Wireless straightening iron equipped with double heaters

Abstract

A wireless straightening iron according to an embodiment of the present application includes a battery charged by an external power source, a first switch, a first heat generating resistor, and a second heat generating resistor connected in series between one end of the external power source and a ground terminal, a second switch connected at one end to a connection point between the first switch and the first heat generating resistor and at the other end to the ground terminal, a third switch connected at one end to a connection point between the first heat generating resistor and the second heat generating resistor and at the other end to one end of the battery, and a control unit that controls opening and closing operations of the first switch, the second switch, and the third switch; the other end of the battery is connected to the ground terminal, and the other end of the external power source is connected to the ground terminal.

Description

Technical Field

[0001] This disclosure relates to a wireless hair straightener, and more specifically, to a wireless hair straightener equipped with dual heaters. Background Technology

[0002] Hair straighteners are used to create hairstyles. Recently, demand for these straighteners has been increasing not only in hair salons but also in households. These straighteners can be used to create various types of hairstyles by placing the hair between a pair of high-temperature heating plates, which heat the hair to straighten it or give it wavy curls.

[0003] Traditional wired hair straighteners supply AC input power to the heater, allowing for rapid temperature increases even as the heater resistance rises. However, cordless hair straighteners, using batteries with limited output, struggle to sustain the same energy supply as the heater resistance increases with temperature. Therefore, a cordless hair straightener is needed that can provide heating performance similar to that of wired straighteners. Summary of the Invention

[0004] The technical problem to be solved by the present invention

[0005] The embodiments disclosed in this specification provide a power control device and method for dual heaters, which can be applied in cases where a heating resistor with a large change in temperature coefficient of resistance (TCR) is used as a heater, and in cases where a heating resistor with a small change in TCR is used as a heater.

[0006] Technical solution

[0007] According to one embodiment of this disclosure, a wireless hair straightener includes: a battery that is charged by an external power source; a first switch, a first heating resistor, and a second heating resistor connected in series between one end of the external power source and a ground terminal; a second switch, one end of which is connected to the connection point between the first switch and the first heating resistor, and the other end of which is connected to the ground terminal; a third switch, one end of which is connected to the connection point between the first heating resistor and the second heating resistor, and the other end of which is connected to one end of the battery; and a control unit that controls the opening and closing of the first switch, the second switch, and the third switch; the other end of the battery is connected to the ground terminal, and the other end of the external power source is connected to the ground terminal.

[0008] According to one embodiment, in a wireless straightener, the first switch is a P-channel MOSFET, the second switch is an N-channel MOSFET, and the third switch is a P-channel MOSFET.

[0009] According to one embodiment, in a wireless hair straightener, the first heating resistor and the second heating resistor are ceramic heaters using molybdenum or tungsten as heating elements, and the first heating resistor and the second heating resistor have the same resistance value.

[0010] According to one embodiment, in a wireless straightener, in a first operating mode where the temperatures of the first and second heating resistors are heated to a target temperature, the control unit performs the following control: controlling the first switch to be in a closed state; controlling the opening and closing switching action of the second switch according to the duty cycle of the PWM signal; controlling the third switch to be in a closed state; the duty cycle of the PWM signal is determined by the following equation to output a current not exceeding the maximum current of the battery.

[0011]

[0012] In the equation, TCR is the variable resistance value of the first heating element, and I... max V is the battery's maximum current output, and V is the voltage value that varies depending on the battery's charging and discharging states.

[0013] According to one embodiment, in a wireless straightener, in a second operating mode that maintains the temperature of at least one of the first or second heating resistors at a target temperature, the control unit performs the following control: when not connected to an external power source, the first and second switches are controlled to be in the off state, and the switching action of the third switch is controlled according to the duty cycle of the PWM signal used to maintain the temperature of the second heating resistor at the target temperature; when connected to an external power source, the switching action of the first switch is controlled according to the PWM duty cycle used to maintain the temperature of the first and second heating resistors at the target temperature, and the second and third switches are controlled to be in the off state.

[0014] According to another embodiment of this disclosure, a wireless hair straightener includes: a first switch, a first heating resistor, a second heating resistor, a second switch, and a battery, which are connected in series between one end of an external power supply and a ground terminal, and a control unit that controls the opening and closing of the first switch and the second switch; the battery is charged by the external power supply, the connection point between the first heating resistor and the second heating resistor is connected to the ground terminal, and the other end of the external power supply is connected to the ground terminal.

[0015] According to one embodiment, in a wireless straightener, the first switch is a P-channel MOSFET and the second switch is a P-channel MOSFET.

[0016] According to one embodiment, in a wireless straightener, the first heating resistor and the second heating resistor are ceramic heaters using palladium as the heating element, and the first heating resistor has a larger resistance value than the second heating resistor.

[0017] According to one embodiment, in a wireless hair straightener, in a first operating mode where the temperatures of the first heating resistor and the second heating resistor are heated to a target temperature, the control unit performs the following control: when not connected to an external power source, the first switch is controlled to be in a closed state and the second switch is controlled to be in a closed state; when connected to an external power source, the first switch is controlled to be in a closed state and the second switch is controlled to be in a closed state.

[0018] According to one embodiment, in a wireless straightener, in a second operating mode that maintains the temperature of the first heating resistor and the second heating resistor at a target temperature, the control unit performs the following control: when not connected to an external power source, the first switch is controlled to be in the off state, and the switching action of the second switch is controlled according to the PWM duty cycle used to maintain the target temperature; when connected to an external power source, the switching action of the first switch is controlled according to the PWM duty cycle used to maintain the target temperature, and the second switch is controlled to be in the off state.

[0019] Beneficial effects

[0020] According to various embodiments of this disclosure, a wireless hair straightener can be configured with multiple heating resistors on each heating plate to efficiently utilize power.

[0021] According to various embodiments of this disclosure, a wireless hair straightener can use a high-output battery to rapidly raise the temperature of the heating plate, thereby reducing the time users spend styling their hair.

[0022] According to various embodiments of this disclosure, when a power adapter is installed, the wireless straightener uses an external power source to maintain the temperature of the heating plate, without needing to control the battery for charging or discharging, thus increasing battery life and effectively managing battery life.

[0023] The effects of this disclosure are not limited to those described above, and those skilled in the art will clearly understand other unmentioned effects through the description in the claims. Attached Figure Description

[0024] Embodiments of this disclosure will be described with reference to the accompanying drawings, which indicate similar elements, but are not limited thereto.

[0025] Figure 1 This is a perspective view of a wireless hair straightener according to an embodiment of the present disclosure.

[0026] Figure 2 This is a wireless hair straightener control circuit using a heating resistor with a high TCR (Temperature Coefficient Resistance) variation amplitude characteristic, according to an embodiment of the present disclosure.

[0027] Figure 3 This is a diagram illustrating the operation of a wireless hair straightener using a heating resistor having a high TCR variation amplitude characteristic in a first operating mode according to an embodiment of the present disclosure.

[0028] Figure 4 This is a diagram illustrating the operation of a second operating mode on a wireless hair straightener using a heating resistor with high TCR variation characteristics according to an embodiment of the present disclosure, when connected to an external power source.

[0029] Figure 5 This diagram illustrates the operation of a second operating mode of a wireless straightener using a heating resistor with high TCR variation characteristics in an embodiment of this disclosure when no external power supply is connected.

[0030] Figure 6 This is a table showing the switching states of various operating modes of a wireless straightener using a heating resistor with high TCR variation characteristics according to an embodiment of the present disclosure.

[0031] Figure 7 This is a wireless straightener control circuit using a heating resistor with low TCR variation characteristics, according to an embodiment of the present disclosure.

[0032] Figure 8 This is a diagram illustrating the operation of a wireless hair straightener using a heating resistor with low TCR variation characteristics in a first operating mode according to an embodiment of the present disclosure.

[0033] Figure 9 This is a diagram illustrating the operation of a wireless straightener using a heating resistor with low TCR variation characteristics in a second operating mode according to an embodiment of the present disclosure.

[0034] Figure 10 This is a table showing the switching states of various operating modes of a wireless straightener using a heating resistor with low TCR variation characteristics according to an embodiment of the present disclosure. Detailed Implementation

[0035] The specific implementation of this disclosure will now be described in detail with reference to the accompanying drawings. However, in the following description, specific descriptions of well-known functions or structures will be omitted where such description would unnecessarily obscure the gist of this disclosure.

[0036] In the accompanying drawings, the same or corresponding constituent elements are given the same reference numerals. Furthermore, in the following description of embodiments, repeated descriptions of the same or corresponding components may be omitted. However, even if the description of constituent elements is omitted, it does not mean that these constituent element components are not included in some embodiments.

[0037] The advantages and features of the disclosed embodiments, as well as methods for implementing them, will become clear from the accompanying drawings and the embodiments described below. However, this disclosure is not limited to the embodiments disclosed below, but can be implemented in many different forms. These embodiments are provided merely to complete this disclosure and to fully inform those skilled in the art of the scope of the invention.

[0038] The terminology used in this specification will be briefly explained, and the disclosed embodiments will be described in detail. The terminology used in this specification is chosen to reflect the functionality of this disclosure, and generally widely used terms have been selected as much as possible. However, these terms may be changed based on the intent of those skilled in the art, precedents, or the emergence of new technologies. Furthermore, in specific cases, terms arbitrarily chosen by the applicant may be used; in such cases, their meanings will be described in detail in the description of the corresponding invention. Therefore, the terms used in this disclosure are not merely name names, but should be defined based on their meanings and the entirety of this disclosure.

[0039] In this specification, singular expressions are included in the plural unless explicitly stated in the context. Conversely, plural expressions are included in the singular unless explicitly stated in the context. When a section of this specification states that a particular element is included, this means that, unless there is a significant contradiction, other elements may be included, rather than excluded.

[0040] Furthermore, the terms "module" or "section" used in this specification refer to software or hardware components that perform a certain function. However, this does not mean that a "module" or "section" is limited to software or hardware. A "module" or "section" can be configured to reside in addressable storage media or to be operable on one or more processors. Thus, as an example, a "module" or "section" may include at least one of the following: software components, object-oriented software components, class components, and task components; processes, functions, attributes, steps, subroutines, fragments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, or variables. The functionality provided within a component and a "module" or "section" may be combined with smaller components and "modules" or "sections," or may be further separated into additional components and "modules" or "sections."

[0041] According to one embodiment of this disclosure, a "module" or "unit" may be implemented by a processor and a memory. "Processor" should be broadly interpreted to include general-purpose processors, central processing units (CPUs), microprocessors, digital signal processors (DSPs), controllers, microcontrollers, state machines, etc. In some contexts, "processor" may refer to application-specific integrated circuits (ASICs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), etc. "Processor" can refer to a combination of processing devices, such as a combination of a DSP and a microprocessor, a combination of multiple microprocessors, a combination of one or more microprocessors combined with a DSP core, or any other combination of the same configuration. Furthermore, "memory" should be broadly interpreted to include any electronic component capable of storing electronic information. "Memory" can refer to various types of processor-readable media, such as random access memory (RAM), read-only memory (ROM), non-volatile random access memory (NVRAM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory, magnetic or optical data storage devices, registers, etc. If the processor can read from and / or record information in the memory, the memory is said to be in electronic communication with the processor. The memory integrated in the processor is in electronic communication with the processor.

[0042] In this specification, “A and / or B” refers to “A” or “B” or “A and B”.

[0043] Figure 1 This is a perspective view of a wireless hair straightener 100 according to an embodiment of the present disclosure. (Refer to...) Figure 1 The wireless hair straightener 100 includes a heating plate 110, a power button 140, a first arm 150, and a second arm 160. A first heating resistor 120 and a second heating resistor 130 may be disposed inside the heating plate 110.

[0044] The heating plate 110 can be powered by an external power source (AC power; not shown) or a battery (DC power; not shown) configured inside the wireless hair straightener 100. The first heating resistor 120 and the second heating resistor 130 configured inside the heating plate can operate as heating elements by power supplied by an external power source or a battery.

[0045] Figure 1The diagram shows a heating plate 110 with two heating resistors 120 and 130 configured on the second arm 160 of the cordless hair straightener 100. However, it is not limited to this; a heating plate with two heating resistors can also be configured on the first arm 150 of the cordless hair straightener 100. The first heating resistor 120 and the second heating resistor are marked to distinguish them; the function of the heating resistors described later is not limited by their names. The user holds the first arm 150 and the second arm 160 of the cordless hair straightener 100 and places hair between the heating plates of each arm to perform hair styling.

[0046] Figure 2 This disclosure describes a wireless hair straightener control circuit 200 that uses a heating resistor with a high TCR (Temperature Coefficient Resistance) variation characteristic, according to one embodiment. When the heating resistor used in the hair straightener is a ceramic heater, the TCR characteristic varies depending on the material of the heating resistor metal. Figure 2 The control circuit for a wireless hair straightener is shown when using a heating resistor 240, 250 with high TCR variation characteristics.

[0047] As shown in the figure, the control circuit 200 includes a battery 220, a first switch 230, a second switch 232, a third switch 234, a first heating resistor 240, a second heating resistor 250, and a ground terminal 280, and can be connected to an external power supply 210. Additionally, the control circuit 200 may also include a control unit (not shown) for controlling the opening and closing actions of the first switch 230, the second switch 232, and the third switch 234. In one embodiment, the first heating resistor 240 and the second heating resistor 250 may have the same resistance value. For example, the first heating resistor 240 and the second heating resistor 250 may have a resistance value of 2.5Ω. In one embodiment, the first heating resistor 240 and the second heating resistor 250 may be ceramic heaters using molybdenum, tungsten, or the like as heating elements. For example, the heating resistor can be manufactured by coating a pattern of a heating metal such as molybdenum or tungsten onto a ceramic pad and stacking the ceramic. In addition, the first switch 230 and the third switch 234 can be P-channel MOSFETs, and the second switch 232 can be an N-channel MOSFET.

[0048] The first switch 230, the first heating resistor 240, and the second heating resistor 250 can be connected in series between one end of the external power supply 210 and the ground terminal 280. Additionally, one end of the second switch 232 can be connected to the connection point 260 between the first switch 230 and the first heating resistor 240, and the other end can be connected to the ground terminal 280. One end of the third switch 234 can be connected to the connection point 270 between the first heating resistor 240 and the second heating resistor 250, and the other end can be connected to one end of the battery 220. The other ends of the external power supply 210 and the battery 220 can be connected to the ground terminal 280. When the wireless hair straightener is connected to the external power supply 210, the battery 220 can be charged by connecting to the external power supply 210 (not shown). The control unit (not shown) can control the opening and closing of the first switch 230, the second switch 232, and the third switch 234 as described later, depending on whether the external power supply 210 is connected and the operating state of the wireless hair straightener.

[0049] Figure 3 This diagram illustrates the operation of a wireless hair straightener using a heating resistor with a high TCR variation range characteristic according to an embodiment of the present disclosure in a first operating mode. The first operating mode may refer to the temperature rise range within which the temperatures of the first heating resistor 240 and the second heating resistor 250 are heated to a target temperature (e.g., 200°C). For example, when a user turns on the power to the wireless hair straightener and heats the heating plate to the target temperature, the control unit can control the wireless hair straightener to operate in the first operating mode.

[0050] In the first operating mode, it is important to raise the temperature of the heating plate to the target temperature as quickly as possible. Due to the large variation in the TCR of the first heating resistor 240 and the second heating resistor 250, the resistance values ​​of the first heating resistor 240 and the second heating resistor 250 increase as the temperature of the heating plate rises. Even with the increased resistance, to continuously supply the maximum output current of the battery 220 to the heating plate, the maximum output current of the battery 220 is maintained by controlling the opening and closing of the second switch 232. If both the first heating resistor 240 and the second heating resistor 250 are kept in the on state starting from room temperature, the maximum current output of the battery 220 (e.g., 7.5A) will be exceeded. To avoid exceeding the maximum output of the battery 220, the control unit can control the first switch 230 to the off state (to ensure that the average current value does not exceed the maximum current output of the battery), and can control the opening and closing of the second switch 232 according to the duty cycle of the PWM (Pulse Width Modulation) signal, and can control the third switch 234 to the on state.

[0051] In one embodiment, the duty cycle of the PWM signal applicable to the second switch 232 can be determined by the following equation to ensure that it does not exceed the maximum current output of the battery 220.

[0052]

[0053] Wherein, TCR is the variable resistance value of the first heating resistor 240 and the second heating resistor 250, I max V is the maximum current output of battery 220, and V is a voltage value that varies depending on the charging and discharging state of battery 220. For reference, since the first heating resistor 240 and the second heating resistor 250 change by the same amount, and the current of battery 220 flows through both the first arm (not shown) and the second arm (not shown), half of the maximum current output of battery 220 (Imax) can be used in the equation when calculating the duty cycle of the PWM signal. max / 2).

[0054] According to the control unit's control described above, the first current i1 flows through the second heating resistor 250, and the second current i2 flows through the first heating resistor 240 according to the duty cycle of the PWM signal. Regardless of whether the external power supply 210 is connected or not connected to the wireless straightener, the control unit can control the switch as described above in the first operating mode. Furthermore, when the external power supply 210 is connected to the wireless straightener, if the battery 220 is fully charged, the control unit does not activate the charging of the battery 220; if the battery is not fully charged, the control unit can activate the charging of the battery 220.

[0055] When the cordless hair straightener operates in the third operating mode (heat loss range), the control unit can switch it to the same mode as in the first operating mode. The third operating mode refers to the range where, during the period when the heating plate maintains a target temperature, the temperature of the heating plate is reheated to the target temperature (e.g., 200°C) due to user use (e.g., on wet hair). In this case, it is necessary to increase the output for rapid temperature compensation. However, since it is difficult to increase the instantaneous output for temperature compensation using only the external power supply 210, the control unit can switch the power control to the same mode as in the first operating mode (temperature rise range), and switch to the second operating mode (described later) when the temperature stabilizes.

[0056] Figure 4This diagram illustrates the operation of a second operating mode of a wireless hair straightener using a heating resistor with a high TCR variation amplitude characteristic, according to an embodiment of this disclosure, when connected to an external power supply 210. The second operating mode may refer to a temperature holding range in which the first heating resistor 240 and the second heating resistor 250 maintain a target temperature (e.g., 200°C). For example, when the temperature of the heating plate of the wireless hair straightener reaches the target temperature through the first operating mode (temperature rise range), the control unit (not shown) can control the wireless hair straightener to operate in the second operating mode. Specifically, when the external power supply 210 is connected to the wireless hair straightener, the control unit in the second operating mode can control the switching action of the first switch 230 according to the PWM duty cycle used to maintain the temperature of the first heating resistor 240 and the second heating resistor 250 at the target temperature, and can control the second switch 232 and the third switch 234 to be in the off state.

[0057] In the second operating mode, maintaining the target temperature of the heating plate is crucial. Since the current required to maintain the target temperature is small, it can be maintained solely by the external power supply 210. For example, when the target temperature is 180°C, within the temperature holding range, the resistance values ​​of the heating resistors 240 and 250 will vary depending on their materials. When the material is tungsten, the resistance rises to approximately 1.6 times that at room temperature (25°C), increasing from 2.5Ω to 4Ω. If the output current of the external power supply 210 is used at room temperature, the resistance will be 2.5Ω, exceeding the over-power protection (OCP) range of the external power supply 210. However, if the power supply is controlled while the resistance is rising, the two heating resistors 240 and 250 are connected in series as a single-resistance heating resistor 240 and 250. At this time, the resistance values ​​of the heating resistors 240 and 250 are approximately 8Ω. Even if the first heating resistor 240 and the second heating resistor 250 are controlled by the external power supply 210, the maximum current will not deviate from the OCP range of the external power supply 210, and the average current can maintain the temperature within the output range of the external power supply 210. Furthermore, if the output current of the battery 220 is continuously supplied to the heating plate, the battery 220's lifespan will be shortened; therefore, the third switch 234 can be controlled to be in the off state. According to the above control by the control unit, the third current i3 can flow from the external power supply 210 through the first heating resistor 240 and the second heating resistor 250. Additionally, even when the external power supply 210 is connected to the wireless straightener in the second operating mode, the control unit can prevent the battery 220 from being charged.

[0058] Figure 5This diagram illustrates the operation of a second operating mode of a wireless straightener using a heating resistor with a high TCR variation amplitude characteristic in an embodiment of this disclosure when no external power supply 210 is connected. As shown, when the external power supply 210 is not connected to the wireless straightener, the control unit can control the first switch 230 and the second switch 232 to the off state in the second operating mode, and control the switching operation of the third switch 234 according to the PWM duty cycle used to maintain the second heating resistor 250 at a target temperature. According to the above control by the control unit, a first current i1 can flow from the battery 220 through the second heating resistor 250.

[0059] Figure 6 This is a table showing the switch states of various operating modes of a wireless hair straightener using a heating resistor with high TCR variation characteristics according to an embodiment of the present disclosure. The switches can be controlled differently depending on whether an external power supply is connected and the operating state. As described above, in both the first operating mode (temperature rise range) and the third operating mode (heat loss range), the control unit can control the first switch 230, the second switch 232, and the third switch 234 identically, regardless of whether an external power supply is connected.

[0060] In the second operating mode (temperature holding range), the control unit can control each switch differently depending on whether an external power supply is connected. When an external power supply is connected, the control unit can control the switching action of the first switch 230 according to the PWM duty cycle used to maintain the target temperature, and can control the second switch 232 and the third switch 234 to the off state. Conversely, when an external power supply is not connected, the control unit can control the first switch 230 and the second switch 232 to the off state, and can control the switching action of the third switch 234 according to the PWM duty cycle used to maintain the target temperature.

[0061] Figure 7 This is a control circuit 700 for a wireless hair straightener using a heating resistor with low TCR variation characteristics, according to an embodiment of the present disclosure. The TCR characteristics of the heating resistors in the ceramic used in the hair straightener can be different from each other. Figure 7 The control circuit 700 of a wireless straightener is shown when using heating resistors 740 and 750 with low TCR variation. For example, the first heating resistor 740 and the second heating resistor 750 can be ceramic heaters using palladium as the heating element.

[0062] In one embodiment, the first heating resistor 740 may have a greater resistance value than the second heating resistor 750. For example, the first heating resistor 740 may be 10Ω, and the second heating resistor 750 may be 2Ω. Additionally, the first switch 730 and the second switch 732 may be P-channel MOSFETs.

[0063] As shown in the figure, the control circuit 700 may include an external power supply 710, a battery 720, a first switch 730, a second switch 732, a first heating resistor 740, a second heating resistor 750, and a ground terminal 770. Additionally, the control circuit 700 may include a control unit (not shown) for controlling the opening and closing of the first switch 730 and the second switch 732. The first switch 730, the first heating resistor 740, the second heating resistor 750, the second switch 732, and the battery 720 may be connected in series between one end of the external power supply 710 and the ground terminal 770. The connection point 760 between the first heating resistor 740 and the second heating resistor 750 may be connected to the ground terminal 770, and the other end of the external power supply 710 may be connected to the ground terminal 770. Furthermore, when the wireless hair straightener is connected to the external power supply 710, the battery 720 can be charged by connecting to the external power supply 710 (not shown). The control unit can control the opening and closing of the first switch 730 and the second switch 732 as described later, depending on whether the external power supply 710 is connected and the operating status of the wireless hair straightener.

[0064] Figure 8 This diagram illustrates the operation of a wireless hair straightener using a heating resistor with a low TCR variation range according to an embodiment of the present disclosure in a first operating mode. The first operating mode refers to the temperature rise range during which the temperatures of the first heating resistor 740 and the second heating resistor 750 are heated to a target temperature (e.g., 200°C). For example, when a user turns on the power to the wireless hair straightener and heats the heating plate to the target temperature, the control unit can control the wireless hair straightener to operate in the first operating mode (temperature rise range). In this case, the first heating resistor 740 and the second heating resistor 750 can be ceramic heaters using palladium as the heating element, which has a low TCR variation range.

[0065] In the first operating mode, it is important to raise the temperature of the heating plate to the target temperature as quickly as possible. Each heating resistor 740 and 750 is a palladium-based ceramic heater, meaning that even as the heating plate temperature rises, the TCR change is minimal. Therefore, the resistance changes of the first heating resistor 740 and the second heating resistor 750 are likely to be small. Thus, the maximum output of the external power supply 710 and the battery 720 can be provided to the heating plate. The control unit (not shown) can control the opening and closing of the first switch 730 and the second switch 732, as described later, based on whether the external power supply 710 is connected and the operating status of the wireless hair straightener.

[0066] like Figure 8 As shown, when the external power supply 710 is connected to the wireless hair straightener, the control unit can control the first switch 730 and the second switch 732 to be in the "on" state. Furthermore, even when the external power supply 710 is connected to the wireless hair straightener in the first operating mode, the control unit can prevent the battery 720 from charging. According to the control unit's control described above, a first current i1 can flow from the battery 720 through the second heating resistor 750, and a second current i2 can flow from the external power supply 710 through the first heating resistor 740.

[0067] Conversely, when the external power supply 710 is not connected to the wireless straightener (not shown), the control unit can control the first switch 730 to the off state and the second switch 732 to the on state in the first operating mode. In this case, the first current i1 can flow from the battery 720 through the second heating resistor 750. Since the first switch 730 is controlled to the off state, the current will not flow through the first heating resistor 740.

[0068] When the cordless hair straightener operates in the third operating mode (heat loss range), the control unit can switch it to the same mode as the first operating mode (temperature rise range). The third operating mode refers to the range during which the heating plate maintains a target temperature, and when the user's use (e.g., with wet hair) causes temperature loss in the heating plate, the temperature of the first heating resistor 740 and the second heating resistor 750 is heated to the target temperature (e.g., 200°C). Additionally, the control unit can switch the power control to the same mode as the first operating mode, and then switch to the second operating mode (described later) when the temperature stabilizes. In this case, even when the external power supply 710 is connected to the cordless hair straightener in the third operating mode, the control unit can prevent the battery 720 from charging.

[0069] Figure 9This diagram illustrates the operation of a wireless hair straightener using a heating resistor with low TCR variation characteristics according to an embodiment of this disclosure in a second operating mode. The second operating mode may refer to a temperature holding range in which the first heating resistor 740 and the second heating resistor 750 maintain a target temperature (e.g., 200°C). For example, when the heating plate temperature of the wireless hair straightener reaches the target temperature through the first operating mode (temperature rise range), the control unit (not shown) can control the wireless hair straightener to operate in the second operating mode (temperature holding range). Specifically, when the external power supply 710 is connected to the wireless hair straightener, the control unit controls the switching of the first switch according to the PWM duty cycle used to maintain the target temperature in the second operating mode, controlling the second switch to be in the off state. In this case, the second current i2 can flow from the external power supply 710 through the first heating resistor 740 according to the PWM duty cycle. Furthermore, even when the external power supply 710 is connected to the wireless hair straightener in the second operating mode, the control unit may not activate the charging of the battery 720.

[0070] When the external power supply 710 is not connected to the wireless straightener (not shown), the control unit can control the first switch 730 to be in the off state in the second operating mode, and control the switching action of the second switch 732 according to the PWM duty cycle used to maintain the target temperature. In this case, the first current (not shown) can flow from the battery 720 through the second heating resistor 750 according to the PWM duty cycle.

[0071] Figure 10 This is a table showing the switch states of various operating modes of a wireless hair straightener using a heating resistor with low TCR variation characteristics according to an embodiment of the present disclosure. The wireless hair straightener can control each switch differently depending on whether an external power supply is connected and the operating state. As described above, the control unit can control the switch 730 and the second switch 732 based on whether an external power supply is connected, such that the first switch 730 and the second switch 732 are identical in the first operating mode (temperature rise range) and the third operating mode (heat loss range), respectively.

[0072] In the second operating mode (temperature holding range), the control unit can control each switch differently depending on whether an external power supply is connected. When connected to an external power supply, the control unit can control the switching action of the first switch 730 according to the PWM duty cycle used to maintain the target temperature, and can control the second switch 732 to be in the off state. Conversely, when not connected to an external power supply, the control unit can control the first switch 730 to be in the off state, and can control the switching action of the second switch 732 according to the PWM duty cycle used to maintain the target temperature.

[0073] The switching control action of the aforementioned wireless straightener can also be implemented as computer-readable code on a computer-readable recording medium. Computer-readable recording media include all types of recording devices that store data readable by a computer system. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical storage, etc. Furthermore, the computer-readable recording medium is distributed across a network-connected computer system to store and execute computer-readable code in a distributed manner. Moreover, the functional programs, code, and code snippets used to implement the above embodiments can be readily deduced by a programmer skilled in the art to which this invention pertains.

[0074] The methods, actions, or techniques of this disclosure can be implemented by various means. For example, these techniques can be implemented in hardware, firmware, software, or a combination thereof. Those skilled in the art will understand that the various exemplary logic blocks, modules, circuits, and algorithm steps described in connection with this disclosure can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate this substitution between hardware and software, various exemplary components, blocks, modules, circuits, and steps have been generally described above from a functional point of view. Whether such functionality is implemented in hardware or software depends on the specific application and the design requirements attached to the overall system. Those skilled in the art can implement the described functionality in various ways for each specific application, but such implementations should not be construed as departing from the scope of this disclosure.

[0075] In a hardware implementation, the processing unit for performing the technology may also be implemented in one or more ASICs, DSPs, digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, electronic devices, other electronic units for performing the functions described in this disclosure, computers, or combinations thereof.

[0076] Therefore, the various exemplary logic blocks, modules, and circuits described in connection with this disclosure can be implemented or performed by any combination of a general-purpose processor, DSP, ASIC, FPGA or other programmable logic device, discrete gate or diode transistor logic gate, discrete hardware element, or object designed to perform the functions described herein. The general-purpose processor can be a microprocessor, but alternatively, it can also be any conventional processor, controller, microcontroller, or state machine. The processor can also be implemented by a combination of computing devices, such as a DSP and a microprocessor, multiple microprocessors, one or more microprocessors associated with a DSP core, or any other combination thereof.

[0077] In terms of firmware and / or software implementation, the technology can also be implemented via commands stored on a computer-readable medium such as random access memory (RAM), read-only memory (ROM), non-volatile random access memory (NVRAM), PROM (programmable read-only memory), EPROM (erasable programmable read-only memory), EEPROM (electrically erasable PROM), flash memory, compact disc (CD), magnetic or optical data storage devices, etc. The commands can be executed by one or more processors, or in a specific manner that causes the processors to perform the functions described in this disclosure.

[0078] When implemented in software, the technology can be stored as one or more commands or codes on or transmitted via a computer-readable medium. Computer-readable media includes any medium that facilitates the transfer of a computer program from one place to another, including both computer storage media and communication media. Storage media can be any available media accessible by a computer. As a non-limiting example, such computer-readable media may include: RAM, ROM, EEPROM, CD-ROM or other optical disk storage; disk storage or other magnetic storage devices; or any other media that can be used to transfer or store desired program code in the form of commands or data structures and that can be accessed by a computer. Additionally, any connection is appropriately referred to as computer-readable media.

[0079] For example, when software is transmitted from a website, server, or other remote source using wireless technologies such as coaxial cable, fiber optic cable, flexible cord, digital subscriber line (DSL), or infrared, wireless, and microwave, these wireless technologies are included within the definition of media. The disks and discs used in this invention include CDs, laser discs, optical discs, DVDs (digital versatile discs), floppy disks, and Blu-ray discs, wherein disks typically regenerate data automatically, while discs utilize lasers for optical data regeneration. The above combinations should also be included within the scope of computer-readable media.

[0080] Software modules can also reside in RAM, flash memory, ROM, EPROM, EEPROM, registers, hard disks, external hard disks, CD-ROMs, or any other known form of storage media. As an example, the storage media can be connected to the processor, allowing the processor to read information from or record information onto the storage media. Alternatively, the storage media can be integrated into the processor. The processor and storage media can also reside within an ASIC. The ASIC can also reside within a user terminal. Alternatively, the processor and storage media can exist as a single component within the user terminal.

[0081] The embodiments described above are presented in a manner that utilizes the now-disclosed subject matter within one or more independent computer systems, but this disclosure is not limited thereto and can be implemented in conjunction with any computing environment such as a network or distributed computing environment. Furthermore, various aspects of the subject matter in this disclosure can also be implemented in multiple processing chips or devices, and memory will be similarly affected by multiple devices. These devices may also include personal computers (PCs), network servers, and portable devices.

[0082] While this disclosure is illustrated with reference to certain embodiments, various modifications and alterations can be made without departing from the scope of this disclosure as would be understood by those skilled in the art. Furthermore, such modifications and alterations should be considered to fall within the scope of the appended claims.

[0083] Explanation of reference numerals in the attached figures

[0084] 100: Wireless hair straightener

[0085] 110: Heating plate

[0086] 120: First heating resistor

[0087] 130: Second heating resistor

[0088] 140: Power button section

[0089] 150: First Arm

[0090] 160: Second arm

[0091] 200: Control circuit

[0092] 210: External power supply

[0093] 220: Battery

[0094] 230: First Switch

[0095] 232: Second Switch

[0096] 234: Third Switch

[0097] 240: First heating resistor

[0098] 250: Second heating resistor

[0099] 260, 270: Connection points

[0100] 280: Grounding terminal

[0101] 700: Control Circuit

[0102] 710: External power supply

[0103] 720: Battery

[0104] 730: First Switch

[0105] 732: Second Switch

[0106] 740: First heating resistor

[0107] 750: Second heating resistor

[0108] 760: Connection point

[0109] 770: Grounding terminal

[0110] i1: First current; i2: Second current; i3: Third current

Claims

1. A wireless straightening iron, characterized by the wireless straightening iron comprising: a battery charged by an external power supply, a first switch, a first heat-generating resistor, and a second heat-generating resistor connected in series between one end of the external power supply and a ground terminal, a second switch connected at one end to a connection point between the first switch and the first heat-generating resistor and at the other end to the ground terminal, a third switch connected at one end to a connection point between the first heat-generating resistor and the second heat-generating resistor and at the other end to one end of the battery, and a control unit that controls the opening and closing actions of the first switch, the second switch, and the third switch; the other end of the battery is connected to the ground terminal; the other end of the external power supply is connected to the ground terminal; the first heat-generating resistor and the second heat-generating resistor have a high Temperature Coefficient Resistance (TCR) variation range characteristic.

2. The wireless straightening iron according to claim 1, characterized in that the first switch is a P-channel MOSFET, the second switch is an N-channel MOSFET, the third switch is a P-channel MOSFET.

3. The wireless straightening iron according to claim 1, characterized in that the first heat-generating resistor and the second heat-generating resistor are ceramic heaters using molybdenum or tungsten as a heat-generating body, the first heat-generating resistor and the second heat-generating resistor have the same resistance value.

4. The wireless straightening iron according to claim 1, characterized in that in a first operation mode in which the temperatures of the first heat-generating resistor and the second heat-generating resistor are heated to a target temperature, the control unit controls as follows: the first switch is controlled to be in the off state, the opening and closing switching action of the second switch is controlled according to the duty ratio of a PWM signal, the third switch is controlled to be in the on state, the duty ratio of the PWM signal is determined by the following equation so as not to exceed the maximum current output of the battery, ， in the equation, TCR is the variable resistance value of the first heat-generating resistor, Imax is the maximum current output of the battery, V is a voltage value that is variable according to the charging and discharging states of the battery.

5. The wireless straightening iron according to claim 1, characterized in that in a second operation mode in which the temperature of at least one of the first heat-generating resistor or the second heat-generating resistor is maintained at a target temperature, the control unit controls as follows: in the case of a state in which the external power supply is not connected, the first switch and the second switch are controlled to be in the off state, the switching action of the third switch is controlled according to the duty ratio of a PWM signal for maintaining the temperature of the second heat-generating resistor at the target temperature, in the case of a state in which the external power supply is connected, The switching operation of the first switch is controlled according to a PWM duty ratio for maintaining the temperatures of the first and second heat generating resistors at the target temperature, and the second and third switches are controlled to be in an off state.

6. A wireless straightening iron, characterized by comprising: The wireless straightening iron comprises: a first switch, a first heat generating resistor, a second heat generating resistor, a second switch, and a battery, which are connected in series between one end of an external power source and a ground terminal, and a control unit that controls the opening and closing operations of the first and second switches; The battery is charged by the external power source; a connection point between the first and second heat generating resistors is connected to the ground terminal; the other end of the external power source is connected to the ground terminal; the first and second heat generating resistors have a low Temperature Coefficient Resistance (TCR) variation amplitude characteristic; In a first operation mode in which the temperatures of the first and second heat generating resistors are heated to a target temperature, the control unit controls as follows: In a state in which the external power source is not connected, the first switch is controlled to be in an off state, and the second switch is controlled to be in an on state, In a state in which the external power source is connected, the first switch is controlled to be in an on state, and the second switch is controlled to be in an on state; In a second operation mode in which the temperatures of the first and second heat generating resistors are maintained at the target temperature, the control unit controls as follows: In a state in which the external power source is not connected, the first switch is controlled to be in an off state, the switching operation of the second switch is controlled according to a PWM duty ratio for maintaining the target temperature; In a state in which the external power source is connected, the switching operation of the first switch is controlled according to a PWM duty ratio for maintaining the target temperature, the second switch is controlled to be in an off state.

7. The wireless straightening iron according to claim 6, characterized in that: the first switch is a P-channel MOSFET, the second switch is a P-channel MOSFET.

8. The wireless straightening iron according to claim 6, characterized in that: the first and second heat generating resistors are ceramic heaters using palladium as a heat generating body, the first heat generating resistor has a larger resistance value than the second heat generating resistor.

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