Patent Publication Number: US-11641882-B2

Title: Electronic vaping device, battery section, and charger

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Divisional Application of, and claims priority under 35 U.S.C. § 120 to, U.S. application Ser. No. 15/224,608, filed on Jul. 31, 2016, the entire contents of which are incorporated herein by reference. 
    
    
     BACKGROUND 
     Field 
     The present disclosure relates to an electronic vaping or e-vaping device. 
     Description of Related Art 
     An e-vaping device includes a heater element which vaporizes a pre-vapor formulation to produce a “vapor.” 
     The e-vaping device includes a power supply, such as a rechargeable battery, arranged in the device. The battery is electrically connected to the heater, such that the heater heats to a temperature sufficient to convert the pre-vapor formulation to a vapor. The vapor exits the e-vaping device through a mouthpiece including at least one outlet. 
     SUMMARY 
     At least one example embodiment relates to a battery section of an electronic vaping device. 
     In at least one example embodiment, a battery section of an electronic vaping device may comprise a housing extending in a longitudinal direction, the housing having a first end and a second end, a power supply in the housing, a control circuit in the housing, and a conductive contact assembly at the second end of the housing, the contact assembly electrically connecting the power supply and the control circuit, the contact assembly configured to receive external power and at least one command. 
     In at least one example embodiment, the control circuit is configured to detect at least one of a change in resistance and a change in capacitance so as to detect the at least one command. 
     In at least one example embodiment, the contact assembly comprises a charge anode and a charge cathode. The control circuit comprises a switch configured to electrically separate the charge cathode from a common ground plane. 
     In at least one example embodiment, the contact assembly comprises a first contact and a second contact insulated from the first contact. One of the first contact and the second contact is generally ring-shaped and one of the first contact and the second contact forms at least a portion of an end wall of the battery section. The end wall extends generally transverse to the longitudinal direction. The first contact may be the end wall and the second contact may be generally ring-shaped, and may extend about a perimeter of the end wall. The end wall may be substantially opaque. 
     In at least one example embodiment, the contact assembly may further comprise an end cap housing configured to hold the first contact therein, the end cap housing including at least one slot. The second contact may be integrally formed with at least one tab extending in the longitudinal direction. The at least one tab may be configured to be received in the at least one slot. The end cap housing may include a generally cylindrical sidewall. The sidewall defining an orifice extending through the end cap housing. A first portion of the generally cylindrical sidewall is received within the housing at the second end thereof. A second portion of the sidewall is not within the housing. The second portion may be substantially transparent. The end wall may include a printed circuit board. 
     In at least one example embodiment, at least one of the first contact and the second contact may be magnetic. At least one of the first contact and the second contact is formed of at least one of stainless steel, gold, or silver. 
     At least one example embodiment relates to an electronic vaping device. 
     In at least one example embodiment, an electronic vaping device comprises a housing extending in a longitudinal direction, the housing having a first end and a second end, a power supply in the housing, a control circuit in the housing, a conductive contact assembly at the second end of the housing, a reservoir configured to contain a pre-vapor formulation, and a heater configured to heat the pre-vapor formulation, the heater electrically connected to the power supply. The contact assembly electrically connects the power supply and the control circuit. The contact assembly may be configured to receive external power and at least one command. 
     In at least one example embodiment, the control circuit is configured to detect at least one of a change in resistance and a change in capacitance so as to detect the at least one command. 
     In at least one example embodiment, the contact assembly comprises a charge anode and a charge cathode. The control circuit comprises a switch configured to electrically separate the charge cathode from a common ground plane. The contact assembly comprises a first contact and a second contact insulated from the first contact. The second contact may be generally ring-shaped and the first contact may form at least a portion of an end wall. The end wall of the battery section may extend generally transverse to the longitudinal direction. 
     In at least one example embodiment, the contact assembly further comprises an end cap housing configured to hold the first contact therein. The end cap housing may include at least one slot. The second contact may be integrally formed with at least one tab extending in the longitudinal direction. The at least one tab is configured to be received in the at least one slot. 
     In at least one example embodiment, the electronic vaping device includes a battery section and a first section. The battery section may contain the power supply, the control circuit, and the conductive contact assembly. The first section may contain the reservoir and the heater 
     At least one example embodiment relates to a USB charger. 
     In at least one example embodiment, a USB charger comprises a housing. The housing includes a top wall having a charging slot therein, a first charger contact in the charging slot, a second charger contact in the charging slot, a bottom wall opposite the top wall, and at least one sidewall between the top wall and the bottom wall. The charging slot may be configured to receive an end of the electronic vaping device. The charger also includes at least one magnet adjacent the charging slot. The charger may also include a light pipe surrounding the charging slot and extending from the charging slot to an external surface of the USB charger. The light pipe may be configured to communicate and/or transmit light from an electronic vaping device to the external surface of the USB charger indicate charge status of the electronic vaping device. The housing defines an internal compartment. The charger may further comprise charger circuitry contained within the internal compartment. The charger circuitry is in communication with the first charger contact and the second charger contact. 
     At least one example embodiment relates to a battery section of an electronic vaping device. 
     In at least one example embodiment, the battery section comprises a housing extending in a longitudinal direction, the housing having a first end and a second end, a power supply in the housing, a conductive contact assembly at the second end of the housing, the contact assembly electrically connecting the power supply and the control circuit, and a control circuit in the housing configured to detect at least one of a change in resistance and a change in capacitance so as to detect input of the at least one command. The contact assembly is configured to receive external power and at least one command. The contact assembly may include a charge anode and a charge cathode. The control circuit comprises a switch configured to electrically separate the charge cathode from a common ground plane. 
     At least one other example embodiment provides an electronic vaping device including a battery section. The battery section includes: a first housing extending in a longitudinal direction; a power supply in the first housing, the power supply configured to provide power to a heater coil when the battery section is engaged with a cartridge section including a reservoir and the heater coil; and a control circuit including a resistance measurement circuit and a controller. The control circuit is configured to: measure an initial resistance of the heater coil in the analog domain; calculate a reference resistance of the heater coil in the digital domain based on the measured initial resistance; measure a current resistance of the heater coil in response to detection of a puff event; calculate a percentage change in resistance of the heater coil based on the measured current resistance and the reference resistance of the heater coil; and control power to the heater coil based on the calculated percentage change in resistance of the heater coil. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The various features and advantages of the non-limiting embodiments herein may become more apparent upon review of the detailed description in conjunction with the accompanying drawings. The accompanying drawings are merely provided for illustrative purposes and should not be interpreted to limit the scope of the claims. The accompanying drawings are not to be considered as drawn to scale unless explicitly noted. For purposes of clarity, various dimensions of the drawings may have been exaggerated. 
         FIG.  1    is a side view of an e-vaping device according to at least one example embodiment. 
         FIG.  2    is a cross-sectional view along line II-II of the e-vaping device of  FIG.  1    according to at least one example embodiment. 
         FIG.  3 A  is an enlarged view of an end of the battery section of an e-vaping device according to at least one example embodiment. 
         FIG.  3 B  is an enlarged view of an end of a battery section of an e-vaping device according to at least one example embodiment. 
         FIG.  4    is an exploded view of the conductive contact assembly of  FIG.  2    according to at least one example embodiment. 
         FIG.  5    is a cross-sectional view of the conductive contact assembly of  FIG.  2    according to at least one example embodiment. 
         FIG.  6    is a circuit diagram illustrating an example embodiment of a control circuit of the e-vaping device shown in  FIG.  1   . 
         FIG.  7    is a diagram of a circuit of the e-vaping device of  FIG.  1    according to at least one example embodiment. 
         FIG.  8    is a diagram of a circuit of the e-vaping device of  FIG.  1    according to at least one example embodiment. 
         FIG.  9    is a perspective view of a charger of an e-vaping device according to at least one example embodiment. 
         FIG.  10    is a top view of the charger of  FIG.  9    according to at least one example embodiment. 
         FIG.  11    is an exploded view of the charger of  FIGS.  9  and  10    according to at least one example embodiment. 
         FIG.  12    is a cross-sectional view of the charger of  FIG.  10    along line XII-XII according to at least one example embodiment. 
         FIG.  13    is an exploded view of a charger contact assembly of the charger of  FIGS.  9 - 12    according to at least one example embodiment. 
         FIG.  14    is a flow chart illustrating an example embodiment of a method of operating the control circuit shown in  FIG.  6   . 
         FIG.  15    is a flow chart illustrating another example embodiment of a method of operating the control circuit shown in  FIG.  6   . 
         FIG.  16    is a flow chart illustrating an example embodiment of a method of operating the control circuit in the calibration phase. 
         FIG.  17    is a flow chart illustrating an example embodiment of a method of operating the control circuit in the resistance measurement phase. 
     
    
    
     DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS 
     Some detailed example embodiments are disclosed herein. However, specific structural and functional details disclosed herein are merely representative for purposes of describing example embodiments. Example embodiments may, however, be embodied in many alternate forms and should not be construed as limited to only the example embodiments set forth herein. 
     Accordingly, while example embodiments are capable of various modifications and alternative forms, example embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit example embodiments to the particular forms disclosed, but to the contrary, example embodiments are to cover all modifications, equivalents, and alternatives falling within the scope of example embodiments. Like numbers refer to like elements throughout the description of the figures. 
     It should be understood that when an element or layer is referred to as being “on,” “connected to,” “coupled to,” or “covering” another element or layer, it may be directly on, connected to, coupled to, or covering the other element or layer or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly connected to,” or “directly coupled to” another element or layer, there are no intervening elements or layers present. Like numbers refer to like elements throughout the specification. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     It should be understood that, although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers, and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, or section from another region, layer, or section. Thus, a first element, component, region, layer, or section discussed below could be termed a second element, component, region, layer, or section without departing from the teachings of example embodiments. 
     Spatially relative terms (e.g., “beneath,” “below,” “lower,” “above,” “upper,” and the like) may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. It should be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the term “below” may encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. 
     The terminology used herein is for the purpose of describing various example embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “includes,” “including,” “comprises,” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     Example embodiments are described herein with reference to cross-sectional illustrations that are schematic illustrations of idealized embodiments (and intermediate structures) of example embodiments. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, example embodiments should not be construed as limited to the shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. 
     Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, including those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
       FIG.  1    is a side view of an e-vaping device according to at least one example embodiment. 
     In at least one example embodiment, as shown in  FIG.  1   , an electronic vaping device (e-vaping device)  60  may include a replaceable cartridge (or first section)  70  and a reusable battery section (or second section)  72 , which may be coupled together at a threaded connector  205 . It should be appreciated that the connector  205  may be any type of connector, such as a snug-fit, detent, clamp, bayonet, and/or clasp. 
     In at least one example embodiment, the connector  205  may be the connector described in U.S. application Ser. No. 15/154,439, filed May 13, 2016, the entire contents of which is incorporated herein by reference thereto. As described in U.S. application Ser. No. 15/154,439, the connector  205  may be formed by a deep drawn process. 
     In at least one example embodiment, the first section  70  may include a housing  6  and the second section  72  may include a second housing  6 ′. The e-vaping device  60  includes a mouth-end insert  8 . 
     In at least one example embodiment, the housing  6  and the second housing  6 ′ may have a generally cylindrical cross-section. In other example embodiments, the housings  6  and  6 ′ may have a generally triangular cross-section along one or more of the first section  70  and the second section  72 . Furthermore, the housings  6  and  6 ′ may have the same or different cross-section shape, or the same or different size. As discussed herein, the housings  6  and  6 ′ may also be referred to as outer or main housings. 
     In at least one example embodiment, the e-vaping device  60  may include a conductive contact assembly  300  including a first contact  310  (shown in  FIGS.  2 - 3  and  5 - 6   ), a second contact  320 , and an end cap housing  340 , which are described in more detail below. Each of the first contact  310  and the second contact  320  may be used in charging the power supply of the e-vaping device. The first contact  310 , the second contact  320 , and the end cap housing  340  are described in more detail below. 
     As discussed in more detail later, the first contact  310  and/or the second contact  320  may be utilized in charging the power supply of the e-vaping device as well as for inputting touch commands. Accordingly, the conductive contact assembly  300  may be configured to be used to charge the power supply of the e-vaping device and to input touch commands to control the e-vaping device. 
       FIG.  2    is a cross-sectional view along line II-II of the e-vaping device of  FIG.  1   . 
     In at least one example embodiment, as shown in  FIG.  2   , the first section  70  may include a reservoir  22  configured to store a pre-vapor formulation and a heater  14  that may vaporize the pre-vapor formulation, which may be drawn from the reservoir  22  by a wick  28 . The e-vaping device  60  may include the features set forth in U.S. Patent Application Publication No. 2013/0192623 to Tucker et al. filed Jan. 31, 2013, the entire contents of which is incorporated herein by reference thereto. In other example embodiments, the e-vaping device may include the features set forth in U.S. patent application Ser. No. 15/135,930 filed Apr. 22, 2016, U.S. patent application Ser. No. 15/135,923 filed Apr. 22, 2016, and/or U.S. Pat. No. 9,289,014 issued Mar. 22, 2016, the entire contents of each of which is incorporated herein by this reference thereto. 
     In at least one example embodiment, the pre-vapor formulation is a material or combination of materials that may be transformed into a vapor. For example, the pre-vapor formulation may be a liquid, solid and/or gel formulation including, but not limited to, water, beads, solvents, active ingredients, ethanol, plant extracts, natural or artificial flavors, and/or vapor formers such as glycerin and propylene glycol. 
     In at least one example embodiment, the first section  70  may include the housing  6  extending in a longitudinal direction and an inner tube (or chimney)  62  coaxially positioned within the housing  6 . 
     At an upstream end portion of the inner tube  62 , a nose portion  61  of a gasket (or seal)  15  may be fitted into the inner tube  62 ; and an outer perimeter of the gasket  15  may provide a seal with an interior surface of the housing  6 . The gasket  15  may also include a central, longitudinal air passage  20  in fluid communication with the inner tube  62  to define an inner passage (also referred to as a central channel or central inner passage)  21 . A transverse channel  33  at a backside portion of the gasket  15  may intersect and communicate with the air passage  20  of the gasket  15 . This transverse channel  33  assures communication between the air passage  20  and a space  35  defined between the gasket  15  and a first connector piece  37 . 
     In at least one example embodiment, the first connector piece  37  may include a male threaded section for effecting the connection between the first section  70  and the second section  72 . 
     In at least one example embodiment, more than two air inlet ports  44  may be included in the housing  6 . Alternatively, a single air inlet port  44  may be included in the housing  6 . Such arrangement allows for placement of the air inlet ports  44  close to the connector  205  without occlusion by the presence of the first connector piece  37 . This arrangement may also reinforce the area of air inlet ports  44  to facilitate precise drilling of the air inlet ports  44 . 
     In at least one example embodiments, the air inlet ports  44  may be provided in the connector  205  instead of in the housing  6 . In other example embodiments, the connector  205  may not include threaded portions. 
     In at least one example embodiment, the at least one air inlet port  44  may be formed in the housing  6 , adjacent the connector  205  to minimize the chance of an adult vaper&#39;s fingers occluding one of the ports and to control the resistance-to-draw (RTD) during vaping. In at least one example embodiment, the air inlet ports  44  may be machined into the housing  6  with precision tooling such that their diameters are closely controlled and replicated from one e-vaping device  60  to the next during manufacture. 
     In at least one example embodiment, the air inlet ports  44  may be sized and configured such that the e-vaping device  60  has a resistance-to-draw (RTD) in the range of from about 60 mm H 2 O to about 150 mm H 2 O. 
     In at least one example embodiment, a nose portion  93  of a second gasket  10  may be fitted into a first end portion  81  of the inner tube  62 . An outer perimeter of the second gasket  10  may provide a substantially tight seal with an interior surface  97  of the housing  6 . The second gasket  10  may include a central channel  63  disposed between the inner passage  21  of the inner tube  62  and the interior of the mouth-end insert  8 , which may transport the vapor from the inner passage  21  to the mouth-end insert  8 . The mouth-end insert  8  includes at least two outlets, which may be located off-axis from the longitudinal axis of the e-vaping device  60 . The outlets may be angled outwardly in relation to the longitudinal axis of the e-vaping device  60 . The outlets may be substantially uniformly distributed about the perimeter of the mouth-end insert  8  so as to substantially uniformly distribute vapor in an adult vaper&#39;s mouth during vaping and create a greater perception of fullness in the mouth. Thus, as the vapor passes into the adult vaper&#39;s mouth, the vapor may enter the mouth and may move in different directions so as to provide a full mouth feel. 
     In at least one example embodiment, the space defined between the gaskets  10  and  15  and the housing  6  and the inner tube  62  may establish the confines of a reservoir  22 . The reservoir  22  may contain a pre-vapor formulation, and optionally a storage medium (not shown) configured to store the pre-vapor formulation therein. The storage medium may include a winding of cotton gauze or other fibrous material about the inner tube  62 . 
     In at least one example embodiment, the reservoir  22  may be contained in an outer annulus between the inner tube  62  and the housing  6  and between the gaskets  10  and  15 . Thus, the reservoir  22  may at least partially surround the inner passage  21 . The heater  14  may extend transversely across the inner passage  21  between opposing portions of the reservoir  22 . In some example embodiments, the heater  14  may extend parallel to a longitudinal axis of the inner passage  21 . 
     In at least one example embodiment, the reservoir  22  may be sized and configured to hold enough pre-vapor formulation such that the e-vaping device  60  may be configured for vaping for at least about 200 seconds. Moreover, the e-vaping device  60  may be configured to allow each puff to last a maximum of about 5 seconds. 
     In at least one example embodiment, the storage medium may be a fibrous material including at least one of cotton, polyethylene, polyester, rayon and combinations thereof. The fibers may have a diameter ranging in size from about 6 microns to about 15 microns (e.g., about 8 microns to about 12 microns or about 9 microns to about 11 microns). The storage medium may be a sintered, porous or foamed material. Also, the fibers may be sized to be irrespirable and may have a cross-section which has a Y-shape, cross shape, clover shape or any other suitable shape. In at least one example embodiment, the reservoir  22  may include a filled tank lacking any storage medium and containing only pre-vapor formulation. 
     During vaping, pre-vapor formulation may be transferred from the reservoir  22  and/or storage medium to the proximity of the heater  14  via capillary action of the wick  28 . The wick  28  may include at least a first end portion and a second end portion, which may extend into opposite sides of the reservoir  22 . The heater  14  may at least partially surround a central portion of the wick  28  such that when the heater  14  is activated, the pre-vapor formulation in the central portion of the wick  28  may be vaporized by the heater  14  to form a vapor. 
     In at least one example embodiment, the wick  28  may include filaments (or threads) having a capacity to draw the pre-vapor formulation. For example, the wick  28  may be a bundle of glass (or ceramic) filaments, a bundle including a group of windings of glass filaments, etc., all of which arrangements may be capable of drawing pre-vapor formulation via capillary action by interstitial spacings between the filaments. The filaments may be generally aligned in a direction perpendicular (transverse) to the longitudinal direction of the e-vaping device  60 . In at least one example embodiment, the wick  28  may include one to eight filament strands, each strand comprising a plurality of glass filaments twisted together. The end portions of the wick  28  may be flexible and foldable into the confines of the reservoir  22 . The filaments may have a cross-section that is generally cross-shaped, clover-shaped, Y-shaped, or in any other suitable shape. 
     In at least one example embodiment, the wick  28  may include any suitable material or combination of materials. Examples of suitable materials may be, but not limited to, glass, ceramic- or graphite-based materials. The wick  28  may have any suitable capillarity drawing action to accommodate pre-vapor formulations having different physical properties such as density, viscosity, surface tension and vapor pressure. The wick  28  may be non-conductive. 
     In at least one example embodiment, the heater  14  may include a wire coil which at least partially surrounds the wick  28 . The wire may be a metal wire and/or the heater coil may extend fully or partially along the length of the wick  28 . The heater coil may further extend fully or partially around the circumference of the wick  28 . In some example embodiments, the heater  14  may or may not be in contact with the wick  28 . 
     In at least one example embodiment, the heater coil may be formed of any suitable electrically resistive materials. Examples of suitable electrically resistive materials may include, but not limited to, copper, titanium, zirconium, tantalum and metals from the platinum group. Examples of suitable metal alloys include, but not limited to, stainless steel, nickel, cobalt, chromium, aluminum-titanium-zirconium, hafnium, niobium, molybdenum, tantalum, tungsten, tin, gallium, manganese and iron-containing alloys, and super-alloys based on nickel, iron, cobalt, stainless steel. For example, the heater  14  may be formed of nickel aluminide, a material with a layer of alumina on the surface, iron aluminide and other composite materials, the electrically resistive material may optionally be embedded in, encapsulated or coated with an insulating material or vice-versa, depending on the kinetics of energy transfer and the external physicochemical properties required. The heater  14  may include at least one material selected from the group consisting of stainless steel, copper, copper alloys, nickel-chromium alloys, super alloys and combinations thereof. In an example embodiment, the heater  14  may be formed of nickel-chromium alloys or iron-chromium alloys. In another example embodiment, the heater  14  may be a ceramic heater having an electrically resistive layer on an outside surface thereof. 
     The inner tube  62  may include a pair of opposing slots, such that the wick  28  and the first and second electrical leads  109  and  109 ′ or ends of the heater  14  may extend out from the respective opposing slots. The provision of the opposing slots in the inner tube  62  may facilitate placement of the heater  14  and wick  28  into position within the inner tube  62  without impacting edges of the slots and the coiled section of the heater  14 . Accordingly, edges of the slots may not be allowed to impact and alter the coil spacing of the heater  14 , which would otherwise create potential sources of hotspots. In at least one example embodiment, the inner tube  62  may have a diameter of about 4 mm and each of the opposing slots may have major and minor dimensions of about 2 mm by about 4 mm. 
     The first lead  109  is physically and electrically connected to the male threaded connector piece  37 . As shown, the male threaded first connector piece  37  is a hollow cylinder with male threads on a portion of the outer later surface. The connector piece is conductive, and may be formed or coated with a conductive material. The second lead  109 ′ is physically and electrically connected to a first conductive post  110 . The first conductive post  110  may be formed of a conductive material (e.g., stainless steel, copper, etc.), and may have a T-shaped cross-section as shown in  FIG.  2   . The first conductive post  110  nests within the hollow portion of the first connector piece  37 , and is electrically insulated from the first connector piece  37  by an insulating shell  111 . The first conductive post  110  may be hollow as shown, and the hollow portion may be in fluid communication with the air passage  20 . Accordingly, the first connector piece  37  and the first conductive post  110  form respective external electrical connection to the heater  14 . 
     In at least one example embodiment, the heater  14  may heat pre-vapor formulation in the wick  28  by thermal conduction. Alternatively, heat from the heater  14  may be conducted to the pre-vapor formulation by means of a heat conductive element or the heater  14  may transfer heat to the incoming ambient air that is drawn through the e-vaping device  60  during vaping, which in turn heats the pre-vapor formulation by convection. 
     It should be appreciated that, instead of using a wick  28 , the heater  14  may include a porous material which incorporates a resistance heater formed of a material having a high electrical resistance capable of generating heat quickly. 
     As shown in  FIG.  2   , the second section  72  includes a power supply  1 , a control circuit  200 , sensor  16 , and conductive contact assembly (also referred to as a contact assembly or connector assembly)  300 . As shown, the control circuit  200  and sensor  16  are disposed in the housing  6 ′. The contact assembly  300  forms one end of the second section  72 , and a female threaded second connector piece  112  forms a second end. As shown, the second connector piece  112  has a hollow cylinder shape with threading on an inner later surface. The inner diameter of the second connector piece  112  matches that of the outer diameter of the first connector pieces  37  such that the two connector pieces  37  and  112  may be threaded together to form a connection  205 . Furthermore, the second connector piece  112 , or at least the other later surface is conductive, for example, formed of or including a conductive material. As such, an electrical and physical connection occurs between the first and second connector pieces  37  and  112  when connected. 
     As shown, a first lead  720  electrically connects the second connector piece  112  to the control circuit  200 . A second lead  730  electrically connects the control circuit  200  to a first terminal  113  of the power supply  1 . A third lead  725  electrically connects a second terminal  114  of the power supply  1  to the power terminal of the control circuit  200  to provide power to the control circuit  200 . The second terminal  114  of the power supply  1  is also physically and electrically connected to a second conductive post  115 . The second conductive post  115  may be formed of a conductive material (e.g., stainless steel, copper, etc.), and may have a T-shaped cross-section as shown in  FIG.  2   . The second conductive post  115  nests within the hollow portion of the second connector piece  112 , and is electrically insulated from the second connector piece  112  by an insulating shell  116 . The second conductive post  115  may also be hollow as shown. When the first and second connector pieces  37  and  112  are mated, the second conductive post  115  physically and electrically connects to the first conductive post  110 . Also, the hollow portion of the second conductive post  115  may be in fluid communication with the hollow portion of the first conductive post  110 . 
     While the first section  70  has been shown and described as having the male connector piece and the second section  72  has been shown and described as having the female connector piece, an alternative embodiment includes the opposite where the first section  70  has the female connector piece and the second section  72  has the male connector piece. 
     In at least one example embodiment, the power supply  1  includes a battery arranged in the e-vaping device  60 . The power supply  1  may be a Lithium-ion battery or one of its variants, for example a Lithium-ion polymer battery. Alternatively, the power supply  1  may be a nickel-metal hydride battery, a nickel cadmium battery, a lithium-manganese battery, a lithium-cobalt battery or a fuel cell. The e-vaping device  60  may be vapable by an adult vaper until the energy in the power supply  1  is depleted or in the case of lithium polymer battery, a minimum voltage cut-off level is achieved. 
     In at least one example embodiment, the power supply  1  is rechargeable. The second section  72  may include circuitry configured to allow the battery to be chargeable by an external charging device. To recharge the e-vaping device  60 , an USB charger or other suitable charger assembly may be used as described below. 
     In at least one example embodiment, the sensor  16  is configured to generate an output indicative of a magnitude and direction of airflow in the e-vaping device  60 . The control circuit  200  receives the output of the sensor  16 , and determines if (1) the direction of the airflow indicates a draw on the mouth-end insert  8  (versus blowing) and (2) the magnitude of the draw exceeds a threshold level. If these vaping conditions are met, the control circuit  200  electrically connects the power supply  1  to the heater  14 ; thus, activating the heater  14 . Namely, the control circuit  200  electrically connects the first and second leads  720  and  730  (e.g., by activating a heater power control circuit  945  as discussed below with regard to  FIG.  6   ) such that the heater  14  becomes electrically connected to the battery  1 . In an alternative embodiment, the sensor  16  may indicate a pressure drop, and the control circuit  200  activates the heater  14  in response thereto. 
     In at least one example embodiment, the control circuit  200  may also include a light  48 , which the control circuit  200  activates to glow when the heater  14  is activated and/or the battery is recharged. The light  48  may include one or more light-emitting diodes (LEDs). The LEDs may include one or more colors (e.g., white, yellow, red, green, blue, etc.). Moreover, the light  48  may be arranged to be visible to an adult vaper during vaping, and may be positioned between a first end  210  and a second end  220  of the e-vaping device  60 . In addition, the light  48  may be utilized for e-vaping system diagnostics or to indicate that recharging is in progress. The light  48  may also be configured such that the adult vaper may activate and/or deactivate the heater activation light  48  for privacy. 
     In at least one example embodiment, the control circuit  200  may include a time-period limiter. In another example embodiment, the control circuit  200  may include a manually operable switch for an adult vaper to initiate heating. The time-period of the electric current supply to the heater  14  may be set or pre-set depending on the amount of pre-vapor formulation desired to be vaporized. In yet another example embodiment, the sensor  16  may detect a pressure drop and the control circuit  200  may supply power to the heater  14  as long as heater activation conditions are met. 
     Next, operation of the e-vaping device to create a vapor will be described. For example, air is drawn primarily into the first section  70  through the at least one air inlet  44  in response to a draw on the mouth-end insert  8 . The air passes through the air inlet  50 , into the transverse channel  33  at the backside portion of the gasket  15  and into the air passage  20  of the gasket  15 , into the inner passage  21 , and through the outlet  24  of the mouth-end insert  8 . If the control circuit  200  detects the vaping conditions discussed above, the control circuit  200  initiates power supply to the heater  14 , such that the heater  14  heats pre-vapor formulation in the wick  28  to form a vapor. The vapor and air flowing through the inner passage  21  combine and exit the e-vaping device  60  via the outlet  24  of the mouth-end insert  8 . 
     When activated, the heater  14  may heat a portion of the wick  28  surrounded by the heater for less than about 10 seconds. 
     In at least one example embodiment, the first section  70  may be replaceable. In other words, once the pre-vapor formulation of the cartridge is depleted, only the first section  70  may be replaced. An alternate arrangement may include an example embodiment where the entire e-vaping device  60  may be disposed once the reservoir  22  is depleted. In at least one example embodiment, the e-vaping device  60  may be a one-piece e-vaping device. 
     In at least one example embodiment, the e-vaping device  60  may be about 80 mm to about 110 mm long and about 7 mm to about 8 mm in diameter. For example, in one example embodiment, the e-vaping device may be about 84 mm long and may have a diameter of about 7.8 mm. 
     In at least one example embodiment, as shown in  FIG.  2   , the e-vaping device  60  includes the contact assembly  300  as described in greater detail below with reference to  FIGS.  4 - 5   . 
       FIG.  3 A  is an enlarged view of an end of the second (or battery) section of an e-vaping device according to at least one example embodiment. 
     In at least one example embodiment, as shown in  FIG.  3 A , the second section  72  is the same as in  FIG.  2   . The control circuit  200  is disposed on a rigid printed circuit board  410 . The circuit board  410  is connected to the first contact  310  via lead  700 . The circuit board  410  is connected to the second contact  320  via lead  710 . 
       FIG.  3 B  is an enlarged view of an end of the second section of an e-vaping device according to at least one example embodiment. 
     In at least one example embodiment, as shown in  FIG.  3 B , the second section  72  is the same as in  FIG.  2   . The control circuit  200  is disposed on a flexible printed circuit board  1000 . The flexible printed circuit board  1000  allows for the inclusion of a larger battery  1  since the flexible printed circuit board  1000  requires less space within the housing  6 ′ than the rigid circuit board  410  of  FIG.  3 A . 
       FIG.  4    is an exploded view of the conductive contact assembly of  FIG.  2    according to at least one example embodiment.  FIG.  5    is a cross-sectional view of an assembled (or non-exploded) version of the conductive contact assembly of  FIG.  4    along line V-V of  FIG.  4    according to at least one example embodiment. 
     As shown in  FIGS.  4  and  5   , the contact assembly  300  is the same as shown in  FIG.  2   , and is shown in greater detail. As shown in  FIG.  4   , the contact assembly  300  includes the first contact  310 , the second contact  320 , and the end cap housing  340 . 
     The first contact  310  has a disk shape. In at least one example embodiment, the first contact  310  may be formed of a printed circuit board (PCB), which may be rigid or flexible. The first contact  310  includes a substrate  315  with a first conductive portion  312  formed on an upper surface thereof and a second conductive portion  314  formed on a bottom surface thereof. At least one conductive via  313  electrically connects the first and second conductive portions  312  and  314  (see  FIG.  5   ). The first conductive portion  312  and the second conductive portion  314  may be copper, stainless steel, magnetic stainless steel, etc. The first conductive portion  312  may have a generally circular shape, and/or form a pattern. For example, the conductive portion  312  forms the outline of the number “10” in the example of  FIG.  4   . The first conductive portion  312  has an area such that the second contact  320  does not overlap the first conductive portion  312 , and the first conductive portion  312  of the first contact  310  is electrically insulated from the second contact  320 . Instead, a non-conductive portion  311  of the substrate  315  is exposed, and the second contact  320  overlaps and/or contacts the non-conductive portion  311 . 
     As shown, the end cap housing  340  has a generally, hollow cylindrical shape defined by a sidewall  350 . A lower portion of the sidewall  350  includes ridges  355 , and an upper portion includes a flange  360 . In at least one example embodiment, the flange  360  has an outer diameter that is about the same as the outer diameter of the housing  6 ′. The sidewall  350  has an outer diameter that is slightly less than an inner diameter of the housing  6 ′ so that the sidewall  350  may be held in place in the housing  6 ′ by friction fit. The sidewall  350  may include the ridges  355  to aid in holding the end cap housing  340  within the housing  6 ′. 
     In at least one example embodiment, the end cap housing  340  includes a ridge or inner ledge  305  projecting from the inner later surface. The first contact  310  rests on the inner ledge  305 . Two projecting fins  315  project from an end of the end cap housing  340 . The projecting fins  315  separate the inner ledge  305  from the flange  360 . The second contact  320  rests on an outer ledge of the flange  360 . While two projecting fins  315 , each extending at least 90 degrees around the end of the end cap housing  340  are shown, it will be understood the more or less than two projecting fins  315  may be formed. 
     As stated above, a portion of the second contact  320  mates with the flange  360  of the end cap housing  340 , and in doing so, tabs  380  of the second contact  320  fit in slots  390  in the sidewall  350  of the end cap housing  340  so as to secure the second contact  320  with the end cap housing  340 , and hold the first contact  310  in place against the inner ledge  305 . As shown in  FIG.  5   , the lead  700  is connected to the second conductive portion  314  and the lead  710  is connected to at least one of the tabs  380 . 
     In at least one example embodiment, the end cap housing  340  may be formed of plastic. At least a portion of the flange  360  of the end cap housing  340  may be transparent so that light from the heater activation light  48  may be seen through the flange  360 . The first contact  310  and the second contact  320  may be opaque (e.g., may include a solder mask to substantially prevent light from being seen through the PCB), such that the light  48  may not be seen through the end of the e-vaping device  60 . 
     As shown in  FIG.  4   , stops  440  are disposed on the tabs  380 , and the stops latch beneath a portion  450  of the flange  360  when the tabs  380  are mated with the slots  390 . The tabs  380  may be resilient such that the tabs  380  bend slightly when being inserted into the slots  390 , but spring back into an original position to lock the tabs  380  within the slots  390 . 
     The second contact  320  is conductive, and conductive portions of the first contact  310  are electrically isolated from the second contact  320  as described above. Also, in at least one example embodiment, the first contact  310  and the second contact  320  are magnetic. Accordingly, the tabs  380  and the slots  390  are configured to lock together so as to prevent magnetic attraction from removing the first contact  310  and the second contact  320  from the e-vaping device  60 . 
     In at least one alternative embodiment, at least a portion of the first contact  310  may be substantially transparent such that the light  48  shines through a side portion of the end cap housing  340 . 
       FIG.  6    is a circuit diagram illustrating an example embodiment of the control circuit  200  of the e-vaping device shown in  FIG.  1   . The control circuit  200  shown in  FIG.  6    is described with regard to a situation in which the first section  70  is connected to the second section  72  as discussed above. Thus, both the heater  14  and the power supply  1  are shown in  FIG.  6   . 
     As shown in  FIG.  6   , the control circuit  200  includes a microcontroller  905 , a charge controller  800 , a mode control switch circuit  920 , a heater power control circuit  945 , a resistance measurement circuit  94  and a resistor  910 . In this example, the mode control switch circuit  920  includes a mode control switch U 3 , and the heater power control circuit  945  includes a heater power control switch U 1 . The microcontroller  905  includes an analog-to-digital converter (ADC)  9052  and a digital-to-analog converter (DAC)  9054 . The ADC  9052  may be a 10-bit ADC and the DAC  9054  may be an 8-bit DAC. However, example embodiments should not be limited to these examples. 
     The resistance measurement circuit  94  includes a first resistor R 1 , a second resistor R 2 , a third resistor R 3 , a fourth resistor R 4 , an operational amplifier (OP-AMP)  947  and a resistance measurement switch circuit  946 . The resistance measurement switch circuit  946  includes a resistance measurement switch U 2 . The OP-AMP  947  may be a differential operational amplifier. 
     Each of the heater power control switch U 1 , the resistance measurement switch U 2  and the mode control switch U 3  may be transistors (e.g., NMOS or MOSFET transistors), although example embodiments should not be limited to these examples. For example purposes, the switches U 1  through U 3  will be described herein as transistors. In this regard, the heater power control switch U 1  may be referred to as a heater power control transistor U 1 , the resistance measurement switch U 2  may be referred to as a resistance measurement transistor U 2 , and the mode control switch U 3  may be referred to as mode control transistor U 3 . Again, however, example embodiments should not be limited to these examples. 
     Referring to  FIG.  6   , a capacitive input  940  of the microcontroller  905  is connected to a first terminal of the resistor  910 . A second terminal of the resistor  910  is connected to the second contact  320  via the lead  710 . 
     A first terminal of the mode control transistor U 3  is connected to a first node NODE1 between the second terminal of the resistor  910  and the second contact  320 . A second terminal of the mode control switch U 3  is connected to the negative terminal of the power supply  1 , a first end of the heater  14  and a first terminal of the fifth resistor R 4  of the resistance measurement circuit  94  at second node NODE2. A gate of the mode control transistor U 3  is connected to a touch/charge enable terminal  930  (also referred to herein as an enable terminal) at the microcontroller  905 . As discussed herein, the negative terminal of the power supply  1  may also be referred to as common ground, ground, ground plane or common ground plane. 
     The charge controller  800  is electrically connected between the first contact  310  (via the lead  700 ) and the charge enable terminal  935  of the microcontroller  905 . The charge controller  800  is also electrically connected to the positive terminal of the power supply  1  at a third node NODE3. The positive terminal of the power supply  1  is connected to the control circuit  200  via lead  703 , and also connected to the power input terminal PWR of the microcontroller  905  via the lead  725  to provide power to the control circuit  200  and the microcontroller  905 . 
     According to at least one example embodiment, the charge controller  800  may be any known charge controller. In one example, the charge controller  800  may include a linear regulator. According to at least one example embodiment, the charge controller  800  may be configured to determine a level of charge of the power supply  1 , and to control application of charging current i CH  and/or voltage to the power supply  1  based on the determined level of charge. The charge controller  800  may also detect input of a charging current i CH  via the first contact  310  and the lead  700 , and output a charge enable signal CHG_EN based on the detected charging current i CH . In at least one example embodiment, the charge enable signal CHG_EN may be disabled (e.g., have a first logic value, such as a logic low) when no charging current is detected, and may be enabled (e.g., have a second logic value, such as a logic high level) when the charging current is detected. In another example, the charge enable signal CHG_EN may be described as being output when the charging current is detected, and not output when no charging current is detected. The charge controller  800  may also output regulated charging current i CH  to the positive terminal of the power supply  1  to charge the power supply  1 . Because charge controllers such as this are well-known, a more detailed discussion is omitted. 
     Still referring to  FIG.  6   , a first terminal of the heater power control transistor U 1  is connected to the positive terminal of the power supply  1  and a second terminal of the heater power control transistor U 1  is connected to a second end of the heater  14  at a fourth node NODE4 via the first lead  720  between the heater  14  and the control circuit  200 . A gate of the heater power control transistor U 1  is electrically connected to a heater power control terminal  955  of the microcontroller  905 . According to at least this example embodiment, the microcontroller  905  outputs a heater power control signal HEAT_PWR_CTRL to control the heater power control transistor U 1  to regulate and control power from the power supply  1  to the heater  14 . 
     The resistance measurement circuit  94  is electrically connected to the first terminal of the heater power control transistor U 1 , the positive terminal of the power supply  1  and the charge controller  800  at a fifth node NODE5, via node NODE3. The resistance measurement circuit  94  is also electrically connected to the ADC  9052 , the DAC  9054  and a resistance measurement enable terminal  956  at the microcontroller  905 . 
     Within the resistance measurement circuit  94 , a first terminal of the resistance measurement transistor  946  is connected to the first terminal of the heater power control transistor U 1 , the positive terminal of the power supply  1  and the charge controller  800  at the fifth node NODE5. A second terminal of the resistance measurement transistor  946  is connected to a first terminal of first resistor R 1 . The gate of the resistance measurement transistor  946  is connected to the resistance measurement enable terminal  956  at the microcontroller  905 . 
     The second terminal of the first resistor R 1  is connected to a positive input of the operational amplifier (OP-AMP)  947 , the second terminal of the heater power control transistor U 1 , the second end of the heater  14  and an analog input ANALOG of the microcontroller  905  at a sixth node NODE6. 
     The output terminal of the OP-AMP  947  is connected to the ADC  9052  at the microcontroller  905 . The second resistor R 2  is connected in parallel between the negative input terminal and the output terminal of the OP-AMP  947 . The negative input terminal of the OP-AMP  947  is also connected to a first terminal of the third resistor R 3  and a second terminal of the fourth resistor R 4 . 
     The second terminal of the third resistor R 3  is connected to the DAC  9054  at the microcontroller  905 . 
     Still referring to  FIG.  6   , the microcontroller  905  is also electrically connected to the sensor  16 . 
     Although the example embodiment shown in  FIG.  6    is discussed with regard the resistance measurement circuit  94  being separate from the microcontroller  905 , example embodiments should not be limited to this example. Rather, according to one or more other example embodiments, the resistance measurement circuit  94 , or one or more components thereof (e.g., the OP-AMP  947 ), may be included and implemented in the microcontroller  905 . 
     Example operation of the control circuit  200  shown in  FIG.  6    will now be described. 
     According to at least one example embodiment, when the first section  70  is connected to the second section  72 , the mode control transistor U 3  is initially set to the ON state. In this example, the mode control transistor U 3  transitions from the ON state to the OFF state periodically based on a monitoring frequency for the control circuit  200  in response to switching of a charge monitoring signal EN_SIG from the microcontroller  905  via the enable terminal  930  (also referred to herein as an enable terminal). The monitoring frequency is discussed in more detail later. 
     According to at least some example embodiments, each time the mode control transistor U 3  transitions from the ON state to the OFF state the control circuit  200  monitors for a touch event for a relatively short interval (sometimes referred to as a touch detection interval). This relatively short interval may occur at the beginning of what may be referred to as a “wake” cycle based on the sleep state of the microcontroller, after which the control circuit  200  may return to a state in which charging of power supply  1  may be initiated. 
     As discussed herein, switching of the charge monitoring signal EN_SIG may refer to transitioning of the signal from the logic high to the logic low level. As discussed herein, switching of the charge monitoring signal EN_SIG to the logic low level may also be referred to as disabling or disabling output of the charge monitoring signal EN_SIG. However, example embodiments should not be limited to this example. 
     As discussed herein, the ON state of the mode control transistor  920  may also be referred to as an active state, or as the mode control transistor  920  being activated. Similarly, the OFF state may also be referred to as an inactive state or as the mode control transistor  920  being deactivated. 
     According to one or more example embodiments, the microcontroller  905  and/or the control circuit  200  may operate in one of a monitoring mode, a touch command mode and a charging mode. Example operation of the control circuit  200  in each of these operating modes will be discussed in more detail below. 
     In the monitoring mode, the charging enable signal CHG_EN is disabled, and the mode control transistor U 3  is periodically deactivated in response to disabling of the charge monitoring signal EN_SIG from the enable terminal  930  of the microcontroller  905 . Disabling of the charge monitoring signal EN_SIG may also be characterized as enabling a touch monitoring signal. 
     The frequency of the charge monitoring signal EN_SIG, and consequently the periodicity of the deactivation of the mode control transistor U 3 , is based on a state of the microcontroller  905  in the monitoring mode. In one example, the monitoring mode may include a plurality of states. In each of the plurality of states, the charge monitoring signal EN_SIG may have a different frequency, and thus, the deactivation of the mode control transistor U 3  may have a different periodicity. In one example, the monitoring mode may include an active state, a standby state and a hibernate state. 
     In an example of the active state, the charge monitoring signal EN_SIG may have a frequency of about 100 Hz, such that the mode control transistor U 3  is deactivated (transitions to the OFF state) about every 0.01 seconds. 
     In an example of the standby state, the charge monitoring signal EN_SIG may have a frequency of about 50 Hz, such that the mode control transistor U 3  is deactivated about every 0.05 seconds. 
     In an example of the hibernate state, the charge monitoring signal EN_SIG may have a frequency of about 10 Hz such that the mode control transistor U 3  is deactivated about every 0.10 seconds. 
     When a cartridge including a heater element (e.g., first section  70 ) is attached to the battery section (e.g., second section  72 ), the microcontroller  905  detects that the cartridge is attached to the battery section and defaults to the active state. As is generally well-known, the microcontroller  905  may detect attachment of a cartridge to the battery section based on a change in resistance (e.g., from essentially infinite resistance to a finite resistance value) resulting from attachment of the cartridge. 
     If a cartridge is attached and no puff event is detected by the sensor  16  within a first threshold interval (e.g., about 20 seconds) from the time the cartridge was attached, then the microcontroller  905  transitions to the standby state. While in the standby state, if no puff event is detected by the sensor  16  within a second threshold time period (e.g., 40 seconds) from attachment of the cartridge (or, alternatively, another interval of 20 seconds from the time at which the microcontroller  905  transitioned to the standby state), then the microcontroller  905  transitions to the hibernate state. The microcontroller stays in the hibernate state until a puff event is detected by the sensor  16 . If the sensor  16  detects a puff event in the standby or hibernate states, the microcontroller  905  transitions to the active state to increase responsiveness to an adult vaper. When no cartridge is attached, the microcontroller  905  remains in the hibernate state until a cartridge is attached. As discussed above, when the cartridge is attached, the microcontroller  905  transitions to the active state. 
       FIG.  14    is a flow chart illustrating an example embodiment of a method of operating the control circuit  200  shown in  FIG.  6   . The example embodiment shown in  FIG.  14    will be discussed with regard to the microcontroller  905  initially operating in the monitoring mode with the mode control transistor  920  in the ON state. However, example embodiments should not be limited to this example. 
     As discussed above, in the monitoring mode, the mode control transistor U 3  is periodically deactivated by disabling the charge monitoring signal EN_SIG output from the enable terminal  930  of the microcontroller  905 . The method shown in  FIG.  14    may be performed periodically when the mode control transistor  920  is deactivated. In this regard, the method shown in  FIG.  14    may be performed according to the frequency of the charge monitoring signal EN_SIG. 
     Referring to  FIG.  14   , when the mode control transistor U 3  is deactivated in response to the disabling of the charge monitoring signal EN_SIG by the microcontroller  905 , at step S 1404  the microcontroller  905  detects whether a touch has been input by an adult vaper. 
     With regard to step S 1404 , in one example, when the mode control transistor U 3  is in the OFF state, and the adult vaper touches the second contact  320 , the part of the adult vaper (e.g., the finger) touching the second contact  320  and the second contact  320  itself act as terminals of a capacitor, which changes the measured capacitance along the circuit path between the second contact  320  and the capacitive input  940 . When the microcontroller  905  detects this change in capacitance, the microcontroller  905  determines that the adult vaper has touched the second contact  320 , thereby detecting a touch input by the adult vaper. 
     If the microcontroller  905  does not detect a touch input by an adult vaper at step S 1404 , then the microcontroller  905  remains in the monitoring mode and operates as discussed above. 
     Still referring to step S 1404 , if the microcontroller  905  detects a touch input, then the microcontroller  905  enters the touch command mode at step S 1406 . 
     In the touch command mode, the mode control transistor  920  is maintained in the OFF state to electrically isolate the contact  320 , lead  710  and resistor  910  from at least the heater  14  and the negative terminal of the power supply  1 . Since the default state of the mode control transistor U 3  is ON, the microcontroller  905  maintains the mode control transistor U 3  in the OFF state by preventing the charge monitoring signal EN_SIG from being enabled (or from being output) and turning on the mode control transistor  920 . 
     Still referring to  FIG.  14   , after entering the touch command mode at step S 1406 , the microcontroller  905  detects a touch command input by the adult vaper at step S 1408 . According to at least some example embodiments, the microcontroller  905  detects the touch command input by the adult vaper based on the frequency and/or length of the touch by the adult vaper. 
     Once having detected the touch command input by the adult vaper at step S 1408 , the microcontroller  905  executes the detected touch command at step S 1410 . 
     The following tables illustrate example touch commands and operations executed in response to said touch inputs according to one or more example embodiments. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Battery Level On-Demand Indication 
               
               
                 Input = Single Tap on Contact Assembly 
               
            
           
           
               
               
            
               
                 Battery Charge Level (%) 
                 Device Response 
               
               
                   
               
               
                 100-20 
                 Display Solid White/Green LED for 5 
               
               
                   
                 seconds 
               
               
                  20-10 
                 Display Solid Yellow LED for 5 seconds 
               
               
                 10-0 
                 Display Solid Red LED for 5 seconds 
               
               
                 0 
                 Blink Solid Red LED 5 times (0.5 seconds 
               
               
                   
                 on and 0.5 second off) 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 Display while Vaping (Option 1) 
               
               
                 Input = Draw on Device 
               
            
           
           
               
               
            
               
                 Battery Charge Level (%) 
                 Device Response 
               
               
                   
               
               
                 100-20 
                 Display Solid White/Green LED during puff 
               
               
                  20-10 
                 Display Solid Yellow LED during puff 
               
               
                 10-0 
                 Display Solid Red LED during puff 
               
               
                 0 
                 Blink Solid Red LED 5 times (0.5 seconds 
               
               
                   
                 on and 0.5 second off) 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 3 
               
             
            
               
                   
               
               
                 Display while Vaping (Option 2) 
               
               
                 Input = Draw on Device 
               
            
           
           
               
               
            
               
                 Battery Charge Level (%) 
                 Device Response 
               
               
                   
               
               
                 100-0 
                 Display Solid White/Green LED during puff 
               
               
                 0 
                 Blink Solid Red LED 5 times (0.5 seconds 
               
               
                   
                 on and 0.5 second off) 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
             
               
                 TABLE 4 
               
             
            
               
                   
               
               
                 LED Off Input = Press and Hold Contact Assembly for 5 seconds 
               
            
           
           
               
               
            
               
                 Battery Charge Level (%) 
                 Device Response 
               
               
                   
               
               
                 100-0 
                 none 
               
               
                   
               
            
           
         
       
     
     In at least one example embodiment, as shown in Tables 1-4, the e-vaping device may respond to a variety of different touch commands. In other example embodiments, the vaping profile may be altered by inputs or the device may be locked from vaping by tapping the contact assembly. 
     Still referring to  FIG.  14   , although not shown explicitly, after executing the detected touch command, the microcontroller  905  may return to the monitoring mode. 
       FIG.  15    is a flow chart illustrating another example embodiment of a method of operating the control circuit  200  shown in  FIG.  6   . The example embodiment shown in  FIG.  15    will also be discussed with regard to the microcontroller  905  initially operating in the monitoring mode with the mode control transistor U 3  in the ON state. However, example embodiments should not be limited to this example. 
     When the mode control transistor  920  is in the ON state, at step S 1504  the microcontroller  905  determines whether the power supply  1  is being charged based on the charging enable signal CHG_EN from the charge controller  800 . As mentioned above, the charge controller  800  outputs the charging enable signal CHG_EN based on the presence of the charging current icH through the first contact  310  and the lead  700 . In one example, the microcontroller  905  determines that the power supply  1  is being charged if the charge enable signal CHG_EN from the charge controller  800  is enabled (e.g., has logic high level). As discussed herein, the enabling of the charge enable signal CHG_EN may also be referred to as output of the charge enable signal CHG_EN. 
     If the microcontroller  905  detects that the power supply  1  is charging at step S 1504 , then the microcontroller  905  enters the charging mode at step S 1508 . 
     In the charging mode, the mode control transistor  920  remains in the ON state until the charge controller  800  indicates that the charging current icH is no longer flowing to the positive terminal of the power supply  1  by disabling the charge enable signal CHG_EN. In one example, while in the charging mode, the microcontroller  905  maintains the mode control transistor  920  in the ON state by preventing disabling of the enabled charge monitoring signal EN_SIG. 
     Although not explicitly shown in  FIG.  15   , when the charge controller  800  disables the charge enable signal CHG_EN, the microcontroller  905  may return to the monitoring mode. 
     Returning to step S 1504 , if the microcontroller  905  does not detect that the power supply  1  is charging, then the microcontroller  905  remains in the monitoring mode and operates as discussed above. 
     As discussed above, the control circuit  200  further includes a resistance measurement circuit  94 . 
     During puff events by an adult vaper, the application of power to the heater  14  changes the resistance of the heater  14 . Using the resistance measurement circuit  94 , the microcontroller  905  is configured to monitor resistance changes in the heater  14  during puff events, and to control power to the heater  14  based on the changes in resistance. In at least one example embodiment, the microcontroller  905  may selectively disable vaping operation by cutting power to the heater  14  based on changes in resistance of the heater  14 . 
     In the resistance measurement circuit  94  shown in  FIG.  6   , the first resistor R 1  is a precise reference resistor with known resistance value (e.g., about 10.00Ω). The resistors R 2 , R 3  and R 4  are stable resistors used to set the gain and bias of the OP-AMP  947 . The resistors R 2 , R 3 , and R 4  also have known resistance values. The DAC  9054  and the ADC  9052  share the same reference voltage V battery . In this case, the reference voltage V battery  is the voltage of the power supply  1 . Given the configuration of the resistance measurement circuit  94  shown in  FIG.  6   , the voltage output V op-amp  of the OP-AMP  947  is given by Equation (1) shown below. 
     
       
         
           
             
               
                 
                   
                     V 
                     
                       op 
                       ⁢ 
                       
                         - 
                       
                       ⁢ 
                       amp 
                     
                   
                   = 
                   
                     
                       
                         
                           
                             R 
                             2 
                           
                           + 
                           
                             
                               
                                 R 
                                 3 
                               
                               ⁢ 
                               
                                 R 
                                 4 
                               
                             
                             
                               
                                 R 
                                 3 
                               
                               + 
                               
                                 R 
                                 4 
                               
                             
                           
                         
                         
                           
                             
                               R 
                               3 
                             
                             ⁢ 
                             
                               R 
                               4 
                             
                           
                           
                             
                               R 
                               3 
                             
                             + 
                             
                               R 
                               4 
                             
                           
                         
                       
                       * 
                       
                         
                           R 
                           coil 
                         
                         
                           
                             R 
                             coil 
                           
                           + 
                           
                             R 
                             1 
                           
                         
                       
                       * 
                       
                         V 
                         battery 
                       
                     
                     - 
                     
                       
                         
                           R 
                           2 
                         
                         
                           R 
                           3 
                         
                       
                       * 
                       
                         
                           CODE 
                           DAC 
                         
                         
                           2 
                           8 
                         
                       
                       * 
                       
                         V 
                         battery 
                       
                     
                   
                 
               
               
                 
                   ( 
                   1 
                   ) 
                 
               
             
           
         
       
     
     According to one or more example embodiments, the resistance measurement circuit  94  may operate in a calibration mode or phase and a monitoring mode or phase. 
       FIG.  16    is a flow chart illustrating an example embodiment of a method of operating the control circuit  200  in the calibration phase. As discussed above, when a cartridge including a heater element (e.g., first section  70 ) is attached to the battery section (e.g., second section  72 ), the microcontroller  905  defaults to the active state. Additionally, when the cartridge including a heater element (e.g., first section  70 ) is attached to the battery section (e.g., second section  72 ), the control circuit  200  enters the calibration phase. The calibration phase is also referred to as the fine resistance calibration phase. 
     The stress on the heater  14  during a puff event may cause a shift in the “at-rest” resistance of the heater coil. In one example, during the first  5  to  10  puff events on a new cartridge, the “at-rest” resistance may change as much as 0.5% from a previous value. Accordingly, the microcontroller  905  may monitor the length of time between puff events, and if the time interval between puff events exceeds a threshold value (e.g., about 25 seconds), the control circuit  200  may also enter the calibration phase. Accordingly, the control circuit  200  may enter the calibration phase in response to at least two trigger events; that is, attachment of a new cartridge to the second section  72 , and if the time interval between puff events exceeds a threshold value. 
     Referring to  FIG.  16   , in response to one or more of the above-mentioned trigger events, at step S 1604  the microcontroller  905  measures the coarse resistance of the heater coil R coil_coarse . In this case, the coarse resistance of the heater coil is a low resolution measurement by the microcontroller  905  in the analog domain. 
     According to at least one example embodiment, the arrangement of heater  14  and the first resistor R 1 , which is a known stable resistance, in the resistance measurement circuit  94  presents a voltage at the sixth node NODE6, which is input to and/or sensed at the analog input ANALOG of the microcontroller  905 . In this example, the first resistor R 1  and the coil of the heater  15  create a voltage divider circuit. The microcontroller  905  then calculates the resistance of heater  14  based on the known voltage of the power supply (e.g., V in ), the sensed/measured voltage at the sixth node NODE6 (e.g., V out ) and the known resistance of the first resistor R 1 . 
     According to at least one other example embodiment, the OP-AMP  947  may be a component integrated in microcontroller  905 . In this example, the coarse resistance measurement R coil_coarse  is acquired by reconfiguring the positive input of OP-AMP  947  as an ADC input of microcontroller  905 . Once the pin is reconfigured, the arrangement of heater  14  and the first resistor R 1 , which is a known stable resistance, presents a voltage on NODE6 based on which the microcontroller  905  may calculate the resistance of heater  14 . The microcontroller  905  may calculate the resistance of the heater  14  in the same manner as discussed above. 
     At step S 1606 , the microcontroller  905  selects an appropriate digital code or word CODE DAC  based on the initial coarse resistance measurement R coil_coarse . According to at least one example embodiment, the microcontroller  905  selects the digital code CODE DAC  so that the output voltage V op-amp  of the OP-AMP  947  does not saturate the input of the ADC  9052  during subsequent measurements. In one example, the digital code CODE DAC  may be selected such that the output of the OP-AMP  947  is substantially zero. 
     At step S 1608 , the ADC  9052  at the microcontroller  905  samples the voltage output V op-amp  of the OP-AMP  947  to generate a digital representation CODE ADC_0  of the voltage output V op-amp  of the OP-AMP  947 . 
     After calibration, or between iterations of the calibration phase, the digital code CODE DAC  is maintained to fix the voltage output of the DAC  9054 . 
     After detection of a puff event by the sensor  16  and during subsequent vaping, the heater power control signal HEAT_PWR_CTRL controls the heater power control transistor U 1  to regulate the voltage output from the power supply  1  to the heater  14 . According to at least one example embodiment, the heater power control signal HEAT_PWR_CTRL has a duty cycle of 64 ms. According to at least this example embodiment, the duty cycle includes a regulating period and a resistance measurement period. The regulating period may be one of the first and the last 60 milliseconds (ms) of the 64 ms, whereas the resistance measurement period may be the remaining portion of the duty cycle (e.g., one of the first and last 4 ms of the duty cycle). 
     During the regulating period of the duty cycle, the heater power control signal HEAT_PWR_CTRL is pulse train causing the heater power control transistor U 1  to switch on and off to regulate the voltage applied to the heater  14  by the power supply  1 . Also during the regulating period of the duty cycle, the resistance measurement enable signal RES_MEAS_EN is disabled such that resistance measurement transistor U 2  is maintained in the OFF (or open) state. 
     During the resistance measurement period, the heater power control transistor U 1  is switched to the OFF (open) state, while the resistance measurement transistor U 2  is maintained in the ON (closed) state for a given time interval sufficient to allow the microcontroller  905  to acquire a voltage sample from the output of the OP-AMP  947 . In one example, the given time interval may be less than or equal to about 4 ms (e.g., about 1 ms). 
       FIG.  17    is a flow chart illustrating an example embodiment of a method of operating the control circuit  200  in the resistance measurement phase. The method shown in  FIG.  17    is performed during the resistance measurement period of the duty cycle during a puff event. 
     Referring to  FIG.  17   , in response to attaching a cartridge including a heater element (e.g., first section  70 ) to the battery section (e.g., second section  72 ), at step S 1702  the microcontroller  905  initiates a counter value i for the cartridge to zero. The microcontroller  905  utilizes the counter value i to track the number of (e.g., consecutive) times power to the heater  14  is cutoff for the attached cartridge. 
     After initializing the counter value i, when the sensor  16  detects a puff event at step S 1704 , the microcontroller  905  measures/samples the output voltage V op-amp  from the OP-AMP  947  at step S 1706 . The microcontroller  905  then generates an updated digital representation (CODE ADC_1 ) of the output voltage V op-amp  of the OP-AMP  947  based on the sampled output voltage V op-amp . 
     At step S 1708 , the microcontroller  905  then calculates the percentage change in resistance % ΔR between the initial measured resistance of the coil R coil_0  and the current resistance R coil_1  of the heater  14  based on the updated digital representation CODE ADC_1  of the output voltage V op-amp  of the OP-AMP  947  according to Equation (2) shown below. 
     
       
         
           
             
               
                 
                   
                     % 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     Δ 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     R 
                   
                   = 
                   
                     
                       
                         
                           R 
                           
                             coil 
                             ⁢ 
                             
                                 
                             
                             ⁢ 
                             _ 
                             ⁢ 
                             
                                 
                             
                             ⁢ 
                             1 
                           
                         
                         - 
                         
                           R 
                           
                             coil 
                             ⁢ 
                             
                                 
                             
                             ⁢ 
                             _ 
                             ⁢ 
                             
                                 
                             
                             ⁢ 
                             0 
                           
                         
                       
                       
                         R 
                         
                           coil 
                           ⁢ 
                           
                               
                           
                           ⁢ 
                           _ 
                           ⁢ 
                           
                               
                           
                           ⁢ 
                           0 
                         
                       
                     
                     = 
                     
                       
                         
                           
                             ( 
                             
                               
                                 R 
                                 
                                   coil 
                                   0 
                                 
                               
                               + 
                               
                                 R 
                                 1 
                               
                             
                             ) 
                           
                           2 
                         
                         ⁢ 
                         
                           ( 
                           
                             
                               CODE 
                               
                                 ADC 
                                 1 
                               
                             
                             - 
                             
                               CODE 
                               
                                 ADC 
                                 ⁢ 
                                 
                                     
                                 
                                 ⁢ 
                                 _ 
                                 ⁢ 
                                 
                                     
                                 
                                 ⁢ 
                                 0 
                               
                             
                           
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                           R 
                           
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                             ⁢ 
                             
                                 
                             
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                             0 
                           
                         
                         ⁡ 
                         
                           [ 
                           
                             
                               
                                 2 
                                 10 
                               
                               ⁢ 
                               
                                 R 
                                 1 
                               
                               ⁢ 
                               
                                 
                                   
                                     R 
                                     2 
                                   
                                   + 
                                   
                                     
                                       
                                         R 
                                         3 
                                       
                                       ⁢ 
                                       
                                         R 
                                         4 
                                       
                                     
                                     
                                       
                                         R 
                                         3 
                                       
                                       + 
                                       
                                         R 
                                         4 
                                       
                                     
                                   
                                 
                                 
                                   
                                     
                                       R 
                                       3 
                                     
                                     ⁢ 
                                     
                                       R 
                                       4 
                                     
                                   
                                   
                                     
                                       R 
                                       3 
                                     
                                     + 
                                     
                                       R 
                                       4 
                                     
                                   
                                 
                               
                             
                             - 
                             
                               
                                 
                                   
                                     ( 
                                     
                                       
                                         CODE 
                                         
                                           ADC 
                                           1 
                                         
                                       
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                                           ⁢ 
                                           
                                               
                                           
                                           ⁢ 
                                           _ 
                                           ⁢ 
                                           
                                               
                                           
                                           ⁢ 
                                           0 
                                         
                                       
                                     
                                     ) 
                                   
                                 
                               
                               
                                 
                                   
                                     ( 
                                     
                                       
                                         R 
                                         
                                           coil 
                                           0 
                                         
                                       
                                       + 
                                       
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                                         1 
                                       
                                     
                                     ) 
                                   
                                 
                               
                             
                           
                           ] 
                         
                       
                     
                   
                 
               
               
                 
                   ( 
                   2 
                   ) 
                 
               
             
           
         
       
     
     After calculating the percentage change in resistance % ΔR, at step S 1710  the microcontroller  905  determines whether to cut power to the heater based on a comparison between the calculated percent change in resistance % ΔR and a threshold percentage change % R TH . If the calculated percentage change in resistance % ΔR exceeds (e.g., is greater than) the threshold percentage change % R TH , then at step S 1711  the microcontroller  905  cuts power to the heater  14  by disabling the heater power control signal HEAT_PWR_CTRL thereby setting the heater power control transistor U 1  to the OFF state (open). 
     The microcontroller  905  then increments the counter value i at step S 1712 , and determines whether the counter value i exceeds a counter threshold LOCK_TH at step S 1714 . The counter threshold LOCK_TH represents a threshold number of times the power to the heater  14  for the current cartridge may be temporarily cutoff before further vaping by the adult vaper using the current cartridge is prevented. The counter value i exceeds the counter threshold LOCK_TH if the counter value is greater than or equal to the counter threshold LOCK_TH. In one example, the counter threshold LOCK_TH may be about 5, but example embodiments should not be limited to this example. 
     If the microcontroller  905  determines that the counter value i exceeds the counter threshold LOCK_TH, then at step S 1716  the microcontroller  905  prevents power from reaching the heater  14  until the current cartridge is removed and replaced. As with step S 1711 , the microcontroller  905  cuts power to the heater  14  by disabling the heater power control signal HEAT_PWR_CTRL thereby setting the heater power control transistor U 1  to the OFF state (open). 
     Returning to step S 1714 , if the counter value i does not exceed the counter threshold LOCK_TH (i&lt;LOCK_TH), then the process returns to step S 1704  and the method continues as discussed above upon detection of a next puff event by the sensor  16 . 
     Returning now to step S 1710 , if the microcontroller  905  determines % ΔR does not exceed the threshold percentage change % R TH  (% ΔR&lt;% R TH ), and thus, power to the heater  14  need not be cutoff, then the microcontroller  905  re-initializes the counter value i to zero at step S 1702 , and continues as discussed above upon detection of a next puff event by the sensor  16 . 
     Although Equation (2) provides a complete analytic solution of the change in resistance, some assumptions may be made to simplify the equation. One assumption is that the resistance change is relatively small so that some intermediate steps may be linearized using Taylor expansion, thereby resulting in Equation (3) shown below. 
     
       
         
           
             
               
                 
                   
                     % 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     Δ 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     R 
                   
                   = 
                   
                     
                       
                         
                           R 
                           
                             coil 
                             ⁢ 
                             
                                 
                             
                             ⁢ 
                             _ 
                             ⁢ 
                             
                                 
                             
                             ⁢ 
                             1 
                           
                         
                         - 
                         
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                             ⁢ 
                             
                                 
                             
                             ⁢ 
                             _ 
                             ⁢ 
                             
                                 
                             
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                           ( 
                           
                             
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                       ⁢ 
                       
                         
                           
                             
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                               3 
                             
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                               4 
                             
                           
                           
                             
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                               3 
                             
                             + 
                             
                               R 
                               4 
                             
                           
                         
                         
                           
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                           + 
                           
                             
                               
                                 R 
                                 3 
                               
                               ⁢ 
                               
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                                 4 
                               
                             
                             
                               
                                 R 
                                 3 
                               
                               + 
                               
                                 R 
                                 4 
                               
                             
                           
                         
                       
                       ⁢ 
                       
                         ( 
                         
                           
                             
                               R 
                               1 
                             
                             
                               R 
                               
                                 coil 
                                 0 
                               
                             
                           
                           + 
                           2 
                           + 
                           
                             
                               R 
                               
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                                 0 
                               
                             
                             
                               R 
                               1 
                             
                           
                         
                         ) 
                       
                     
                   
                 
               
               
                 
                   ( 
                   3 
                   ) 
                 
               
             
           
         
       
     
     Because of a potentially increased quiescent current draw, to use the capacitive touch channel on the microcontroller  905 , the control circuit  200  may detect an effect of an adult vaper&#39;s body on the resistance of the circuit in at least one example embodiment. Differences in skin moisture should not affect the ability of the circuit to respond to an adult vaper&#39;s input. 
     As discussed above, according to one or more example embodiments, the mode control transistor  920  may be a MOSFET or NMOS transistor and may provide more reliable detection even when sensitivity of the capacitance measurement is decreased. 
     In at least one other example embodiment, a diode (not shown) may be added to the charge controller input. In this example, the diode acts as an open circuit until a charge voltage is present across the second contact  320  and the first contact  310 . 
       FIG.  7    is a diagram of a control circuit according to another example embodiment. 
     In at least one example embodiment, an adult vaper&#39;s commands may be detected through changes in resistance, rather than capacitance. In this example, the second contact  320  is the charge cathode, which is electrically connected to the negative terminal  70  of the power supply. The first contact  310 ′ is the charge anode, which is electrically connected to an input of an analog-to-digital (ADC)  1010  included in the microcontroller  905 ′. 
     According to at least this example embodiment, the microcontroller  905 ′ may be configured to detect a resistance between the charge anode  310 ′ and the charge cathode  320 ′. When an adult vaper places, for example, a finger on the across the charge anode  310 ′ and the charge cathode  320 ′, the connection between the charge anode  310 ′ and the charge cathode  320 ′ is closed thereby changing the resistance of the input to the microcontroller  905 ′. The microcontroller  905 ′ detects this change in resistance to detect a touch input by the adult vaper. 
     The circuit of  FIG.  7    may allow for a lower quiescent current draw. The resistive detection circuit may be configured as an interrupt to the microcontroller  905 ′, which may allow for the microcontroller  905 ′ and accessories to be in a low power sleep state until an adult vaper closes the circuit by touching the second contact  320  of the e-vaping device  60 , which wakes the e-vaping device  60  so that an appropriate response to the touch may be given. 
       FIG.  8    is a diagram of a control circuit according to yet another example embodiment. 
     In at least one example embodiment, as shown in  FIG.  8   , the first contact  310 ″ is a charge anode, which is electrically connected to a charge controller  1120  via a diode  1140 . The first contact  310 ″ is also electrically connected to the capacitive input  1110  of the microcontroller  905 ″ via a resistor  1100 . In this example, the control circuit enables both resistive touch detection and capacitive touch detection by the e-vaping device  60 . 
     According to at least this example embodiment, a more sensitive resistance measurement may be used to wake the e-vaping device  60  when an adult vaper touches the second contact  320  of the e-vaping device  60 . After measuring the resistance, capacitance is measured to verify that the adult vaper has touched the second contact  320 , and to suppress quiescent current draw requirements of circuits utilizing capacitive touch detection alone. 
       FIG.  9    is a perspective view of a charger of an e-vaping device according to at least one example embodiment. 
     In at least one example embodiment, as shown in  FIG.  9   , the battery  1  of the e-vaping device  60  of  FIGS.  1 - 8    may be recharged using a charger  500 . 
     In at least one example embodiment, the charger  500  includes a housing  510  including a top wall  520 . The top wall  520  may be rounded and/or generally bell-shaped or dome-shaped in cross-section, such that side portions of the top wall  520  are angled downward from a central portion of the top wall  520 . The housing  510  may also include a sidewall  530  connected to the top wall  520 . The top wall  520 , at least one sidewall  530 , and a bottom wall  535  (shown in  FIG.  12   ) define an internal compartment that houses a charging circuit as discussed below. The housing  510  may be formed from one or more pieces of a material, such as a plastic or a metal. 
     In at least one example embodiment, the sidewall  530  has generally rounded corners, such that the sidewall  530  extends entirely about a perimeter of the charger  500 . In at least one example embodiment, the sidewall  530  is integrally formed with the top wall  520 , and edges where the sidewall  530  and top wall  520  meet are generally rounded. 
     In other example embodiments, the housing  510  may include four sidewalls  530  that meet at corners (not shown). 
     In at least one example embodiment, a charging slot  540  is formed in the top wall  520  of the housing  510 . The charging slot  540  may be generally cylindrical. The charging slot  540  is defined by a bottom wall  600  and at least one internal side wall  610 . The charging slot  540  may be sized and configured to receive the second end  220  of the e-vaping device  60 . The bottom wall  600  may be generally flat. In other example embodiments, the bottom wall  600  may include bumps or curves. 
     In at least one example embodiment, a light pipe  550  substantially surrounds the charging slot  540 . The light pipe  550  is generally tubular in shape, such that when the second end  220  of the e-vaping device  60  is inserted in the charging slot  540 , the second end  220  passes through the light pipe  550 . The light pipe  550  may include an extension  550   a  that extends through an internal compartment  525  and through a portion of the sidewall  530 , such that the extension  550   a  is visible at a first end  605  of the charger  500 . The light pipe  550  may be formed of a substantially transparent material that allows light from the e-vaping device  60  to be viewed while the e-vaping device  60  is docked in the charging slot  540 . An apex  505  of the top wall  520  may be about a same height as a top surface of the light pipe  550 . 
     In at least one example embodiment, the charger  500  also includes a USB plug  560 . In other example embodiments, instead of a USB plug  560 , a mini-USB plug or other power connection plug may be included with the charger  500 . The charger  500  may be connected to a power source via the USB plug  560  to allow charging of the battery  1  of the e-vaping device  60  connected to the charger  500 . 
     In at least one example embodiment, the housing  510  is smooth. In other example embodiments, the housing  510  may include bumps and/or ridges that assist in gripping of the charger  500  when plugging the USB plug  560  into an outlet or removing the USB plug  560  from the outlet. 
       FIG.  10    is a top view of the charger of  FIG.  10    according to at least one example embodiment.  FIG.  12    is a cross-sectional view of the charger of  FIG.  10    along line XII-XII according to at least one example embodiment. 
     In at least one example embodiment, the charger  500  is the same as in  FIG.  9   . As shown, the charger  500  includes a first charging contact  630  and a second charging contact  640 . At least one of the first charging contact  630  and the second charging contact  640  may be magnetic. The first charging contact  630  has a T-shaped cross-section with a circular, flat top surface projecting up into the charging slot  540 . The first charging contact  630  is sized and configured to attract and/or contact the first contact  310  of the e-vaping device  60  so as to form a first electrical connection therewith and align the second end  220  of the e-vaping device  60  within the charging slot  540 . The second charging contact  640  is cylindrical with a top surface having in inwardly projecting flange. The second charging contact  640  surrounds the first charging contact  630 , and is electrically insulated from the first charging contact  630  by an insulator  635 . The insulator  635  is cylindrical with a top surface having an outwardly projecting flange. The second charging contact  640  is sized and configured to attract and/or contact the second contact  320  of the e-vaping device  60  so as to form a second electrical connection therewith and align the second end  220  of the e-vaping device  60  within the charging slot  540 . The first charging contact  630  and/or the second charging contact  640  may be formed of magnetic stainless steel or any other suitable material that provides good conduction and is magnetic. 
     As shown in  FIG.  12   , the internal components of the charger  500  are shown arranged within the internal compartment  525 . As shown, the USB plug  560  extends through a sidewall  520  of the housing  510  into the internal compartment  525 . The USB plug  560  is in direct electrical communication with a charger printed circuit board  650 , which is in electrical communication with the first charging contact  630  and the second charging contact  640  via leads  645 ,  647 . A magnet  683  is positioned beneath a portion of the second charging contact  640  and between the insulator  635  and the second charging contact  640 . The flanges of the insulator  635  and the second charging contact  640  extend over the top surface of the magnet  683 . The magnet  683  is cylindrical and the first charging contact  630  extends through a center of the magnet  683 . The first charging contact  630  may be biased upwards into the charging slot by a spring  632  disposed within the insulator  635  such that the first charging contact  630  has a top surface that is above a top surface of the second charging contact  640  when no e-vaping device  60  is inserted in the charging slot  540 .  FIG.  13    shows an exploded view of a charger contact assembly of the charger of  FIGS.  9 - 12   .  FIG.  11    is an exploded view of the charger of  FIG.  9   . In at least one example embodiment, a shroud  675  at least partially surrounds the light tube  550 . The shroud  675  may substantially prevent and/or reduce visibility of light through a portion of the light tube  550 . As shown, the light tube  550  may include a first tubular portion  552 , and the extension  554 , which extends through an outlet in the sidewall  525 . 
     Example embodiments have been disclosed herein, it should be understood that other variations may be possible. Such variations are not to be regarded as a departure from the spirit and scope of the present disclosure, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.