CN117607212A - Conductivity detection circuit and beauty equipment - Google Patents

Abstract

The present application relates to a conductivity detection circuit and a cosmetic device. The conductivity detection circuit includes: the electrode module comprises a first electrode and a second electrode, and the first electrode and the second electrode are used for contacting detection liquid; the first power supply end is connected with a first electrode of the electrode module and is used for outputting a first reference voltage to the first electrode; the first input end of the detection module is connected with the second electrode; the second power supply end is connected with a second input end of the detection module and is used for outputting a second reference voltage to the detection module, one of the second input end and the first input end is a normal phase input end, and the other is an opposite phase input end; the first control module is connected with the output end of the detection module and is used for calculating the conductivity of the detection liquid according to the pressure drop generated by the current flowing through the detection liquid. The electrode module is arranged to contact the detection liquid, and a voltage drop is generated by utilizing current to flow through the detection liquid, and the voltage drop is related to the conductivity, so that the conductivity of the detection liquid is rapidly calculated based on the voltage drop.

Description

Conductivity detection circuit and beauty equipment

Technical Field

The application relates to the technical field of detection circuits, in particular to a conductivity detection circuit and beauty equipment.

Background

Cosmetic liquids are often used in conjunction with cosmetic devices. The conductivity of different beauty liquids has larger difference, and under the condition that the beauty equipment uses the same power output, the beauty liquid is often matched with the beauty equipment to generate the beauty effect with larger difference. Therefore, there is a need for a conductivity detection circuit that accurately detects the conductivity of different cosmetic liquids.

Disclosure of Invention

Based on this, it is necessary to provide a conductivity detection circuit and a cosmetic device that accurately detect the conductivities of different cosmetic liquids.

In one aspect, there is provided a conductivity detection circuit for detecting conductivity of a liquid, comprising:

an electrode module comprising a first electrode and a second electrode for contacting a detection liquid;

the first power supply end is connected with a first electrode of the electrode module and is used for outputting a first reference voltage to the first electrode;

the first input end of the detection module is connected with the second electrode;

the second power supply end is connected with a second input end of the detection module and is used for outputting a second reference voltage to the detection module, one of the second input end and the first input end is a normal phase input end, and the other is an opposite phase input end;

and the first control module is connected with the output end of the detection module and is used for calculating the conductivity of the detection liquid according to the pressure drop generated when the current flows through the detection liquid.

In one embodiment, the output terminal of the detection module is connected to the first input terminal through a resistor, and the conductivity detection circuit includes:

the first switch module is connected between the first power end and the first electrode, and is provided with a detection state and a depolarization state which are alternately arranged, and when the switch module is in the detection state, current flows from the first power end to the second electrode through the first electrode; when the first switch module is in a depolarized state, the current flows from the second power supply terminal to the first electrode through the detection module and the second electrode.

In one embodiment, the conductivity detection circuit includes a cancellation module connected between the output of the detection module and the first control module for canceling parasitic capacitance between the first electrode and the second electrode.

In one embodiment, the conductivity detection circuit comprises a second switch module connected between the output end of the detection module and the cancellation module and linked with the first switch module;

the elimination module comprises a first operational amplifier, when the first switch module is in a detection state, the first switch module conducts the first power end and the first electrode, and the second switch module conducts the output end of the detection module and the inverting input end of the first operational amplifier; when the first switch module is in a depolarization state, the first switch module conducts the first electrode and the grounding end, and the second switch module conducts the output end of the detection module and the non-inverting input end of the first operational amplifier.

In one embodiment, the cancellation module includes a first capacitor connected between the non-inverting input terminal of the first operational amplifier and the first power supply terminal, and a second capacitor connected between the inverting input terminal of the first operational amplifier and a ground terminal.

In one embodiment, the conductivity detection circuit includes:

the second control module is connected with the first switch module and the second switch module and is used for controlling the connection state of the first switch module and the first switch module.

In one embodiment, the conductivity detection circuit includes:

the voltage dividing circuit is used for converting the voltage output by the second power supply end into a standard comparison voltage which is one half of the voltage output by the second power supply end.

In one embodiment, the conductivity detection circuit comprises an integration circuit and an amplification circuit which are connected in series, wherein the integration circuit is connected with the output end of the detection module, and the amplification circuit is connected with the first control module.

In one embodiment, the conductivity detection circuit includes:

the protection circuit comprises a first bidirectional transient suppression diode and a second bidirectional transient suppression diode, wherein the first bidirectional transient suppression diode is connected with the first electrode and the grounding terminal, and the second bidirectional transient suppression diode is connected with the second electrode and the grounding terminal.

In one aspect, a cosmetic device is provided, which is characterized by comprising a conductivity detection structure and the aforementioned conductivity detection circuit, wherein the conductivity detection structure is connected with the electrode module.

According to the conductivity detection circuit and the beauty equipment, the electrode module is arranged to contact the detection liquid, and the voltage drop is generated by the current flowing through the detection liquid, and the voltage drop is related to the conductivity, so that the conductivity of the detection liquid is accurately and rapidly calculated based on the voltage drop.

Drawings

In order to more clearly illustrate the technical solutions of embodiments or conventional techniques of the present application, the drawings required for the descriptions of the embodiments or conventional techniques will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort for a person of ordinary skill in the art.

FIG. 1 is a schematic diagram of a conductivity detection circuit according to an embodiment;

fig. 2 is a schematic diagram of a conductivity detection circuit according to another embodiment.

Reference numerals illustrate: a conductivity detection circuit-100; an electrode module-110; a first power supply terminal-120; a detection module-130; a second power supply terminal-140; a first control module-150; a first switch module-160; a second switch module-161; an elimination module-170; a voltage dividing circuit-180; an integrating circuit-190; an amplifying circuit-191.

For a better description and illustration of embodiments and/or examples of those inventions disclosed herein, reference may be made to one or more of the accompanying drawings. Additional details or examples used to describe the drawings should not be construed as limiting the scope of the disclosed invention, the presently described embodiments and/or examples, and any of the presently understood modes of carrying out the invention.

Detailed Description

In order to facilitate an understanding of the present application, a more complete description of the present application will now be provided with reference to the relevant figures. Examples of the present application are given in the accompanying drawings. This application may, however, be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

It will be understood that the terms "first," "second," and the like, as used herein, may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another element. For example, a first resistance may be referred to as a second resistance, and similarly, a second resistance may be referred to as a first resistance, without departing from the scope of the present application. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

It is to be understood that in the following embodiments, "connected" is understood to mean "electrically connected", "communicatively connected", etc., if the connected circuits, modules, units, etc., have electrical or data transfer between them.

It is understood that "at least one" means one or more and "a plurality" means two or more. "at least part of an element" means part or all of the element.

As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," and/or the like, specify the presence of stated features, integers, steps, operations, elements, components, or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or groups thereof. Also, the term "and/or" as used in this specification includes any and all combinations of the associated listed items.

In one embodiment, referring to fig. 1 and 2, a conductivity detection circuit 100 is provided. As an example, the conductivity detection circuit 100 is used to detect the conductivity of the cosmetic liquid. The conductivity detection circuit 100 includes: the electrode module 110, the first power terminal 120, the detection module 130, the second power terminal 140, and the first control module 150.

The electrode module 110 includes a first electrode and a second electrode. The first electrode and the second electrode are for contacting the detection liquid. As an example, the materials of the first electrode and the second electrode may be copper or aluminum or other metal. Referring to fig. 2, TP1 in fig. 2 may be a first electrode, and TP2 may be a second electrode.

The first power terminal 120 is connected to a first electrode of the electrode module 110. The first power supply terminal 120 is configured to output a first reference voltage to the first electrode. As an example, the first reference voltage may range from 0.1V to 0.5V. The specific value of the first reference voltage is not specifically limited in this embodiment.

The first power supply terminal 120 may further include a power supply and a follower circuit. In a default case, the power supply provides a default smaller voltage. However, when the conductivity of the cosmetic liquid is low, the power supply may output a larger voltage to improve the resolution of the conductivity detection circuit.

The detection module 130 includes a first input terminal, a second input terminal, and an output terminal. As an example, the detection module 130 may include an operational amplifier.

The first input of the detection module 130 is connected to the second electrode. A second input terminal of the detection module 130 is connected to the second power supply terminal 140. The output end of the detection module 130 is connected to the first control module 150. One of the second input end and the first input end is a positive input end, and the other is an opposite input end. As an example, the second electrode is connected to the inverting input terminal and the second power supply terminal 140 is connected to the non-inverting input terminal.

The second power supply terminal 140 is configured to output a second reference voltage to the detection module 130. As an example, the voltage value of the second reference voltage may be identical to the voltage value of the first reference voltage, and of course, the voltage value of the second reference voltage may be inconsistent with the voltage value of the first reference voltage. For example, the voltage value of the second reference voltage may be one half of the voltage value of the first reference voltage.

The first power terminal 120 is configured to output a first reference voltage to the first electrode, and a current flows into the second electrode through the first electrode and the detection liquid. Since the detection liquid has a resistance, the first reference voltage generates a voltage drop at the detection liquid, i.e. the potential of the second electrode is smaller than the potential of the first electrode. At this time, the resistance value of the detection liquid can be obtained by comparing the current values input by the first input end and the second input end of the detection module 130.

The first control module 150 is connected to the output end of the detection module 130, and after the first control module 150 obtains the comparison result, the electrical conductivity of the detected liquid is calculated based on the resistance value of the detected liquid. Illustratively, the conductivity of the test liquid is inversely related to the resistance. Therefore, when the resistance value of the detection liquid is obtained, the conductivity can be directly calculated. As an example, the first control module 150 may be a chip.

In one example, the first reference voltage is consistent with the second reference voltage, at which time the detection module 130 includes an operational amplifier. The operational amplifier calculates a voltage difference between the first input terminal and the second input terminal (e.g., the second reference voltage). The resistance value of the detection liquid can be calculated based on the voltage difference value without other electronic devices in the conductivity detection circuit. In the case where the conductivity detection circuit has other electronic devices (for example, the conductivity detection circuit includes a plurality of resistors), the resistance value of the detection liquid can be calculated based on the voltage difference and the resistance value of the other electronic devices. Of course, at this time, the first power source terminal 120 and the second power source terminal 140 may be the same power source terminal.

In another example, the first reference voltage is inconsistent with the second reference voltage, e.g., the second reference voltage may be adjusted in real time. At this time, the detection module 130 includes a comparator. The comparator compares the voltage between the first input terminal and the second input terminal (e.g., the second reference voltage), and transmits the comparison result to the first control module 150. Furthermore, the first control module 150 is connected to the second input terminal, and the first control module 150 regulates the second reference voltage based on the comparison result, so that the voltage between the first input terminal and the second input terminal (for example, the second reference voltage) is consistent. At this time, the regulated second reference voltage may calculate the resistance value of the detection liquid.

Further, when the voltage of the first input terminal is greater than the voltage of the second reference voltage, the comparator outputs a high level. The first control module 150 regulates and controls the second reference voltage after receiving the high level, so that the second reference voltage is reduced until the voltage of the first input end is less than or equal to the voltage of the second reference voltage, and the comparator outputs the low level. After receiving the low level, the first control module 150 calculates the resistance value of the detection liquid based on the second reference voltage at this time. Of course, at this time, the first power source terminal 120 and the second power source terminal 140 are not the same power source terminal.

In this embodiment, the electrode module 110 is disposed to contact the detection liquid, and a voltage drop is generated by flowing an electric current through the detection liquid, and the voltage drop is related to the conductivity, so that the conductivity of the detection liquid is rapidly calculated based on the voltage drop.

In one embodiment, the output of the detection module 130 is connected to the first input via a resistor. For example, the resistance may be R14. The two ends of the resistor are respectively connected with the inverting input end and the output end of the detection module 130.

Meanwhile, the conductivity detection circuit 100 includes a first switching module 160.

The first switch module 160 is connected between the first power supply terminal 120 and the first electrode, and the first switch module 160 has a detection state and a depolarization state alternately arranged. Since the detection liquid contains a compound, the compound may precipitate or corrode the electrode when the first electrode and the second electrode are turned on for a long period of time. At this time, in order to prevent damage of the first electrode and the second electrode by the compound, a depolarized state of the first switch module 160 is set.

When the switch module is in the detection state, current flows from the first power supply terminal 120 to the second electrode through the first electrode. Meanwhile, when the first switch module 160 is in the depolarized state, current flows from the second power terminal 140 to the first electrode through the detection module 130 and the second electrode.

For example, referring to fig. 2, COM1 and NC1 are turned on when the switch module is in the detection state. When the first switch module 160 is in the depolarized state, COM1 and NO1 are turned on. Wherein NC1 is grounded, and NO1 is connected to the first power supply terminal 120.

In one example, when the first switch module 160 is in a detection state or a depolarization state, both the first power supply terminal 120 and the second power supply terminal 140 have voltages. In another example, when the first switch module 160 is in the detection state, both the first power supply terminal 120 and the second power supply terminal 140 have voltages, and when the first switch module 160 is in the depolarized state, the first power supply terminal 120 has no voltage, and the second power supply terminal 140 has a voltage.

In the detection state and the depolarization state, the voltages of the first power supply terminal 120 and the second power supply terminal 140 may be the same, and the voltages of the first power supply terminal 120 and the second power supply terminal 140 may be different. As an example, the voltage of the second power supply terminal 140 may be one-half of the first power supply terminal 120 in the depolarized state.

In one embodiment, conductivity detection circuit 100 includes a cancellation module 170. The cancellation module 170 is connected between the output terminal of the detection module 130 and the first control module 150, and the cancellation module 170 is configured to cancel parasitic capacitance between the first electrode and the second electrode.

At this time, the conductivity detection circuit 100 includes a second switch module 161, the second switch module 161 is connected between the output end of the detection module 130 and the cancellation module 170, and the second switch module 161 is coupled with the first switch module 160. It is understood that the second switch module 161 is consistent with the first switch module 160 in the on or off state. Referring to fig. 2, when the first switch module 160 turns on COM1 and NC1, the second switch module 161 turns on COM2 and NC2. When the first switch module 160 turns on COM1 and NO1, the second switch module 161 turns on COM2 and NO2.

Further, the cancellation module 170 includes a first operational amplifier. Referring to fig. 2, the first operational amplifier is O1. Meanwhile, referring to fig. 2, the cancellation module 170 may further include resistors R3, R4, R5, R6, etc.

When the first switch module 160 is in the detection state, the first switch module 160 turns on the first power source terminal 120 and the first electrode, and the second switch module 161 turns on the output terminal of the detection module 130 and the inverting input terminal of the first operational amplifier. When the first switch module 160 is in the depolarized state, the first switch module 160 turns on the first electrode and the ground, and the second switch module 161 turns on the output terminal of the detection module 130 and the non-inverting input terminal of the first operational amplifier.

Since the first switch module 160 has the detection state and the depolarization state alternately arranged, the inverting input terminal and the non-inverting input terminal of the first operational amplifier also alternately receive the output signal of the output terminal of the detection module 130. In order to make the first operational amplifier work normally, the cancellation module 170 includes a first capacitor and a second capacitor. The first capacitor is connected between the non-inverting input terminal of the first operational amplifier and the first power supply terminal 120, and the second capacitor is connected between the inverting input terminal of the first operational amplifier and the ground terminal. Referring to fig. 2, the first capacitor is C1, and the second capacitor is C2.

It can be understood that the first capacitor and the second capacitor are both energy storage elements. When the first switch module 160 is in the detection state, the second switch module 161 conducts the output terminal of the detection module 130 and the inverting input terminal of the first operational amplifier, and at this time, the first capacitor stores the voltage after the voltage drop generated by the detection liquid. When the first switch module 160 is in the depolarized state, the second switch module 161 turns on the output terminal of the detection module 130 and the non-inverting input terminal of the first operational amplifier, and at this time, the second capacitor stores the voltage of the parasitic capacitor between the first electrode and the second electrode.

In the case of power-on, there is a possibility of parasitic capacitance between the first electrode and the second electrode, which affects the conductivity detection accuracy, and therefore, it is necessary to cancel the voltage of the parasitic capacitance.

In this embodiment, when the first switch module 160 is in the depolarized state, the voltage output by the detection module 130 is the voltage of the parasitic capacitance between the first electrode and the second electrode, that is, the difference between the second reference voltage and the second electrode in the detection module 130 is the voltage of the parasitic capacitance. Other methods for obtaining the voltage of the parasitic capacitor are also possible, and the specific method for obtaining the voltage of the parasitic capacitor is not limited in this embodiment.

The first capacitor and the second capacitor both store electric energy, and in the process that the first switch module 160 and the second switch module 161 are linked and are alternately conducted, the inverting input end and the non-inverting input end of the first operational amplifier can simultaneously receive voltage signals. As an example, when the first switch module 160 is in the detection state, the inverting input terminal of the first operational amplifier receives the voltage after the voltage drop generated by the detection liquid, and at the same time, the non-inverting input terminal of the first operational amplifier receives the voltage of the parasitic capacitance released by the first capacitance. When the first switch module 160 is in the depolarized state, the non-inverting input terminal of the first operational amplifier receives the voltage of the parasitic capacitor, and at the same time, the inverting input terminal of the first operational amplifier receives the voltage of the detection liquid released by the second capacitor after the voltage drop.

The first operational amplifier comprises a differential circuit, and the difference between the inverting input end and the non-inverting input end is the voltage generated by voltage drop of the detection liquid after the influence of parasitic capacitance is eliminated. As an example, the inverting input terminal inputs the voltage V1, and the non-inverting input terminal inputs the voltage V2, at which time the first operational amplifier outputs the difference between V1 and V2.

In this embodiment, the first switch module 160 and the second switch module 161 are connected in a linkage and alternate manner, and cooperate with the first capacitor and the second capacitor to eliminate the influence of parasitic capacitance in real time, thereby improving the test accuracy of conductivity.

In one embodiment, the conductivity detection circuit 100 includes a second control module.

The second control module is connected to the first switch module 160 and the second switch module 140, and is used for controlling the connection state of the first switch module 160 and the second switch module 140.

As an example, referring to fig. 2, the second control module outputs control instructions to the first switch module 160 and the second switch module 140 through the PWMA terminal. When pwma=1, the first switch module 160 is in a depolarized state, and the first power supply terminal 120 outputs the reference voltage. When pwma=0, the first switch module 160 is in the detection state, and the second power terminal 140 outputs one half of the reference voltage. The second control module alternately outputs a pwma=1 signal and a pwma=0 signal such that the first switch module 160 is alternately in a depolarized state and a detected state.

The first control module 150 and the second control module may be one control module or two independent control modules.

In one embodiment, conductivity detection circuit 100 includes a voltage divider circuit 180.

The voltage divider circuit 180 is used for converting the voltage output by the second power terminal 140 into a standard comparison voltage. Specifically, the voltage dividing circuit 180 includes a first resistor and a second resistor, where the resistances of the first resistor and the second resistor are the same, the first resistor is connected to the second power supply terminal 140 and the second resistor, and the second resistor is connected to the detection module 130 and the ground terminal. At this time, the voltage received by the detection module 130 is one half of the voltage output by the second power supply terminal 140, that is, the standard comparison voltage is one half of the voltage output by the second power supply terminal 140.

The voltage divider circuit 180 may further include a third resistor, which connects the detection module 130 and the first resistor. Referring to fig. 2, the first resistor may be a resistor R11, the second resistor may be a resistor R12, and the third resistor may be a resistor R13.

In the alternate detection state and depolarization state of the first switch module 160, the voltage dividing circuit 180 is arranged to generate currents with equal magnitude and magnitude in the forward and reverse directions in the detection liquid, so as to eliminate the influence of polarization.

In one embodiment, the conductivity detection circuit 100 includes an integrating circuit 190 and an amplifying circuit 191 connected in series, the integrating circuit 190 being connected to the output of the detection module 130, and the amplifying circuit 191 being connected to the output.

Referring to fig. 2, the integrating circuit 190 is composed of a resistor R7 and a capacitor C3. The integrating circuit 190 may integrate the voltage output from the cancellation module 170, smooth the voltage signal, and transmit the signal to the amplifying circuit 191.

Referring to fig. 2, the amplifying circuit 191 includes an amplifier O2, resistors R8, R9, R10, and a capacitor C4. The amplifying circuit 191 amplifies the voltage signal processed by the integrating circuit 190 and feeds back to the first control module 150.

The integrating circuit 190 and the amplifying circuit 191 enable the conductivity detecting circuit 100 to avoid the influence of noise, jitter and other factors, and improve the accuracy of the detected value.

By way of example, the PWMA terminal receives a signal having a frequency of 0-20KHz. When the frequency is high, the first control module is inconvenient to collect. The integration circuit 190 can realize the high PWMA frequency still without distinction collection.

In one embodiment, conductivity detection circuit 100 includes a protection circuit. The protection circuit comprises a first bidirectional transient suppression diode and a second bidirectional transient suppression diode, wherein the first bidirectional transient suppression diode is connected with the first electrode and the grounding terminal, and the second bidirectional transient suppression diode is connected with the second electrode and the grounding terminal.

Referring to fig. 2, the first bidirectional transient suppression diode is D1, and the second bidirectional transient suppression diode is D2.

The first bidirectional transient suppression diode and the second bidirectional transient suppression diode are used for protecting a circuit from sudden voltage or current spikes.

In one embodiment, referring to FIG. 2, conductivity detection circuit 100 includes resistors R1 and R2. The resistors R1 and R2 are used to protect the conductivity detection circuit 100 from damage by other circuits of the cosmetic device, such as electronic muscle stimulation (Electronic Muscle Stimulation, EMS) microcurrent circuits.

It will be appreciated that the conductivity detection circuit 100 described above may take other forms as well, and is not limited to the forms already mentioned in the above embodiments, as long as it is capable of achieving the function of the conductivity detection circuit 100.

Based on the same inventive concept, in one embodiment, a cosmetic device is provided. The cosmetic device comprises a conductivity detection structure and a conductivity detection circuit 100 as in any of the previous embodiments. The conductivity detection structure is connected to the electrode module 110. As an example, the conductivity detection structure may be used to hold a detection liquid.

The conductivity detection structure detects the conductivities of different beauty liquids at first, and then adjusts the electrotherapy output power of the beauty equipment, so as to realize more beauty and skin care effects.

In the description of the present specification, reference to the term "some embodiments," "other embodiments," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples only represent a few embodiments of the present application, which are described in more detail and are not to be construed as limiting the scope of the present application. It should be noted that it would be apparent to those skilled in the art that various modifications and improvements could be made without departing from the spirit of the present application, which would be within the scope of the present application. Accordingly, the scope of protection of the present application shall be subject to the appended claims.

Claims (10)

1. A conductivity detection circuit for detecting conductivity of a liquid, comprising:

an electrode module comprising a first electrode and a second electrode for contacting a detection liquid;

the first power supply end is connected with a first electrode of the electrode module and is used for outputting a first reference voltage to the first electrode;

the first input end of the detection module is connected with the second electrode;

the second power supply end is connected with a second input end of the detection module and is used for outputting a second reference voltage to the detection module, one of the second input end and the first input end is a normal phase input end, and the other is an opposite phase input end;

and the first control module is connected with the output end of the detection module and is used for calculating the conductivity of the detection liquid according to the pressure drop generated when the current flows through the detection liquid.

2. The conductivity detection circuit of claim 1, wherein an output of said detection module is connected to said first input via a resistor, said conductivity detection circuit comprising:

the first switch module is connected between the first power end and the first electrode, and is provided with a detection state and a depolarization state which are alternately arranged, and when the switch module is in the detection state, current flows from the first power end to the second electrode through the first electrode; when the first switch module is in a depolarized state, the current flows from the second power supply terminal to the first electrode through the detection module and the second electrode.

3. The conductivity detection circuit according to claim 2, wherein,

the conductivity detection circuit comprises a cancellation module, and the cancellation module is connected between the output end of the detection module and the first control module and is used for canceling parasitic capacitance between the first electrode and the second electrode.

4. The conductivity detection circuit according to claim 3, wherein,

the conductivity detection circuit comprises a second switch module which is connected between the output end of the detection module and the elimination module and is linked with the first switch module;

the elimination module comprises a first operational amplifier, when the first switch module is in a detection state, the first switch module conducts the first power end and the first electrode, and the second switch module conducts the output end of the detection module and the inverting input end of the first operational amplifier; when the first switch module is in a depolarization state, the first switch module conducts the first electrode and the grounding end, and the second switch module conducts the output end of the detection module and the non-inverting input end of the first operational amplifier.

5. The conductivity detection circuit according to claim 4, wherein the cancellation module comprises a first capacitor connected between the non-inverting input terminal of the first operational amplifier and the first power supply terminal, and a second capacitor connected between the inverting input terminal of the first operational amplifier and a ground terminal.

6. The conductivity detection circuit according to claim 4, wherein said conductivity detection circuit comprises:

the second control module is connected with the first switch module and the second switch module and is used for controlling the connection state of the first switch module and the first switch module.

7. The conductivity detection circuit according to claim 1, wherein the conductivity detection circuit comprises:

the voltage dividing circuit is used for converting the voltage output by the second power supply end into a standard comparison voltage which is one half of the voltage output by the second power supply end.

8. The conductivity detection circuit of claim 1, wherein the conductivity detection circuit comprises an integrating circuit and an amplifying circuit connected in series, the integrating circuit being connected to the output of the detection module, the amplifying circuit being connected to the first control module.

9. The conductivity detection circuit according to claim 1, wherein the conductivity detection circuit comprises:

the protection circuit comprises a first bidirectional transient suppression diode and a second bidirectional transient suppression diode, wherein the first bidirectional transient suppression diode is connected with the first electrode and the grounding terminal, and the second bidirectional transient suppression diode is connected with the second electrode and the grounding terminal.

10. Cosmetic device, characterized in that it comprises a conductivity detection structure and a conductivity detection circuit according to any one of claims 1 to 9, said conductivity detection structure being connected to said electrode module.