is the hottest region of the heating element (during a heating cycle). By monitoring the temperature of the hottest region of the heating element, it may be possible to prevent overheating of the device.
Thus, in embodiments (where the heating element does not heat uniformly), the temperature which is determined may be a temperature of a hottest region (for example a region which it is known in advance will be the hottest region) of the heating element. In embodiments the power supply to the heating element is reduced (and for example stopped) when (in response to determining that) the temperature of the hottest region of the heating element is greater than a predetermined threshold, for example corresponding to a desired operating temperature, for example when the temperature is greater than about 250 degrees Celsius, in embodiments greater than about 300 degrees Celsius.
Alternatively, it would be possible to determine the temperature at any other suitable and desired position of the heating element, for example approximately at a midpoint between the first and second electrical connectors 131, 132 (e.g. approximately in the middle of the longitudinal length of the heating element).
In embodiments, the temperature of the heating element (at a given (selected) position) is determined (by the temperature monitoring circuit 170) by comparing the measured voltage drop between the first electrical connector 131 and the heating element 130 (and/or by comparing the measured voltage drop between the second electrical connector 132 and the heating element 130) against information representative of the relationship between the voltage drop and the temperature (at the given location) for the (particular) aerosol provision device. The information representing the relationship may, for example, comprise data for a voltage drop verses temperature curve. In embodiments the information is stored locally in a memory of the aerosol provision device.
Alternatively (or additionally) the temperature of the heating element could be determined by correlating a change in the measured voltage drop with a change in temperature, for example by determining a temperature increase of the heating element based on a decrease in the measured voltage drop.
The determined temperature of the heating element could be used for any suitable and desired purpose, for example for monitoring (e.g. by the control circuit) the temperature of the heating element when power is supplied (during a usage (heating) cycle), for example to check whether the heating element has reached an operating temperature for aerosol generation, to check whether the heating element is overheating, or other purpose.
As illustrated in the data in Figs. 3B to 3E the voltage drop between the first electrical connector and the heating element (and between the second electrical connector and the heating element) varies depending on the amount of power supplied. In particular, the voltage drop increases with increasing amount of power supplied.
When generating the data for Figs. 3B to 3E, the power supplied was varied by varying the current provided from a "constant current source". However, it would equally be possible to use a "constant voltage source" for which the voltage supplied (and so the voltage across the heating element, between the first and second electrical connectors) can be selected (with the current caused to flow in the heating element then varying as a result of changing the voltage supplied). It will be understood that, regardless of the type of power supply used, varying the power (by varying the current or voltage supplied from the power source) will affect the voltage drop with the temperature of the heating element.
Thus, in embodiments, the temperature monitoring circuit is configured to determine the temperature of the heating element based on the measured voltage drop between the first electrical connector and the heating element (and/or between the second electrical connector and the heating element), and based on (accounting for) the amount of power supplied by the power supply.
In embodiments where a (another) condition of the aerosol provision device is determined based on the measured voltage drop between the first electrical connector and the heating element (and/or between the second electrical connector and the heating element), this may likewise be based on (account for) the amount of power supplied by the power supply.
As illustrated in the data in Figs. 3B to 3E the voltage drop between an electrical connector and the heating element also varies depending on the direction in which current is caused to flow through the heating element, and thus the direction which current flows across the junction between the electrical connector and heating element (in other words, whether the electrical connector in question forms a positive or negative junction with the heating element). In this regard, as can be seen from Figs. 3B to 3E, for first and second electrical connectors formed of the same material (e.g. same metal, e.g. nickel or copper) the electrical connector forming a positive junction with the heating element experiences a greater voltage drop than the electrical connector forming a negative junction.
Thus, in embodiments, the temperature monitoring circuit is configured to determine the temperature of the heating element based on the measured voltage drop between the first electrical connector and the heating element (and/or between the second electrical connector and the heating element), and based on (accounting for) the direction of current flow through the heating element (or in other words the direction of current flow through across the junction between the electrical connector in question and the heating element, corresponding to whether the electrical connector in question forms a positive or negative junction).
In embodiments where a (another) condition of the aerosol provision device is determined based on the measured voltage drop between the first electrical connector and the heating element (and/or between the second electrical connector and the heating element), this may likewise be based on (account for) the direction of current flow through the heating element.
The temperature determination may account for the amount of power supplied and/or the direction of current flow in any suitable and desired way. For example, the temperature monitoring circuit may compare the measured voltage drop against information (e.g. stored locally in a memory of the aerosol provision device) representative of the relationship between the temperature and voltage drop, for the aerosol provision device, this information also accounting for the amount of power and/or direction of current. The information may comprise, for example, data for voltage drop verses temperature curves for various amounts of power which may be applied and/or for different current directions.
Alternatively (or additionally) in example embodiments where the temperature of the heating element is determined by correlating a change in the measured voltage drop with a change in temperature, the determined temperature may be adjusted based on the amount of power supplied and/or direction of current flow.
As discussed above, the accuracy of the temperature determination (or determination of a condition associated with the aerosol provision device) can be improved by using a measured voltage drop between the first electrical connector 131 and the heating element 130 and also a measured voltage drop between the second electrical connector 131 and the heating element 130.
The Applicant has recognised that another way to improving the accuracy of the temperature determination (or determination of a condition associated with the aerosol provision device) can be to measure the voltage drop (between the first electrical connector 131 and the heating element 130, and/or between the second electrical connector 131 and the heating element 130) when different amounts of power are provided and/or when current is caused to flow in different directions. This may provide additional voltage drop data points to feed into the determination.
Thus, in embodiments, the aerosol provision device is controlled (by the controller 160) during a usage (heating) cycle to provide a first amount of power from the power supply to the heating element, and then provide a second different amount of power to the heating element.
In embodiments, a temperature of the heating element (or a condition of the aerosol provision device) is determined based on the voltage drop(s) measured when the first amount of power is supplied to the heating element, and based on the voltage drop(s) measured when the second different amount of power is supplied to the heating element.
This could be done, for example by determining a temperature of the heating element (or a condition of the aerosol provision device) based on the voltage drop(s) measured when the first amount of power is supplied, and updating the determination based on the voltage drop(s) when the second amount of power is supplied. For example, this may comprise determining a temperature when the first amount of power is supplied, and determining a temperature when the second amount of power is supplied, and comparing (e.g. averaging) these determined temperatures.
In embodiments, the aerosol provision device is (additionally or alternatively) controlled (by the controller 160) during a usage (heating) cycle to cause current to flow in the heating element in a first direction, and then cause current to flow in a second (opposite) direction (by swapping which of the first and second electrical connectors 131, 132 are positive and negative). In embodiments, a temperature of the heating element (or a condition of the aerosol provision device) is determined based on the voltage drop(s) measured when the current is caused to flow in the first direction, and based on the voltage drop(s) measured when the current is caused to flow in the second direction.
This could be done, for example by determining a temperature of the heating element (or a condition of the aerosol provision device) based on the voltage drop(s) measured when current is caused to flow in the first direction, and updating the determination based on the voltage drop(s) measured when the current is caused to flow in the second direction. For example, this may comprise determining a temperature when the current is caused to flow in the first direction, and determining a temperature when the current is caused to flow in the second direction, and comparing (e.g. averaging) these determined temperatures.
The amount of power (e.g. voltage) supplied to the heating element 130 and/or direction of current caused to flow in the heating element 130 could be varied during a heating (usage) cycle according to any suitable and desired scheme. For example, the amount of power supplied could alternate (modulate) (e.g. periodically) between two or more different amounts of power. Example modulation schemes are illustrated in Figs. 4A and 4B, in which the power provided by the power source is alternates between a first amount of power α provided for a time period t1 and a second amount of power β provided for a time period t2 until the expiry of a heating cycle at time T.
The time period for which each amount of power is provided t1, t2 could be the same (as shown for example in Fig. 4A) or could differ (as shown for example in Fig. 4B). The voltage drop(s) used for determining a temperature of the heating element could be measured at any suitable and desired time during the heating cycle, for example being measured (e.g. substantially immediately) before and (e.g. substantially immediately) after the power supplied is changed, as indicated for example by M₁ and M₂ illustrated in Figs. 4A and 4B, for example so that the temperature of the heating element will not have substantially changed between the two measurements. The temperature of the heating element (or a condition of the aerosol provision device) may be determined each time the power is changed, by taking measurements M1 and M2 each time the power is changed. Whilst Figs. 4A and 4B shows relatively few modulations in power before the heating cycle ends at time T, the power could modulate more or less rapidly if desired.
The direction of current could be caused to alternate (e.g. periodically) between first and second opposite directions in a similar manner as discussed with regards to Fig. 4A and 4B, with measurements of voltage drop similar taken before and after (e.g. each time) the direction of current is changed.
A skilled person will appreciate that other schemes for altering the power supplied and/or direction of current can also be used.
The temperature of the heating element (or a condition of the aerosol provision device) may be determined at any suitable and desired time when power is supplied to the first and second electrical connectors (during a usage cycle of the aerosol provision device, for example when an amount of power and/or direction of current supplied is changed as discussed above). In embodiments, the temperature (or condition) is determined at plural different times, for example periodically, during a usage cycle.
Fig. 5 is a flowchart showing steps for determining the temperature of a heating element in embodiments of the present disclosure. A heating cycle is started (step 50), and power is supplied to the first and second electrical connectors of the heating element (step 51). Whilst power is being supplied, a voltage drop between first electrical connector and heating element is measured and a temperature for the heating element is determined based on the measured voltage drop (step 32). The temperature determined may account for one or more of: a voltage drop between the second electrical connector and the heating element; an amount of power supplied; and a direction in which current is caused to flow in the heating element (step 53). The temperature determination may be updated in response to (or otherwise account for) a change in the amount of power supplied and/or a change in the direction in which current is caused to flow.
Analogous steps to those shown in Fig. 5 could be used when determining a condition of the aerosol provision device, the determination being based on voltage drop between first electrical connector and heating element, and optionally accounting for one or more of: voltage drop between the second electrical connector and the heating element; amount of power supplied; direction of current flow. The determination may optionally be updated in response to a change in the amount of power supplied and/or direction of current flow.
The various embodiments described herein are presented only to assist in understanding and teaching the claimed features. These embodiments are provided as a representative sample of embodiments only, and are not exhaustive and/or exclusive. It is to be understood that advantages, embodiments, examples, functions, features, structures, and/or other aspects described herein are not to be considered limitations on the scope of the invention as defined by the claims or limitations on equivalents to the claims, and that other embodiments may be utilised and modifications may be made without departing from the scope of the claimed invention. Various embodiments of the invention may suitably comprise, consist of, or consist essentially of, appropriate combinations of the disclosed elements, components, features, parts, steps, means, etc., other than those specifically described herein. In addition, this disclosure may include other inventions not presently claimed, but which may be claimed in future.

Claims

An aerosol provision device comprising a heating arrangement configured to heat an aerosol generating material, comprising:
a heating element comprising a semiconductor material;

a first electrical connector and a second electrical connector connecting the heating element to a power supply, for supplying power to and causing heating of the heating element; and

a temperature monitoring circuit configured to determine a temperature of the heating element based on a voltage drop measured between the first electrical connector and the heating element.
The aerosol provision device of claim 1, wherein the first electrical connector comprises a metal which contacts the semiconductor material of the heating element to form a Schottky barrier.
The aerosol provision device of any preceding claim, wherein the semiconductor material comprises at least one of: silicon carbide or gallium nitride.
The aerosol provision device of any preceding claim, wherein the voltage drop is measured between the first electrical connector, and a third electrical connector that contacts the heating element.
The aerosol provision device of claim 4, wherein the third electrical connector contacts the heating element closer to the first electrical connector than to the second electrical connector.
The aerosol provision device of any preceding claim, wherein the temperature monitoring circuit is configured to determine the temperature of a first region of the heating element adjacent the first electrical connector.
The aerosol provision device of any preceding claim, wherein the aerosol provision device has a mouth end and a distal end; and
wherein the first electrical connector contacts the heating element closer towards the mouth end of the aerosol provision device than the second electrical connector.
The aerosol provision device of any preceding claim, wherein the temperature monitoring circuit is configured to determine the temperature of the heating element based on the measured voltage drop, and based on one or more of: the amount of power supplied by the power supply; and the direction of current flow through the heating element.
The aerosol provision device of any preceding claim, further configured to:
during a heating cycle, provide a first amount of power from the power supply to the heating element, and then provide a second different amount of power to the heating element; and/or

during a heating cycle, cause current to flow in the heating element in a first direction, and then cause current to flow in a second different direction.
The aerosol provision device of any preceding claim, wherein the temperature monitoring circuit is configured to determine the temperature of the heating element based on a voltage drop measured between the second electrical connector and the heating element.
An aerosol provision system comprising:
the aerosol provision device of any preceding claim; and

an article comprising an aerosol generating medium.
A method of controlling a heating arrangement of an aerosol provision device, the heating arrangement comprising a heating element comprising a semiconductor material, and a power supply electrically connected to the heating element by a first electrical connector and a second electrical connector, the method comprising:
when providing power to the first electrical connector and the second electrical connector of the electrical connectors to cause heating of the heating element, measuring a voltage drop between the first electrical connector and the heating element, and determining a temperature of the heating element based on the measured voltage drop.
The method of claim 12 comprising, determining the temperature of the heating element based on the voltage drop measured when a first amount of power is supplied to the heating element, and based on the voltage drop measured when a second different amount of power is supplied to the heating element.
The method of claim 12 or 13 comprising, determining the temperature of the heating element based on the voltage drop measured when current is caused to flow in the heating element in a first direction, and based on the voltage drop measured when current is caused to flow in the heating element in a second opposite direction.
The method of any of claims 12 to 14, comprising determining the temperature of the heating element based on the voltage drop measured between the first electrical connector and the heating element, and based on a voltage drop measured between the second electrical connector and the heating element.