Portable device and related method

Abstract

The present disclosure relates to a portable device comprising: an electrical component that, in use, provides a variable power demand; an energy storage device; a power supply; and control circuitry configurable between a first configuration in which the power source outputs power to the electrical component and to the energy storage device via the electrical component, and a second configuration in which the power source outputs power to the energy storage device via the electrical component; and in a second configuration, the power source outputs power to the electrical component and the energy storage device outputs power to the electrical component.

Description

Technical Field

[0001] The present invention relates to portable devices using power obtained from a power source, such as a battery of the device. The invention particularly, but not exclusively, relates to hair styling and / or hair drying devices that output heat for drying or styling hair. Such hair drying and styling may be performed by a user on his own hair, or by, for example, a hair stylist. Background Art

[0002] There are many types of portable devices that use power obtained from a battery or power supply unit of the device. These devices include, for example, hair stylers, heated brushes, curling irons, electronic cigarettes, hot glue guns, soldering irons and irons.

[0003] Heated hair styling tools use heat to raise the temperature of the hair to a desired styling temperature. Hair straighteners with heated plates apply heat directly via conduction to heat the user's hair, which may be wet or dry, to achieve the desired temperature for styling. The hair may be heated to a temperature particularly suitable for styling the hair (e.g., heated to or above the glass transition temperature). Similarly, heated brushes or curling irons may also be used to style the hair by heating the hair to a temperature suitable for styling.

[0004] As used herein, the expressions "drying the hair," "drying the hair," or "reducing the moisture level of the hair," and the like, may refer to both the removal of "unbound" water that is present on the exterior of the hair when it is wet, or the removal of "bound" water that is present within individual strands of hair that may interact with the hair when it is heat styled. It is not necessary to remove "bound" water when drying the hair, although some removal of bound water may occur during the drying or styling process. It should also be noted that the term "wet" as used in this disclosure should be broadly interpreted to include not only hair that is wetted with water, but also hair that is wetted with a liquid other than water. For example, the hair may be wetted by a solvent-based colorant of the present invention that may be used for drying and / or styling.

[0005] It is also desirable for a cordless battery powered device to have an improved run time while minimizing any corresponding increase in size and weight of the device. One way to increase the run time is to provide a higher capacity battery, for example by using an alternative type of battery cell chemistry. However, there is a problem that higher capacity batteries typically have a lower maximum power output (and a correspondingly lower maximum rated current) which may be lower than the maximum power required by the device during normal use. For example, a Li-ion battery cell having a maximum power output of between 100W and 150W typically has a capacity of between about 2000mAh and 3000mAh, while a higher capacity Li-ion battery cell having a capacity of between about 3000mAh and 3500mAh typically has a significantly lower maximum power output of between about 30W and 60W, which is insufficient for many applications.

[0006] Therefore, there is a need for more efficient battery powered devices with improved runtime while also ensuring sufficient maximum power output. In addition, for devices that draw power from the mains supply via a power supply unit (PSU) of the device, it is desirable to reduce the size and cost of the PSU that needs to be provided in order to deliver sufficient power during use.

[0007] The object of the present invention is to solve or at least partially improve one or more of the above problems. Summary of the invention

[0008] The present invention provides a hair styling appliance and a portable device as described in the accompanying claims.

[0009] The disclosed method and apparatus enable the use of batteries with larger capacity (or a smaller and lighter PSU) by smoothing the power demand on the battery. The inventors have recognised that the combination of a power source and a capacitor enables improved run time of a device while also providing adequate power output. Advantageously, providing a capacitor enables the use of a wider range of battery technologies and / or PSUs, as the lower power output of certain types of battery cells (or lower power PSUs, which are typically smaller and / or less complex and less expensive) can be mitigated by smoothing the peaks in the power demand.

[0010] According to a first aspect of the present invention, there is provided a portable device comprising: an electrical component which provides a variable power demand during use; an energy storage device; a power supply; and a control circuit system which is configurable between a first configuration and a second configuration: in the first configuration, the power supply outputs power to the electrical component and outputs power to the energy storage device via the electrical component; and in the second configuration, the power supply outputs power to the electrical component and the energy storage device outputs power to the electrical component.

[0011] The control circuitry may be configured into the first configuration or the second configuration based on a magnitude of the variable power demand.

[0012] The control circuit system can be configured to the first configuration or the second configuration based on the size of the variable power demand and the threshold power output of the power supply; and when the variable power demand is greater than the threshold power output of the power supply, the control circuit system can be configured to the second configuration.

[0013] The threshold power output may be based on an available power output of the power supply.

[0014] The variable power demand may be a periodic power demand.

[0015] According to a second aspect of the present invention, there is provided a portable device comprising: an electrical component which provides a variable power demand during use; an energy storage device; a power supply; and a control circuit system which is configured to: control the power supply to output power to the component at a first power level; when the variable power demand is greater than the first power level, control the energy storage device to output power to the component; and when the variable power demand is less than a second power level, control the power supply to output power to the energy storage device and to the component.

[0016] The variable power demand may be a periodic power demand.The portable device may be a hair styling device.The energy storage means may comprise a capacitor.

[0017] The electrical component may include a first portion that provides a first variable power demand in use and a second portion that provides a second variable power demand in use; wherein the power supply is operable to charge the capacitor via the first portion; and wherein the power supply and the capacitor are operable to output power to the second portion.

[0018] The electrical component may include a heater.

[0019] The portable device is operable to charge the energy storage device without passing current through the component providing the variable power demand.

[0020] The power supply is operable to charge the capacitor via at least one heater electrode of the heater. The at least one heater electrode may include a first heater electrode and a second heater electrode; wherein the power supply is operable to charge the capacitor via the first heater electrode; and wherein the capacitor is operable to discharge via the second heater electrode.

[0021] The first heater electrode and the second heater electrode may be arranged in series.

[0022] The second heater electrode may have a lower resistance than the first heater electrode.

[0023] The first heater electrode may be powered by the power supply at a higher voltage than a voltage from the energy storage device used to power the second heater electrode.

[0024] The heater may have one or more heating zones, each heating zone comprising the first heater electrode and the second heater electrode for heating the heating zone.

[0025] The heater may comprise a heating surface for heating hair in contact with the heating surface, and each heating zone may comprise a respective portion of the heating surface.

[0026] The first heater electrode and the second heater electrode may each heat the portion of the heating surface of the heating zone.

[0027] The heating surface may be defined by a common heating member, or each heating zone may have a respective heating member.The heating member may be planar, tubular, corrugated or ribbed.

[0028] The first heater electrodes and the second heater electrodes of the heating zones may be interleaved.

[0029] The heater may include a plurality of heating zones, and the portable device may include a single controller for controlling whether the energy storage device is able to discharge via the second heater electrode of each of the heating zones.

[0030] The portable device may further include a heater controller for controlling power supplied to the first heater electrode and the second heater electrode by outputting a common control signal applied to a first switch and a second switch, wherein the first switch is coupled to the first heater electrode and the second switch is coupled to the second heater electrode.

[0031] The heater controller may be configured to simultaneously control power supplied to the first heater electrode and the second heater electrode by outputting the common control signal.

[0032] The capacitance of the capacitor may be between 10 F and 100 F. The power supply may comprise a battery cell or a battery. The power supply may comprise a power supply unit configured to draw power from a mains supply.

[0033] The control circuitry may also be configured to control power output to the energy storage device based on a state of charge of the energy storage device.

[0034] The power output to the component providing the variable power demand and the power output to the energy storage device may be interleaved in the time domain.

[0035] According to a third aspect of the present invention, there is provided a portable device comprising: a power source; an energy storage device; an electrical component which provides power requirements during use; wherein the power source is configured to charge the energy storage device via the electrical component.

[0036] The electrical component may include a heater; wherein the heater includes at least one heater electrode; and wherein the power supply is configured to charge the energy storage device via the heater electrode of the heater.

[0037] The energy storage device may comprise a capacitor.The capacitor is operable to discharge via a heater electrode of the heater.

[0038] The power source is operable to charge the capacitor via a first heater electrode of the heater; and wherein the capacitor is operable to discharge via a second heater electrode of the heater that is different from the first electrode.

[0039] The second heater electrode may have a lower resistance than the first heater electrode.

[0040] The first heater electrode may be powered by the power supply at a higher voltage than a voltage from the capacitor used to power the second heater electrode.

[0041] The portable device may be a hair styling device.

[0042] According to a fourth aspect of the present invention, a portable device is provided, comprising: a power supply; a capacitor; a heater comprising a first heater electrode and a second heater electrode; and a control circuit system, which can be configured in the following configurations: a first configuration, wherein the power supply charges the capacitor via the first heater electrode; a second configuration, wherein the power supply charges the capacitor via the second heater electrode; a third configuration, wherein the capacitor discharges via the first heater electrode and the power supply outputs power to the first heater electrode and the second heater electrode; and a fourth configuration, wherein the capacitor discharges via the second heater electrode and the power supply outputs power to the first heater electrode and the second heater electrode.

[0043] The portable device may be a hair styling device.

[0044] The control circuitry may include a plurality of switches; and wherein the control circuitry is configurable between the first configuration, the second configuration, the third configuration, and the fourth configuration by operation of the switches.

[0045] The first heater electrode and the second heater electrode may be arranged in series.

[0046] According to a fifth aspect of the present invention, there is provided a hair styling device comprising: an electrical component which provides a variable power demand during use; an energy storage device; a power supply; and a control circuit system which is configurable between a first configuration and a second configuration: in the first configuration, the power supply outputs power to the electrical component and the power supply outputs power to the energy storage device via the electrical component; and in the second configuration, the power supply outputs power to the electrical component and the energy storage device outputs power to the electrical component.

[0047] According to a sixth aspect of the present invention, there is provided a hair styling device, comprising: an electrical component which provides a variable power demand during use; an energy storage device; a power supply; and a control circuit system, which is configured to: when the variable power demand is lower than a first threshold power demand, control the power supply to output power to the electrical component and to output power to the energy storage device; and when the variable power demand is greater than or equal to a second threshold power demand, control the power supply to output power to the electrical component and to control the energy storage device to output power to the electrical component.

[0048] According to a seventh aspect of the present invention, there is provided a hair styling device, comprising: an electrical component which provides a variable power demand during use; an energy storage device; a power supply; and a control circuit system, which is configured to: control the power supply to output power to the electrical component at a first power level; when the variable power demand is greater than the first power level, control the energy storage device to output power to the electrical component; and when the variable power demand is less than a second power level, control the power supply to output power to the energy storage device and to the electrical component.

[0049] According to an eighth aspect of the present invention, there is provided a hair styling device comprising: a power supply; a capacitor; a heater comprising at least one heater electrode; wherein the power supply is operable to charge the capacitor via the heater electrode of the heater.

[0050] According to the ninth aspect of the present invention, there is provided a hair styling device comprising: a power supply; a capacitor; a heater comprising a first heater electrode and a second heater electrode; and a control circuit system which can be configured in the following configurations: a first configuration, wherein the power supply charges the capacitor via the first heater electrode; a second configuration, wherein the power supply charges the capacitor via the second heater electrode; a third configuration, wherein the capacitor is discharged via the first heater electrode and the power supply outputs power to the first heater electrode and the second heater electrode; and a fourth configuration, wherein the capacitor is discharged via the second heater electrode and the power supply outputs power to the first heater electrode and the second heater electrode.

[0051] According to a tenth aspect of the present invention, there is provided a hair styling device comprising: a heater having one or more heating zones, each heating zone comprising a first heater track and a second heater track for heating the heating zone; a power source for providing power to heat one or more of the heating zones using the first heater track in the heating zone; an energy storage device for providing power to heat one or more of the heating zones using the second heater track in the heating zone; and a charging circuit system for charging the energy storage device using power from the power source.

[0052] The hair styling appliance is operable to charge the energy storage device using the charging circuitry without passing current through the first heater track or the second heater track.

[0053] The second heater track may have a lower electrical resistance than the first heater track.

[0054] The first heater rail may be powered by the power supply at a higher voltage than a voltage from an energy storage device used to power the second heater rail.

[0055] The heater may comprise a plurality of heating zones, and the hair styling device may further comprise a single controller for controlling whether the capacitor is able to discharge via the second heater track of each heating zone.

[0056] The hair styling device may further include a heater controller for controlling power supplied to the first heater track and the second heater track by outputting a common control signal applied to a first switch coupled to the first heater track and a second switch coupled to the second heater track.

[0057] The heater controller may be configured to simultaneously control power supplied to the first heater rail and the second heater rail by outputting the common control signal.

[0058] The heater may comprise a heating surface for heating hair in contact with the heating surface, and each heating zone may comprise a respective portion of the heating surface.

[0059] The first heater track and the second heater track may each heat the portion of the heating surface of the heating zone.

[0060] The heating surface may be defined by a common heating member, or each heating zone may have a respective heating member.

[0061] The heating member may be planar, tubular, corrugated or ribbed.

[0062] The first heater tracks and the second heater tracks of the heating zones may be staggered.

[0063] The power source may include a battery cell or battery.

[0064] The charging circuitry may include a DC-DC converter.

[0065] The charging circuitry may be configured to control a rate of charging of the energy storage device based on a power demand on the power source from the heater and based on a state of charge of the energy storage device.

[0066] The charging circuitry may be configured to charge the energy storage device using power from the power source when a power demand on the power source from the heater is below a threshold.

[0067] The charging of the energy storage device and the output of power from the power source to the heater may be staggered in the time domain.

[0068] The hair styling device may comprise a plurality of heaters, each heater having one or more respective heating zones.

[0069] The energy storage device may include a capacitor.

[0070] According to an eleventh aspect of the present invention, a method for controlling power delivery in a portable device is provided, the method comprising: providing a device according to any one of the first to tenth aspects; and controlling power delivery from the power supply and the energy storage device. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Embodiments of the present invention will now be described, by way of example only, and with reference to the accompanying drawings, in which:

[0072] Figure 1a shows a schematic diagram of an exemplary hair styling device;

[0073] Figure 1b The hair styling device is shown in use;

[0074] Figure 2 A simplified block diagram of a hair styling device is shown;

[0075] Figure 3 a graph showing the periodic power demand of a device;

[0076] Figure 4a shows the periodic power demand of the device and the corresponding power output of the power supply of the device;

[0077] Figure 4b shows the periodic power demand of the device and the otherwise corresponding power output of the device's power supply;

[0078] Figure 4c A graph showing instantaneous peak current from a power supply;

[0079] Figure 4d a graph showing the duty cycle of the device;

[0080] Figure 4e a graph showing dissipated energy losses at a power supply;

[0081] Figure 5 shows a table indicating maximum discharge current, maximum peak power, and capacity for three power supply configurations;

[0082] Figure 6a a circuit diagram showing the configuration of the power control circuitry of the apparatus;

[0083] Figure 6b a circuit diagram showing another configuration of the power control circuitry of the apparatus;

[0084] Figure 7 A heater comprising two heater tracks is shown;

[0085] Figure 8 a circuit diagram showing another configuration of the power control circuitry of the apparatus;

[0086] Fig. 9 a circuit diagram showing another configuration of the power control circuitry of the apparatus;

[0087] Fig.10 Shows the use of Fig. 9The state of the power control circuit system;

[0088] Fig.11 Shows the use of Fig. 9 another state of the power control circuit system;

[0089] Fig.12 Shows the use of Fig. 9 another state of the power control circuit system;

[0090] Fig.13 Shows the use of Fig. 9 another state of the power control circuit system;

[0091] Fig.14 Shows the use of Fig. 9 another state of the power control circuit system;

[0092] Fig.15 a circuit diagram showing another configuration of power control circuitry for an apparatus; and

[0093] Fig.16 A graph of hair temperature versus drying time is shown. DETAILED DESCRIPTION

[0094] The embodiments represent the best ways known to the applicant to put the invention into practice. However, these embodiments are not the only ways to implement the invention.

[0095] Device Overview

[0096] Figure 1a A schematic diagram of a hair styling device 10 suitable for implementing one or more methods of the present invention is shown. However, the device 10 need not necessarily be Figure 1a Any other suitable type of device 10 (e.g., a suitable portable or handheld device) using power obtained from a power source (e.g., a battery or PSU) may be used, such as a heated hair straightening brush, a heated hair volume brush, a curling iron, an electronic cigarette, a hot glue gun, or a portable iron. The present disclosure is particularly relevant to devices having intermittent or periodic power loads during use. It will be appreciated that the term "portable device" is used to refer to both corded and cordless devices.

[0097] For ease of understanding, the main reference Figure 1a The present invention will be described with reference to an apparatus 10 of the type shown in FIG. Figure 1aThe device 10 is a hair straightener that includes a pair of arms 11a, 11b and a corresponding pair of heating plates 12a, 12b for transferring heat to the user's hair 17 by conduction. The device 10 may include one or more conduction heaters, convection heaters, radiant heaters (or any combination thereof), or any other suitable heating device for transferring heat to the user's hair 17.

[0098] Figure 1b The device 10 is shown being used during a styling process. In use, the device 10 will typically receive a section (lock) of hair 17 for heating and styling using the heating plates 12a, 12b. As the user heats the lock of hair 17, heat is transferred from the heating plates 12 to the hair 17, and the total power output required to maintain the plates 12 at an operating temperature increases by 10. When the device 10 is not passing over the user's hair 17, the total power output required by the device to maintain the heating plates 12 at an operating temperature is relatively low. Therefore, the total power load of the device is periodic or intermittent. It should be understood that references to "periodic" power requirements used herein also include power requirements that are approximately periodic (i.e., not necessarily exactly periodic). In other words, as later referenced Figure 3 As mentioned, the time period of the power demand does not have to be constant.

[0099] The user interface 13 is provided to allow the user to set user-defined parameters and to allow the device 10 to output information to the user. For example, the temperature or humidity level of the hair 17 can be indicated to the user via the user interface 13, and / or the user can set a desired temperature, humidity level or hairstyle for the hair 17 via the user interface 13. The user interface 13 may include a dial, a button or a touch display for allowing the user to input information to the device 10, and the user interface 13 may include an indicator light, a display, a sound generator or a tactile feedback generator for outputting information to the user. In this example, the user interface 13 also includes: a control button or switch 14 to enable the user to turn the device on or off; and an indicator light 15 to display whether the power is on. It is understood that the user interface 13 can be provided at any suitable location on the device 10. Alternatively, the user interface can be omitted, or can simply include an on / off switch 14.

[0100] The printed circuit board assembly may be provided at any suitable location within the housing of the device 10 and carries control circuitry for controlling the operation of the device 10 and for controlling interaction with a user via the user interface 13. In this example, power is provided to the device 10 by one or more DC batteries or battery cells (not shown) provided inside the housing of the device 10. The batteries may be rechargeable, for example from a mains power supply or from a DC power source via a charging cord, thereby enabling the device 10 to be a cordless product.

[0101] Alternatively, power may be provided by means of a PSU provided within the housing of the device 10 via a power cord for drawing power from the mains supply.

[0102] The device 10 may include one or more sensors for determining the temperature or moisture level of the hair 17, or the temperature of a portion of the device 10. Measurements obtained using the sensors may be used to control the operation of the device 10 (eg, controlling the power output of a heater).

[0103] The present invention is not limited to Figure 1a The type of device 10 shown in FIG. 10 . For example, a device such as a heated brush may be used.

[0104] When the device 10 uses heated air to heat the user's hair 17, the device 10 may include a heater having an electric heating coil (or any other suitable type of heating element) that is operable to heat air drawn in by the fan assembly.

[0105] More generally, the invention relates to any suitable device using power obtained from a power source, such as a battery or a PSU provided within the housing of the device.

[0106] Schematic block diagram

[0107] Figure 2 is a simplified block diagram of apparatus 10 showing its major components.

[0108] As shown, the device 10 includes a power supply 21. The power supply 21 may be a PSU that obtains power from the mains supply via a power line. Alternatively, the power supply 21 may be a battery, in which case the mains supply input may be used to charge the battery via an AC-DC converter, which may be external or internal to the device 10. The device 10 also includes a capacitor 22. The capacitor 22 may be a supercapacitor (or a plurality of supercapacitors arranged in series or in parallel) having a capacitance between, for example, 10F and 100F. Two or more capacitors may be arranged in series to increase the operating capacitor voltage. Two or more capacitors may be arranged in parallel to increase the total capacity while providing greater flexibility in size / occupancy. As described in more detail below, the capacitor 22 is configured to receive power from the power supply 21 to charge the capacitor 22, and to output power to the heater 23 (which may be a heating plate 12) by discharging via one or more heater tracks (which may also be referred to as "heater electrodes") of the heater 23. The power supply 21 is also arranged to output power to the heater 23, so that the heater 23 may receive power from the power supply 21 and the capacitor 22 at the same time.

[0109] In use, when the power output of the heater 23 is below a first threshold, the capacitor 22 receives power from the power source 21 to charge the capacitor 22, and when the power output of the heater 23 is above a second threshold, the capacitor 22 outputs power to the heater 23. The first threshold and the second threshold may be the same, or alternatively may be different. The first threshold and / or the second threshold may correspond to the average power output of the device 10. The first threshold and / or the second threshold may alternatively be based on the power output available from the power source 21. The power output available from the power source 21 is not necessarily the maximum possible power that can be output from the power source 21, but may be a preconfigured operational maximum power output (e.g., a preconfigured threshold maximum power output that prevents the power source 21 from operating at an inefficient power level or operating at a power level that causes excessive dissipation losses and heat generation of the power source 21). In use, when the power source 21 charges the capacitor 22, the maximum power that can be output from the power source 21 to the heater 23 may also depend on the charge state of the capacitor 22. The capacitor 22 acts as a buffer of stored energy that can be output to the heater 23 according to the power demand at the heater 23 to supplement the power delivered to the heater 23 from the battery 23. During periods of low power demand at the heater 23, the capacitor 22 is recharged using power from the power supply 21. Figure 4a and Figure 4b As described, providing the capacitor 22 thus smoothes the power output required from the power supply 21 , reducing the maximum power output required (and therefore reducing the peak “instantaneous” current) whilst ensuring that sufficient power is delivered to the heater 23 .

[0110] In this example, the power output of the power supply 21 (to the capacitor 22 and to the heater 23) and the power output of the capacitor 22 (to the heater 23) are controlled by a controller 29 having a microprocessor 30. The microprocessor 30 is coupled to a memory 31 (which is typically a non-volatile memory) that stores processor control code. The controller 29 controls the overall operation of the device 10 according to the instructions stored in the memory 31. The power supplied to the (one or more) heaters 23 can be controlled using one or more power semiconductor switching devices (triacs) to control the supply of AC mains voltage (or a DC voltage obtained from the AC mains using an internal or external power supply unit, or a DC voltage obtained from a battery) to the heater 23. Any suitable voltage can be used to provide power to the heater, for example 20V to 80V. Examples of power supply and control circuit systems that can be used in the device 10 will be referred to later. Figure 6a , Figure 6b and Figure 7 However, it is not necessary to use a controller 29 having a microprocessor 30 to control the power output of the power source 21 and the power output of the capacitor 22. Alternatively, for example, the device 10 may simply include a control circuit system including one or more voltage-dependent, current-dependent, or temperature-dependent switches for controlling the power output of the power source 21 and the power output of the capacitor 22.

[0111] In this example, power is provided from the power supply 21 and the capacitor 22 to one or more heaters 23 for subsequent transfer of heat to the hair 17. For the device 10 that uses a heated air flow to transfer heat to the hair 17, the heater 23 heats the air flow generated by one or more fans, which are rotated by one or more fan motors (not shown in the figure). The device 10 does not necessarily need to include the heater 23; the advantages of the present invention are achieved when the device 10 includes any other suitable component(s) or part(s) that needs to be supplied with power from the power supply 21 and the capacitor 22 to meet the load (and in particular, an intermittent, periodic or time-dependent (variable) load).

[0112] When the device 10 includes multiple heaters 23 (or multiple heater tracks of a single heater 23), during the initial warm-up phase, two or more heaters 23 may be powered to reduce the time taken to reach the desired operating temperature. Similarly, if the temperature of the hair contacting surface of the heater 23 drops below the desired operating temperature, for example due to wet hair contacting the heater 23, two or more heaters 23 may be powered to provide a heat boost (in a so-called "boost mode") to offset the heat loss of the hair 17 and increase the rate of water removal. This boost mode results in a relatively sudden increase in power demand at the heater(s) 23. At other times, only one of the heaters 23 or heater tracks may be powered to maintain the desired operating temperature, thereby requiring a lower power demand. It will therefore be appreciated that the periodic activation of the boost mode results in a periodic total power demand for the device. However, it will be appreciated that even for a device with a single heater, periodic power demands may be caused by periodic loading of hair onto the styling surface 12.

[0113] Figure 2 Also shown is a user interface 27 coupled to the microprocessor 30, for example to provide one or more user controls and / or output indications, such as visual indications or audible alarms.(One or more) outputs can be used to indicate to the user, for example, when the temperature or moisture level of the hair 17 is within a predetermined range of a corresponding target temperature or moisture level.

[0114] The device 10 may include one or more temperature sensors 26 for sensing the temperature of the hair 17, or for sensing the temperature of the hair contact surface of the heater 23. The temperature sensor(s) 26 may be a non-contact type sensor (e.g., an infrared sensor). In order to help control the moisture level of the hair 17, it is advantageous to accurately measure (directly or indirectly) the current moisture level of the hair 17. Therefore, the device 10 may also be provided with one or more humidity sensors (not shown). The temperature measurement of a portion of the device 10 may be measured directly or indirectly. For example, a heat pipe may be used to transfer heat from the portion whose temperature is to be measured to an internal sensor by conduction.

[0115] The device 10 may include one or more wetline product dispensers (not shown) for dispensing liquid, such as water or styling products, onto the hair 17. The device 10 may be configured to dispense liquid from the dispenser onto the hair 17 during the drying or styling process to provide improved control of the moisture level of the hair 17. Alternatively, the wetline product dispenser may be provided separately from the device 10, such as as a separate diffuser (e.g., a table-based diffuser).

[0116] Device 10 may include communication circuitry 28 to allow device 10 to communicate with remote sensors, remote servers, or remote applications (e.g., on a mobile phone). Communication circuitry 28 may communicate with remote devices using, for example, Bluetooth, Wi-Fi, and / or 3GPP communication protocols.

[0117] Microprocessor 30 may be configured to communicate with heater 23, temperature sensor 26, user interface 27, communication circuitry 28, power source 21, and capacitor 22 (as well as any other suitable elements of device 10) via one or more communication interfaces or transceivers according to software stored in memory 31. For example, memory 31 may store one or more operating profiles or parameters. The software stored in memory 31 may include, for example, an operating system.

[0118] Those skilled in the art will appreciate that the device 10 need not have Figure 2 For example, communication circuitry 28 need not necessarily be provided.

[0119] Cyclic power demand

[0120] Figure 3 1 shows a graph illustrating the periodic power demand of the device 10. The solid line represents the total power demand of the device 10 (in this example, caused by the power required at the heater 23), and the dashed line 31 represents the average power demand. As shown, there are time periods t where the power demand exceeds the average power demand. D1 to D5 , and the time period t during which the power demand is lower than the average power demand C1 to C5 Time period t D1 to D5 do not have to be of equal duration. Similarly, the time period t C1 to C5 do not have to be of equal duration. Figure 3 The t shown in D and t C The value of does not have to be constant or nearly constant.

[0121] In this example, the periodic load is generated by the user periodically moving the device 10 through the hair 17 to transfer heat from the heater 23 to the hair 17. The time period used (corresponding to t D +t C ) can be, for example, about 20 seconds (but can also be longer or shorter, for example 2 seconds). This corresponds to the time that the user selects and places a lock of hair 17 into the device 10 and the device 10 moves along the lock of hair.

[0122] A period of high load occurs when a new lock of hair 17 is introduced onto the hair contact surface of the heater 23 and when the user moves the device along the lock of hair 17 (in order to maintain the hair contact surface of the heater 23 at the desired operating temperature). Conversely, when the lock of hair 17 is removed from the hair contact surface of the heater 23, the required power drops sharply to a relatively low level (e.g., Figure 3 The power required by the device 10 is about 12W (about 12W in the example shown), which is just enough to maintain the hair contact surface of the heater 23 at the desired operating temperature. Therefore, although the instantaneous maximum power required by the device 10 is relatively high (about 70W in this example), the average power required is significantly lower (about 42W in this example).

[0123] While the maximum power demand may be met by providing two so-called "high range" battery cells having relatively high maximum power outputs (e.g., about 200W), these types of battery cells typically have relatively low capacities (and therefore do not last as long between charges). Conversely, while higher capacity "mid range" battery cells may be provided instead, these may not output sufficient power to meet the maximum power demand. For example, when the maximum power output is below about 70W, the styling performance of the hair styling device may be poor. However, the inventors have recognized that by using capacitor 22 as an energy buffer, the power demand of power source 21 may be "smoothed," thereby reducing the maximum power output required of power source 21 and enabling the use of higher capacity battery cells (including next generation solid state batteries with increased capacity but reduced maximum current / power output) that extend the operating time of the device (or the use of a smaller / reduced weight PSU). More generally, the provision of capacitor 22 and the corresponding "smoothing" of the power demand of power source 21 enables higher capacity battery cells with lower power output (or lower power PSU) to be used as power source 21.

[0124] In this example, as will be referred to later Figure 4a and Figure 4b The power output of the power supply 21 is shown by a black solid line, and the power supply 21 is configured to output Figure 3 The power corresponding to the average power demand of the device (approximately 42 W in this example) is shown by the dashed line 31. Alternatively, the power supply 21 can be configured to deliver a power demand greater than the average power demand of the device 10, which reduces the power demand on the capacitor 22 (enabling the use of a lower value capacitor 22) and helps mitigate the variation in the average power draw.

[0125] During the time period t where the power demand of the heater 23 is less than the power available from the power source 21 C In the embodiment, the power source 21 is used to charge the capacitor 22. For example, Figure 3 As shown, at t C1 The energy transferred from the power source 21 to the capacitor 22 during the period corresponds to the area E between the solid line and the dotted line. C1 (and respectively in time period t C2 to C5 For region E C2 To E C5 are similar).

[0126] During the time period t when the power demand of the heater 23 is greater than the power available from the power source 21 D In the embodiment, the power output from the power source 21 is fully output to the heater 23 and is supplemented by the power output from the capacitor to the heater 23 to meet the demand. The power is output from the capacitor 22 to the heater 23 by discharging the capacitor 22 through one of the multiple heater rails of the heater 23. Figure 3 As shown, in the time period t D1 The energy output from the capacitor 22 to the heater 23 during the period corresponds to the area E between the solid line and the dotted line. D1 (and respectively in time period t D2 to D5 For region E D2 To E D5 Capacitor 22 acts as a buffer to store energy, which enables power supply 21 to output power at a level lower than the maximum power required at heater 23 by supplementing the power output of the heater during periods of high power demand (and by being recharged using energy from power supply 21 during periods of low power demand).

[0127] The fully charged voltage of the capacitor may be, for example, about 3V, and the average charge / discharge energy per pass through the user's hair may be about 180J. The capacitor may be, for example, a Tecate Group TPLH-3RO 40F capacitor, or a Vishay MAL22091001E3 40F capacitor. The capacitance of the capacitor may be, for example, greater than or equal to 40F. However, it will be appreciated that any other suitable capacitor (e.g., 15F) may be provided. The capacitor may also be referred to as a so-called "supercapacitor".

[0128] In this example, the peak discharge power of the supercapacitor is (approximately) given by:

[0129] P D =P Max -P Avg

[0130] Where Pd is the peak discharge power (about 27W in this example), P Max is the maximum power required by the heater 23, and PAvg is the average power of the heater (which corresponds to the power output of the power supply 21 in this example). Figure 4a The periodic power demand of the device 10 and the nearly constant power output of the power supply 21 are shown. The dashed line shows the periodic total power demand of the device 10 and the solid line shows the power output of the power supply 21. As shown, due to the provision of the capacitor 22, the power output from the power supply 21 is smoother than the highly variable power demand of the heater 23, thereby reducing the peak power output required by the power supply 21. In addition, the reduction in the peak power output required by the power supply 21 enables the use of a heater with a higher resistance, resulting in a reduction in peak current. Figure 4a The small drop in power output of power supply 21 shown in corresponds to a period of time when capacitor 22 is fully charged and the power output of heater 23 is low (and therefore the full power output of power supply 21 is not required). Device 10 does not necessarily need to be configured to output a constant (or nearly constant) power level from the power supply, such as Figure 4a Alternatively, Figure 4b As shown in FIG. 1 (where the dashed line shows the periodic total power demand of the device 10 and the solid line shows the power output of the power source 21), providing capacitor 22 can reduce the amplitude of the variation of the power demand of the power source 21 without completely eliminating the periodic variation. However, reducing the amplitude of the variation of the power demand of the power source 21 advantageously reduces the peak power required by the power source 21. Similarly, referring to Figure 4c and Figure 4d , providing capacitor 22 enables sufficient power to be provided to meet the total power demand of the heater, while using a heater element with a higher resistance enables the instantaneous peak current to be reduced and the dissipation losses at the power supply 21 to be reduced. The increased resistance of the heater element results in a reduction in the peak current of the power supply 21, while capacitor 22 ensures that the power demand at the heater can still be met. Figure 4c , the solid line shows the instantaneous peak current from the power supply 21 when the capacitor 22 is provided, and the dotted line shows the instantaneous peak current from the power supply 21 when the capacitor 22 is not provided (ie, when the total power demand is provided directly only from the power supply 21). Figure 4d The corresponding duty ratio is shown in FIG. 1 , wherein the solid line shows the duty ratio when the capacitor 22 is provided, and the dotted line shows the duty ratio when the capacitor 22 is not provided. Figure 4c and Figure 4d As shown, providing capacitor 22 enables power supply 21 to operate in a "normally on" state (i.e., 100% duty cycle), wherein power supply 21 can be used to power a heater or charge capacitor 22, and operate at a lower instantaneous peak current. In contrast, when capacitor 22 is not provided, the duty cycle is non-constant and the instantaneous peak current is higher. It will be understood that Figure 4cThe graph of shows the instantaneous peak current rather than the current itself, and the current when no capacitor is provided is not constant (as it will depend on the total power demand and the duty cycle). Figure 4e As shown, it shows the cumulative energy loss at the power supply 21 when the capacitor 22 is provided (shown by the solid line) and when the capacitor 22 is not provided (shown by the dotted line). The provision of the capacitor and the corresponding reduced peak current significantly reduce the dissipation loss at the power supply 21 (in this example, the dissipation loss is reduced by approximately 60%).

[0131] Figure 5 A table indicating the maximum discharge current, maximum peak power and capacity of three power configurations is shown, and the advantages of providing a capacitor 22 in addition to the power source 21 are shown. As shown, when two "high range" battery cells with lower capacity but higher power output are provided, the maximum peak power is higher. However, the capacity of the high range battery cell is relatively low, resulting in a lower operating time of the device. When two "medium range" battery cells with higher capacity but lower power output are provided, the capacity and operating time are improved. Beneficially, the operating time can be improved by about 25%. However, the maximum peak power of the higher capacity medium range battery cell is not enough for many applications. On the contrary, in addition to the medium range battery cell (or alternatively, any other suitable type of higher capacity battery cell, such as the next generation solid-state battery cell), providing a capacitor 22 increases the maximum peak power available while still obtaining the advantages of the capacity improvement of the medium range battery cell. Providing a capacitor 22 advantageously reduces the power output required by the battery cell, so that a battery cell with a lower maximum peak power but a higher capacity can be used as the power source 21 of the device 10. Furthermore, even for battery cells with relatively high maximum power outputs, operating the battery cells at lower maximum power outputs increases the efficiency and operating time of the device. This is because the correspondingly reduced maximum instantaneous current reduces the dissipation losses that occur in the battery cells due to internal resistance when the battery cells are discharged. For example, when the battery cells are operated according to Figure 4a When the power output distribution indicated by the dotted line shown in FIG. 1 outputs power, where there is a large peak in the power output, the temperature of the battery cell increases due to the relatively large dissipation loss. In contrast, in the present invention, a capacitor is provided so that the power supply 21 can be Figure 4a or Figure 4bThe device 10 may be configured to output power in a manner consistent with the distribution indicated by the solid line in the figure (where the maximum power output of the power source 21 is lower), while still meeting the total power demand indicated by the dashed line. The smoother power output distribution reduces dissipative losses in the battery cells, resulting in improved efficiency and operating time, and also reduces the degradation of battery cell performance over the life of the device 10. In addition, the reduction in dissipative losses in the battery reduces the risk that the battery cells will overheat before the battery can be fully discharged. For example, a higher capacity mid-range battery operating at 70W may reach a safe shutoff temperature of 65°C after approximately 10 minutes of operating time (corresponding to approximately 50% to 60% of the battery capacity having been used). In contrast, a higher capacity mid-range battery operating at 40W may reach a safe shutoff temperature after approximately 32 minutes of operating time, or may not reach a safe shutoff temperature at all.

[0132] Power control circuit system

[0133] Examples of power control circuitry that may be used in device 10 will now be described.

[0134] When charging a capacitor using power from a power supply, most of the energy output by the power supply to charge the capacitor is dissipated as heat in the charging circuit. There is a theoretical limit to how efficiently capacitor 22 can be charged from power supply 21. The total energy transferred from a constant voltage power supply is the product of the total charge moved and the power supply voltage:

[0135] E s =Q·V s

[0136] The moved charge is stored on capacitor 22 and is a function of the capacitor voltage:

[0137] Q=C·V C (t)

[0138] Therefore, the total energy transferred is given by:

[0139] E S =C·V S ·V C (t)

[0140] And the energy stored on capacitor 22 is given by:

[0141]

[0142] The ratio of the energy stored on capacitor 22 to the energy delivered by power source 21, which corresponds to the storage efficiency, is given by:

[0143]

[0144] The charging system is most effective when the capacitor is already charged to the supply voltage:

[0145]

[0146] Therefore, even in an ideal situation, energy can only be output from the power supply 21 to be stored on the capacitor 22 at an efficiency of 50%. This relatively high energy loss reduces the efficiency and operating time of the device 10. However, the inventors have recognized that by charging the capacitor 22 via the heater 23 itself, energy that would normally be wasted as dissipative losses can be output as useful heat energy at the heater 23. An example of a configuration is set forth below in which the capacitor 22 is advantageously charged via the heater rail of the heater 23. However, it will be appreciated that the advantages of improved efficiency may be obtained for any other suitable configuration in which the capacitor is charged via the heater rail of the heater 23.

[0147] Split heater configuration

[0148] Figure 6a A circuit diagram of a device including two heaters 23A, 23B is shown, wherein the capacitor 22 is charged (and discharged) via the heaters 23A, 23B. In this example, each heater 23 is formed by a resistive track having two sections: a charging section 231A, 231B, through which the capacitor 22 is charged; and a discharging section 232A, 232B, through which the capacitor 22 is discharged. The power source 21 can also discharge through the charging section 231A, 231B and the discharging section 232A, 232B of each heater 23. This configuration results in smooth power delivery from the power source 21 while reducing dissipative losses. Advantageously, energy that would normally be wasted due to resistive losses in the capacitor charging circuit is output as useful heat energy at the heater (because the capacitor is charged via the charging section 231A of the first heater 23A, and charged via the charging section 231B of the second heater 23B), thereby improving the efficiency and operating time of the device 10.

[0149] In this example, two heaters 23A, 23B are arranged in parallel with the battery 21. The operation of each heater 23A, 23B is controlled by a corresponding heater controller 72A, 72B using a switch 73A, 73B (for example, the switch may be a field effect transistor). For example, when the controller 72A of heater A performs control to close the switch 73A (thereby connecting the discharge section 232A of the heater 23A to the ground), the current from the power supply 21 (and the current from the capacitor 22 when the capacitor is discharged) flows through the corresponding heater 23A to the ground, which causes heating of the heater 23A. Similarly, when the controller 72B of heater B performs control to close the switch 73B (thereby connecting the discharge section 232B of the heater 23B to the ground), the current from the power supply 21 (and the current from the capacitor 22 when the capacitor is discharged) flows through the corresponding heater 23B to the ground, which causes heating of the heater 23B. When different heaters 23 may be at different temperatures, and therefore one heater may require more heat than another heater, an independent heater controller 72 is provided. The heater controller 72 may control the opening and closing of the switch 73 (and thereby the heat output of the heater 23) based on, for example, measurements of the heater temperature, measurements of the temperature of the user's hair 17, measurements of the moisture level of the user's hair 17, or any other suitable measurements or parameters.

[0150] like Figure 6a As shown, the power source 21 can also output power to the capacitor 22 through the charging section 231A of the first heater 23A and the charging section of the second heater 23B to charge the capacitor 22. The charging of the capacitor 22 (and the discharging of the capacitor 22) is controlled by the capacitor charging controller 75, which opens and closes the switch 76. Specifically, when the switch 76 is closed and the capacitor 22 is grounded, the capacitor 22 can be charged and discharged. However, when the switch 76 is open, the capacitor 22 is isolated from the ground and cannot be charged or discharged.

[0151] When switch 76 is closed and switch 73 is open, current will flow from power supply 21 to capacitor 22 until capacitor 22 is charged to a desired level (controlled by capacitor charging controller 75), at which point charging is stopped by capacitor charging controller 75 opening switch 76. It should be understood that when power supply 21 charges capacitor 22 via heater charging sections 231A, 231B, and switches 73A and 73B controlled by heater controllers 72A, 72B are open, the maximum power that power supply 21 can provide to heater 23 depends on the state of charge of the capacitor (and the corresponding voltage V c). When the capacitor is to be discharged, the capacitor charging controller 75 closes the switch 76 again while one or both of the switches 73A and 73B are closed. Specifically, when the power demand of one or both heaters 23 is greater than what the power source 21 can provide (or greater than the operational available power of the power source 21, which is lower than the absolute maximum power that the power source 21 can output, for example, to improve the efficiency of the power source 21), the capacitor charging controller 75 closes the switch 76, and one or both heater controllers 72 close the corresponding switch 73, the capacitor 22 will be discharged to the ground through the corresponding discharge portion 232 of one or both heaters 23.

[0152] In more detail, if the heater 23A requires more power than the power available for operation of the power supply 21, the capacitor charging controller 75 closes the switch 76, and the controller 72A of the heater A closes the switch 73A (if it is not already closed). As a result, current flows from the power supply 21 through the charging section 231A and the discharging section 232A of the heater 23A to the ground; and current will flow from the capacitor 22 through the discharging section 232A of the heater 23A to the ground. Similarly, if the heater 23B requires more power than the power available for operation of the power supply 21, the capacitor charging controller 75 closes the switch 76, and the controller 72B of the heater B closes the switch 73B (if it is not already closed). As a result, current flows from the power supply 21 through the charging section 231B and the discharging section 232B of the heater 23B to the ground; and current will flow from the capacitor 22 through the discharging section 232B of the heater 23B to the ground. If it is necessary to heat both heaters 23A and 23B, the available current from the power supply 21 and the capacitor 22 will be distributed between the two heaters 23.

[0153] Figure 6b Shows Figure 6aA modification in which four controllers are used to control the current through the first heater and the second heater 23. The load 1 controller 601 controls the current through the charging section 231A of the first heater 23A by controlling the state of the switch 701. The load 2 controller 602 controls the current through the discharge section 232A of the first heater 23A by controlling the state of the switch 702. The load 3 controller 603 controls the current through the charging section 231B of the second heater 23B by controlling the state of the switch 703. The load 4 controller 604 controls the current through the discharge section 232B of the second heater 23B by controlling the state of the switch 704. Therefore, advantageously, a finer control of the power output at each resistive heating element of the heater (and a finer control of the charging of the capacitor 22) is achieved. For example, the load 1 controller 601 and the load 3 controller 3 can perform control to close the corresponding switches 701, 703, output heat from the charging sections 231A, 231B of the first heater and the second heater, and charge the capacitor 22. The load 1 controller 601 and the load 3 controller 604 can perform control to stagger the power delivery of the first heater and the second heater. In other words, the load 1 controller 601 and the load 2 controller 602 can perform control to stagger the power output between the charging section 231A of the first heater and the charging section 231B of the second heater. The staggered power distribution between the first heater and the second heater does not have to be evenly distributed, and can depend on the individual power requirements of the corresponding heaters 23 at the time. The load 3 controller 603 and the load 4 controller 604 can perform similar control to control the power output at the discharge section 232A, 232B of the heater (e.g., for staggered power output). More generally, the load controller can perform control to achieve a specific power output distribution over time between each heater 23. For example, this is advantageous when there is an uneven load on the heater (e.g., due to the user placing wet hair unevenly on the heater).

[0154] exist Figure 6a and Figure 6b In the example shown, the heater (load) controller and the capacitor charge controller 75 are shown as separate controllers. Those skilled in the art will appreciate that these controllers may be provided by Figure 2The microprocessor 30 shown is provided with a separate routine executed by the microprocessor 30. Alternatively, for example, the device can be operated under the control of a single controller that controls the operation of the heater, the power provided by the power supply 21, and the operation (charging and discharging) of the capacitor 22. The controller can obtain the voltage of the capacitor 22, the voltage of the power supply 21, the temperature of the (one or more) heaters, and the power required by the (one or more) heaters (which can also be referred to as "the power required by the heater"), can determine how power is supplied from the power supply 21 and / or the capacitor 22 to the (one or more) heaters, and can control the charging / discharging of the capacitor 22 to supply the required power to the heater 23 and manage the charging state of the capacitor 22. The controller can perform control of the power output and the charging / discharging of the capacitor 22 so as to minimize (or reduce) the current from the power supply 21, thereby reducing the power loss caused by the internal resistance at the power supply 21. The controller can also perform control to prevent the capacitor 22 from being overcharged (e.g., exceeding the desired operating voltage).

[0155] Figure 6a and Figure 6b It is shown that different sized capacitors and resistors of the track may be used and their values ​​will be chosen depending on the application and the time period over which the capacitor 22 is expected to be able to release its stored energy to the load (in this case the load is the heater 23). Similarly, the supply voltage used in the circuit shown in Figure 6 is given as an example and of course different supply voltages may be used.

[0156] The number of heaters 23 need not be two. For example, in some applications, a single heater 23 having a charging portion 231A and a discharging portion 232A may be provided. Figure 1a ), the first heater 23A may correspond to the first heating plate 12a, and the second heater 23B may correspond to the second heating plate 12b.

[0157] exist Figure 6a and Figure 6b In the example circuit shown, when the capacitor voltage V cWhen V drops too low, capacitor 22 may not provide adequate power buffering and may not act as a source of power for heater 23 (depending on the resistance of the heater rail). This may occur during periods of particularly intensive use of device 10. A solution to this problem is to temporarily direct all of the power output of power supply 21 through charging section 231A, 231B of heater 23 to charge capacitor 22 back to operating voltage. However, this may result in an increase in total power output from power supply 21 (significantly higher than the average power output), and so instead, as described above, the capacitor may be recharged when power demand at heater 23 is low. Charging of capacitor 22 may be temporarily disabled (e.g., by opening the corresponding switch 76 under control of capacitor charging controller 75) to ensure that all power from power supply 21 is available for output at heater 23 during periods of high power demand. In order to reduce capacitor voltage V c To avoid the risk of falling too low, the power supply 21 may be operated at a constant (or near constant) power output that is higher than the average power requirement of the heater 23 (but still less than the maximum power output that would be required if the capacitor 22 were not provided).

[0158] Figure 7 Shows the formation of Figure 6a and Figure 6b An exemplary configuration of heater tracks for one of the heaters 23 used in the example of . The heater 23 includes a first heater track 91 and a second heater track 92. Each heater track has corresponding input terminals 93, 94 and corresponding output terminals 95, 96. In use, current flows along the heater tracks 93, 94 to generate heat that heats the heater 23, which then heats the hair 17 in contact with the hair contact surface of the heater 23. The first heater track 93 can be used as a charging section 231, through which the capacitor 22 is charged, and the second heater track 94 can be used as a capacitor discharge section 232, through which the capacitor 22 is discharged. The first heater track 93 and the second heater track 94 are interlaced (or "nested") with each other, and each is arranged to heat a heating area of ​​the heater 23 (in this example, a heating area of ​​the heater 23). Figure 7 ). However, the heater track 23 need not necessarily be as Figure 7 Any other suitable heater track configuration may alternatively be used.

[0159] Interleaved power delivery configuration

[0160] Figure 8A circuit diagram of another example of a power control circuit system for the device 10 is shown. Compared to the example of FIG. 6A where separate discharge sections 231A, 231B and charging sections 232A, 232B are provided, in this example, each heater 23 need only include a single heater track for charging and discharging the capacitor 22. With this circuit, power is interleaved between the two heaters 23A and 23B so that at a given time when the capacitor is charging, only one heater 23 receives power from the power source 21, and when the capacitor 22 is discharging, only one heater 23 receives power from the capacitor 22. When the capacitor is discharging, both heaters 23 receive power from the power source 21.

[0161] The two heaters are arranged in series with the power supply 21, and as Figure 6a , sharing a common capacitor 22 charged by the heater 23. Alternatively, instead of providing separate heaters 23A, 23B, two heater tracks of a single heater 23 may be used. The charging (and discharging) of the capacitor 22 is controlled by a capacitor charging controller 83, which opens or closes switch 81E. Specifically, when switch 81E is open and switch 81F is closed, the capacitor 22 is grounded through switch 81F, so when current flows from the power supply 21 through either of the heaters 23A or 23B, the current will charge the capacitor 22 until it is charged to the desired level. When charging, the capacitor can be discharged by closing switch 81E, so that the current from the capacitor 22 can flow through one of the heaters 23A or 23B, through one of the switches 81B or 81D and back to ground through switch 81F. The on / off controller 82 can cut off all power to the heater by opening the switch and thereby isolating the circuit from ground.

[0162] Whether the capacitor 22 is charged by the current flowing from the power supply 21 through the first heater 23A or through the second heater 23B depends on the state of the switches 81A to 81D, which in turn depends on the state of the switch 86 controlled by the heater alternator controller 85. Specifically, when the switch 86 is closed, the switches 81A and 81D will be closed, and the switches 81C and 81B will be open. As a result, the current will flow from the power supply 21 through the switch 81A into the heater 23A. If the switch 81E is open and the switch 81F is closed, the current will flow into the capacitor 22 to charge the capacitor 22. However, if the switch 81E is closed, the current will flow from the power supply 21 through the heater 23A, and then through the heater 23B before passing to the ground via the switch 81F; and the current will flow from the capacitor 22 through the heater 23B to the ground via the switch 81F. On the other hand, when the switch 86 is open, the switches 81C and 81B will be closed, and the switches 81A and 81D will be open. As a result, the current will flow from the power supply 21 through the switch 81C into the heater 23B. Likewise, if switch 81E is open and switch 81F is closed, current will flow into capacitor 22 to charge capacitor 22. However, if switch 81E is closed, current will flow from power source 21 through heater 23B and then through heater 23A before being transferred to ground via switch 81F; and current will flow from capacitor through heater 23A to ground via switch 81F. Thus, switches 81A to 81D operate as an "H bridge" for alternating power connection between the two heaters 23A and 23B. Switching of switch 86 can be performed quickly so that the two heaters 23 are effectively heated at the same time.

[0163] The advantage is that Figure 8 The configuration shown enables the use of a heater having only a single heater track while still obtaining the advantages of charging and discharging the capacitor through the heater 23. In addition, by changing the duty cycle of the switch 86, the ratio of the power output between the first heater 23A and the second heater 23B can be changed. For example, at a 50% duty cycle, the first and second heaters receive the same amount of power. If the duty cycle is increased to 60%, the second heater 23B will receive 60% of the power and the first heater 23A will receive 40% of the power. Thus, advantageously, the power distribution between the first heater 23A and the second heater 23B can be controlled, which is useful for mitigating differences in heater resistance caused by manufacturing as well as different loads (for example, uneven loads caused by the user at the heater due to uneven placement of hair on the heater).

[0164] The frequency of switching power between the first heater 23A and the second heater 23B may be any suitable frequency, but will typically be faster than the frequency of the periodic power demand at the heaters 23 caused by loading the hair.

[0165] Although in Figure 8 In the example shown, the heater alternator controller 85 and the capacitor charging controller 83 are provided separately, but this is not necessarily the case. Alternatively, for example, the device can operate under the control of a single controller (e.g., a microprocessor 30) that controls the operation of the heater 23, the power provided by the power source 21, and the operation (charging and discharging) of the capacitor 22. The controller can obtain the voltage of the capacitor 22, the voltage of the power source 21, and the power required by the (one or more) heaters (also referred to as "heater required power"), and can determine how to provide power to the (one or more) heaters from the power source 21 and / or the capacitor 22 to provide the required power.

[0166] Although in Figure 8 Illustrative resistances, voltages, and capacitances are shown in , but it will be appreciated that any other suitable values ​​of resistances, voltages, and capacitances may be used.

[0167] Independent capacitor charging

[0168] Although Figures 6a to 8 The example shown in advantageously enables charging of capacitor 22 via the heater track so that energy that would normally be wasted as dissipative losses can be output as useful heat energy at heater 23, but this is not necessarily the case. In the event that there is a demand for power at heater 23 even when device 10 is not being used to dry or style hair (e.g., to maintain the hair contacting surface of heater 23 at styling temperature even when the hair contacting surface is not in contact with hair), Figures 6a to 8 The example shown in is particularly advantageous because the charging of capacitor 22 can be used to provide this "background" power output at heater 23. However, for some installations, the background power demand may be lower, in which case charging capacitor 22 via the heater track may result in more heat output at the heater than desired.

[0169] Fig. 9 An example is shown where capacitor 22 can be charged without current passing through the heater track. Thus, advantageously, capacitor 22 can be charged without causing heat output via the heater track when power demand at heater 23 is low (or zero) and additional heat output at heater 23 is not desired. Fig. 9The power control circuitry shown in still retains the advantages of providing capacitor 22, namely allowing a more constant power to be drawn from power source 21, and allowing a higher available maximum peak power. Providing capacitor 22 advantageously reduces the power output required from the battery cell, enabling battery cells with lower maximum peak power but higher capacity to be used as power source 21 for device 10. In addition, even for battery cells with relatively high maximum power output, operating the battery cells at a lower maximum power output increases the efficiency and operating time of device 10.

[0170] like Fig. 9 As shown, in this example, four resistive heating elements (R 1A , R 1B , R 2A , R 2B ). Heating element R 1A and R 2A Powered directly by power source 21. Heating element R 1B and R 2B The power supply 21 can be used to supply power to the heating element R using a power supply 21 greater than that from the capacitor 22. 1B and R 2B The voltage supplied is high voltage for the heating element R 1A and R 2A Power supply. Heating element R 1A and R 2A (powered directly by power source 21) can be a relatively high resistance track, the heating element R 1B and R 2B (powered by capacitor 22) can be a relatively low resistance heater track. Therefore, advantageously, by providing a dedicated heating element R powered by capacitor 22 1B , R 2B , capacitor 22 can be discharged to output power at heater 23 without the need to boost the voltage from capacitor 22 (which would require more complex and larger circuitry, such as a boost converter). However, it will be appreciated that the resistors need not be different, and that the resistors selected depend on the voltages provided by power source 21 and capacitor 22, and on the desired heat output at heater 23. Fig. 9 In the example shown, two heaters 23 are used. The first heater comprises a heating element R 1A and R 1B , the second heater comprises a heating element R 2A and R 2B Each heater 23 may be Fig. 9 For example, the first heater track 91 of each heater may be used to provide a heating element R 1A and R 2A, the second heater track 92 of each heater can be used to provide a heating element R 1B and R 2B However, it should be understood that the heater track need not be Figure 7 The form shown is shown, and any other suitable shape and configuration of heater track 92 may alternatively be used.

[0171] A capacitor charging circuit 900 is provided for charging the capacitor 22 by a flow of current from the power supply 21 not via the heater track. Thus, advantageously, the capacitor 22 can be charged without heat output from the heater (which would occur due to dissipation losses when the capacitor 22 is charged via the heater track). In other words, the charging of the capacitor 22 is independent of the flow of current through the heater track. In this example, the capacitor charging circuit 900 comprises a DC-DC step-down converter (a "buck" converter) having a controllable and variable voltage output to the capacitor 22. However, any other suitable capacitor charging circuit 900 may be used instead. The capacitor charging circuit 900 controls the voltage applied across the capacitor 22 and thus controls the charging rate of the capacitor 22. The voltage across the capacitor 22 is monitored using a capacitor voltage monitoring sensor 901. The sensed voltage across the capacitor 22 is used as an input to the capacitor charging circuit 900 for controlling the charging of the capacitor 22, for example to prevent overcharging. The capacitor charging circuit 900 performs control to control the voltage across the capacitor 22 between zero and a maximum voltage. The maximum voltage will depend on the particular capacitor 22 in use. Advantageously, the capacitor charging circuit 900 enables the capacitor 22 to be charged on demand, independent of the power output at the heater 23.

[0172] When the power demand at the heater 23 is greater than the power that the power source 21 can provide, the capacitor 22 is discharged through the heating element R under the control of the capacitor discharge controller 902. 1B or R 2B The capacitor discharge controller 902 controls the discharge of the capacitor 22 by controlling the state of the corresponding switch 909. When the capacitor discharge controller 902 performs control to close the switch 909, and at least one of the switches 905 and 907 is also closed, the capacitor is grounded and will be connected to the heating element R via the heating element R. 1B and / or R 2B Discharge (when switch 905 is closed, capacitor 22 will be discharged through heating element R 1B discharge, and when switch 907 is closed, it will pass through the heating element R 2B Discharge). Advantageously, in this example, a single capacitor discharge controller 902 controls the heating element R through which the capacitor 22 is discharged. 1B and R 2BIn other words, a single capacitor discharge controller 902 controls whether the capacitor 22 can be discharged to output heat at each heater 23 (and therefore, for each heating zone when each heater 23 corresponds to one or more heating zones). The first heater controller 903 and the second heater controller 904 do not need to know the state of the switch 909 through which the capacitor is discharged (in other words, the first heater controller 903 and the second heater controller 904 do not need to know whether the circuit system is configured for the discharge of the capacitor 22), because when the capacitor 22 is discharged, the first heater controller 903 and the second heater controller 904 will simply record the reduced power demand at the corresponding heater and perform corresponding control (for example, by adjusting the duty cycle of the first heater and the second heater). The first heater controller 903 uses a common control signal output by the first heater controller 903 to control the state of switches 905 and 906, and the second heater controller 904 uses a common control signal output by the second heater controller 904 to control the state of switches 707 and 708. Beneficially, there is no need to independently control switches 905 and 906, or there is no need to independently control switches 907 and 908.

[0173] Does the current flow through the heater track R of the first heater? 1A , R 1B The first heater controller 903 controls whether the current flows through the heater track R of the second heater. 2A , R 2B The heater controllers 903 and 904 control whether current flows through the corresponding heater rails by controlling the states of switches 906 to 908. The first heater controller 903 controls the state of switch 906 to control whether current flows through the heating element R 1A , and controls the state of switch 905 to control whether the current flows through the heating element R 1B (Whether the current flows through the heating element R 1B will also depend on the state of switch 909, which is under the control of the capacitor discharge controller). Similarly, the second heater controller 904 controls the state of switch 908 to control whether current flows through the heating element R 2A , and controls the state of switch 907 to control whether the current flows through the heating element R 2B (Whether the current flows through the heating element R 2BThe control of the heater controllers 903, 904 is based on the power demand at the respective heater. Advantageously, the control of a pair of switches by each heater controller 903, 904 enables the two heating elements of each heater to be controlled by a single controller, thereby enabling particularly simple control of the duty cycle of the heater 23 (while the capacitor discharge controller 902 performs the duty cycle of the heating elements R according to the power demand at each heater and the charge state of the capacitor). 1B and R 2B additional control whether it is in use).

[0174] Fig. 9 The switches shown in can be, for example, field effect transistors. However, any other suitable switches may be used instead.

[0175] Now refer to Figures 10 to 14 Describe in more detail Fig. 9 The operation of the circuit system is shown. Fig.10 A state is shown in which there is little or no power demand at the heater, but the capacitor 22 is to be charged. Therefore, the first heater controller 903 performs control to open switches 905 and 906, and the second heater controller 904 performs control to open switches 907 and 908, so that current does not flow through the heater track of the first heater or the second heater. The capacitor charging circuit 900 controls the current output to the capacitor 22 to charge the capacitor 22. The capacitor charging circuit 900 can perform control to output a constant current (in this example, a current of 5A is shown).

[0176] Fig.11 1 shows a state where the power source 21 is used to supply power to the heater 23, the capacitor 22 is not used to supply power to the heater 23, and the capacitor 22 is not charged. The capacitor charging circuit 900 does not output power to charge the capacitor 22. The first heater controller 903 and the second heater controller 904 control switches 905, 906, 907, and 908 to close, thereby completing the power supply from the power source 21 via the heating element R 1A and R 2A However, since the switch 909 is controlled to be open by the capacitor discharge controller 902, the capacitor discharge controller 902 does not pass through the heating element R 1B and R 2B Power is output from capacitor 22. Fig.11 In the example shown, the flow through the heating element R 1A and R 2A The current is the same (because the heating element R 1A and R 2A have the same resistance), but this is not necessary, and the heating element R 1Aand R 2A The resistance can be different.

[0177] Fig.12 2 shows a state where both the power source 21 and the capacitor 22 output power to the heater 11. The configuration of the circuit system is similar to Fig.11 The same as shown, except that the capacitor discharge controller 902 controls the switch 909 to be in the closed position, completing the discharge from the capacitor 22 via the heating element R 1B and R 2B When the power demand at the heater 23 is greater than that provided directly by the power source 21, it can be advantageously used Fig.12 The configuration shown. Fig.11 and Fig.12 In the example, the current drawn from the power supply is the same (5A), but Fig.12 In the example shown, the total power output of heater 23 is higher due to the additional power output generated by the discharge of capacitor 22.

[0178] Fig.13 FIG. 2 shows a state where only one of the heaters 23 is used to output power and the capacitor 22 is charged. Fig.13 As shown, the first heater controller controls switches 905 and 906 to be in a closed configuration, thereby completing the heating from the power source 21 through the heating element R 1A However, since the switch 909 is controlled to be open by the capacitor discharge controller 902, the capacitor discharge controller 902 does not pass through the heating element R 1B The power is output from the capacitor 22. Since the second heater controller controls switches 907 and 908 to be in an open configuration, the second heater (corresponding to the heating element R 2A and R 2B ) also does not output power. The capacitor charging circuit 900 controls the charging of the capacitor 22. In this example, 2.5A flows through the first heater (through the heating element R 1A ), 2.5A flows through the capacitor charging circuit. Therefore, the total current from the power supply is 5A, which is Fig.12 The total current is the same as described in (the voltage of the power supply 21 may be, for example, 40 V, in which case, in all Figure 10 to Figure 14 The total power drawn from the power supply 21 as illustrated in FIG. 1 will be 200 W, but the power supply 21 may be configured to output any other suitable voltage). Fig.14 Shown with Fig.13 The state shown is similar to the state shown, except that the circuit system is configured to output heat through the second heater instead of the first heater (switch 908 is closed instead of switch 906), and the total current drawn from the power supply is also 5A. Therefore, advantageously, in Figure 12 to Figure 14In each of the states shown, the power demand from the power supply 21 is constant. However, it should be understood that when the capacitor is fully charged and there is no power demand at the heater 23, the power output from the power supply 21 can be zero (or less than the constant power demand when the power demand at the heater 23 is sufficiently low). It should also be understood that the current value can be different from Figures 10 to 14 , and the actual current will depend on the power requirements of the heater 23, the resistance of the heater track, and the voltage of the power supply 21 and the voltage of the capacitor 22.

[0179] The heater controllers 903, 904, the capacitor discharge controller 902 and the capacitor charging circuit 900 can perform control to provide a charge to the capacitor 22 within a cycle according to the power demand at the heater and the charge state of the capacitor 22. Figures 10 to 14 The circuit system switches between the states shown. The power delivered to the heating element and the capacitor 22 is staggered in the time domain. For example, when the capacitor is to be charged, the circuit system may initially be in Fig.12 The state shown (power output to the heater and capacitor 22 is not charging), changes to Fig.13 The state shown (power output to the first heater and capacitor 22 is being charged) returns to Fig.12 The state shown changes to Fig.14 The state shown (power output to the second heater and capacitor being charged) and then returns to Fig.12 The states shown are used to complete the cycle. Each state does not have to be active for the same amount of time. For example, a duty cycle may be used where the capacitor and the first and second heaters all receive the same amount of power, or the duty cycle may be modified so that more power is output to the heater 23 than to the capacitor 22 (e.g., based on the higher power demand of the heater). Thus, advantageously, the power distribution between the capacitor 22 and the heater 23 (and between the first and second heaters, through control of the duty cycle) may be controlled based on the power demand at the heater (and based on the charge state of the capacitor 22; when the capacitor 22 is fully charged, no power needs to be output to the capacitor 22 through the capacitor charging circuit 900). Thus, advantageously, when the power demand at the heater 23 is met by the power supply 21, any additional power available from the power supply 21 may be used to charge the capacitor 22. Control is performed to maintain a constant or near-constant power drawn from the power supply 21. When the power demand at the heater 23 is below the target power of the power supply 21, the additional power output may be used to charge the capacitor 22. If the power demand at the heater 23 exceeds the power available from the power supply 21, then Fig.12 , where capacitor 22 is discharged to provide additional power output at heater 23 (via heating element R 1Band / or heating element R 2B discharge).

[0180] The frequency of switching the power output between the capacitor 22, the first heater and the second heater may be any suitable frequency, but will typically be faster than the frequency of the periodic power demand at the heater 23 caused by loading the hair.

[0181] Although in Figures 9 to 14 In the example shown, a capacitor discharge controller is provided for controlling the discharge of the capacitors via all heaters 23, and the overall operation of each heater 23 is controlled by a separate respective controller 903, 904, but this is not necessarily the case. Fig.15 An alternative is shown in which the control of the activation of each heater track is performed independently using a corresponding dedicated controller and dedicated switch. Fig.15 The configuration shown uses four controllers 903, 904, 910 and 911 (in contrast, Figures 9 to 14 The example shown advantageously uses only three controllers, reducing the complexity of the circuit system), but Fig.15 The configuration can be independent of the heating element R 2B To control the heating element R 1B In other words, when both heaters 23 are turned on, Fig.15 The configuration enables additional power from the capacitor 22 to be selectively output at a specific heater 23. This approach can be used, for example, when the power demand of one heater 23 exceeds the maximum power output of the power supply 21, while the power demand at another heater 23 does not exceed.

[0182] Although Figures 9 to 15 shows the use of two heaters (including heating elements R 1A and R 1B The first heater comprises a heating element R 2A and R 2B Alternatively, only one heater may be provided (for example, only the heating element R may be provided). 1A and R 1B ). In another alternative, three or more heaters may be used.

[0183] Multi-zone heaters

[0184] Each heater 23 may include a plurality of independently controllable heating zones. In this case, each heating zone has a corresponding pair of heater tracks (e.g., Figure 7 ). The heat output from the heater track heats the heating zone. Figure 7In the example shown, the heating zone is the area defined by the outer rectangular area 700. The heating zone may be a plurality of adjacent heating zones arranged, for example, along the length of the heater. Independently controllable heating zones are described, for example, in the earlier application WO 2012 / 028862.

[0185] Heater Power Control - Illustrative Example

[0186] An example of how the total power output of heater 23 may be controlled will now be described.

[0187] Temperature measurement results

[0188] The device can be configured to determine the temperature of the hair 17 (or the change in temperature over time), or the temperature of the heater, using (one or more) temperature sensors 26 when heat is applied to the hair 17. The temperature sensor 26 can be configured to measure the temperature by direct contact measurement using (for example) a thermistor, a negative temperature coefficient (NTC) sensor, or a thermocouple. Alternatively or additionally, non-contact measurement (for example, using an infrared sensor) can be used to measure the temperature. Alternatively, the temperature can be obtained by measuring the current and voltage of each heater to determine the heater resistance (which is proportional to the temperature of the heater). This can be achieved, for example, using a circuit including a shunt resistor and an operational amplifier, wherein an analog-to-digital converter is configured to convert the voltage across the shunt resistor and output it to a controller. More generally, the device 10 can include any suitable sensor or circuit system for measuring temperature.

[0189] Humidity level

[0190] Fig.16 1 shows a graph of hair temperature versus drying time when heat is transferred to the hair 17. The device 10 may be configured to control the power output of the heater 23 based on the moisture level of the user's hair 17. Fig.16 As shown, the hair passes through a preheating period, and then passes through a first drying period and a second drying period, as described below. The first drying period corresponds primarily to the removal of unbound water, and the second drying period corresponds primarily to the removal of bound water. The amount of unbound water and bound water in the hair (which corresponds to the moisture level of the hair 17) can be determined by the controller 29 by measuring the change in the temperature of the hair 17 over time when heat is transferred to the hair 17 using the temperature sensor 26.

[0191] Fig.16 The following stages are shown:

[0192] "Preheating Period": During this period (point A to point B), the device 10 uses the heater 23 to transfer heat to the hair, raising the temperature of the hair 17 to the temperature of the drying period (in which the phase change of the liquid occurs). Figure 1a When a hair straightener of the type shown in FIG. 1 is used to transfer heat to the hair 17, the hair contact surface of the heater 23 is typically operated at a temperature below about 100° C. to 135° C. (e.g., 120° C.) to avoid water cavitation (so-called “sizzle”) from occurring. The controller 29 identifies the preheating period using the output of the temperature sensor 26, which senses the temperature increase of the hair 17 after the device 10 begins to transfer heat to the hair.

[0193] "Drying Period 1": During this phase (points B to C), the device 10 continues to transfer heat to the water on the hair 17, but the temperature of the hair 17 remains relatively constant. This is because the evaporation of unbound water limits the increase in temperature. This first drying period can be identified by the controller 29 using the output of the temperature sensor 26, which senses the constant temperature of the hair 17 after the initial preheating period.

[0194] "Drying period 2": In this stage (point C to point E), the non-bound water has evaporated, and the bound water on the hair begins to evaporate and leave the hair fiber. In this stage, the temperature of the hair 17 increases from the initial temperature (corresponding to the equilibrium temperature in the drying period 1) to the final temperature (at point E). The controller 29 can identify this stage using the output of the temperature sensor 26, which detects the increase in hair temperature, which is higher than the constant temperature maintained in the drying period 1. In other words, the start of this stage can be identified by identifying the increase in temperature, which starts at the "elbow" of point C.

[0195] By monitoring the temperature of the hair over time, the moisture level of the hair 17 during the styling / heating process can therefore be determined or estimated, such as for controlling the power output of the heater 23. When the amount of hair 17 received by the device 10 is known (or estimated), the moisture level of the hair 17 at point B can be determined based on the heat output of the heater 23 and the time taken to heat the hair 17 from the temperature at point A to the temperature at point B. The moisture level of the hair 17 during drying session 1 (between points B and C) can be determined based on the amount of heat transferred from the device 10 to the hair 17 (which can be used to calculate the amount of evaporation of unbound water), the determined or estimated moisture level of the hair at point B, and the amount of time that has elapsed since the start of drying session 1. Similarly, the moisture level of the hair 17 during drying time period 2 may be determined based on the heat transferred from the device 10 to the hair 17, the determined or estimated moisture level of the hair 17 at point C (which is known because point C corresponds to the point at which all unbound water has left the hair 17 and removal of bound water begins), and the amount of time that has elapsed since the start of drying time period 2. Thus, by controlling the heater 23 to heat the hair 17 at a specific power output of the heater 23 for a corresponding amount of time after the “bend” at point C is detected, a specific moisture level may be achieved. A table mapping the moisture level of the hair to the time elapsed after point C in the graph may be experimentally determined in advance and stored in the memory 31 of the device 10. Alternatively, an experimentally determined formula may be stored in the memory 31.

[0196] The device 10 may be configured to measure the thermal load on one or more components of the device 10 to determine the moisture level of the hair 17, and to control the power output of the heater 23 based on the determined moisture level. The energy required to heat the hair depends on the amount of moisture retained within the hair. For a given lock of hair heated by the device 10, the thermal load is related to the temperature and moisture content of the lock of hair. Thus, by measuring the thermal load, the moisture level of the hair 17 may be determined (estimated) via a suitable lookup table or calculation that previously determines and relates the measured thermal load to the moisture level of the hair. For example, for a given lock of hair heated by the device 10, the thermal load is related to the temperature and moisture content of the lock of hair. Figure 1a In a hair straightener of the type shown in , the moisture level of the hair can be determined based on the heat load on the hair contact surface of the heater 23.

[0197] Thermal load and thus determined hair moisture level depends on the amount of heated hair. The moisture level of hair can be determined (estimated) via a suitable lookup table or calculation based on an estimation of the typical amount of hair received by the device 10 in normal use. Alternatively, a pair of sequentially arranged heating plates can be used to improve the accuracy of determining the moisture level. When the user pulls the device 10 over the hair, the hair passes through the first plate of the sequentially arranged heating plates, and then passes through the second plate of the sequentially arranged heating plates. Therefore, the hair is first heated by the first heater plate, and then heated by the second heater plate. Due to the fact that some water is removed from the hair at the first heater plate before the hair passes through the second heater plate (that is, the moisture level of the hair at the first heater plate is greater than the moisture level of the hair at the second heater plate), the thermal load on the first heater plate is greater than the thermal load on the second heater plate. Advantageously, since the first plate and the second plate both receive the same amount of hair, the differential thermal load can be used to determine the moisture level of the hair in a manner independent of the amount of hair being heated.

[0198] More generally, the device 10 may include a plurality of temperature sensors (or sensors for measuring heat load) for measuring the temperature at two or more regions of a heatable surface (or multiple heatable surfaces) that the hair passes sequentially (i.e., a lock of hair first passes through a first region in the two or more regions and then passes through a second region in the two or more regions). The device may be configured to determine the moisture level of the hair 17 based on the measured temperature (or measured heat load), for example, based on the temperature difference or heat load between the regions. Determining the moisture level using the measured temperature or measured heat load may be combined with the measurement results of the moisture level of the user's hair 17 obtained using other methods to increase the accuracy of determining the moisture level. The determined moisture level may then be used to control the power output of the heater 23.

[0199] Instead of using sequentially arranged heating plates to eliminate the effect of users using locks of different volumes, the device 10 may include a sensor for sensing the amount of hair in the lock being heated by the device so that the moisture level of the hair can be more accurately determined based on the heat load.

[0200] Variations and substitutions

[0201] Detailed embodiments and some possible substitutions have been described above. As will be appreciated by those skilled in the art, many variations and further substitutions may be made to the above embodiments while still benefiting from the invention embodied in the embodiments. Therefore, it should be understood that the present invention is not limited to the described embodiments and includes variations that are obvious to those skilled in the art and fall within the scope of the appended claims.

[0202] The present invention has been described above with reference to a device 10 comprising a capacitor or "supercapacitor" 22. It will be appreciated that a capacitor having any suitable capacitance may be used. Figure 2 , Figure 6 and Figure 8 The capacitor 22 shown in the figure may also conceivably be replaced by any other suitable device for storing electrical energy (which may also be referred to as an "energy storage device" or "energy storage device"), such as a battery (e.g., a high-discharge lithium-ion battery) having a sufficiently high power output (which can then be charged by the power source 21 and output power to the heater 23, as described above for the capacitor 22).

[0203] In any of the above examples, the power source 21 may be a lithium ion battery cell, a solid state battery cell, a lithium sulfur battery cell, a lithium air battery cell, or any other suitable type of power source. The capacitor may be a double layer capacitor, a hybrid lithium ion capacitor, or any other suitable type of capacitor. Combinations of power sources 21 and capacitors 22 (alternatively, high power battery cells) that may be used include, for example: lithium ion battery cells and double layer capacitors; lithium ion battery cells and hybrid lithium ion capacitors; solid state battery cells and double layer capacitors; and lithium sulfur battery cells and double layer capacitors; lithium air battery cells and double layer capacitors; solid state battery cells and hybrid lithium ion capacitors; lithium sulfur battery cells and hybrid lithium ion capacitors; lithium air battery cells and hybrid lithium ion capacitors; solid state battery cells and high discharge lithium ion battery cells; lithium sulfur battery cells and high discharge lithium ion battery cells; and lithium air battery cells and high discharge lithium ion battery cells. Any other suitable combination of power source 21 and capacitor 22 (or other high power source) may be used. The power source 21 may be a power supply unit that receives power from an AC power grid supply and converts it into a DC power supply at a suitable voltage to provide power to the heater. In this case, capacitor 22 may be provided in a power supply unit (which may be provided inside a plug, or inside a separate housing) located between a socket providing AC mains power and handheld device 10, thereby reducing the size of the circuitry required inside device 10.

[0204] In the above examples, the device 10 may include a single heater 23, or alternatively may include two or more heaters 23. More generally, the device 10 may include any suitable means for transferring heat to the hair 17, such as any suitable conduction heater, thick film printed heater, steam heater or radiant heater. Figure 1aThe device shown uses a heating plate commonly used to straighten the user's hair. Alternatively, a heater 23 having any other suitable type of hair contact surface can be used instead of having a generally flat hair contact plate. For example, during a styling process, a ribbed heater can be used to curl the hair 17. Similarly, the heating surface can be defined by a cylindrical heater commonly used in curling tongs. In some examples, no hair contact surface is required at all (e.g., when a hot air stream is used to heat the hair 17).

[0205] It will be appreciated that the device 10 need not include a temperature sensor 26 for measuring the temperature of the hair 17 or for measuring the temperature of a portion of the device 10. For example, the device 10 may heat the hair 17 according to a predetermined operating profile. The predetermined operating profile (which may include, for example, heater power output, duration of heating the hair, or any other suitable operating parameter) may be stored in a memory 29 of the device 10.

[0206] Although the invention has been described primarily with reference to examples in which the power requirements of the device are primarily generated by the heater 23 (which may be part of a hair styler, heated brush, curling iron, electronic cigarette, hot glue gun, soldering iron, and iron), this is not required. More generally, the advantages of the invention are obtained for devices 10 having any other suitable type of time-dependent, periodic or intermittent electrical load. For example, Figure 2 The heater 23 shown in the figure may alternatively be a motor or a light source. The advantages of the present invention may be obtained by any suitable device 10 having a battery or other type of power source 21 (e.g. a PSU) for which there is a time-dependent (e.g. periodic or intermittent) power demand. For example, the device 10 may be a vehicle (e.g. an electric car) and the time-dependent power demand may be provided by the vehicle's motor, in which case the power source may charge a capacitor via the motor. As described above, the present invention allows the use of batteries and other power sources with lower maximum power outputs by smoothing the power required from the power source.

[0207] The device 10 may be partially or completely formed from a unitary structure, such as by 3D printing.

[0208] Throughout the description and claims of this specification, the words "include" and "comprises" and variations of the words, such as "including" and "comprising", mean "including but not limited to", and are not intended to (and do not) exclude other components, integers or steps.

[0209] Various other variations will be apparent to those skilled in the art and are not described in further detail here.

Claims

1. A portable device comprising: Electrical components that provide variable power requirements during use; Energy storage devices; power supply; as well as Control circuitry configurable between a first configuration and a second configuration: In the first configuration, the power source outputs power to the electrical component and outputs power to the energy storage device via the electrical component; as well as In the second configuration, the power source outputs power to the electrical component and the energy storage device outputs power to the electrical component.

2. The portable device according to claim 1, wherein: The control circuitry is configured to the first configuration or the second configuration based on a magnitude of the variable power demand.

3. The portable device according to claim 2, in, the control circuitry being configured to the first configuration or the second configuration based on a magnitude of the variable power demand and a threshold power output of the power supply; as well as Wherein, when the variable power demand is greater than the threshold power output of the power supply, the control circuit system is configured to the second configuration.

4. The portable device according to claim 2 or 3, wherein: The threshold power output is based on an available power output of the power supply.

5. The portable device according to any one of the preceding claims, wherein: The variable power demand is a periodic power demand.

6. A portable device comprising: Electrical components that provide variable power requirements during use; Energy storage devices; power supply; as well as A control circuit system configured to: controlling the power supply to output power to the component at a first power level; When the variable power demand is greater than the first power level, controlling the energy storage device to output power to the component; as well as When the variable power demand is less than a second power level, the power source is controlled to output power to the energy storage device and to output power to the component.

7. The portable device according to claim 6, wherein: The variable power demand is a periodic power demand.

8. The portable device according to any one of the preceding claims, wherein: The portable device is a hair styling device.

9. The portable device according to any one of the preceding claims, wherein: The energy storage device includes a capacitor.

10. The portable device according to claim 9, in, The electrical component comprises a first portion providing, in use, a first variable power demand and a second portion providing, in use, a second variable power demand; wherein the power source is operable to charge the capacitor via the first portion; and Wherein, the power source and the capacitor are operable to output power to the second portion.

11. The portable device according to any one of the preceding claims, wherein: The electrical component includes a heater.

12. The portable device according to any one of claims 6 to 9, wherein: The portable device is operable to charge the energy storage device without passing current through the component providing the variable power demand.

13. A portable device according to claim 11, when dependent on claim 9 or 10, wherein: The power supply is operable to charge the capacitor via at least one heater electrode of the heater.

14. The portable device according to claim 11 or 13, wherein: The at least one heater electrode includes a first heater electrode and a second heater electrode; wherein the power supply is operable to charge the capacitor via the first heater electrode; and Wherein the capacitor is operable to discharge via the second heater electrode.

15. The portable device according to claim 14, wherein: The first heater electrode and the second heater electrode are arranged in series.

16. The portable device according to claim 14, wherein: The second heater electrode has a lower resistance than the first heater electrode.

17. The portable device according to claim 16, wherein: The first heater electrode is powered by the power supply at a higher voltage than a voltage from the energy storage device used to power the second heater electrode.

18. The portable device according to any one of claims 14 to 17, wherein: The heater has one or more heating zones, each heating zone including the first heater electrode and the second heater electrode for heating the heating zone.

19. The portable device according to claim 18, wherein: The heater comprises a heating surface for heating hair in contact with the heating surface, and each heating zone comprises a respective portion of the heating surface.

20. The portable device according to claim 19, wherein: The first heater electrode and the second heater electrode each heat the portion of the heating surface of the heating zone.

21. The portable device according to claim 19 or 20, wherein: The heating surface is defined by a common heating member, or each heating zone has a respective heating member.

22. The portable device according to claim 21, wherein: The heating member is planar, tubular, corrugated or ribbed.

23. The portable device according to any one of claims 18 to 22, wherein: The first heater electrodes and the second heater electrodes of the heating zones are interleaved.

24. The portable device according to any one of claims 18 to 23, wherein: The heater comprises a plurality of the heating zones, and the portable device comprises a single controller for controlling whether the energy storage device is dischargeable via the second heater electrode of each of the heating zones.

25. The portable device according to any one of claims 14 to 24, wherein: The portable device also includes a heater controller for controlling power supplied to the first heater electrode and the second heater electrode by outputting a common control signal applied to a first switch and a second switch, wherein the first switch is coupled to the first heater electrode and the second switch is coupled to the second heater electrode.

26. The portable device according to claim 25, wherein: The heater controller is configured to simultaneously control power supplied to the first heater electrode and the second heater electrode by outputting the common control signal.

27. The portable device according to any one of claims 9 to 26, wherein: The capacitance of the capacitor is between 10F and 100F.

28. A portable device according to any preceding claim, wherein: The power source comprises a battery cell or a battery.

29. A portable device according to any preceding claim, wherein: The power supply comprises a power supply unit configured to draw power from a mains supply.

30. A portable device according to any preceding claim, wherein: The control circuitry is also configured to control power output to the energy storage device based on a state of charge of the energy storage device.

31. A portable device according to any preceding claim, wherein: Power output to the component providing the variable power demand and power output to the energy storage device are interleaved in the time domain.

32. A portable device comprising: power supply; Energy storage devices; Electrical components, which provide the power requirements when in use; Wherein, the power source is configured to charge the energy storage device via the electrical component.

33. The portable device according to claim 32, in, The electrical component includes a heater; wherein the heater comprises at least one heater electrode; and Wherein the power source is configured to charge the energy storage device via a heater electrode of the heater.

34. The portable device according to claim 32 or 33, wherein: The energy storage device includes a capacitor.

35. A portable device according to claim 34, when dependent on claim 33, wherein: The capacitor is operable to discharge via a heater electrode of the heater.

36. The portable device according to claim 35, in, the power source being operable to charge the capacitor via a first heater electrode of the heater; as well as Wherein the capacitor is operable to discharge via a second heater electrode of the heater different from the first electrode.

37. The portable device according to claim 36, wherein: The second heater electrode has a lower resistance than the first heater electrode.

38. The portable device according to claim 37, wherein: The first heater electrode is powered by the power supply at a higher voltage than a voltage from the capacitor used to power the second heater electrode.

39. The portable device according to any one of claims 32 to 38, wherein: The portable device is a hair styling device.

40. A portable device comprising: power supply; Capacitors; a heater comprising a first heater electrode and a second heater electrode; as well as Control circuitry that can be configured in the following configurations: a first configuration wherein the power source charges the capacitor via the first heater electrode; a second configuration, wherein the power source charges the capacitor via the second heater electrode; a third configuration, wherein the capacitor is discharged via the first heater electrode, and the power supply outputs power to the first heater electrode and the second heater electrode; as well as A fourth configuration wherein the capacitor is discharged via the second heater electrode, and the power supply outputs power to the first heater electrode and the second heater electrode.

41. The portable device according to claim 40, wherein: The portable device is a hair styling device.

42. The portable device according to claim 40 or 41, wherein: The control circuit system includes a plurality of switches; and The control circuit system can be configured among the first configuration, the second configuration, the third configuration and the fourth configuration through the operation of the switch.

43. The portable device according to any one of claims 40 to 42, wherein: The first heater electrode and the second heater electrode are arranged in series.

44. A hair styling device comprising: Electrical components that provide variable power requirements during use; Energy storage devices; power supply; as well as Control circuitry configurable between a first configuration and a second configuration: In the first configuration, the power source outputs power to the electrical component, and the power source outputs power to the energy storage device via the electrical component; as well as In the second configuration, the power source outputs power to the electrical component and the energy storage device outputs power to the electrical component.

45. A hair styling device comprising: Electrical components that provide variable power requirements during use; Energy storage devices; power supply; as well as A control circuit system configured to: controlling the power supply to output power to the electrical component and to output power to the energy storage device when the variable power demand is below a first threshold power demand; and When the variable power demand is greater than or equal to a second threshold power demand, the power source is controlled to output power to the electrical component, and the energy storage device is controlled to output power to the electrical component.

46. ​​A hair styling device comprising: Electrical components that provide variable power requirements during use; Energy storage devices; power supply; as well as A control circuit system configured to: controlling the power supply to output power to the electrical component at a first power level; When the variable power demand is greater than the first power level, controlling the energy storage device to output power to the electrical component; as well as When the variable power demand is less than a second power level, the power source is controlled to output power to the energy storage device and to output power to the electrical component.

47. A hair styling device comprising: power supply; Capacitors; a heater comprising at least one heater electrode; Wherein the power supply is operable to charge the capacitor via a heater electrode of the heater.

48. A hair styling device comprising: power supply; Capacitors; a heater comprising a first heater electrode and a second heater electrode; as well as Control circuitry that can be configured in the following configurations: a first configuration wherein the power source charges the capacitor via the first heater electrode; a second configuration, wherein the power source charges the capacitor via the second heater electrode; a third configuration, wherein the capacitor is discharged via the first heater electrode, and the power supply outputs power to the first heater electrode and the second heater electrode; as well as A fourth configuration wherein the capacitor is discharged via the second heater electrode, and the power supply outputs power to the first heater electrode and the second heater electrode.

49. A hair styling device comprising: a heater having one or more heating zones, each heating zone comprising a first heater track and a second heater track for heating the heating zone; a power source for providing power to heat one or more of the heating zones using the first heater track in the heating zones; an energy storage device for providing power to heat one or more of the heating zones using the second heater track of the heating zones; as well as Charging circuitry is provided for charging the energy storage device using power from the power source.

50. A hair styling device according to claim 49, wherein The hair styling appliance is operable to charge the energy storage device using the charging circuitry without passing current through the first heater track or the second heater track.

51. A hair styling device according to claim 49 or 50, wherein The second heater track has a lower electrical resistance than the first heater track.

52. A hair styling device according to claim 51, wherein The first heater rail is powered by the power supply at a higher voltage than a voltage from the energy storage device used to power the second heater rail.

53. A hair styling device according to any one of claims 49 to 52, wherein The heater comprises a plurality of heating zones and the hair styling device further comprises a single controller for controlling whether the capacitor is able to discharge via the second heater track of each of the heating zones.

54. A hair styling device according to any one of claims 49 to 53, wherein The hair styling device further comprises a heater controller for controlling power supplied to the first heater track and the second heater track by outputting a common control signal applied to a first switch coupled to the first heater track and a second switch coupled to the second heater track.

55. A hair styling device according to claim 54, wherein The heater controller is configured to simultaneously control power supplied to the first heater rail and the second heater rail by outputting the common control signal.

56. A hair styling device according to any one of claims 49 to 55, wherein The heater comprises a heating surface for heating hair in contact with the heating surface, and each heating zone comprises a respective portion of the heating surface.

57. A hair styling device according to claim 56, wherein The first heater track and the second heater track each heat the portion of the heating surface of the heating zone.

58. A hair styling device according to claim 56 or 57, wherein The heating surface is defined by a common heating member, or each heating zone has a respective heating member.

59. A hair styling device according to claim 58, wherein The heating member is planar, tubular, corrugated or ribbed.

60. A hair styling device according to any one of claims 49 to 59, wherein The first heater tracks and the second heater tracks of the heating zones are staggered.

61. A hair styling device according to any one of claims 49 to 60, wherein The power source comprises a battery cell or a battery.

62. A hair styling device according to any one of claims 49 to 61, wherein The charging circuitry includes a DC-DC converter.

63. A hair styling device according to any one of claims 49 to 62, wherein The charging circuitry is configured to control a rate of charging of the energy storage device based on a power demand on the power source from the heater and based on a state of charge of the energy storage device.

64. A hair styling device according to any one of claims 49 to 63, wherein The charging circuitry is configured to charge the energy storage device using power from the power source when a power demand on the power source from the heater is below a threshold.

65. A hair styling device according to any one of claims 49 to 64, wherein The charging of the energy storage device and the output of power from the power source to the heater are interleaved in the time domain.

66. A hair styling device according to any one of claims 40 to 65, wherein The hair styling device comprises a plurality of heaters, each heater having one or more respective heating zones.

67. A hair styling device according to any one of claims 49 to 66, wherein The energy storage device includes a capacitor.

68. A method for controlling power delivery in a portable device, the method comprising: Providing an apparatus according to any one of claims 1 to 67; as well as Power delivery from the power source and the energy storage device is controlled.

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