Current control system for skin treatment devices

Abstract

To provide a current control system for a skin treatment device.SOLUTION: A skin treatment device (800) has one or more electrodes (120, 820) adapted for application of a current to a skin surface of a subject, a voltage or current supply (514, 840) configured to generate the current, and a controller (500, 850) configured to modulate the power output to the skin surface. The controller (500, 850) includes a monitor circuit (510) configured to generate feedback responsive to a change in the power output to the skin surface based at least in part on the current, and a control circuit (520) configured to modulate the current, based on the feedback.SELECTED DRAWING: None

Description

[Technical Field]

[0001] (Cross-reference of related applications) This application claims priority to U.S. Provisional Patent Application No. 63 / 256,106, “Current Control System for Skin Treatment Device,” filed on 15 October 2021, which is incorporated herein by reference in its entirety for any purpose.

[0002] (Field) This application relates to power modulation and control for skin treatment systems. More generally, it relates to systems, devices, processes, and methods for controlling power delivery in skin treatment to improve user comfort while maintaining effectiveness. Preferred uses include, but are not limited to, microcurrent therapy, galvanic therapy, and pulse-modulated current therapy for cosmetic skin care and skin treatment, as well as other cosmetic and non-cosmetic applications adapted to address applicable regulatory requirements. [Background technology]

[0003] (background) The skin covers the surface of the body, forming a physical and insulating barrier against the environment and protecting against foreign objects, insects, and other non-human organisms. The skin also regulates the pathways of body temperature, water, and electrolytes, and contains nerves for touch, heat sensitivity, and other forms of bodily sensation.

[0004] The outer or epidermal layer of skin is formed from cells called keratin-producing cells, which form an environmental barrier and synthesize vitamin D. The epidermis also contains melanocytes, which produce melanin to protect against harmful ultraviolet radiation; Merkel cells, which provide sensitivity to contact; and Langerhans cells, which are a type of white blood cell or macrophage that protects the body against infection as part of the immune system.

[0005] The epidermis surrounds the dermis. The structure of the dermis is provided by fibroblasts, which form the extracellular matrix, synthesizing collagen and elastin proteins, with collagen fibers providing strength and toughness, and elastin threads or filaments providing elasticity and flexibility. Fibroblasts also produce proteoglycans, which are sticky proteins that provide hydration and lubrication and regulate ionic bonding and molecular transport. The epidermis also contains macrophages and mast cells, which are part of the immune system, as well as hair follicles, sweat glands and sebaceous glands, nerve cells, and blood vessels.

[0006] The epidermis and dermis constitute the cutis. Subcutaneous tissue connects the cutis to other connective tissues, including the underlying muscles and fascia, as well as the periosteum (which covers the bone). Subcutaneous tissue also contains elastinocytes and adipose (fat) cells. Skin health, in turn, depends on all of these components, from the subcutaneous tissue to the outer layers of the epidermis.

[0007] A range of personalized skincare products have been developed to help maintain skin health and vitality, including devices for cleansing, exfoliating, and smoothing the outer epidermal layer, as well as products for improving hardness and elasticity, which are associated with the production of type I collagen, elastin, proteoglycans, and other components in the extracellular matrix within and below the dermis. Healthy skin can also exhibit better strength and elasticity, provide enhanced environmental protection, boost the immune response, and offer cosmetic benefits, including improved color, tone, and overall appearance.

[0008] Advanced skincare devices also employ current-based therapies, including both galvanic systems that work to improve local delivery and microcurrent-based (pulsed) electrical waveforms that can stimulate the skin tissue itself. However, the skin's response to electrical current flow involves several complex and interacting biological processes that can trigger a range of user sensations. Consequently, there is a continuing need for more advanced current control techniques, including techniques to continuously monitor and control current levels and improve the effectiveness of the treatment, while maintaining user comfort and, where appropriate, reducing treatment time requirements. [Overview of the project] [Means for solving the problem]

[0009] (summary) A skin treatment device is disclosed, comprising one or more electrodes adapted for applying an electric current to a target skin surface. A voltage source or current source may be configured to generate a current for application through one or more electrodes when power is output to the skin surface. A controller may be configured to modulate the power output using a monitoring circuit configured to generate feedback in response to changes in the power output, based at least partially on one or more of the electrodes or across them.

[0010] The controller may include, for example, a control circuit configured to modulate current based on feedback, with a level control unit adapted to modulate current via a nonlinear current control device. Methods for operating such a device are also included, in addition to a non-transient computer-readable medium with executable program code for operating such a device. For example, the present invention provides the following items: (Item 1) It is a device, One or more electrodes adapted for applying an electrical current signal to the target skin surface, A voltage source or current source configured to generate the current signal for application via one or more of the electrodes, wherein the power is output to the skin surface, A controller configured to modulate the power output to the skin surface, Equipped with, The above controller is A monitoring circuit is configured to generate a feedback signal in response to a change in the current signal or power output to the skin surface, based at least in part on a voltage sensed in close proximity to one or more of the electrodes. A control circuit comprising a control device coupled to one or more of the electrodes, configured to modulate the change in the current signal based on the feedback signal, and A device equipped with the following features. (Item 2) The control device described above comprises a first terminal coupled to one or more of the electrodes, a second terminal coupled to the monitoring circuit, and a gate coupled to the control circuit. (Item 3) The control device described above is a device according to any of the above items, comprising one or more of a transistor, a field-effect transistor, or a junction-gate field-effect transistor. (Item 4) The monitoring circuit comprises a voltage sensor coupled to a second terminal of the control device, and the feedback signal includes the voltage sensed by the voltage sensor at the second terminal, which is adjacent to one or more of the electrodes, according to any of the above items. (Item 5) The control circuit comprises a level control unit coupled to the gate of the control device, wherein the level control unit defines a response curve of the control device based on a change in the voltage, the current signal, or the power output, according to any of the above items. (Item 6) The level control unit is configured to define the response curve between a predetermined minimum power level and a maximum power level based on the feedback signal from the monitoring circuit, the device according to any one of the above items. (Item 7) The level control unit is configured to lower the response curve to or towards the predetermined minimum power level based on the change in the feedback signal, the device according to any one of the above items. (Item 8) The change in the feedback signal is defined by the difference between the average value of a first series of the feedback signals and the average value of a second series of the feedback signals that exceeds a pre-defined threshold, the device according to any one of the above items. (Item 9) The first and second series of feedback signals are at least partially overlapping or in a sequential order, The change in the feedback signal is further defined by the average value of the second series of feedback signals that is less than the average value of a third series of feedback signals, the third series being longer than the second series and at least partially overlapping both the first and the second series, or The change in the feedback signal is in response to the removal of the device from the skin surface of the subject, the device according to any one of the above items. (Item 10) The control circuit is configured to raise the response curve of the three-terminal device to or towards the predetermined maximum power level based on the absence of a change in the feedback signal, the device according to any one of the above items. (Item 11) The control circuit is configured to repeatedly raise the response curve towards the predetermined maximum power level based on the continued absence of the change, the device according to any one of the above items. (Item 12) The feedback signal is further based on one or more of an accelerometer signal or a velocity sensor signal responsive to the speed of the device relative to the skin surface, a pressure signal responsive to a force from the skin surface to one or more of the electrodes, and a temperature signal responsive to a temperature at the skin surface or at a location adjacent thereto, for the device according to any of the above items. (Item 13) The control circuit is configured to modulate the current signal by defining a gain curve in the control device based on the feedback signal, and the voltage source or current source is coupled to one or more of the other ones of the electrodes that are spaced apart from one or more of the electrodes coupled to the control device, for the device according to any of the above items. (Item 14) The control circuit is configured to define the gain curve between a minimum value and a maximum value of the gain curve based on the feedback signal, or configured to decrease the gain curve in response to a predefined change in the feedback signal and increase the gain curve in response to the absence of the predefined change in the feedback signal, for the device according to any of the above items. (Item 15) A method of operating the device according to any of the above items. (Item 16) A non-transitory computer-readable medium having program code stored thereon, the program code being executable on a computer processor or a controller to operate the device according to any of the above items, the non-transitory computer-readable medium. [[ID= 23]] (Item 17) A skin treatment device, a plurality of electrodes adapted for the application of a current signal to a skin surface of a subject, A voltage source or current source configured to generate the current signal for application via one or more of the electrodes, wherein the power is output to the skin surface, A controller configured to modulate the power output to the skin surface, Equipped with, The above controller is A monitoring circuit is configured, at least in part, to generate a feedback signal in response to a change in the current signal or power output to the skin surface, based on a voltage sensed in close proximity to or across one or more of the electrodes. A control circuit is configured to modulate the current signal within a predefined range based on the above feedback signal. A device equipped with the following features. (Item 18) The above multiple electrodes are, Two or more electrodes configured for electrical contact with the skin surface, wherein the current signal is delivered to the skin surface between the two electrodes, or At least one electrode configured for electrical contact with the skin surface, and at least one other electrode configured for electrical contact with the hand or other body part of the subject, spaced apart from the skin surface, wherein the current signal is delivered to the skin surface between the at least one electrode in electrical contact with the skin surface and the at least one other electrode spaced apart from the skin surface. A device comprising any of the above items. (Item 19) The device according to any of the above items, wherein the above change in the current signal or output power is associated with the comfort level of the subject in response to the above power output to the skin surface. (Item 20) The above control circuit is, In response to the above change associated with the above decrease in comfort level, the current signal is adjusted to a lower or minimum value within the above predefined range, or Adjusting the current signal to a higher or maximum value within the predefined range in response to the above change, which is associated with the above increase in comfort level or the absence of the above decrease in comfort level. A device according to any of the above items, comprising a power level control unit configured to perform the following: (Summary) A skin treatment device (800) comprises one or more electrodes (120, 820) adapted for applying an electric current to the surface of the target skin, a voltage source or current source (514, 840) configured to generate an electric current, and a controller (500, 850) configured to modulate the power output to the skin surface. The controller (500, 850) includes a monitoring circuit (510) configured to generate feedback in response to changes in the power output to the skin surface, at least partially based on the current, and a control circuit (520) configured to modulate the current based on the feedback. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a cross-sectional view illustrating the application of a device for delivering electrotherapy.

[0012] [Figure 2] Figure 2 shows power output versus skin resistance plots for three representative skin treatment devices.

[0013] [Figure 3A] Figure 3A shows a plot of current versus skin resistance for different current control parameters.

[0014] [Figure 3B] Figure 3B is a plot of power output versus skin resistance with respect to the current control parameters in Figure 3A.

[0015] [Figure 4] Figure 4 is a current / voltage plot illustrating the drain characteristics of a current-controlled device.

[0016] [Figure 5] Figure 5 is a typical electronic circuit diagram illustrating a current control circuit that uses the device shown in Figure 5, for example.

[0017] [Figure 6] Figure 6 is a block logic diagram relating to current control, illustrating, for example, the operation of the current control circuit shown in Figure 5.

[0018] [Figure 7] Figure 7 is a flowchart illustrating the operation of the control logic according to Figure 7, for example, and relates to current control.

[0019] [Figure 8] Figure 8 is a block diagram of a typical skin treatment device with continuous current control.

[0020] [Figure 9] Figure 9 is a block diagram of a method for current control relating to the operation of the device shown in Figure 8, for example. [Modes for carrying out the invention]

[0021] (Detailed explanation) While this disclosure describes specific examples and preferred embodiments of the invention, those skilled in the art will understand that modifications can be made in forms and details that do not depart from the scope of the claims. Various examples and embodiments are also described with reference to drawings, where similar reference numerals represent similar structural and functional components throughout several figures. These examples and embodiments do not limit the practice of the invention to those claimed; rather, this specification merely describes representative applications to different systems, methods, and devices, and the practice of the invention is not limited to those described in the appended claims.

[0022] (Overview) This disclosure describes a method by which the electrical output from a skin treatment device may be adjusted for user comfort while maintaining therapeutic effectiveness. The solution can be manufactured without the prior art design limitations that may reduce the maximum voltage and / or current output levels and impair the effectiveness of the device, while maintaining other beneficial operating characteristics.

[0023] Conventional galvanic, microcurrent (or similar) skin therapy devices generally utilize a constant current source to assist in the delivery of topical medications into the skin or to otherwise promote skin health, vitality, and well-being. However, users of prior art devices may sometimes experience stinging or puncture sensations, which can, in some cases, induce discomfort. In response, designers sometimes provide adjustable level settings that allow the user to electronically reduce the current or voltage output at their discretion.

[0024] Unfortunately, some adjustment level settings can also reduce the device's effectiveness, for example, by reducing the current to below the level required to maintain effectiveness. To provide a more effective solution that allows the device to operate at better (or maximum) effectiveness while also providing a positive user experience, a continuously acting "constant comfort control" function is introduced to regulate the device's power output. Suitable applications include, but are not limited to, galvanic, microcurrent, TENS (transcutaneous electrical nerve stimulation), and iontophoresis-based skin treatment devices, as described in U.S. Public Documents No. 2007 / 0185431 A1, No. 2021 / 0162212 A1, and No. 2021 / 0308452 A1, and U.S. Patents No. 10,046,160 B1, No. 10,080,428 B2, No. 10,765,199 B2, and No. 10,772,473 B2 (all of which are incorporated herein by reference for any purpose) respectively.

[0025] Constant current power supplies have output characteristics that allow them to deliver a constant current to a load despite changes and fluctuations in resistance. However, the practical output performance of these sources is limited by the voltage used to supply the source and defined by the resistance according to Ohm's law.

[0026] In addition, the output power is non-uniform because it depends on the electrical resistance of the load. This relationship is defined by the following power equation. P=I 2 ×R (1) In the equation, I is the current output, R is the resistance, and P is the power delivered to the load (e.g., the user's skin). Alternatively, the following apply: P = I × V (2) In the equation, again following Ohm's law, the voltage V = I × R.

[0027] When galvanic (or similar) current-based devices are used on the skin, their equivalent resistance characteristics change continuously depending on skin thickness, moisture level, the presence (or absence) of topical medications and facial or body hair, as well as other characteristics. In some cases, these changes in resistance R are abrupt and rapid, as the source attempts to maintain the current I at a constant value, which can result in similarly rapid changes in voltage V and power output P.

[0028] These “hyperpolarization” events can expose the skin to significant power difference transients, which are associated with a likelihood of stinging or puncture sensations and (if any) user discomfort. Several factors contribute to hyperpolarization events (including rapid voltage and / or power fluctuations), among others, including the electrical properties of the device, the speed at which the device moves across the skin surface under treatment, the skin contact surface area, the pressure applied, the dryness and moisture levels of the skin, the thickness of the skin, and the location of the treatment area.

[0029] Figure 1 is a cross-sectional view illustrating the application of a skin treatment or skin care device 100 to deliver electrical stimulation or current therapy S to the skin 110 of a subject, for example, a user of device 100. Device 100 can also be applied to the subject's skin 110 by a skin care technician, specialist, or other person.

[0030] As shown in Figure 1, the skin treatment device 100 includes one or more electrodes 120 adapted for applying an electrotherapy S to the surface 111 of the target skin 110, either in combination with a topical drug 112, as shown, or applied directly onto the skin surface 111. The skin (or "cutis") 110 extends from the skin surface 111 through the epidermal layer (or epidermis) 114 to the lower dermal layer (dermis) 116. The subcutaneous tissue (or subcutaneous tissue) 118 comprises subcutaneous tissue beneath the cutis 110.

[0031] The dermis 116 includes an upper papillary layer and a lower reticular layer, both of which are arranged in a more relaxed state and are formed from denser collagen fibers. The collagen fibers extend from the dermis 116 through the subcutaneous tissue 118, forming connective tissue (fascia) that attaches the skin (cutis) 110 to the underlying muscles and other connective tissues. The subcutaneous tissue 118 also includes adipose tissue, which is in the form of lipid cells (adipocytes) and intracellular or intercellular lipids, for example, forming between the collagen fibers. A network of microvessels or capillaries provides circulation and extends from the subcutaneous tissue 118 into the dermis 116.

[0032] Depending on the application, the electrical stimulation S can be generated by one or more electrodes 120 positioned along the skin surface 111. A topical drug 112 can be applied to the skin surface 111 to improve conductivity and provide nutrients and other beneficial drugs (e.g., in the form of a gel, fluid, or other skin therapeutic substance) to the skin 110.

[0033] As shown in Figure 1, the electrical stimulation S can propagate through the skin surface 111 to the upper epidermal layer 114, and through the epidermal layer 114 to one or both of the dermis 116 and subcutaneous tissue 118. The stimulation S can therefore promote beneficial responses within a range of tissues in the epidermal tissue, dermal (skin) tissue, and subcutaneous tissue.

[0034] The electrotherapy S can be applied as a steady-state (constant or alternating) voltage signal, for example, in the form of galvanic therapy, or using a modulated waveform, for example, a pulsed microcurrent waveform generated by two or more electrodes 120 spaced apart along the skin surface 111. One or more of the electrodes 120 can also be placed on or adjacent to the skin surface 111 on a selected treatment site, for example, the face, arms, torso, or legs, with another electrode 120 remotely coupled, for example, via contact with the user's hand or another part of the body being treated.

[0035] In more advanced devices, a control network is provided to regulate the applied current therapy S in order to maintain effectiveness and promote ion transport and other beneficial effects. In each of these applications, there is a trade-off between user / subject comfort and therapeutic effectiveness based on the applied current level. Current control can also be complicated by skin conditions, including dryness, topical medications, and the presence or absence of facial or body hair, as well as other skin conditions, which can affect conductivity across different areas of the skin surface to be treated by the device 100. To address these issues, a sustained comfort-based current control system can be employed, using a feedback loop for power adjustment within a range of galvanic, microcurrent, TENS, and iontophoresis-based skin treatment devices, as described herein.

[0036] Figure 2 shows power output versus resistance plots (200) for three representative skin treatment devices A (line 210), B (line 220), and C (line 230). Power output (or "skin power") P is shown on the vertical axis and skin resistance R is shown on the horizontal axis, both shown in arbitrary units.

[0037] In this embodiment, when prior art devices A and B are subjected to a dry skin spot or a sudden change in skin resistance (e.g., in the range of about 30 kΩ to about 70 kΩ), the current sources may approach their maximum settings, exposing the subject to an uncontrolled transient power difference (e.g., a value of about 1.5 to 2.0 mW or greater). Power differences within these ranges have been observed to cause stinging and piercing sensations leading to user discomfort.

[0038] This problem can be addressed by providing a continuously acting power modulation and control function that enables the control of power output during hyperpolarization and other transient events. This is in contrast to conventional constant current sources, which would be unable to control power output during hyperpolarization events and other rapid transients without resorting to absolute device performance limits.

[0039] These absolute limits, such as user-selectable fixed current levels or "one-time" maximum settings, act to reduce the device's maximum current output by a pre-selected amount, for example, 25% to 75% or more, which can significantly reduce the device's overall effectiveness. To provide a more effective solution that allows the device to operate at higher or maximum effectiveness while also providing a positive user experience, the power supply can be controlled to provide a more constant power output.

[0040] Device C (line 230) in Figure 1 represents such a device (e.g., a galvanic device or a similar skin treatment device) that uses such a constant power supply. As can be seen from the much flatter response curve of line 230, such a device can be much more suitable for controlling the power output during hyperpolarization events or other rapid changes in resistance and / or power output.

[0041] Based on this practical embodiment, device C can better control power output over similar changes in skin resistance (e.g., from 30kΩ to about 70kΩ) that exceed two factors of skin resistance, with a much smaller overall power difference (e.g., less than about 0.25mW compared to the 2mW and 1.5mW transients for devices A and B). In addition, device C was able to deliver and maintain substantially higher power levels across a wider resistance range.

[0042] Figure 3A is a plot (300) of current versus skin resistance for different current control parameter (or "suppression") values ​​ranging from minimum (line 310) to maximum (line 320). Current I is shown on the vertical axis and skin resistance R is shown on the horizontal axis, both in arbitrary units.

[0043] Figure 3B is a plot (350) of power output versus skin resistance (350) for current control parameter values ​​ranging from minimum (line 360) to maximum (line 370), as shown in Figure 3A. Power output P is shown on the vertical axis, and skin resistance is shown on the horizontal axis, both expressed in arbitrary units.

[0044] As shown in Figure 3A, the current curve is adjusted to fluctuate in a nonlinear manner as skin resistance increases and decreases. The current curve is not constant; the current changes dynamically with skin resistance in a nonlinear manner. The curve also demonstrates a much higher dynamic range between the minimum value (line 310) and the maximum value (line 320), depending on the selected parameters.

[0045] The nonlinear current changes can be adapted to resemble a square law function, or alternatively, as shown in Figure 3B, to provide a more substantially constant power output over a wider range of different resistance values ​​R. This current modulation technique prevents or reduces the occurrence of abrupt transient power states, resulting in a more dynamic power range represented by different power curves between a minimum "suppression" or a maximum control parameter value (line 360) and a maximum control parameter value (line 370).

[0046] As shown in Figure 3B, abrupt power transients no longer exist. Instead, the power rises more smoothly to its maximum and then gradually declines toward a constant or asymptotic value. This is in contrast to devices A (line 210) and B (line 220) in Figure 2, where the power level has a high peak value (e.g., at 4.5 kW or higher), increases from a rapidly increasing range with a high gradient with respect to resistance R below the peak value, and then decreases more rapidly after the peak value.

[0047] In Figure 3A, the peak current curve shows a more subtle increase, reflecting the nonlinear response. Furthermore, rather than exhibiting a sharp drop in power as shown for devices A (line 210) and B (line 220) in Figure 2, which can be associated with physiological skin responses (e.g., pain, puncture, or discomfort), the power curve in Figure 3B approaches a constant or asymptotic value within a higher resistance range (e.g., values ​​up to 100 kΩ or higher). This more carefully controlled constant power modulation also provides a better dynamic range, as described above, and is less susceptible to skin sensations or discomfort associated with sharp power transients.

[0048] While instances of sudden power transients can be mitigated or substantially eliminated by the application of a constantly modulated power supply, subjects may still experience pain or stinging sensations associated with hyperpolarization events, resulting from sudden changes in resistance, such as unstable skin contact with electrodes, the presence or absence of topical medications, or the skin surface itself becoming more or less conductive.

[0049] When a minute current or galvanic source is placed across the skin, the skin will typically become more conductive after a certain amount of current exposure or after a given exposure time. Once this occurs and the current becomes substantially constant, the voltage across the electrodes will decrease due to Ohm's law (V = I × R).

[0050] As the voltage begins to decrease (for example, as the skin becomes more conductive), certain skin sensations may begin. If the decrease in voltage is rapid, this may be considered a hyperpolarization event. When the skin becomes less resistant over a relatively short time period, as associated with a hyperpolarization event, skin irritation, stinging, or discomfort may occur.

[0051] Skin sensation can also occur when there is a sudden increase in voltage, rather than a decrease (i.e., a hyperpolarization event caused by increased resistance due to dry spots on the skin, or when the user establishes insufficient electrode contact with the skin surface). More generally, skin sensation and discomfort can be associated with hyperpolarization events, regardless of how the hyperpolarization event is caused and whether the voltage and power are substantially increased or decreased. Additional adjustments to the power output can be applied to address these events and further improve user comfort.

[0052] (Power Modulation Circuit Design) To counteract tactile sensation, constant power modulation can be used to vary the power level according to voltage changes, as described above. To achieve this, control parameters or "suppression" values ​​are determined to control the output power level.

[0053] This mechanism can be adapted to suppress (reduce) the power output to a minimum or range each time a hyperpolarization event occurs, in order to prevent or reduce the possibility of tactile sensation and discomfort. After the power has been reduced, suppression or control parameters can be applied to increase the power more slowly toward a maximum value, which is enabled or defined by constant power source modulation.

[0054] To design a more substantially constant power source for skin treatment, nonlinear (e.g., square-law or power-law-like output) control circuits are adapted for current sources. Nonlinear source control can be operated or tuned using a range of analog and / or digital components that exhibit a suitable square-law or power-law response.

[0055] For example, a diode can be used to shape current behavior in a substantially square-law manner by driving a diode in the "knee" region with a nonlinear (power-law) response. Transistors, such as field-effect transistors (FETs), or junction-gate field-effect transistors (JFETs), or other three-terminal devices can also be used. In these applications, the device can also be driven toward or into the breakdown region or an inverted "knee" region to obtain the desired power-law response curve shape.

[0056] Figure 4 is a current / voltage plot (400) illustrating the drain characteristics of a current-controlled device, such as a JFET or other three-terminal device. Drain current I D This is shown on an unscaled vertical axis in, for example, milliamperes (mA) or other preferred units. Drain-source voltage (V DS ) is also shown on an unscaled horizontal axis in volts (V) or other preferred units. The response curve is shown, for example, depending on the device polarity and other device characteristics, for a typical input gate-source voltage V GS For example, V GS This is shown for =V0 (line 410), ±V1 (line 420), ±V2 (line 430), and ±V3 (line 440).

[0057] As shown in Figure 4, the response curve increases to a nearly flat or linear region in the center of the plot, then increases within the inverted knee region, and approaches the breakdown region. Output current (drain current I D The device exhibits a nonlinear (e.g., power-law) response within the knee region, making it suitable for controlling or modulating power output within skin treatment devices. Due to the presence of a control gate, the output current can also be modulated at different levels as desired for mode-completed constant-current control designs.

[0058] FIG. 5 is an electronic circuit diagram showing a representative current controller or control circuit 500 for use in combination with a control device operating according to FIG. 4, for example. As shown in FIG. 5, the control circuit 500 is divided into a software controller section 510 and a hardware control section 520.

[0059] The software side (or section) 510 of the control circuit 500 includes a programmable microprocessor or microcontroller (MCU) module 512, a signal generator 514, a level control unit (or control circuit) 516, and a voltage monitoring or feedback circuit 518. The hardware side (or section) 520 includes, for example, a sequence of operational amplifiers (op-amps) 522, 523 coupled to a first electrode 120A (electrode A) operating according to FIG. 4, a current control device 524 coupled to a second electrode 120B (electrode B), and another suitable three-terminal or non-linear device 524. The electrodes 120A, 120B are adapted to provide a current stimulation to the target skin 110 that is modulated by the control circuit 500 to reduce power transients and improve user comfort while maintaining the effectiveness of the treatment, as described herein.

[0060] The hardware section 520 of the control circuit 500 operates continuously, for example, in analog mode. The software-controlled section 510 operates sequentially using a series of registers R1, R2, R3 to control feedback and determine gain, based on the digital sampling rate of the signal generator 514 coupled to electrode A via the op-amps 522, 523. The signal itself can be generated as a modulated waveform for applying a microcurrent treatment or galvanic signal, as described above.

[0061] The level control unit 514 is coupled to the current control device 524 that generates a gate voltage V G via a register R GS . The feedback circuit 518 has a current limit register (ILIMIT) R LWith the current limiting register R connected to ground (GND), it is connected between the (second) operational amplifier 523 and the current control device 524. The MCU 512 in the control circuit 500 controls the current limiting register R (in Figure 5). L For example, it can be adapted to measure the voltage drop across a fixed-value register. A software routine coded within (or for its operation) the MCU512 can be adapted to convert this voltage reading to a current level, e.g., a microampere (μA) or milliampere (mA) reading or other suitable scaling, using Ohm's law. These readings are then digitized and fed into a moving average filter with short-term and long-term averaging rates, which include moving averages of individual samples (e.g., the last 9 and 30 samples, or the last 2-10 samples and the last 10-50 samples, or more or fewer, etc., at other suitable sampling rates). See Figure 7.

[0062] To maintain more constant power control while preventing or avoiding tactile sensations associated with transient discomfort, the control circuit 500 is adapted to provide power control parameters or signals to the current control device 524, for example, in a range from minimum to maximum, as described above. During operation of the circuit 500, the parameter value or level may be shifted up or down based on voltage monitoring (or other feedback signals) from the circuit 518, for example, using a voltage sensor 535 coupled to a second terminal of the control device 524 and connected to a microcontroller 512, and in the form of, for example, an analog-to-digital converter (ADC). Alternatively, a suitable voltage sensor 535 may be integrated into the microcontroller 512.

[0063] The control circuit 500 may not directly measure power itself, but power has a certain mathematical relationship defined by skin resistance and the amount of current applied. While the resistance of the skin 110 is determined independently of the operation of the control circuit 500, the hardware section 520 actively controls the power applied to the skin 110. Hardware power control further measures voltage and / or skin current through a software-controlled section 520, for example via a feedback circuit 518, and provides a gate voltage V to the control device 524. GS This is improved by conditionally controlling the power level applied to the skin 110 based on a feedback signal.

[0064] The output deviation is the gate input voltage V of the current control device 524. GS This is done by manipulating the gate voltage V. GS However, when set to -V3 according to Figure 4, the current level output by device 524 is equal to the gate voltage V GS It will be lower than when it is set to V0. This deviation of the control parameter value corresponds to the deviation of the current and power levels between the minimum and maximum curves, as shown in Figures 3A and 3B. In other words, the gate voltage V in device 524 GS By manipulating this, the power level can be shifted to establish and reduce transient effects, and the dynamic range of the current output can be expanded.

[0065] (Additional feedback features) To further address hyperpolarization events and transients, one or more of the following features may also be included either within the constant power source modulation circuit 500 or elsewhere on the device, and may be coupled, for example, in data communication with the MCU 512 via the feedback circuit 518.

[0066] An accelerometer or velocity sensor / detector 530 may also be employed as part of the feedback circuit 518. If the user moves the device too quickly, insufficient electrode contact may occur, causing a hyperpolarization event. In this case (for example, when a pre-selected velocity or acceleration value is reached or exceeded), the power modulation circuit 500 may be adapted to warn the user and suppress (reduce) the power output back until the movement returns to the normal recommended range for velocity and / or acceleration.

[0067] One or more pressure sensors 540 can be adapted to sense proper contact between one or more electrodes 120A, 120B and the surface of the skin 110, for example, based on a predefined range of force or load on the electrode surface. In the event of improper contact (force or load outside the predefined range), the system can warn the user and / or suppress (reduce) the power output until time has passed for the recommended pressure to be re-established (force or load within the predefined range).

[0068] A skin temperature sensor 550 may be employed to perform additional feedback for the power modulation circuit 500 in order to help prevent or reduce hyperpolarization events. In these embodiments, the skin temperature sensor may also be used to modulate the feedback voltage according to a predefined function related to skin temperature and skin sensitivity, or related to skin temperature and resistance.

[0069] Figure 6 is a block logic diagram or control logic (600) relating to current control, illustrating, for example, the operation of a control circuit 500 according to Figure 5. As shown in Figure 6, the control logic 600 includes generating a suitable current signal (block 610), amplification (block 620), power modulation (block 630), application to the target skin (block 640), and a feedback loop (block 650).

[0070] The current signal (block 610) can be generated by the signal generator 514 in Figure 5, for example, as a galvanic current, a pulsed minute current signal, or a TENS signal. The signal can be amplified through one or more amplifiers 522, 523 (block 620) using a suitable feedback array for determining the gain, as described above.

[0071] Power modulation / curve adjustment (block 630) can be performed using a nonlinear current control device 524, such as a transistor, JFET, or other three-terminal device 524, as shown in Figure 5. The current and power response to the change in resistance is controlled by the gate voltage V on the control device 524. GS This can be determined using a level control unit 516 for determining a “suppression” value or similar power control parameter used for determination. In certain embodiments, a positive junction P-JFET or PJET may be used as shown in Figure 5, or the control circuit 500 may be adapted for use with a negative junction N-JFET or NJFET, or other suitable nonlinear control device 524.

[0072] The term "suppression value" refers to, for example, a register R as shown in Figure 5. G The potential V applied to the gate of the PJFET or other nonlinear control device 524 through this process GS This is used to explain the maximum suppression value, which represents a lower or minimum input gate potential, while the minimum suppression value represents a higher or maximum input gate potential. This inverse voltage control logic is constrained by the characteristics of the selected PJFET or other nonlinear control device 524. In effect, the level control unit 516 controls the input gate potential V GSThe voltage can be configured or adapted to vary within a suitable range for the selected control device 524, for example, 10V to 30V for a specific PJFET device 524, as shown in Figure 5. Other nonlinear devices such as NJFETs or other FET devices, or transistors or similar three-terminal devices 524, can also be used. Depending on the application, the voltage control can be inverse or positive, and the applied power range will vary accordingly.

[0073] A modulated and regulated current signal can be applied to the target skin using one or more electrodes 120A, 120B (block 640). A feedback loop (block 650) is used for determined changes in the control value, for example, based on a voltage feedback circuit 518 as described above, or using an accelerometer or velocity sensor 530, a pressure sensor 540, or a skin temperature sensor 550.

[0074] Figure 7 is a flowchart illustrating a method 700 for operating the control logic 600 according to Figure 6, for example, for current control. As shown in Figure 7, a constant power modulation or current tracking routine starts from step 710 and proceeds to updating the short-term and long-term moving averages of the feedback signal, for example, to an analog-to-digital converter (ADC) of voltage feedback, as shown in Figure 5.

[0075] As is evident from Figure 7, the current control tracking routine 700 can be invoked whenever a new ADC sample of the current waveform (or other current or voltage output) is obtained. For minute currents, TENS, and other waveform-based systems, ADC samples can be obtained at specific time intervals between waveform generation (e.g., every half cycle, i.e., three samples during the "on" phase of pulse generation, or two, four, or more samples, or at another preferred rate). For galvanic systems, ADC sampling can occur at preferred periodic or aperiodic intervals. In effect, the sampling rate can also be changed to increase or decrease the responsiveness of the software-controlled portion of the control circuit, or to adapt to changes in waveform shape or frequency.

[0076] Short-term averages may include, for example, one, two, or more pulse trains or sequences for microcurrent devices, e.g., 10–60 millisecond (ms) pulse sequences or longer, and sampling in one, two, three, or more pulses per sequence. Long-term averages may include three, four, five, six, or more pulse sequences at similar sampling rates. TENS waveforms can be sampled similarly, while galvanic waveforms can be sampled at similar regular or irregular intervals, e.g., up to 30 samples every 1.2 seconds, or at higher or lower rates.

[0077] Removal of the device from the skin can be detected by a substantial and prolonged increase in pressure via a pressure sensor adapted to correspond to the absence of an electrical current path through the target skin or to sense a reaction force on the electrode surface (step 730). If the device is removed (branch "yes"), the control value is set to its minimum (step 740), the current and power curves are reduced to their lowest ranges, and the routine is terminated until the next ADC sampling cycle to determine, for example, whether the device was unintentionally removed during skin treatment, temporarily removed, or intentionally removed to terminate the treatment cycle (step 780). In these cases, routine 700 can also be restarted whenever the device is replaced on or adjacent to the skin surface using, for example, a voltage feedback signal or a pressure sensor to detect skin contact, or whenever the device is turned on and used again (step 710).

[0078] While the device is bonded to the skin surface (not removed, branch "no"), a new short-term mean of the feedback signal can be compared to the previous value to determine a substantial or significant difference that may indicate a change in skin resistance and / or power output (step 750). If the change is significant, for example, corresponding to a change in current of 20 μA or more, or a relative change of 5%, 10%, 20%, or more (branch "yes"), the new short-term and long-term mean values ​​can be compared to determine the direction of the change (step 755). Depending on the direction, the current control ("suppression") value can be set to a minimum (branch "yes") by utilizing lower current and power output response curves to avoid transients, for example, as shown in Figures 3A and 3B.

[0079] If there is no substantial change in the short-term average, or if the direction and amount of change are favorable (branch "no"), the current control parameter ("suppress") can be checked against its maximum value (step 760). If the maximum value has already been reached (branch "yes"), the routine can be terminated (step 785). Otherwise (branch "no"), the value can be increased before terminating (step 785) until the next tracking / control sequence begins (step 710) (step 770). Steps 780 and 785 represent independent termination points, but method 700 can also be executed iteratively before cycling back to updating the moving average (step 720), with or without explicit termination (steps 780, 785) and with or without explicit start or restart (step 710).

[0080] During operation, depending on the startup (block 710), a suitable MCU or other control processor may be adapted to sample the feedback and digitize the signal, for example, a voltage drop across a fixed-value current-limiting register as shown in Figure 5, or other suitable feedback signal at a specific rate (block 720). A control software routine may be coded to convert the digitized feedback signal into a current or power level, for example, using Ohm's law or by directly sampling the voltage feedback. The results are digitized (e.g., using an ADC) and then fed into fast (short-term) and slow (long-term) filters using relatively shorter and longer time-averaging or sampling windows, respectively, to determine and update the short-term and long-term averages.

[0081] Short-term and long-term moving averages (fast and slow filter signals) respond to transients, for example, including one or more hyperpolarization events. In block 750, the processor compares short-term sample readings to the immediately preceding (short-term) sample mean, reflecting relatively abrupt, i.e., "extreme" changes in skin resistance (either increasing or decreasing resistance).

[0082] For example, the previous average and the current or new average may be based on a first and second set of feedback signals that are distinctly different in time, consecutive, or at least partially overlapping. A change in the feedback signal can then be defined by the difference between the mean values ​​of the first and second sets of feedback signals, where the change exceeds a predefined threshold. The average may be simple, or weighted, for example, weighting earlier signals more heavily on later signals, or all signals in a separate set may have the same weight.

[0083] Changes in both skin properties and waveform properties, as well as the current control ("suppression") position, can affect the magnitude of mean difference in response to hyperpolarization events and other transients. Additional long-term mean comparisons (block 755) can be used to identify conditions under which skin resistance increases relatively rapidly, or other relevant conditions that may cause short-term sample mean to fall below long-term mean.

[0084] For example, a change in the feedback signal can be further defined by a new average value (e.g., based on a second set of feedback signals) that is less than the average value of a third set of feedback signals, the third set being longer than the second set and overlapping with the first and second sets at least partially. In this event, the software control loop can be configured to minimize the suppression position (block 740) to prevent or reduce the possibility of significant spikes in the skin current. In block 730, process 700 can further improve the control loop by incorporating motion sensor (velocity or accelerometer) readings or pressure sensor readings (responding to force on the electrode surface) that may indicate the removal of the device from the skin and may cause or contribute to a hyperpolarization event.

[0085] (Application of devices and processes) Figure 8 is a block diagram of a typical skin treatment device 800 having a housing 810 with one or more electrodes or emitters 820. The electrodes 820 are adapted to provide electrical stimulation S to the target skin 110, for example, according to device 100, as shown in Figure 1.

[0086] As shown in Figure 8, the microcurrent device 800 also includes a power source (P / S) 830, a current or voltage source (IV) 840 electrically connected to one or more of the electrodes 820, a microprocessor (μP)-based controller 850 with memory 855, and an external communication interface (I / F) 860.

[0087] The power source 830 may be provided in the form of a rechargeable capacitor or battery system, with a power port (P) 835 adapted for external wired or wireless (e.g., inductive) charging. The microprocessor controller 850 is provided in data communications, with memory 855 providing storage for control codes 856 and operational data 858. The communication interface (I / F) 860 may be adapted for both data communications and control communications with the controller 850, for example, using a wired communication port or a wireless communication device (D) 865.

[0088] During the operation of device 800, the power source 830 provides power to the voltage or current generator (or source) 840, as well as the microprocessor controller 850, memory 855, and interface 860. The controller 850 is configured to control potential (V) or current (I) signals generated by source 840, for example, by executing control code 856 stored in memory 855.

[0089] Control parameters and other operational data 858 can be used to modulate the signals provided to each selected electrode or emitter 820 in order to deliver a desired minute current pulse waveform, TENS, or galvanic signal. The controller 850 can also be provided as a control circuit adapted for constant power modulation, for example, as described according to the control circuit 500 in Figure 5.

[0090] Depending on the embodiment, the device 800 may include a plurality of at least two electrodes 820 adapted for applying an electrical signal to the target skin surface, and a voltage source or current source 840 configured to generate an electrical signal for application via at least two electrodes (e.g., a galvanic source or a waveform generator), the power being output to the surface of the skin 110.

[0091] The controller / microprocessor 850 may be configured to modulate the power output to the surface of the skin 110, including a monitoring circuit configured to generate a feedback signal in response to a change in the current signal (or power output to the surface of the skin 110), the change being associated with the comfort level of the subject based on the power output. For example, the change may be associated at least in part with the likelihood of a decrease in the comfort level or discomfort, based on a voltage detected in close proximity to or across one or more electrodes associated with the sensor 870. Additional sensors 870, such as one or more acceleration or velocity sensors, pressure sensors, or temperature sensors, or any combination thereof, as described herein, may also be incorporated into the device 800.

[0092] The controller may be provided as a control circuit 850, which includes a level controller configured to modulate the current within a predefined range (e.g., a predefined comfort range) based on a feedback signal from the control circuit 500 in Figure 5. The level controller may be coupled to a current control device, for example, configured to modulate the current to the gate of a three-terminal current control device coupled between a monitoring circuit and one or more electrodes. The level control unit can therefore define the response curve of the current control device within a predefined range.

[0093] The control circuit 850 may be configured to modulate or adjust the current signal to a predefined, adjusted, lower or minimum value within a predefined comfort range in response to a predefined change in the current signal or a change in the power output to the surface of the skin 810. The change may be associated with a decrease in the comfort level or a likelihood of discomfort. The control circuit 850 may then be configured to respond to detection by a monitoring circuit from the mean of a sample of voltages sensed or detected at one or more of the electrodes 820, adjacent to or across them, and after modulation to an adjusted, lower current signal value, so that the signal or power output to the skin surface at that time is no longer associated with a likelihood of discomfort, and in that case, if such a value is available within the comfort range, the control circuit 850 may be configured to modulate the current to an adjusted, higher or maximum current value within a predefined comfort range.

[0094] Figure 9 is a block diagram of a method 1000 for current control relating to the operation of device 800 according to Figure 8, for example. The method 1000 for operating the device according to any of the above embodiments also includes a non-transient computer-readable medium with program code stored thereon, where the program is code executable on a computer processor or controller for operating the device according to any of the above embodiments.

[0095] The skin treatment device 800 may be provided with any combination of the disclosed features as described herein. The control circuit 850 may be configured to modulate power delivered by one or more electrodes 820, including any combination of the disclosed features as described herein. Method 1000 may be practiced to modulate power delivered by one or more such electrodes 820, including any combination of the disclosed features as described herein.

[0096] A method 1000 for operating a device comprises one or more electrodes adapted for applying an electric current signal (S) (1010) to a target skin surface; a voltage source or current source configured to generate (1020) an electric current (I) signal for application through one or more of the electrodes, which outputs power (P) to the skin surface (1025); and a controller configured to modulate (ΔP) (1026) the power output to the skin surface. The controller comprises a monitoring circuit configured to generate (1030) a feedback (FDBK) signal in response to a change in the electric current signal or power output to the skin surface, at least in part based on a voltage (V) (1035) sensed in close proximity to one or more of the electrodes; and a control circuit configured to modulate (ΔI) (1036) the current based on the feedback signal (FDBK).

[0097] The control circuit includes a nonlinear current control device adapted to modulate (1040) a change in the current signal applied to the skin surface based on a feedback signal (FDBK). The current control device comprises one or more transistors, field-effect transistors, or junction-gate field-effect transistors. The current control device comprises a first terminal coupled to one or more electrodes, a second terminal coupled to a monitoring circuit, and a gate coupled to the control circuit.

[0098] The monitoring circuit includes a voltage sensor coupled to a second terminal of the control device, and the control circuit is configured to convert the pressure (V) sensed at the second terminal into a current signal or power (P-OUT) output (1050). The control circuit includes a level control unit coupled to the gate of the current control device, and the level control unit defines a response curve (RESP) of the current control device based on changes in voltage, current signal, or power output (1060).

[0099] The level control unit is configured to define a response curve (RESP) between a predetermined minimum power level and a maximum power (P-LEV) level (1070) based on a feedback signal (FDBK) from the monitoring circuit. The level control unit is configured to reduce the response curve (LO-R) of the three-terminal device to or toward a predetermined minimum power level (1080) based on a change in the feedback signal (ΔFDBK).

[0100] The change in the feedback signal (ΔFDBK) is defined by the difference between the average value (AVG) of a first set of feedback signals and the average value of a second set of feedback signals, which exceeds a predefined threshold (1090). The first and second sets of feedback signals are at least partially overlapping or in a consecutive order. The change in the feedback signal is further defined by the average value of a second set of feedback signals which is less than the average value (ΔAVG) of a third set of feedback signals (1110), the third set being longer than the second set and at least partially overlapping with both the first and second sets.

[0101] The level control unit is configured to raise the response curve (HI-R) of the three-terminal device to or toward a predetermined maximum power level based on the absence of change (1120). The control circuit is configured to iteratively raise the response curve toward a predetermined maximum (P-MAX) value based on the continued absence of change (1130).

[0102] A feedback signal (FDBK) responds to the removal of the device from the skin surface (1140). The control circuit is configured to reduce the response curve to or toward a minimum (P-MIN) value (1150) based on the removal of the device from the target skin surface.

[0103] The feedback signal is further based on one or more of the following: an accelerometer signal or velocity sensor signal (SIG-A) (1160) in response to the speed of the device relative to the skin surface; a pressure signal (SIG-P) (1162) in response to the force from the skin surface to one or more of the electrodes; and a temperature signal (SIG-T) (1164) in response to the temperature at or adjacent to the skin surface. A voltage source or current source is coupled to the first of the electrodes, and a control circuit is configured to modulate the current by defining a gain curve (gain) at the second of the electrodes (1170) based on the feedback signal.

[0104] The control circuit is configured to define a gain curve in a nonlinear or three-terminal control device (3TD) coupled to a second electrode (1180) that operates according to the control circuit 500 in Figures 4 and 5, for example, using a suitable three-terminal or nonlinear control device 524. The control circuit is configured to define a gain curve (1190) at one of several discrete values ​​between a minimum (G-MIN) and a maximum (G-MAX) of the gain curve, based on a feedback signal (FDBK). The control circuit is configured to decrease the gain curve in response to a predefined change in the feedback signal (LOW-G) (1192) and increase the gain curve in response to the absence of a predefined change in the feedback signal (HI-G) (1194), respectively, based on the operating conditions.

[0105] The control circuit 500 in Figure 5 is therefore configured to modulate power delivered by one or more electrodes using a control device 424 that operates according to Figure 4 and as described in Method 1000.

[0106] (Examples) The device may comprise one or more electrodes adapted for applying an electric current signal to the target skin surface. A voltage source or current source may be configured to generate an electric current signal for application through one or more of the electrodes, and the power is output to the skin surface.

[0107] The controller may be configured to modulate the power output to the skin surface and may be accompanied by a monitoring circuit configured, for example, to generate a feedback signal in response to a change in the current signal or power output to the skin surface, based at least partially on a voltage sensed at or across one or more of the electrodes. The control circuit may be configured to modulate the current based on the feedback signal.

[0108] The control circuit may include a nonlinear current control device adapted to modulate changes in the current applied to the skin surface based on a feedback signal. The nonlinear current control device may include one or more transistors, field-effect transistors, and / or junction-gate field-effect transistors.

[0109] A nonlinear current control device may include a three-terminal device coupled to one or more of the electrodes. The control circuit may include, for example, a level control coupled to the gate of the three-terminal device, where the level control defines the response curve of the three-terminal device.

[0110] The monitoring circuit may include, for example, a voltage sensor that responds to a voltage detected at or across one or more electrodes, which are adapted by the control circuit to convert the voltage into a current signal or power output. The level control unit can respond to changes in voltage, current signal, or power output. The level control unit may be configured to define a response curve for a three-terminal device between a predetermined minimum and maximum power level, based on feedback signals from the monitoring circuit.

[0111] The level control unit can be configured to reduce the response curve of a three-terminal device to or toward a predetermined minimum power level based on a change in the feedback signal. The change in the feedback signal can be defined, for example, by the difference between the average value of a first set of feedback signals and the average value of a second set of feedback signals, exceeding a predefined threshold. The first and second sets of feedback signals may be at least partially overlapping or in a consecutive order.

[0112] The variation in the feedback signal can further be defined by the average value of a second set of feedback signals, which is less than the average value of a third set of feedback signals, for example, the third set being longer than the second set and overlapping, at least partially, with both the first and second sets.

[0113] The level control unit may be configured, for example, to raise the response curve of a three-terminal device to or toward a predetermined maximum power level based on the absence of change. The control circuit may be configured, for example, to iteratively raise the response curve toward a predetermined maximum value based on the continued absence of change.

[0114] The feedback signal can respond, for example, to the removal of the device from the target skin surface based on a change in the feedback signal. The control circuit can be configured to reduce the response curve to or toward a minimum value based on the removal of the device.

[0115] The feedback signal may further be based on one or more of the following: an accelerometer signal or velocity sensor signal that responds to the speed of the device relative to the skin surface; a pressure signal that responds to the force from the skin surface to one or more of the electrodes; and a temperature signal that responds to the temperature of the skin surface or an adjacent location.

[0116] A voltage source or current source can be coupled to a first electrode, and a control circuit can be configured to modulate the current by defining a gain curve in a second electrode based on a feedback signal. For example, the control circuit can be configured to define a gain curve in a nonlinear or three-terminal device coupled to the second electrode.

[0117] A control circuit can be configured to define a gain curve at one of several discrete values ​​between a minimum and maximum value of the gain curve, based on a feedback signal. For example, the circuit can be configured to decrease the gain curve in response to a change in a predefined feedback signal and increase the gain curve in response to the absence of a change in the predefined feedback signal.

[0118] A method for operating the device according to any of the above embodiments is also included, as well as a non-transient computer-readable medium with program code stored thereon, where the program is code executable on a computer processor or controller for operating the device according to any of the above embodiments.

[0119] A skin treatment device may be provided with any combination of the disclosed features as described herein. A control circuit may be configured to modulate power delivered by one or more electrodes, including any combination of the disclosed features as described herein. A method may be practiced to modulate power delivered by one or more such electrodes, including any combination of the disclosed features as described herein.

[0120] The device may comprise multiple electrodes adapted for applying an electrical signal to the target skin surface. A voltage source or current source may be configured to generate an electrical signal for application through the electrodes, for example, power being output to the skin surface.

[0121] The controller may be configured to modulate the power output to the skin surface and may include a monitoring circuit configured, for example, at least in part, to generate a feedback signal in response to a change in the current signal or power output based on a voltage sensed in close proximity to or across one or more electrodes. The controller may include a control circuit configured to modulate the current within a predefined range based on the feedback signal.

[0122] The multiple electrodes may include two or more electrodes configured for electrical contact with a skin surface. The multiple electrodes may include at least one electrode configured for electrical contact with a skin surface and at least one other electrode spaced apart from the skin surface, configured for electrical contact with the hand or other body part of the subject.

[0123] The feedback signal can respond to an average sample of voltage values ​​detected in close proximity to or across one or more electrodes. A change in current signal or output power can be associated with the comfort level of the subject, for example, in a state where the comfort level responds to power output to the skin surface.

[0124] The control circuit may include a power level control unit configured to adjust a current signal to a lower or minimum value within a predefined range in response to a change associated with a decrease in comfort level, for example. The power level control unit may be configured to adjust a current signal to a higher or maximum value within a predefined range in response to a change associated with an increase in comfort level or the absence of a decrease in comfort level. For example, the control circuit may be configured to define a power level coupled to the gate of a three-terminal device coupled between a monitoring circuit and one or more electrodes, setting the gain curve of the three-terminal device between a predefined maximum and minimum range.

[0125] In any of these embodiments and examples, the skin treatment device may comprise one or more electrodes adapted for applying an electric current signal to the surface of the target skin, a voltage source or current source configured to generate an electric current signal for application through one or more of the electrodes, the power of which is output to the skin surface, and a controller configured to modulate the power output to the skin surface. The controller may at least in part include a monitoring circuit configured to generate a feedback signal in response to a change in the electric current signal or power output to the skin surface based on a voltage sensed in close proximity to one or more of the electrodes, and a control circuit coupled to one or more of the electrodes, configured to modulate the change in the electric current signal based on the feedback signal.

[0126] In any of these embodiments and configurations, the control device may include a first terminal coupled to one or more electrodes, a second terminal coupled to a monitoring circuit, and a gate coupled to a control circuit. For example, the control device may comprise one or more transistors, field-effect transistors, or junction-gate field-effect transistors.

[0127] In any of these embodiments and configurations, the monitoring circuit may include a voltage sensor coupled to a second terminal of the control device, for example, the feedback signal may include a voltage sensed by the voltage sensor at the second terminal adjacent to one or more of the electrodes. The control circuit may include a level control unit (or level control circuit) coupled to the gate of the control device, for example, the level control unit may define a response curve of the control device based on a change in voltage, current signal, or power output.

[0128] In any of these embodiments and examples, the monitoring circuit or level control unit may be configured to define a response curve between a predetermined minimum power level and a predetermined maximum power level based on a feedback signal from the monitoring circuit. For example, the level control unit may be configured to reduce the response curve to or toward a predetermined minimum power level based on a change in the feedback signal.

[0129] A change in the feedback signal can be defined by the difference between the mean value of a first set of feedback signals and the mean value of a second set of feedback signals, which exceeds a predefined threshold. The first and second sets of feedback signals may be at least partially overlapping or in a consecutive order. A change in the feedback signal can further be defined by the mean value of a second set of feedback signals which is less than the mean value of a third set of feedback signals, the third set being longer than the second set and at least partially overlapping with both the first and second sets. A change in the feedback signal may also respond to the removal of the device from the target skin surface.

[0130] In any of these embodiments and examples, the control circuit may be configured to raise the response curve of the three-terminal device to or toward a predetermined maximum power level based on the absence of change in the feedback signal. The control circuit may also be configured to iteratively raise the response curve toward a predetermined maximum power level based on the continued absence of change.

[0131] In any of these embodiments and examples, the feedback signal may further be based on one or more of the following: an accelerometer signal or velocity sensor signal in response to the speed of the device relative to the skin surface; a pressure signal in response to the force from the skin surface to one or more of the electrodes; and a temperature signal in response to the temperature at or adjacent to the skin surface. The control circuit may be configured to modulate the current signal by defining a gain curve in the control device based on the feedback signal, for example, a voltage source or current source coupled to one or more other electrodes that are spaced apart from one or more of the electrodes coupled to the control device.

[0132] In any of these embodiments and configurations, the control circuit may be configured to define a gain curve between a minimum and a maximum value of the gain curve based on a feedback signal. The control circuit may be configured to decrease the gain curve in response to a predefined change in the feedback signal, increase the gain curve in response to the absence of a predefined change in the feedback signal, or both.

[0133] A method for operating a device according to any of the examples and embodiments described herein is provided. A non-transient computer-readable medium may comprise program code stored thereon, which is executable on a computer processor or controller to operate the device described in claim 1.

[0134] In any of these embodiments and examples, the skin treatment device may comprise a plurality of electrodes adapted for applying an electric current signal to the surface of the skin to be treated, and a voltage source or current source configured to generate an electric current signal for application through one or more of the electrodes, the power being output to the skin surface. The controller may comprise a monitoring circuit configured to modulate the power output to the skin surface, and for example, configured to generate a feedback signal in response to a change in the electric current signal or power output to the skin surface based on a voltage sensed in close proximity to or across one or more of the electrodes, and a control circuit configured to modulate the electric current signal within a predefined range based on the feedback signal.

[0135] In any of these embodiments and designs, the plurality of electrodes may include two or more electrodes configured for electrical contact with a skin surface, for example, a current signal delivered to the skin surface between the two electrodes. At least one electrode may be configured for electrical contact with a skin surface, and at least one other electrode may be configured for electrical contact with the hand or other body part of the subject, spaced apart from the skin surface, for example, a current signal delivered to the skin surface between at least one electrode in electrical contact with the skin surface and at least one other electrode spaced apart from the skin surface.

[0136] In any of these embodiments and examples, a change in the current signal or output power may be associated with the comfort level of the subject, for example, in a state where the comfort level responds to the power output to the skin surface. The control circuit may include a power level control (or control circuit) configured to adjust the current signal to a lower or minimum value within a predefined range in response to a change associated with a decrease in the comfort level. The power level control may be configured to adjust the current signal to a higher or maximum value within a predefined range in response to a change associated with, for example, an increase in the comfort level or the absence of a decrease in the comfort level.

[0137] This disclosure is prepared for representative examples and embodiments. Any exemplary embodiment of the invention disclosed herein may be used alone or in combination with any other embodiment or example described or illustrated herein, each of which may be incorporated by those skilled in the art, as read and understood, and without departing from the claimed practice of the invention, and may incorporate additional modifications, changes, equivalents, and substitutions that fall within the scope of this disclosure. These various examples and embodiments are provided for illustrative purposes and should not be construed as limiting the scope of the invention or limiting the boundaries of coverage as defined by the plain language of the claims herein.

Claims

1. A device, wherein the device is One or more electrodes adapted for applying an electrical current signal to the target skin surface, A voltage source or current source configured to generate the current signal for application via one or more of the aforementioned electrodes, wherein power is output to the skin surface, A controller configured to modulate the power output to the skin surface Equipped with, The aforementioned controller, A monitoring circuit configured to generate a feedback signal in response to a change in the current signal or the power output to the skin surface, at least partially based on a voltage sensed in close proximity to one or more of the one or more electrodes, A control circuit comprising a control device coupled to one or more of the one or more electrodes, wherein the control circuit is configured to modulate the change in the current signal based on the feedback signal, and Equipped with, The control device comprises a first terminal coupled to one or more of the one or more electrodes, a second terminal coupled to the monitoring circuit, and a gate coupled to the control circuit. The control circuit comprises a level control unit coupled to the gate of the control device, the level control unit defines the response curve of the control device based on the change in voltage, current signal, or power output to the skin surface, The level control unit is configured to define the response curve between a predetermined minimum power level and a predetermined maximum power level based on the feedback signal from the monitoring circuit. The level control unit is configured to reduce the response curve to or toward the predetermined minimum power level based on the change in the feedback signal. A device in which the change in the feedback signal is defined by the difference between the average value of a first set of feedback signals and the average value of a second set of feedback signals, which exceeds a predefined threshold.

2. The control device comprises one or more of a transistor, a field-effect transistor, or a junction-gate field-effect transistor, as described in claim 1.

3. The device according to claim 1, wherein the monitoring circuit comprises a voltage sensor coupled to the second terminal of the control device, and the feedback signal includes a voltage sensed by the voltage sensor at the second terminal adjacent to one or more of the one or more electrodes.

4. The first series of feedback signals and the second series of feedback signals overlap at least partially, or are in a consecutive order. The change in the feedback signal is further defined by the average value of the second set of feedback signals, which is less than the average value of the third set of feedback signals, wherein the third set of feedback signals is longer than the second set of feedback signals and at least partially overlaps with both the first set of feedback signals and the second set of feedback signals, or The device according to claim 1, wherein the change in the feedback signal is in response to the removal of the device from the skin surface of the target.

5. The control device comprises a three-terminal device having the first terminal, the second terminal, and the gate. The device according to claim 1, wherein the control circuit is configured to raise the response curve defined by the three-terminal device to or toward the predetermined maximum power level based on the absence of a change in the feedback signal.

6. The device according to claim 5, wherein the control circuit is configured to iteratively increase the response curve toward a predetermined maximum power level based on the continued absence of the change.

7. The device according to claim 1, wherein the feedback signal is further based on one or more of the following: an accelerometer signal or velocity sensor signal in response to the speed of the device relative to the skin surface; a pressure signal in response to a force applied to one or more of the one or more electrodes from the skin surface; and a temperature signal in response to the temperature on the skin surface or the temperature at a location adjacent to the skin surface.

8. The control circuit is configured to modulate the current signal by defining a gain curve in the control device based on the feedback signal. The device according to claim 1, wherein the voltage source or the current source is coupled to one or more other electrodes of the one or more electrodes, which are different from and spaced apart from the one or more electrodes of the one or more electrodes to which the control device is coupled.

9. The aforementioned control circuit is Based on the feedback signal, define the gain curve between the minimum value and the maximum value of the gain curve, or The gain curve is reduced in response to a predefined change in the feedback signal, and the gain curve is increased in response to the absence of the predefined change in the feedback signal. The device according to claim 8, configured to perform the following:

10. A non-transient computer-readable medium in which program code is stored, wherein the program code is executable on a computer processor or controller to operate the device described in Claim 1.

11. A skin treatment device, wherein the skin treatment device is Multiple electrodes adapted for applying an electrical current signal to the target skin surface, A voltage source or current source configured to generate the current signal for application via one or more of the plurality of electrodes, wherein power is output to the skin surface, A controller configured to modulate the power output to the skin surface Equipped with, The aforementioned controller, A monitoring circuit is configured to generate a feedback signal in response to a change in the current signal or the power output to the skin, based at least partially on a voltage sensed in close proximity to or across one or more of the multiple electrodes, A control circuit configured to modulate the current signal within a predefined range based on the feedback signal, wherein the control circuit comprises a control device and Equipped with, The control device comprises a first terminal coupled to one or more of the plurality of electrodes, a second terminal coupled to the monitoring circuit, and a gate coupled to the control circuit. The control circuit comprises a level control unit coupled to the gate of the control device, the level control unit defines the response curve of the control device based on the change in voltage, current signal, or power output to the skin surface, The level control unit is configured to define the response curve between a predetermined minimum power level and a predetermined maximum power level based on the feedback signal from the monitoring circuit. The level control unit is configured to reduce the response curve to or toward the predetermined minimum power level based on the change in the feedback signal. A device in which the change in the feedback signal is defined by the difference between the average value of a first set of feedback signals and the average value of a second set of feedback signals, which exceeds a predefined threshold.

12. The aforementioned plurality of electrodes are Two or more electrodes configured for electrical contact with the skin surface, wherein the current signal is delivered to the skin surface between the two or more electrodes, or At least one electrode and at least one other electrode, wherein the at least one electrode is configured for electrical contact with the skin surface, and the at least one other electrode is configured for electrical contact with the hand or other body part of the subject, spaced apart from the skin surface, and the current signal is delivered to the skin surface between the at least one electrode in electrical contact with the skin surface and the at least one other electrode spaced apart from the skin surface. The device according to claim 11, comprising:

13. The device according to claim 11, wherein the change in the current signal or the power output to the skin surface is associated with a comfort level of the target that responds to the power output to the skin surface.

14. The control circuit includes a power level control unit, The power level control unit, In response to the change being associated with a decrease in the comfort level, the current signal is adjusted to a lower or minimum value within the predefined range, or In response to the change being associated with an increase in the comfort level or the absence of a decrease in the comfort level, the current signal is adjusted to a higher value or maximum value within the predefined range. The device according to claim 13, configured to perform the following:

15. The control device comprises a three-terminal device having a first terminal, a second terminal, and a gate, wherein the three-terminal device defines the response curve, according to claim 12.

Images