CN117240254A - Pulse signal transmission circuit and pulse signal transmission control method - Google Patents
Pulse signal transmission circuit and pulse signal transmission control method Download PDFInfo
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Abstract
The invention relates to a signal transmission control circuit, and discloses a pulse signal transmission circuit, which comprises: a first impedance conversion unit whose impedance is capable of being converted between at least two impedance values in response to a first control signal; a second impedance conversion unit whose impedance is capable of being converted between at least two impedance values in response to a second control signal; a first level conversion unit to which the pulse signal is input; a second level conversion unit to which an inverted signal of the pulse signal is input; a first upper transistor, a first lower transistor, and a second upper transistor, a second lower transistor. According to the invention, the voltage and the current of the circuit are regulated by the first impedance conversion unit and the second impedance conversion unit, pulse signals with different frequencies can be transmitted through the same circuit, the arrangement of a relay or a change-over switch and a transformer can be canceled, the circuit volume and the cost are reduced, and the circuit structure is simplified.
Description
Technical Field
The invention relates to the field of signal transmission control circuits, in particular to a micro-electric and radio-frequency function control circuit with micro-electric function, radio-frequency function and skin pricking prevention function, a beauty instrument and a skin pricking prevention method.
Background
In some prior arts, a micro-Electric (EMS) function and a Radio Frequency (RF) function are required to be simultaneously provided on the same device, and in order to achieve this, a micro-electric transmission circuit and a radio frequency transmission circuit are often simultaneously provided in a function control circuit (hereinafter referred to as a circuit) of the device, and the use of the micro-electric transmission circuit and the radio frequency transmission circuit is switched by a relay or a switch or the like, and a micro-electric signal, a radio frequency signal or the like is output to a load (for example, a human body) after flowing through a transformer, for example, CN218356948U is a micro-electric radio frequency mutual switching control circuit for a cosmetic instrument, CN210078605U is a control circuit for a cosmetic instrument, CN115607826a is a cosmetic instrument, and the like. The circuit is generally designed based on a transformer structure, for example: CN112234830AEMS and RF mode switching circuit and massage instrument, CN209448656U is a physiotherapy and beauty radio frequency circuit, CN215120761U is a radio frequency circuit for beauty instrument, CN109245745a is a signal generating method, device and radio frequency device, CN218356948U is a control circuit for micro-electric radio frequency mutual switching of beauty instrument, CN210078605U is a control circuit for beauty instrument, CN114306962A is a multifunctional beauty instrument radio frequency circuit and beauty instrument, etc.
However, the independent radio frequency transmission circuit, the micro-electro-transmission circuit, the relatively high-price transformer and the relay or the change-over switch are arranged, so that the peripheral circuit structure of the equipment is complex, the hardware volume is large, the cost is high, and the design requirement of products is not met. And because of being limited by the magnetic core of the transformer, the centralized capacitance is relatively large, the power conversion of high frequency cannot be realized (the higher the frequency is, the worse the output response of the transformer is), the output frequency of radio frequency signals is limited, the highest radio frequency of the existing circuit can only achieve 3MHZ, the functions of the existing circuit are limited, the user experience degree is influenced, and meanwhile, the transformer has the deformation problem in the waveform of the high-frequency part. In addition, since the general relay generates obvious noise during switching operation, in order to reduce the noise, 2 solid state relays must be used, which results in more complicated circuits, and if the switching output of multi-stage micro-electricity and radio frequency is to be realized, a plurality of transformers, a plurality of relays or a switch are also required to be arranged, which further results in complicated circuits, and in addition, the complexity of the circuits is increased, which also results in increased probability of faults of the whole circuit system, especially the switching devices such as the relays or the switch may be damaged after the switching operation is performed for many times, so that the service life of the equipment is shorter.
In the radio frequency transmission circuit, the MOS tube is connected with the control unit, the source electrode of the MOS tube is grounded, and when the MOS tube is conducted, the output current flows through the MOS tube to form a loop, so that great electric energy waste can be caused, and the battery capacity for providing electric energy needs to be more than 1000 MAH. For example: the CN109245745A signal generating method, device and radio frequency device comprises a signal generating circuit, an MOS tube and a transformer, wherein the signal generating circuit is connected with the first end of the MOS tube, the second end of the MOS tube is connected with the transformer, the MOS tube provides current for the transformer, the third end of the MOS tube is connected with a low-level signal, and a large amount of current reaches the ground through the MOS tube, so that the power loss is high. Meanwhile, a boosting chip is generally arranged in the circuit, the price of the boosting chip is 3 yuan/piece, and the price of the circuit is high, so that the price of the circuit is influenced. For example: CN112234830a EMS and RF mode switching circuit and massage instrument, CN114306962a multifunctional cosmetic instrument radio frequency circuit and cosmetic instrument, etc.
In addition, when the contact between the human skin and the output electrode is not complete, the contact area between the output electrode and the human skin is small, so that the charges scattered on the whole output electrode are concentrated on a small area of the skin to cause stinging, and the user experience is affected. However, the existing stabbing pain preventing function generally needs to be provided with a change-over switch, a change-over circuit or the like to switch the functions, and a detection circuit with a relatively complex structure needs to be additionally arranged. Such as CN112234830AEMS and RF function switching circuits and massagers.
Disclosure of Invention
In order to simplify the peripheral circuit of the circuit, the application provides a pulse signal transmission circuit and a pulse signal transmission control method, an impedance conversion unit adjusts the voltage and the current of a route where the pulse signal is located, pulse signals with various different frequencies are output through the same set of circuit and act on a load, a function switching element is not required to be arranged in the circuit, the arrangement of a transformer is omitted, the hardware structure and the volume of the circuit are simplified, and the cost is reduced.
In a first aspect, the present application provides a pulse signal transmission circuit. The following technical scheme is adopted:
a pulse signal transmission circuit comprising:
a first impedance conversion unit whose impedance is capable of being converted between at least two impedance values in response to a first control signal;
a second impedance conversion unit whose impedance is capable of being converted between at least two impedance values in response to a second control signal;
the first level conversion unit and the first impedance conversion unit are sequentially connected in series between a power supply and ground, the pulse signal is input to the first level conversion unit, and the pulse signal is used for controlling the on and off of the first level conversion unit;
The second level conversion unit and the second impedance conversion unit are sequentially connected in series between the power supply and the ground, an inverted signal of the pulse signal is input to the second level conversion unit, and the inverted signal of the pulse signal is used for controlling the on and off of the second level conversion unit;
the first upper transistor, the load and the first lower transistor are sequentially connected in series between the power supply and the ground, the grid electrode of the first upper transistor is connected with the output end of the first level conversion unit, and the pulse signal is input to the grid electrode of the first lower transistor; and
The second upper transistor, the load and the second lower transistor are sequentially connected in series between the power supply and the ground, the grid electrode of the second upper transistor is connected with the output end of the second level conversion unit, and the inverted signal of the pulse signal is input to the grid electrode of the second upper transistor.
The circuit is provided with a first impedance conversion unit for converting the voltage and the current of the route of the first level conversion unit and a second impedance conversion unit for converting the voltage and the current of the route of the second level conversion unit, so that high-frequency or low-frequency pulse signals can be input from the first level conversion unit, enter a load through a first upper transistor and then enter a ground through a first lower transistor, and inverted signals of the high-frequency or low-frequency pulse signals can be input from the second level conversion unit, enter the load through a second upper transistor and then enter the second lower transistor and then enter the ground, and the pulse signals with different frequencies can be transmitted through the same circuit, and different transmission circuits with different parameters are not required to be arranged in the traditional circuit for transmitting the pulse signals with different frequencies, so that a relay or a change-over switch can be omitted; meanwhile, the arrangement of a transformer can be omitted in the circuit, so that the circuit structure is simplified, and the volume and cost of the circuit are reduced.
The arrangement of the transformer is canceled, so that the problem that the traditional circuit is limited by the magnetic core of the transformer and cannot output radio frequency signals with the frequency higher than 3MHz can be solved.
Meanwhile, the large current in the circuit goes to the ground after passing through the load, so that the power loss can be reduced, and the defect that most of current in the traditional circuit goes to the ground through the MOS tube and has larger loss is overcome.
Further, the first level conversion unit is a first level conversion transistor, a gate of the first level conversion transistor receives the pulse signal, and a source or a drain of the first level conversion transistor is connected with the first impedance conversion unit; or (b)
The second level conversion unit is a second level conversion transistor, the grid electrode of the second level conversion transistor receives the inverted signal of the pulse signal, and the source electrode or the drain electrode of the second level conversion transistor is connected with the second impedance conversion unit.
The first level conversion unit and the second level conversion unit are used as switching tubes for controlling alternate transmission of pulse signals and inverted signals of the pulse signals.
Further, the grid electrode of the first upper transistor is connected with the output end of the first level conversion unit through a first push-pull unit; or (b)
The grid electrode of the second upper transistor is connected with the output end of the second level conversion unit through a second push-pull unit.
The first push-pull unit and the second push-pull unit not only improve the load capacity of the circuit, but also improve the switching speed.
Further, the first push-pull unit comprises two triodes, wherein the two triodes are PNP triodes and NPN triodes respectively, bases of the two triodes are connected and then serve as input ends, the base is connected with the output end of the first impedance conversion unit, emitters of the two triodes are connected and then serve as output ends, and the emitters of the two triodes are connected with the grid electrode of the first upper transistor.
The first push-pull unit is used for providing larger grid current for the first upper transistor so that the grid junction capacitance of the first upper transistor can be charged rapidly, the first upper transistor can be conducted rapidly, the rising edge of an output waveform is very steep by utilizing the high-speed switching benefit of the transistor, the output waveform is improved, and meanwhile the problem that the waveform of a transformer in a high-frequency part in a traditional circuit is deformed can be solved. The second push-pull unit is the same.
Further, the first impedance conversion unit includes a seventh resistor R7 and a switching structure connected in series with the seventh resistor R7.
Whether the seventh resistor R7 is connected into the circuit is controlled by the opening and closing of the switching structure.
Further, the first impedance conversion unit further includes an eighth resistor R8, and the switch structure is connected in series with the seventh resistor R7 and then connected in parallel with the eighth resistor R8.
Setting a seventh resistor R7 and an eighth resistor R8, wherein when the switch structure is disconnected, the impedance value of the first impedance conversion unit is the impedance value of the eighth resistor R8, so that the output impedance value is improved; when the switch structure is turned on, the impedance value of the first impedance conversion unit is the impedance value of the seventh resistor R7 and the eighth resistor R8 connected in parallel, and the output impedance value is reduced.
Further, the switch structure includes a fifth triode Q11 and a sixth triode Q12, an emitter of the fifth triode Q11 is connected to a base of the sixth triode Q12, a collector of the sixth triode Q12 is connected to the seventh resistor R7, and the base of the fifth triode Q11 receives the first control signal.
Two triodes are arranged in the switch structure, so that the seventh resistor R7 is conveniently connected, the circuit structure is simple, the size is small, and the cost is low.
Further, the first control signal and the second control signal are the same signal.
The first control signal and the second control signal are both output by the same control unit.
Further, the power supply is a boost unit.
Further, the BOOST unit is a BOOST unit, the BOOST unit includes a power supply V, an inductor L, a diode D, a capacitor C, and a third MOS transistor Q15, where one end of the inductor L is connected to the power supply V, one end of the diode D and a drain electrode of the third MOS transistor Q15 are all connected to the other end of the inductor L, a gate electrode of the third MOS transistor Q15 receives a BOOST pulse signal, the other end of the diode D is connected to one end of the capacitor C, and a connection point of the two is used as an output end of the BOOST unit.
The BOOST unit replaces the traditional BOOST chip module, the cost of the BOOST unit is far lower than that of the BOOST chip module, the size of the BOOST unit is smaller, compared with the BOOST chip module and the like, the BOOST unit works more stably, the price is lower, higher voltage and current can be provided, and the BOOST unit is not easy to be limited by other unit modules.
Further, the receiving of the BOOST pulse signal by the gate of the third MOS transistor Q15 specifically includes: and a grid electrode of the third MOS tube Q15 is connected with the output end of the third push-pull unit, and the input end of the third push-pull unit receives the BOOST pulse signal.
The third push-pull unit can improve the switching frequency of the third MOS transistor Q15, improve the output efficiency of the BOOST unit, and provide stable high voltage and high current for the circuit.
Further, the device also comprises a control unit, wherein the control unit is used for outputting the pulse signal, an inverted signal of the pulse signal, the first control signal and the second control signal.
Further, the sampling feedback unit comprises two resistors which are sequentially connected in series, the two resistors are connected in series between the power supply and the ground, and the connection point between the two resistors is connected with the control unit, so that a feedback signal is transmitted to the control unit, and the feedback signal is the voltage value of the power supply after voltage division.
The sampling feedback unit consisting of two serially connected resistors is arranged, the feedback signal of the sampling feedback unit is detected through the control unit, and the contact condition of the output electrode and the skin of a human body is judged, so that whether the pulse signal is to be continuously transmitted or not is confirmed, and the purpose of preventing skin pricking is achieved. And the sampling feedback unit has a simple circuit structure.
Further, the load is a human body.
The pulse signal can be applied to the human body to perform the functions of beautifying and the like.
In a second aspect, the present application provides a cosmetic device. The following technical scheme is adopted:
a cosmetic instrument comprises the circuit.
The circuit eliminates transformers, relays or change-over switches, boost chips and the like, reduces the volume and cost of a circuit board, integrates the transmission of pulse signals with different frequencies into the same set of circuit, and simplifies the structure of the circuit.
In a third aspect, the present application provides a method for controlling transmission of a pulse signal. The following technical scheme is adopted:
a method for controlling transmission of a pulse signal, the method inputting the pulse signal to human skin through the above-mentioned circuit for transmitting a pulse signal, the method comprising the steps of:
combining a micro-electric signal and a skin impedance detection signal to form the pulse signal, respectively inputting the pulse signal into the first level conversion unit and the grid electrode of the first lower transistor, and respectively inputting the inverted signal of the pulse signal into the second level conversion unit and the grid electrode of the second lower transistor;
detecting the feedback signal from the sampling feedback unit and judging whether the amplitude of the feedback signal is lower than a set threshold value;
If so, determining that the human skin is in good contact with the output electrode, continuously outputting the micro-electrical signal and the skin impedance detection signal to the human skin, and repeatedly detecting the feedback signal;
if not, determining that the skin of the human body is not completely contacted with the output electrode, and stopping outputting the micro-electric signal.
The skin impedance detection signals are the same as the radio frequency signals, are high-frequency pulse signals, can be transmitted with the radio frequency signals, micro-electric signals and other pulse signals in the same circuit, do not need to be additionally provided with a transmission circuit, a change-over switch and other structures, simplify the circuit structure, and can detect skin impedance in real time and realize the function of preventing skin pricking. The threshold value of the feedback signal is preset, and the contact condition between the output electrode and the human skin is confirmed by comparing the preset threshold value with the detected feedback signal, so that whether the micro-electric signal is stopped to be output is confirmed, and the function of preventing skin pricking is achieved. For simplicity, the skin impedance detection signal may be a radio frequency signal in the radio frequency mode.
Further, the step of combining the micro-electric signal with the skin impedance detection signal to form the pulse signal is specifically: after each pulse of one micro-electric signal is sent, a plurality of pulses of skin impedance detection signals are sent immediately; and is also provided with
The detection of the feedback signal from the sampling feedback unit is in particular: each time a pulse of the skin impedance detection signal is transmitted, the feedback signal is detected once, and the average value of the amplitudes of all the pulses of the feedback signal detected between two adjacent pulses of the micro-electric signal is taken as a detection result.
The frequency of the micro-electric signals is very low, so that a high-frequency skin impedance detection signal is sent between the pulses of two adjacent micro-electric signals to detect skin impedance, and at least one pulse of the skin impedance detection signal is sent immediately after each pulse of one micro-electric signal is sent to detect the feedback signal of the sampling feedback unit once, thereby achieving the purpose of avoiding skin stinging and improving the working efficiency.
In order to improve the accuracy of the detection result, at least two pulses of skin impedance detection signals can be sent between two adjacent pulses of micro-electrical signals, so that the situation that when only one feedback signal is detected and the feedback signal is abnormal, the anti-stabbing function is invalid or the micro-electrical function is turned off by mistake is avoided.
The invention has the remarkable technical effects due to the adoption of the technical scheme:
the structure of a traditional circuit provided with an independent micro-electric transmission circuit, a radio frequency transmission circuit, a relay or a change-over switch and a transformer is canceled, pulse signals (including radio frequency signals and micro-electric signals) with different frequencies are all output through the same control unit, and meanwhile, the output impedance values of the routes where the first impedance conversion unit and the second impedance conversion unit are arranged are converted, so that the voltage and the current of the routes where the first impedance conversion unit and the second impedance conversion unit are arranged are regulated, the pulse signals with different frequencies can be transmitted in the same circuit and act on a load (human skin is an example), the structure, the volume and the cost of the circuit are simplified, and the noise during the switching can be reduced because the traditional relay or the change-over switch and other radio frequency/micro-electric functions are canceled. The frequency of the high-frequency pulse signals (such as radio frequency signals) is not limited by the magnetic core of the traditional transformer, the energy efficiency conversion rate of the bridge driving structure formed by the first upper transistor, the first lower transistor, the second upper transistor and the second lower transistor is high, and the first upper transistor, the first lower transistor, the second upper transistor and the second lower transistor are suitable for transmitting radio frequency signals with the frequency of 6MHz, so that the practicability of the circuit is improved.
The bridge driving structure formed by the first upper transistor, the first lower transistor, the second upper transistor and the second lower transistor utilizes the high-speed switching benefit of the MOS transistor, the first push-pull unit can provide large gate current for the first upper transistor, and the second push-pull unit can provide large gate current for the second upper transistor, so that the gate junction capacitance of the MOS transistors of the first upper transistor and the second upper transistor can be charged rapidly, and the rising edge of an output waveform is steep; after the MOS transistors of the first upper transistor and the second upper transistor are turned off, the MOS transistors of the first lower transistor and the second lower transistor are turned on rapidly to respectively discharge the voltage of parasitic capacitance of the MOS transistors of the second upper transistor and the first upper transistor in time, so that the falling edge of an output waveform is very steep, the output waveform is improved, and the problem of waveform deformation of a transformer in a high-frequency part is solved. The bridge driving structure is structurally provided with a radio frequency signal, a micro-electric signal, a skin impedance detection signal and other pulse signals and reverse signals thereof respectively enter a load through an output electrode after passing through a first upper transistor and a second upper transistor, and then form a loop from the other output electrode through a first lower transistor and a second lower transistor, so that most of power consumption can be reduced, the battery capacity of power supply is saved, and the traditional circuit possibly needs 1000mAH battery capacity through testing.
The BOOST unit adopts a BOOST unit, a BOOST chip and the like are not required to be arranged, the cost and the volume are reduced, and meanwhile, the stability of voltage and current in the circuit is improved.
The transformer is very large, and if the traditional circuit needs to do multi-stage output, two transformers are needed, and the circuit hardware is very large. If the circuit is to be a multi-stage output circuit, only a plurality of MOS transistors and triodes are needed to be added, so that the structure of the circuit is greatly simplified, the volume and the cost are reduced, and more design choices are provided for equipment.
The skin impedance detection signal, the micro-electrical signal and the radio frequency signal used for the puncture-preventing function are all output to the skin of a human body through the same circuit, so that a special transmission circuit is not required to be arranged, a change-over switch or a relay and other components are not required to be used for performing function switching, the circuit structure is simplified, the skin impedance detection signal is performed in a micro-electrical mode, at least one skin impedance detection signal is transmitted for detection after each pulse of the micro-electrical signal is input, the detection is performed while the micro-current stimulation is performed, the function of preventing the skin from being punctured in real time is realized, and the user experience is improved; meanwhile, the switching function keys are not needed to be additionally used, so that the use of a user is convenient, and the practicability is high.
The application has the functions of skin pricking prevention, micro-electricity and radio frequency with three gears (the frequency is 1MHz, 3MHz and 6MHz respectively), and PWM signals with other frequencies can be added to realize other more functions.
The circuit of the application can be applied to a circuit board of a radio frequency beauty instrument and also can be applied to a circuit board of a massage instrument.
Drawings
Fig. 1 is a functional block diagram of a pulse signal transmission circuit according to an embodiment of the present application;
fig. 2 is a circuit diagram of pulse signal transmission according to an embodiment of the present application;
fig. 3 is a schematic diagram (time t on abscissa and voltage U on ordinate) of an input waveform (shown by a solid line) of PWM1 measured at the gate of the first upper transistor Q1 and an input waveform (shown by a dashed line) of PWM2 measured at the gate of the second lower transistor Q2 according to an embodiment of the present application;
FIG. 4 is a circuit diagram of a BOOST unit according to an embodiment of the present application;
FIG. 5 shows the output waveforms (time t on the abscissa and voltage U on the ordinate) measured at the output electrode when the frequencies of PWM1 (shown by solid lines) and PWM2 (shown by dashed lines) are 1MHz in accordance with the embodiment of the present application;
FIG. 6 shows the output waveforms (time t on the abscissa and voltage U on the ordinate) measured at the output electrode when the frequencies of PWM1 (shown by solid lines) and PWM2 (shown by dashed lines) are 3MHz according to the embodiment of the present application;
FIG. 7 shows the output waveforms (time t on the abscissa and voltage U on the ordinate) measured at the output electrode when the frequencies of PWM1 (shown by solid line) and PWM2 (shown by dotted line) are both 6MHz according to the embodiment of the present application;
fig. 8 is a flowchart of a pulse signal transmission control method (an example of a skin pricking prevention method) according to an embodiment of the present application.
The names of the parts indicated by the numerical references in the drawings are as follows: the device comprises a 1-first impedance conversion unit, a 2-first level conversion unit, a 3-first push-pull unit, a 5-output electrode, a 6-switch structure, a 7-third push-pull unit and an 8-sampling feedback unit.
Detailed Description
In order to make the technical problems, technical schemes and beneficial effects to be solved more clear, the application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application.
It will be understood that when an element is referred to as being "mounted" or "disposed" on another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.
It is to be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like are merely for convenience in describing and simplifying the description based on the orientation or positional relationship shown in the drawings, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus are not to be construed as limiting the application.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.
The following examples illustrate the principles of operation of the present application using the micro-electrical and radio frequency functions and the skin pricking prevention function.
Examples
As shown in fig. 1, the pulse signal transmission circuit includes: a control unit for outputting a logic signal (high level or low level, which is an example of the first control signal, the second control signal), a pulse signal, the output pulse signal may be a pulse signal of high frequency (frequency higher than 500 KHZ) (for example, a radio frequency signal of 500KHZ or 800KHZ or 1MHZ or 3MHZ or 6MHZ or the like or a skin impedance detection signal) and a pulse signal of low frequency (frequency lower than 500 HZ) (for example, a micro electric signal of 33HZ or 50HZ or 100HZ or 120HZ or the like) and an inverted signal thereof; a first impedance conversion unit whose impedance is capable of being converted between at least two impedance values in response to a first control signal output from the control unit; for transforming the output impedance value;
A second impedance conversion unit whose impedance is capable of being converted between at least two impedance values in response to a second control signal output from the control unit;
the first level conversion unit and the first impedance conversion unit are sequentially connected in series between a power supply (a boosting unit in fig. 1 and 4 and the same applies below) and ground, the pulse signal is input to the first level conversion unit, and the pulse signal is used for controlling the first level conversion unit to be turned on and off;
the second level conversion unit and the second impedance conversion unit are sequentially connected in series between the power supply and the ground, an inverted signal of the pulse signal is input to the second level conversion unit, and the inverted signal of the pulse signal is used for controlling the on and off of the second level conversion unit;
a first upper transistor, a first lower transistor, wherein the first upper transistor, a human body (an example of a load), and the first lower transistor are sequentially connected in series between the power supply and the ground, a gate of the first upper transistor is connected to an output end of the first level conversion unit, and the pulse signal is input to the gate of the first lower transistor; and
The second upper transistor, the human body and the second lower transistor are sequentially connected in series between the power supply and the ground, the grid electrode of the second upper transistor is connected with the output end of the second level conversion unit, and the inverted signal of the pulse signal is input to the grid electrode of the second upper transistor.
The circuit comprises a first level conversion unit, a first upper transistor and a first lower transistor, wherein the circuit is used for enabling a pulse signal output by the control unit to act on a human body through an output electrode, and the circuit is used for enabling an inverted signal of the pulse signal output by the control unit to act on the human body through the output electrode so as to transmit a micro-Electric (EMS) signal or a Radio Frequency (RF) signal or a skin impedance detection signal to the human body. Thus, the pulse signal of the input circuit may be any one of an EMS signal, an RF signal, a skin impedance detection signal, or a combination of signals having a certain time length. Generally, the frequency of the micro-electric signal is low, and the micro-electric signal needs to be matched with the transmission of relatively high voltage (such as 25V, 30V, 40V and 60V); the frequency of the radio frequency signal is higher, and the radio frequency signal needs to be matched with the transmission of relatively high current (30 mA for example); the skin impedance detection signal may be generated by a radio frequency signal that the control unit is inherently required to generate. One of the advantages of the embodiments of the invention is that one circuit can be used to transmit these several pulse signals compatibly.
In the working process, pulse signals are output from a first upper transistor to enter a human body through an output electrode, then enter a first lower transistor from another output electrode to form a loop, inverted signals of the pulse signals are output from a second upper transistor to enter the human body through an output electrode, then enter the second lower transistor from another output electrode to form a loop, and most of current in the circuit enters the human body and then reaches the ground, so that the power loss can be reduced, especially under the condition of radio frequency mode heating, the power consumption can be reduced by about 50%, the battery capacity is greatly saved, and the battery capacity only needs 500mAh; and the output electrode 5 is used for being attached to a human body and transmitting radio frequency signals or micro-electric signals or skin impedance detection signals to the skin of the human body.
Optionally, the circuit further comprises a voltage boosting unit, wherein the voltage output ends of the voltage boosting unit are electrically connected with the power supply end of the control unit, the input end of the first impedance conversion unit, the input end of the second impedance conversion unit, the source electrode of the first upper transistor, the source electrode of the second upper transistor, the first push-pull unit and the second push-pull unit, so that stable high voltage and high current are provided for the circuit.
The control unit outputs a pulse signal and an inverted signal thereof, wherein the pulse signal and the inverted signal thereof are PWM waves (PWM is generally called Pulse Width Modulation, namely pulse width modulation) with a phase difference of 180 degrees, and the pulse signal and the inverted signal of the pulse signal are respectively named PWM1 and PWM2. The circuit can realize three modes: 1. the micro-electric signals are output independently to perform micro-electric functions (micro-electric mode), and the radio frequency signals are not output: 2. independently outputting a radio frequency signal to perform a radio frequency function (radio frequency mode) without outputting a micro-electric signal; 3. the micro-electric signal and the radio frequency signal are simultaneously output, and the micro-electric function and the radio frequency function are simultaneously carried out. The circuit is provided with the first impedance conversion unit and the second impedance conversion unit, and the voltage and the current of the route can be regulated, so that the circuit can be suitable for outputting pulse signals with different frequencies, the control unit outputs micro-electric signals, radio frequency signals and skin impedance detection signals, the micro-electric signals, the radio frequency signals and the skin impedance detection signal transmission circuits are shared, the circuit structure is simplified, a transformer is not needed, and the circuit volume is reduced.
Optionally, the output electrode 5 includes a set of positive and negative electrode plates, named as a first electrode PA and a second electrode PB, respectively, and the first upper transistor and the second lower transistor are both connected to the first electrode PA, and the first lower transistor and the second upper transistor are both connected to the second electrode PB. The control unit is provided with a first IO port for outputting PWM1 (first initial PWM signal), and a second IO port for outputting PWM2 (second initial PWM signal).
Optionally, the circuit structures, parameter settings and functions of the first impedance conversion unit and the second impedance conversion unit are the same, the circuit structures, parameter settings and functions of the first level conversion unit and the second level conversion unit are the same, the circuit structures, parameter settings and functions of the first upper transistor and the second upper transistor are the same, the circuit structures, parameter settings and functions of the first lower transistor and the second lower transistor are the same, and the difference is that the first impedance conversion unit, the first level conversion unit, the first upper transistor, the first lower transistor and the first push-pull unit transmit pulse signals, and the second impedance conversion unit, the second level conversion unit, the second upper transistor, the second lower transistor and the second push-pull unit transmit reverse signals of the pulse signals. For brevity of description, the specific circuit structure, function and parameters of the first impedance conversion unit, the first level conversion unit, the first upper transistor, the first lower transistor and the first push-pull unit are described by taking the first impedance conversion unit, the first level conversion unit, the first upper transistor, the first lower transistor and the first push-pull unit as examples, and a second impedance conversion unit, a second level conversion unit, a second upper transistor, a second lower transistor and a second push-pull unit which are not described are respectively the same as the first impedance conversion unit, the first level conversion unit, the first upper transistor, the first lower transistor and the first push-pull unit.
The control end of the first impedance conversion unit is connected with the CTL port of the control unit, the input end of the voltage of the first impedance conversion unit is connected with the output end of the boosting unit, the output end of the first impedance conversion unit is connected with the input end of the first push-pull unit, and the control unit can control the first impedance conversion unit 1 to convert the output impedance value through outputting a logic signal (an example of a first control signal). When the control unit outputs a high-frequency pulse signal (for example, a radio frequency signal with frequencies of 1MHZ, 3MHZ and 6MHZ, and a high-frequency skin impedance detection signal is the same), the control unit controls the first impedance conversion unit 1 to output a low impedance (for example, an impedance smaller than 2kΩ) to provide a base current large enough for the first push-pull unit of the next stage, ensures that the first upper transistor is quickly transited from an amplified state to a conducting state, improves an output waveform, and the output electrode 5 transmits the radio frequency signal (a specific example of the pulse signal) to the skin of the human body, locally heats the surface of the skin of the human body, and promotes collagen regeneration of the bottom layer of the skin so as to achieve the beauty effect on the skin of the human body. When the control unit outputs a low-frequency pulse signal (for example, a micro-electric signal with the frequency of 33HZ or 100 HZ), the control unit controls the first impedance conversion unit 1 to output high impedance (for example, impedance larger than 50kΩ), and the boost unit is matched to ensure that the pulse voltage of the micro-electric signal can be adjusted so that the voltage of the circuit can reach the requirement for transmitting the micro-electric signal (a specific example of the pulse signal), the output electrode transmits the micro-electric signal to the human body, and micro-current stimulation is performed on the muscle of the human body to massage the muscle of the human body, thereby achieving the effect of skin tightening. The second impedance transformation unit is the same.
The control end of the first level converting unit 2 is connected with the signal end of the control unit. One signal end of the first level conversion unit 2 is connected with the output end of the first impedance conversion unit, the input end of the first push-pull unit, and the other signal end is grounded. The second level shifting unit is the same.
The output end of the first push-pull unit 3 is connected with the grid electrode of the first upper transistor, so that larger grid current is provided for the first upper transistor, the first upper transistor can be rapidly conducted, the output end of the second push-pull unit is connected with the grid electrode of the second upper transistor, larger grid current is provided for the second upper transistor, so that the second upper transistor can be rapidly conducted, the rising edge of an output waveform is steep, output waveform data are improved, and the problem of output waveform deformation is solved.
The control end of the first level conversion unit 2 and the grid electrode of the first lower transistor are connected with the control unit through a first IO port, and the control end of the second level conversion unit and the grid electrode of the second lower transistor are connected with the control unit through a second IO port.
Optionally, fig. 2 is a circuit diagram of pulse signal transmission according to an embodiment of the present invention. Based on the above embodiment, as shown in fig. 2, the control unit may be an MCU or a DSP (Digital Signal Processing, data signal processor) or an FPGA (Field-Programmable Gate Array, i.e., field programmable gate array), etc., and for convenience of explanation, the control unit is exemplified by an MCU.
Optionally, the first upper transistor, the second upper transistor, the first lower transistor and the second lower transistor are all MOS transistors, and are named as a first upper transistor Q1, a second lower transistor Q2, a second upper transistor Q3 and a first lower transistor Q4, respectively. The first upper transistor Q1 and the second upper transistor Q3 are PMOS transistors, and the second lower transistor Q2 and the first lower transistor Q4 are NMOS transistors.
Optionally, the first push-pull unit 3 includes two triodes, where the two triodes are a PNP triode and an NPN triode respectively, bases of the two triodes are connected and then used as input ends of the first push-pull unit, and are connected to output ends of the first impedance conversion unit and signal ends of the first level conversion unit, emitters of the two triodes are connected and then used as output ends of the first push-pull unit, and connected to a gate of the first upper transistor. The second push-pull unit is the same.
Specifically, the bases of the two triodes are connected and then connected with one end of a pull-down resistor, the other end of the pull-down resistor is connected with the output end of the first impedance conversion unit 1 and one signal end of the first level conversion unit 2, the emitters of the two triodes are connected and then connected with one end of a feedback resistor, and the other end of the feedback resistor is connected with the grid electrode of the first upper transistor. In the first push-pull unit, two triodes are respectively named as a first triode Q7 and a second triode Q8, the collector of the first triode Q7 is connected with the output end of the boosting unit, the collector of the second triode Q8 is grounded, the pull-down resistor is named as a fifteenth resistor R15, the feedback resistor is named as a sixteenth resistor R16, and the other end of the sixteenth resistor R16 is connected with the grid electrode of the first upper transistor Q1; in the second push-pull unit, two triodes are respectively named as a third triode Q9 and a fourth triode Q10, the collector of the third triode Q9 is connected with the output end of the boosting unit, the collector of the fourth triode Q10 is grounded, the pull-down resistor is named as a seventeenth resistor R17, the feedback resistor is named as an eighteenth resistor R18, and the other end of the eighteenth resistor R18 is connected with the grid electrode of the second upper transistor Q3. The first triode Q7 and the third triode Q9 are NPN type triodes, and the second triode Q8 and the fourth triode Q10 are PNP type triodes.
Optionally, the circuit further comprises a nineteenth resistor R19 and a twentieth resistor R20 which are connected in series, wherein one end of the nineteenth resistor R19 is connected with the output end of the boosting unit, the other end of the nineteenth resistor R19 is connected with one end of the twentieth resistor R20, the other end of the twentieth resistor 20 is grounded, and connection points of the nineteenth resistor R19 and the twentieth resistor R20 are connected with the other end of the sixteenth resistor and the grid electrode of the first upper transistor Q1. The power supply circuit further comprises a twenty-first resistor R21 and a twenty-second resistor R22 which are connected in series, one end of the twenty-first resistor R21 is connected with the output end of the boosting unit, the other end of the twenty-first resistor R21 is connected with one end of the twenty-second resistor R22, the other end of the twenty-second resistor R22 is grounded, and connection points of the twenty-first resistor R21 and the twenty-second resistor R22 are connected with the other end of the eighteenth resistor R18 and the grid electrode of the second upper transistor Q3. The nineteenth resistor R19, the twentieth resistor R20, the twenty first resistor R21, and the twenty second resistor R22 play a role in voltage division, and protect the first upper transistor Q1 and the second upper transistor Q3, wherein the resistance values of the nineteenth resistor R19 and the twenty first resistor R21 may be set to be larger, for example, 100K, 80K, 50K, etc., and the resistance values of the twentieth resistor R20 and the twenty second resistor R22 may be set to be relatively smaller than the resistance values of the nineteenth resistor R19 and the twenty first resistor R21, for example, 15K, 10K, 5K, etc.
Optionally, the first level conversion unit 2 is a first level conversion transistor, a gate of the first level conversion transistor receives the pulse signal, and a source or a drain of the first level conversion transistor is connected with the first impedance conversion unit; or (b)
The second level conversion unit is a second level conversion transistor, the grid electrode of the second level conversion transistor receives the inverted signal of the pulse signal, and the source electrode or the drain electrode of the second level conversion transistor is connected with the second impedance conversion unit.
Specifically, the first level shift transistor is a MOS transistor and is an NMOS transistor. The MOS transistor of the first level conversion unit 2 is named as a first level conversion transistor Q5, the grid electrode of the first level conversion transistor Q5 is connected with the first IO port, the drain electrodes of the first level conversion transistor Q5 are connected with the other end of the fifteenth resistor R15 and the output end of the first impedance conversion unit 1, and the source electrode of the first level conversion transistor Q is grounded. The MOS transistor of the second level conversion unit is named as a second level conversion transistor Q6, the grid electrode of the second level conversion transistor Q6 is connected with the second IO port, the drain electrodes of the second level conversion transistor Q6 are connected with the other end of the seventeenth resistor R17 and the output end of the second impedance conversion unit, and the source electrode of the second level conversion transistor Q6 is grounded. The first level conversion transistor Q5 and the second level conversion transistor Q6 are switching MOS transistors, and are controlled to be alternately switched on and switched off by PWM1 and PWM2 respectively.
The junction capacitance of the first level shift transistor Q5 and the second level shift transistor Q6 is very small, and only tens of PFs are provided, so that the MCU can be directly driven. However, the power of the first level shift transistor Q5 and the power of the second level shift transistor Q6 are low, the required current is only several hundred MA, the loss is small, the voltage and the current required by the high-frequency pulse signal (including the inversion signal) and the low-frequency pulse signal (including the inversion signal) are different, the high voltage (for example, higher than 25V) is required when the low-frequency pulse signal is transmitted, the high current (for example, higher than 30 MA) is required when the high-frequency pulse signal is transmitted, and therefore, when the high-frequency pulse signal (for example, radio frequency signal) and the low-frequency pulse signal (for example, micro electric signal) are switched and transmitted in the same circuit, the following problems occur: when the MOS transistors of the first level conversion unit 2 and the second level conversion unit are turned off, if the resistance of the line connected with the drain electrode of the MOS transistor (i.e., the line where the first impedance conversion unit and the second impedance conversion unit are located) is too large, the circuit current is too small, the base currents of the triodes provided to the first push-pull unit 3 and the second push-pull unit at the back are extremely small, and then the triodes of the first push-pull unit 3 and the second push-pull unit are in an amplified state and cannot be saturated and conducted immediately, so that the output frequency of the triodes is seriously affected, and when a pulse signal with high frequency (for example, a radio frequency signal is output) is input, the rising edge of an output waveform is very slow, the deformation of the output waveform is serious, and meanwhile, the radio frequency signal with the frequency higher than 3MHZ cannot be transmitted; when the MOS transistors of the first level conversion unit 2 and the second level conversion unit are turned on, if the impedance of the line connected to the drain of the MOS transistor is too small, a large current is generated from the MOS transistors of the first level conversion unit 2 and the second level conversion unit to the ground, which results in clamping the voltage provided by the boost unit, and when a pulse signal with a low frequency is input (for example, a micro-electric signal is output), the voltage cannot reach a voltage value higher than 25V in the micro-electric mode because the circuit voltage is not increased, for example, the micro-electric signal cannot be transmitted. Therefore, the application sets the first impedance conversion unit 1, the second impedance conversion unit, is used for converting the output impedance value of the circuit where it is located, regulate the voltage, electric current of the circuit where it is located, in order to make when MCU outputs and is pulse signal and its reverse signal of low frequency, the first impedance conversion unit 1, the second impedance conversion unit outputs the high impedance, the MOS tube of the first level conversion unit 2, second level conversion unit will not clamp the voltage that the boost unit provides, can raise the voltage of the circuit, for example the voltage can reach 25V and above, can convey pulse signal and reverse signal of low frequency which needs high voltage; when the MCU outputs a high-frequency pulse signal and a reverse signal thereof, the first impedance conversion unit 1 and the second impedance conversion unit output low impedance, the triodes of the first push-pull unit 3 and the second push-pull unit can obtain larger base current, the first triode Q7 and the third triode Q9 can be rapidly conducted to transmit the pulse signal, the first triode Q7 and the third triode Q9 are prevented from entering an amplifying state to influence the output waveform of the circuit, and therefore the first triode Q7 and the third triode Q9 can be rapidly conducted to transmit the high-frequency pulse signal requiring high current and the reverse signal thereof.
Optionally, the control ends of the first impedance conversion unit 1 and the second impedance conversion unit are connected with the CTL port of the MCU, the input end is connected with the output end of the boost unit, and the output ends are connected with the signal end of the first level conversion unit 2 and the input end of the first push-pull unit 3. The first impedance conversion unit 1 comprises a seventh resistor R7, an eighth resistor R8 and a switch structure 6 connected with a CTL port of the MCU, wherein one end of the switch structure 6 connected with the seventh resistor R7 forms a branch, the branch is connected with the eighth resistor R8 in parallel, and the opening and closing of the switch structure 6 are controlled through the output logic signal of the MCU, so that the opening and closing circuit states of the branch where the switch structure 6 is located are controlled. When the branch circuit is disconnected, the output impedance value of the first impedance conversion unit 1 is the resistance value of the eighth resistor R8; when the branch circuit is connected into the circuit, the output impedance value of the first impedance conversion unit 1 is the resistance value of the seventh resistor R7 and the eighth resistor R8 which are connected in parallel, so that the output impedance value is reduced. The connection point between one end of the branch and one end of the eighth resistor R8 is used as the input end of voltage and is connected with the output end of the boosting unit, and the connection point between the other end of the branch and the other end of the eighth resistor R8 is used as the output end and is connected with the other end of the pull-down resistor and the drain electrode of the first level conversion transistor Q5.
Optionally, the switching structure 6 comprises two transistors and two resistors connected in parallel. The two triodes of the first impedance conversion unit 1 are respectively named as a fifth triode Q11 and a sixth triode Q12, wherein the fifth triode Q11 is an NPN triode, the sixth triode Q12 is a PNP triode, and the two parallel resistors are respectively named as an eleventh resistor R11 and a twelfth resistor R12. The base electrode of the fifth triode Q11 is connected with the CTL port of the MCU, the emitter electrode of the fifth triode Q11 is grounded, the collector electrode of the fifth triode Q11 is connected with one end of an eleventh resistor R11, the other end of the eleventh resistor R11 is connected with the base electrode of the sixth triode Q12 and one end of a twelfth resistor R12, the collector electrode of the sixth triode Q12 is connected with one end of a seventh resistor R7, the other end of the seventh resistor R7 is connected with one end of an eighth resistor R8, the connection point of the seventh resistor R7 and the eighth resistor R8 is used as an output end and is connected with the input end of a first push-pull unit, and the emitter electrode of the sixth triode Q12, the other end of the eighth resistor R8 and the other end of the twelfth resistor R12 are connected with each other to be used as the input end of voltage and are connected with the output end of the boosting unit. The second impedance conversion unit comprises a ninth resistor R9, a tenth resistor R10 and a switch structure 6 connected with a CTL port of the MCU, wherein one end of the switch structure 6 connected with the ninth resistor R9 forms a branch, the branch is connected with the tenth resistor R10 in parallel, two triodes of the second impedance conversion unit are respectively named as a seventh triode Q13 and an eighth triode Q14, the seventh triode Q13 is an NPN triode, the eighth triode Q14 is a PNP triode, and the two parallel resistors are respectively named as a thirteenth resistor R13 and a fourteenth resistor R14. The base electrode of the seventh triode Q13 is connected with the CTL port of the MCU, the emitter electrode of the seventh triode Q13 is grounded, the collector electrode of the seventh triode Q13 is connected with one end of a thirteenth resistor R13, the other end of the thirteenth resistor R13 is connected with the base electrode of an eighth triode Q14 and one end of a fourteenth resistor R14, the collector electrode of the eighth triode Q14 is connected with one end of a ninth resistor R9, the other end of the ninth resistor R9 is connected with one end of a tenth resistor R10, the connection point of the ninth resistor R9 and the tenth resistor R10 is used as an output end, the connection point of the eighth triode Q14, the other end of the tenth resistor R10 and the other end of the fourteenth resistor R14 are connected with each other to be used as input ends of voltage, and the output end of the boosting unit is connected. The high level or the low level is input to the fifth triode Q11 and the seventh triode Q13 through the CTL port of the MCU to control the cut-off or the cut-on of the fifth triode Q11 and the seventh triode Q13, so that the branch circuits where the seventh resistor R7 and the ninth resistor R9 are located are controlled to be connected into a circuit or disconnected. When the branch circuit is disconnected, the output impedance value of the first impedance conversion unit 1 is the resistance value of the eighth resistor R8, and the output impedance value of the second impedance conversion unit is the resistance value of the tenth resistor R10; when the branch circuit is connected to the circuit, the output impedance value of the first impedance conversion unit 1 is the resistance value obtained by connecting the seventh resistor R7 and the eighth resistor R8 in parallel, and the output impedance value of the second impedance conversion unit is the resistance value obtained by connecting the ninth resistor R9 and the tenth resistor R10 in parallel.
Optionally, the resistance of the seventh resistor R7 is smaller than the resistance of the eighth resistor R8 (the principles of the resistance of the ninth resistor R9 and the tenth resistor R10 are the same as the principles of the seventh resistor R7 and the eighth resistor R8, and are not described herein). Meanwhile, the resistance values of the seventh resistor R7 and the eighth resistor R8, and the resistance values of the ninth resistor R9 and the tenth resistor R10 can be selected according to the frequency of the pulse signals required by different scenes. Specifically, the resistance values of the seventh resistor R7 and the eighth resistor R8 satisfy: when the circuit is in a micro-electric mode, the CTL port of the MCU outputs a low level, the two triodes of the first impedance conversion unit 1 are both cut off, the branch is disconnected, the output impedance value of the first impedance conversion unit is equal to the resistance value of the eighth resistor R8, the eighth resistor R8 is set to be a larger resistor (such as 50KΩ), the current from the first level conversion transistor Q5 to the ground is small, the voltage provided by the boosting unit is not clamped, the voltage of the circuit can be increased, for example, the voltage reaches 25V or more, and micro-electric signal transmission is performed; when the circuit is in a radio frequency mode, a CTL port of the MCU outputs a high level, two triodes of the first impedance conversion unit 1 are both conducted, a branch is connected into the circuit, the output impedance value of the first impedance conversion unit is equal to the resistance value of a seventh resistor R7 and an eighth resistor R8 which are connected in parallel, the seventh resistor R7 is set to be a smaller resistor (for example, 2KΩ), so that the output impedance value is reduced, the circuit current is large, a large enough base current can be provided for the first push-pull unit 3, the first push-pull unit 3 can be quickly saturated and conducted, a large grid electrode is provided for the first upper transistor Q1, the first upper transistor Q1 is quickly conducted, the rising edge of an output waveform of a pulse signal is very fast, and the radio frequency function is realized at most only by a delay of dozens of nanoseconds; the output waveform is perfect, and meanwhile, the radio frequency signal with the frequency reaching 6MHz can be transmitted. Optionally, the seventh resistor R7 may be 2kΩ and the eighth resistor R8 may be 50kΩ; or the seventh resistor R7 may be 5KΩ and the eighth resistor R8 may be 100KΩ; or the seventh resistor R7 may be 1kΩ and the eighth resistor R8 may be 40kΩ. The three groups of resistance values can simultaneously realize the micro-electric mode and the radio frequency mode.
The boost unit may provide a high voltage to the circuit, for example, may provide a voltage of 25V or 40V or 60V or 80V, etc. In the following, the seventh resistor R7 and the ninth resistor R9 are each 2kΩ, and the eighth resistor R8 and the tenth resistor R10 are each 50kΩ. When the MCU outputs a radio frequency signal (for example, the frequency is 6 MHZ), the CTL port of the MCU outputs a high level, the fifth transistor Q11, the sixth transistor Q12, the seventh transistor Q13, and the eighth transistor Q14 are all turned on, the output impedance value of the first impedance conversion unit is the resistance value obtained by connecting the seventh resistor R7 and the eighth resistor R8 in parallel, which is approximately equal to the resistance value of the seventh resistor R7, that is, 2kΩ, the output impedance value of the second impedance conversion unit is the resistance obtained by connecting the ninth resistor R9 and the tenth resistor R10 in parallel, which is approximately equal to the resistance value of the ninth resistor R9, that is, 2kΩ, and the output impedance value is lower, which can provide a larger base current for the first push-pull unit and the second push-pull unit, for example, the base current can reach 30mA or 40mA or 50mA, so that the transistors of the first push-pull unit and the second push-pull unit can be turned on quickly, so that the rising edge of the radio frequency signal output waveform is very steep, the output waveform is improved, and the circuit can realize a radio frequency mode. Therefore, after selecting the appropriate seventh resistor R7, eighth resistor R8, ninth resistor R9 and tenth resistor R10 (for example, three pairs of resistors are listed in the application), the circuit can realize the output of the radio frequency signal with the high frequency reaching 6MHZ, so that the radio frequency mode can set the working range with the frequencies of 500KHZ, 1MHZ, 3MHZ, 6MHZ and the like, the frequency is not limited, and the problem that the frequency of the radio frequency signal in the traditional circuit is limited by the transformer and the output of the radio frequency of 6MHZ can not be realized is solved. When the MCU outputs a micro-electric signal (for example, the frequency is 30 HZ), the CTL port of the MCU outputs a low level, the fifth transistor Q11, the sixth transistor Q12, the seventh transistor Q13 and the eighth transistor Q14 are all turned off, the seventh resistor R7 and the ninth resistor R9 are all open circuits, the output impedance value of the first impedance conversion unit is 50kΩ of the resistance value of the eighth resistor R8, the output impedance value of the second impedance conversion unit is 50kΩ of the resistance value of the tenth resistor R10, the output impedance value is larger, and the current passing through the first level conversion unit and the second level conversion unit is small, so that the voltage clamp provided by the voltage boosting unit can not be ensured, the voltage boosting unit can provide a high voltage for the circuit, and the micro-electric mode can be smoothly realized.
Optionally, the gate of the second lower transistor Q2 is connected to the second IO port of the MCU, the source thereof is grounded, and the drain thereof is connected in series with a second resistor R2 and then connected to the first electrode PA; the gate of the first upper transistor Q1 is connected to the other end of the sixteenth resistor R16, the drain is connected in series with a first resistor R1 and then connected to the first electrode PA, and the source is connected to the output end of the boosting unit. The grid electrode of the first lower transistor Q4 is connected with the first IO port of the MCU, the source electrode of the first lower transistor Q4 is grounded, and the drain electrode of the first lower transistor Q is connected with a fourth resistor R4 in series and then is connected with the second electrode PB; the gate of the second upper transistor Q3 is connected to the other end of the eighteenth resistor R18, the drain is connected in series with a third resistor R3 and then connected to the second electrode PB, and the source is connected to the output end of the boosting unit. The PWM1 is acted on the human body from the first upper transistor Q1 through the first electrode PA after passing through the first level conversion transistor Q5 and the first push-pull unit, then is acted on the ground from the first lower transistor Q4 through the second electrode PB, the PWM2 is acted on the human body from the second upper transistor Q3 through the second electrode PB after passing through the second level conversion transistor Q6 and the second push-pull unit, and then is acted on the ground from the second lower transistor Q2 through the first electrode PA.
The working logic principle of the first upper transistor Q1, the second upper transistor Q3, the first lower transistor Q4, and the second lower transistor Q2 is as follows: the control unit outputs PWM1 and PWM2 simultaneously, and at the same time, if the first upper transistor Q1 and the first lower transistor Q4 are turned on, the second lower transistor Q2 and the second upper transistor Q3 are necessarily turned off at the moment; conversely, if the second lower transistor Q2 and the second upper transistor Q3 are turned on, the first upper transistor Q1 and the first lower transistor Q4 are necessarily turned off at this time. The specific logic sequence is as follows:
when the PWM1 is at a high level, the first level shift transistor Q5 is turned on, the gate of the first upper transistor Q1 is at a low level, the first upper transistor Q1 is turned on, the gate of the first lower transistor Q4 is at a high level, the first lower transistor Q4 is turned on, and the first lower transistor Q4 rapidly releases the voltage on the third resistor R3 and the voltage of the parasitic capacitor of the second upper transistor Q3 in time, so that the falling edge of the output waveform is very steep, and a high-speed switching effect is achieved; since the phase difference between the PWM1 and the PWM2 is 180 °, the two PWM waves are a pair of PWM waves input in a center synchronous complementary manner, the second lower transistor Q2 connected to the second IO port of the MCU is turned off, the second level conversion transistor Q6 is turned off, the gate of the lower left transistor Q3 is at a high level, and the lower left transistor Q3 is turned off. When the PWM2 is at a high level, the second level converting transistor Q6 is turned on, the second upper transistor Q3 is turned on, the second lower transistor Q2 is also in a turned-on state, and the second lower transistor Q2 can rapidly release the voltage on the first resistor R1 and the voltage of the parasitic capacitor of the first upper transistor Q1 in time, so that the falling edge of the output waveform is very steep, and the falling edge of the output waveform has a delay of only a few nanoseconds at most, so as to achieve a high-speed switching effect; similarly, since PWM1 and PWM2 are 180 ° out of phase, the right lower transistor Q1 connected to the first IO port of the MCU is turned off, the first level shift transistor Q5 is turned off, the gate of the first lower transistor Q4 is at a high level, and the first lower transistor Q4 is turned off.
Optionally, fig. 3 is a schematic diagram of an input waveform of PWM1 measured at the gate of the first upper transistor Q1 and an input waveform of PWM2 measured at the gate of the second lower transistor Q2 according to an embodiment of the present invention. If the gates of the first level-shifting transistor Q5 and the second lower transistor Q2 are both connected to the first IO port, or the gates of the second level-shifting transistor Q6 and the first lower transistor Q4 are both connected to the second IO port, the circuit may have a dead zone problem, and taking the first level-shifting transistor Q5 and the second lower transistor Q2 are both connected to the first IO port as an example, it is seen that when the gate of the first upper transistor Q1 and the gate of the second lower transistor Q2 are in the process of level-to-high transition, i.e., when the voltage of the pulse signal is in the (2, 4) interval (the voltage unit of the pulse signal is V), there is a case that the first upper transistor Q1 and the second lower transistor Q2 are simultaneously turned on, which causes the MOS transistor to burn out. Therefore, in order to avoid this, the gates of the first level-shifting transistor Q5 and the second lower transistor Q2 are connected to the first IO port and the second IO port one by one, and at the same time, as shown in fig. 3, the input waveform of PWM1 at the gate of the first upper transistor Q1 and the input waveform of PWM2 at the gate of the second lower transistor Q2 are as follows: the rising edge section of the input waveform of PWM1 and the rising edge section of the input waveform of PWM2 do not overlap in time, the falling edge section of the input waveform of PWM1 and the falling edge section of the input waveform of PWM2 do not overlap in time, and the maximum pulse amplitude of PWM1 is larger than the maximum pulse amplitude of PWM 2. Specifically, when the input waveform of PWM1 is in the rising edge section, the input waveform of PWM2 is still in the lowest pulse amplitude; when the input waveform of the PWM2 is in a rising edge interval, the input waveform of the PWM1 is in the state that the pulse amplitude is highest; when the input waveform of the PWM2 is in a falling edge interval, the input waveform of the PWM1 is still in the highest pulse amplitude; when the input waveform of PWM1 is in the falling edge section, the input waveform of PWM2 is at the lowest pulse amplitude. That is, the input waveform of the PWM2 is completely enveloped in the input waveform of the PWM1, the voltage of rising edges or falling edges of the two input waveforms is not in the region of 2V to 4V at the same time, the dead zone problem is perfectly solved, the situation that the first upper transistor Q1 and the second lower transistor Q2 are simultaneously turned on and/or the second upper transistor Q3 and the first lower transistor Q4 are simultaneously turned on is avoided, the condition that the MOS transistor is burnt out is avoided, and the working stability of the circuit can be improved. The dashed-dotted line (as an auxiliary line) in fig. 3 shows that the rising edge region of PWM1 and the rising edge region of PWM2, and the falling edge region of PWM1 and the falling edge region of PWM2 do not intersect in time.
Optionally, the second IO port of the MCU is connected in series with one end of a fifth resistor R5, the other end of the fifth resistor R5 is connected to the gate of the second lower transistor Q2, the first IO port of the MCU is connected in series with one end of a sixth resistor R6, and the other end of the sixth resistor R6 is connected to the gate of the first lower transistor Q4. The fifth resistor R5 and the sixth resistor R6 are used for limiting the grid current of the MOS tube and inhibiting oscillation.
The first upper transistor Q1, the second lower transistor Q2, the second upper transistor Q3 and the first lower transistor Q4 form a full-bridge driving structure, the driving force is strong, the power is large, the energy efficiency conversion rate is high, wherein the first upper transistor Q1, the second lower transistor Q2, the second upper transistor Q3 and the first lower transistor Q4 all adopt MOS transistors, the first push-pull unit provides larger grid current for the MOS transistor of the first upper transistor Q1, the second push-pull unit provides larger grid current for the second upper transistor Q3, so that the grid junction capacitance of the first upper transistor Q1 and the second upper transistor Q3 can be charged rapidly, by utilizing the high-speed switching benefit of the MOS transistor, the rising edge of an output waveform can be very steep in a radio frequency mode, meanwhile, after the first upper transistor Q1 and the second upper transistor Q3 are cut off, the second lower transistor Q2 and the first lower transistor Q4 are rapidly conducted and respectively discharge the power of parasitic capacitance of the first upper transistor Q1 and the second upper transistor Q3 in time, so that the falling edge of the output waveform is very steep, the output waveform is more perfect, the problem of waveform deformation of a transformer in a high-frequency part is solved, the problem that a traditional circuit is limited by the transformer is solved, the function that the output frequency can reach 6MHZ is realized, and the function of the circuit is improved. Fig. 5 to 7 show the output waveforms of the pulse signals at the output electrodes, wherein the solid lines in fig. 5 to 7 each represent the output waveform of PWM1, and the broken lines represent the output waveform of PWM 2. In fig. 5, the output waveforms of PWM1 and PWM2 have the frequency of 1MHZ, the voltage amplitudes of the output waveforms of PWM1 and PWM2 after the conversion by the MOS transistor are 30.79v, the positive duty ratio of the output waveform of PWM1 is 43.4%, and the positive duty ratio of the output waveform of PWM2 is 47.7%. It can be seen that the output waveform of 1MHZ frequency is quite perfect, the rising edge is almost the same as that of the MOS transistor, only twenty-several nanoseconds of delay is provided, and the falling edge is almost 0 delay. Fig. 6 shows output waveforms when the frequencies of PWM1 and PWM2 are 3MHZ, the voltage amplitudes of the output waveforms of PWM1 and PWM2 are 30.39v after the conversion by the MOS transistor, the positive duty ratio of the output waveform of PWM1 is 43.4%, and the positive duty ratio of the output waveform of PWM2 is 31.1%. It can be seen that the rising edge of the output waveform at 3MHZ frequency has a delay of substantially only twenty-several nanoseconds and the falling edge has a delay of substantially only several nanoseconds. Fig. 7 shows output waveforms when the frequencies of PWM1 and PWM2 are both 6MHZ, the voltage amplitudes of the output waveforms of PWM1 and PWM2 after the conversion by the MOS transistor are both 27.72v, the positive duty ratio of the output waveform of PWM1 is 24.1%, and the positive duty ratio of the output waveform of PWM2 is 25%. It can be seen that the rising edge of the output waveform at the 6MHZ frequency has a delay of substantially only thirty nanoseconds and the falling edge has a delay of substantially only a few nanoseconds.
Optionally, with continued reference to fig. 2, the BOOST unit is a BOOST unit based on the above embodiment.
Optionally, fig. 4 is a circuit diagram of a BOOST unit according to an embodiment of the present invention. On the basis of the above embodiment, as shown in fig. 4, the control end of the BOOST unit is connected to the PWM port of the MCU, and the BOOST unit has a v_boost interface as the output end of the voltage, and is used to connect the input end of the first impedance conversion unit, the input end of the second impedance conversion unit, the signal end of the first push-pull unit, the signal end of the second push-pull unit, the source of the first upper transistor Q1, the source of the second upper transistor Q3, and the power end of the control unit, and provide a power supply voltage thereto, where the MCU controls the voltage value at the v_boost interface of the BOOST unit through the PWM port, that is, controls the output voltage value of the BOOST unit. The BOOST unit comprises a power supply V, an inductor L, a diode D, a capacitor C and a third MOS tube Q15, wherein one end of the inductor L is connected with the power supply V, the other end of the inductor L is connected with the anode of the diode D and the drain electrode of the third MOS tube Q15, the cathode of the diode D is connected with one end of the capacitor C, the connecting point of the capacitor C and the cathode is used as a V_boost interface, the output end of the voltage is the output end of the voltage, and the grid electrode of the third MOS tube Q15 is connected with a PWM (pulse width modulation) port. The PWM port outputs the pwm_boost signal of fig. 4, which is a pulse signal, and one skilled in the art will appreciate that the duty cycle of the pwm_boost signal affects the level of v_boost, and that the desired level of v_boost may be obtained by adjusting the duty cycle of the pwm_boost signal. The larger the duty ratio of the pwm_boost signal is, the smaller the v_boost interface output voltage value of the BOOST unit is, whereas the smaller the duty ratio of the pwm_boost signal is, the larger the v_boost interface output voltage value of the BOOST unit is. The source electrode of the third MOS transistor Q15 and the other end of the capacitor C are grounded. The power source V may be a 12V battery.
Optionally, on the basis of the above embodiment, as shown in fig. 4, in order to increase the switching frequency of the third MOS transistor Q15 to make the switching frequency reach more than 1MHZ, a gate of the third MOS transistor Q15 is connected to a third push-pull unit 7 formed by a ninth triode Q16 and a tenth triode Q17, a base of the ninth triode Q16 and a base of the thirteenth triode Q17 are connected to one end of a third resistor R23, another end of the third resistor R23 is connected to one end of a fourth resistor R24, a drain of the fourth MOS transistor Q18 serving as a level conversion function, and another end of the fourth resistor R24 is connected to a power source V. The PWM mouth of MCU connects the grid of fourth MOS pipe Q18, and the source of fourth MOS pipe Q18 ground. The arrangement of the third push-pull unit 7 composed of the ninth triode Q16 and the tenth triode Q17 can improve the output efficiency of the BOOST unit and provide stable high voltage and high current for the circuit.
Optionally, with continued reference to fig. 2 based on the foregoing embodiment, the device further includes a sampling feedback unit 8, where the sampling feedback units are connected to the v_boost interface of the BOOST unit and the ADC port of the MCU. The branch where the sampling feedback unit 8 is located is connected in parallel with the output electrode and the branch where the human skin is located, the voltages of the two branches are provided by the BOOST unit, when the impedance of the human skin in the branch where the output electrode and the human skin are located changes, the current of the total trunk is influenced, the BOOST unit is influenced to the voltage values provided by the branch where the sampling feedback unit 8 is located and the branch where the output electrode and the human skin are located, so that the current and the voltage of the branch where the sampling feedback unit 8 is located are influenced, and the MCU detects the feedback signal of the sampling feedback unit 8 through the ADC port to judge the contact condition between the human skin and the output electrode so as to judge whether the micro-electric signal is required to be stopped to be output.
When the skin impedance detection signal passes through the output electrode, if the output electrode is not in contact with the skin of a human body, the amplitude of the skin impedance detection signal is not changed and is the largest; when the output electrode is in contact with human skin, the amplitude of the skin impedance detection signal is reduced; wherein the amplitude of the skin impedance detection signal is lowest when the output electrode is in full contact with the human skin (i.e., the output electrode is in full contact with the human skin).
Specifically, the sampling feedback unit comprises two resistors which are sequentially connected in series, the two resistors are connected in series between the power supply and the ground, the two resistors are a twenty-fifth resistor R25 and a twenty-sixth resistor R26 respectively, one end of the twenty-fifth resistor R25 is connected with one end of the twenty-sixth resistor R26, the connection point between the two is connected with an ADC port of the MCU, so that a feedback signal is transmitted to the control unit, the other end of the twenty-fifth resistor R25 is connected with a V_BOOST interface (voltage output end) of the BOOST boosting unit, and the other end of the twenty-sixth resistor R26 is grounded.
The voltage provided by the BOOST unit is divided by a twenty-fifth resistor R25 and a twenty-sixth resistor R26, and the ADC port of the MCU detects feedback signals (the feedback signals can be voltage signals or current signals) at two ends of the twenty-fifth resistor R25, and the magnitude of skin impedance is reflected through the magnitude of the feedback signals.
Because the frequency of the micro-electric signal is very low, generally only tens of HZ, the human skin is capacitive in general, the direct current impedance can reach tens of megaohms for a low-frequency pulse signal, but the impedance is very low for a high-frequency pulse signal. Therefore, in order to solve the problem of skin pricking caused by poor contact between the output electrode and the skin of a human body, and simultaneously improve the accuracy of circuit detection, after each pulse of a micro-electric signal is output, the MCU immediately transmits at least one pulse of a high-frequency pulse signal (namely, a skin impedance detection signal) to specially detect skin impedance so as to obtain a more accurate detection result. Optionally, on the basis of the above embodiment, as shown in fig. 8, the pulse signal control transmission method includes the steps of: combining a micro-electric signal and a skin impedance detection signal to form the pulse signal, respectively inputting the pulse signal into the first level conversion unit and the grid electrode of the first lower transistor, and respectively inputting the inverted signal of the pulse signal into the second level conversion unit and the grid electrode of the second lower transistor;
detecting the feedback signal from the sampling feedback unit and judging whether the amplitude of the feedback signal is lower than a set threshold value;
If so, determining that the human skin is in good contact with the output electrode, continuously outputting the micro-electrical signal and the skin impedance detection signal to the human skin, and repeatedly detecting the feedback signal;
if not, determining that the skin of the human body is not completely contacted with the output electrode, and stopping outputting the micro-electric signal.
Optionally, the pulse signal control transmission method is used for preventing skin pricking, and the specific method is as follows: when the circuit is in micro-electric mode, the MCU transmits a pulse of micro-electric signal to the circuit, then the MCU inputs a high-frequency pulse signal (for example, the signal frequency is 500KHZ or 800KHZ or 1MHz, 3MHz, 6MHz, etc.), and the high-frequency pulse signal is named as skin impedance detection signal. Alternatively, the skin impedance detection signal may be a radio frequency signal in a radio frequency mode, that is, in a micro-electric mode, at least one pulse of the radio frequency signal is output after each pulse of one micro-electric signal is output to perform skin impedance detection. The skin impedance detection signal acts on human skin through the output electrode, when the output electrode contacts with the human skin, the output electrode is connected with a load (skin impedance), and the change of the load can influence the voltage value of the V_BOOST and the current and the voltage of the branch circuit where the sampling feedback unit is located, so that the voltage division of two series resistors of the sampling feedback unit can be influenced. If the micro-electric signal is still sent to stimulate the skin of the human body at this time, the skin will feel stinging. The ADC port of the MCU detects feedback signals at two ends of the twenty-fifth resistor R25, a threshold value is set, and the set threshold value is compared with the feedback signals, so that whether the contact between the human skin and the output electrode is good or not can be reflected. If the feedback signal is smaller than the set threshold value, the skin of the human body is determined to be in good contact with the output electrode, the micro-electric mode continues to work, the control unit continues to output the micro-electric signal for muscle stimulation, then the skin impedance detection signal continues to carry out skin impedance detection, and the step of detecting the feedback signal fed back by the sampling feedback unit by the control unit is repeated; if the feedback signal is greater than the set threshold value, the control unit determines that the human skin is not fully contacted with the output electrode, and stops outputting the micro-electric signal. Meanwhile, the MCU can calculate the impedance value of the human skin at the moment according to the detected feedback signal, and more functions of the intracellular water and the cell membrane exist in the characteristic of capacitance, so that the water-oil characteristic of the human skin can be obtained, the oil characteristic, the dryness characteristic, the mixability and other skin characteristics of the human skin are reflected, the moisture content, the fat content and the like of the human skin can be reflected, the current skin state of a user can be prompted, and the user can carry out skin care in a targeted mode later. The feedback signals obtained by different skin impedance effects are different in size, so that the MCU can also adjust the frequency of the transmitted micro-electric signals according to the skin impedance values obtained by detection and calculation, and realize the transmission of the micro-electric signals with different frequencies according to different skin characteristics, thereby better achieving the effect of improving the skin; or the frequency of the micro-electrical signal may be tailored to the user to suit the characteristics of the skin thereof to enhance the user experience.
And detecting feedback signals at two ends of the twenty-fifth resistor R25 through an ADC port of the MCU to feed back the contact condition between the output electrode and the skin of the human body. For example, the MCU detects voltage signals at two ends of the twenty-fifth resistor R25, if the voltage signals are lower than a set threshold (for example, the set threshold may be 400mV or 500mV or 600mV or 700mV, etc.), the skin of the human body is considered to be in good contact with the output electrode, the micro-electric mode continues to work, the MCU continues to output micro-electric signals for muscle stimulation, and then continues to output skin impedance detection signals for cycle detection and judgment; otherwise, if the voltage signal is higher than the set threshold value, the human skin is not completely contacted with the output electrode, and in order to avoid skin pricking, the MCU turns off the micro-electric mode and stops outputting the micro-electric signal and the skin impedance detection signal.
Optionally, in order to improve the work efficiency of the circuit, and in order to effectively achieve the effect of preventing skin pricking in real time in the micro-electric mode, the skin impedance detection signal outputs and detects in the micro-electric mode, the MCU sends at least one pulse of the skin impedance detection signal after sending each pulse of a micro-electric signal, the skin impedance detection signal is transmitted to the circuit through the first IO port and the second IO port of the MCU and then acts on the skin of a human body through the output electrode, and the MCU detects and samples the feedback signal of the feedback unit.
Optionally, in order to improve the accuracy of feedback of the sampling feedback unit, at least two pulses of skin impedance detection signals are sent between two adjacent pulses of micro-electrical signals, when each pulse of skin impedance detection signal is sent, an ADC port of the MCU detects a feedback signal once, the MCU analyzes whether the sampled feedback signal is available (i.e. whether the sampled feedback signal is an abnormal value, the abnormal value is dropped), the unavailable feedback signal is removed, and an average value of all available feedback signals is taken as a detection result between the pulses of two adjacent micro-electrical signals at this time, and the MCU controls on/off of the micro-electrical mode according to the average value.
Specifically, each time a pulse of a micro-electric signal is sent, namely, ten pulses of skin impedance detection signals are sent continuously, after each time a pulse of skin impedance detection signals is sent, an ADC port of the MCU detects a feedback signal, the MCU analyzes whether all feedback signals are available or not, and after unavailable feedback signals are removed, the rest feedback signals are used as an average algorithm to improve the accuracy of each feedback.
The implementation process of the stabbing pain preventing function is described below by taking the feedback signal as a voltage signal and the threshold value set by the voltage signal as 650 mV:
When the circuit is in a micro-electric mode, the MCU sends pulses of one micro-electric signal, then, ten pulses of skin impedance detection signals are continuously sent to the circuit, the frequency of the skin impedance detection signals is 1MHz, the skin impedance detection signals are transmitted to the skin of a human body through the output electrode, and an ADC port of the pulse MCU which sends one skin impedance detection signal detects a feedback signal, wherein voltage signals (unit is mV) measured when the output electrode is not contacted with the skin are as follows:
[00:02:10.408]touch_value:1169
[00:02:10.711]touch_value:1133
[00:02:11.014]touch_value:1305
[00:02:11.317]touch_value:1238
[00:02:11.620]touch_value:1139
[00:02:11.923]touch_value:1257
[00:02:12.225]touch_value:1324
[00:02:12.528]touch_value:1233
[00:02:12.842]touch_value:1298
[00:02:13.179]touch_value:1310
it can be seen that the voltage signal greatly exceeded the set threshold when the output electrode was completely out of contact with the skin (it was previously known that the output electrode was considered to be completely out of contact with the skin if the measured voltage signal exceeded 1100 mV).
When the output electrode is in full contact with the face, the measured voltage signal is as follows:
[00:04:17.045]touch_value:588
[00:04:16.369]touch_value:612
[00:04:16.701]touch_value:582
[00:04:17.014]touch_value:698
[00:04:17.317]touch_value:562
[00:04:17.619]touch_value:592
[00:04:17.922]touch_value:574
[00:04:18.225]touch_value:578
[00:04:18.528]touch_value:515
[00:04:18.831]touch_value:487
the MCU judges 698mV of the feedback signals to be an abnormal value and removes the abnormal value, takes the average value 565.6mV of the rest 9 feedback signals as the detection result of the time, and the detection result is lower than a set threshold value, so that the output electrode is considered to be well contacted with the skin of the human body, and the MCU continuously outputs a pulse of a micro-electric signal and ten pulses of skin impedance detection signals to perform micro-electric stimulation and skin pricking prevention detection.
The ten feedback signals sampled by the ADC ports of the secondary MCU are as follows:
[00:04:48.515]touch_value:747
[00:04:48.817]touch_value:894
[00:04:49.120]touch_value:895
[00:04:49.423]touch_value:942
[00:04:49.726]touch_value:798
[00:04:50.028]touch_value:759
[00:04:50.331]touch_value:770
[00:04:50.634]touch_value:851
[00:04:50.937]touch_value:882
[00:04:51.241]touch_value:823
the MCU judges that the feedback signal has no abnormal value, takes the average value 836.1mV as the detection result of the time, and the detection result is higher than the set threshold value, so that the output electrode is not completely contacted with the skin of the human body, and the current acted on the skin of the human body is larger (the current exceeds the acceptable value of the human body and can generate stinging feeling), so that the MCU stops conveying micro-electric signals to the circuit and skin stinging is avoided.
The application also provides a beauty instrument, which comprises a shell and a circuit board arranged in the shell, wherein the circuit board is provided with an MCU and a circuit for transmitting pulse signals, the circuit comprises an output electrode, a first impedance conversion unit, a first level conversion unit, a first push-pull unit, a first upper transistor, a first lower transistor, a second impedance conversion unit, a second level conversion unit, a second push-pull unit, a second upper transistor, a second lower transistor and a boosting unit, and the output electrode is exposed outside the shell and is used for contacting with human skin. The MCU transmits pulse signals with different frequencies to the same circuit, so that a relay, a change-over switch and the like are not required to be arranged to switch the output circuit, a transformer is not required, the cost can be saved, the volume is reduced, and no noise is generated. The circuit board of the beauty instrument can realize the function of preventing skin pricking.
The circuit board also comprises a sampling feedback unit connected with the ADC port of the MCU, the ADC port of the MCU detects a feedback signal of the sampling feedback unit, when the feedback signal is higher than a set threshold value, the MCU stops outputting the micro-electric signal, the micro-electric mode is closed, skin pricking is prevented, and when the feedback signal is lower than the set threshold value, the MCU continues to output the micro-electric signal and the skin impedance detection signal successively.
In summary, the foregoing description is only of the preferred embodiments of the present invention, and all equivalent changes and modifications made in accordance with the claims should be construed to fall within the scope of the invention.
Claims (17)
1. A circuit for transmitting a pulsed signal, comprising:
a first impedance conversion unit whose impedance is capable of being converted between at least two impedance values in response to a first control signal;
a second impedance conversion unit whose impedance is capable of being converted between at least two impedance values in response to a second control signal;
the first level conversion unit and the first impedance conversion unit are sequentially connected in series between a power supply and ground, the pulse signal is input to the first level conversion unit, and the pulse signal is used for controlling the on and off of the first level conversion unit;
The second level conversion unit and the second impedance conversion unit are sequentially connected in series between the power supply and the ground, an inverted signal of the pulse signal is input to the second level conversion unit, and the inverted signal of the pulse signal is used for controlling the on and off of the second level conversion unit;
the first upper transistor, the load and the first lower transistor are sequentially connected in series between the power supply and the ground, the grid electrode of the first upper transistor is connected with the output end of the first level conversion unit, and the pulse signal is input to the grid electrode of the first lower transistor; and
The second upper transistor, the load and the second lower transistor are sequentially connected in series between the power supply and the ground, the grid electrode of the second upper transistor is connected with the output end of the second level conversion unit, and the inverted signal of the pulse signal is input to the grid electrode of the second upper transistor.
2. The circuit according to claim 1, wherein the first level shift unit is a first level shift transistor, a gate of the first level shift transistor receives the pulse signal, and a source or a drain of the first level shift transistor is connected to the first impedance shift unit; or (b)
The second level conversion unit is a second level conversion transistor, the grid electrode of the second level conversion transistor receives the inverted signal of the pulse signal, and the source electrode or the drain electrode of the second level conversion transistor is connected with the second impedance conversion unit.
3. The circuit of claim 1, wherein:
the grid electrode of the first upper transistor is connected with the output end of the first level conversion unit through a first push-pull unit; or (b)
The grid electrode of the second upper transistor is connected with the output end of the second level conversion unit through a second push-pull unit.
4. A circuit according to claim 3, wherein the first push-pull unit comprises two triodes, the two triodes being respectively a PNP-type triode and an NPN-type triode, bases of the two triodes being connected as input terminals to be connected to the output terminal of the first impedance conversion unit, emitters of the two triodes being connected as output terminals to be connected to the gate of the first upper transistor.
5. The circuit of claim 1, wherein the first impedance transformation unit comprises a seventh resistor R7 and a switching structure, the switching structure being connected in series with the seventh resistor R7.
6. The circuit of claim 5, wherein the first impedance transformation unit further comprises an eighth resistor R8, and the switching structure is connected in series with the seventh resistor R7 and then in parallel with the eighth resistor R8.
7. The circuit of claim 5, wherein the switching structure comprises a fifth transistor Q11 and a sixth transistor Q12, an emitter of the fifth transistor Q11 is connected to a base of the sixth transistor Q12, a collector of the sixth transistor Q12 is connected to the seventh resistor R7, and a base of the fifth transistor Q11 receives the first control signal.
8. The circuit of claim 1, wherein the first control signal and the second control signal are the same signal.
9. The circuit of claim 1, wherein the power source is a boost unit.
10. The circuit of claim 9, wherein the BOOST unit is a BOOST unit, the BOOST unit includes a power source V, an inductor L, a diode D, a capacitor C, and a third MOS transistor Q15, wherein one end of the inductor L is connected to the power source V, one end of the diode D and a drain electrode of the third MOS transistor Q15 are both connected to the other end of the inductor L, a gate electrode of the third MOS transistor Q15 receives a BOOST pulse signal, the other end of the diode D is connected to one end of the capacitor C, and a connection point of the two is used as an output end of the BOOST unit.
11. The circuit of claim 10, wherein the gate of the third MOS transistor Q15 receives the BOOST pulse signal specifically is: and a grid electrode of the third MOS tube Q15 is connected with the output end of the third push-pull unit, and the input end of the third push-pull unit receives the BOOST pulse signal.
12. The circuit of claim 1, further comprising a control unit for outputting the pulse signal, an inverted signal of the pulse signal, the first control signal, and the second control signal.
13. The circuit of claim 12, further comprising a sampling feedback unit, wherein the sampling feedback unit comprises two resistors sequentially connected in series, the two resistors are connected in series between the power supply and the ground, and a connection point between the two resistors is connected with the control unit, so as to transmit a feedback signal to the control unit, wherein the feedback signal is a voltage value of the power supply after voltage division.
14. The circuit of any of claims 1, wherein the load is a human body.
15. A cosmetic device comprising the circuit of any one of claims 1-14.
16. A method for controlling transmission of a pulse signal, characterized in that the method inputs the pulse signal to human skin by the circuit for transmitting a pulse signal according to claim 13, the method comprising the steps of:
combining a micro-electric signal and a skin impedance detection signal to form the pulse signal, respectively inputting the pulse signal into the first level conversion unit and the grid electrode of the first lower transistor, and respectively inputting the inverted signal of the pulse signal into the second level conversion unit and the grid electrode of the second lower transistor;
detecting the feedback signal from the sampling feedback unit and judging whether the amplitude of the feedback signal is lower than a set threshold value;
if so, determining that the human skin is in good contact with the output electrode, continuously outputting the micro-electrical signal and the skin impedance detection signal to the human skin, and repeatedly detecting the feedback signal;
if not, determining that the skin of the human body is not completely contacted with the output electrode, and stopping outputting the micro-electric signal.
17. The method of claim 16, wherein combining the micro-electrical signal with the skin impedance detection signal to form the pulse signal is specifically: after each pulse of one micro-electric signal is sent, a plurality of pulses of skin impedance detection signals are sent immediately; and is also provided with
The detection of the feedback signal from the sampling feedback unit is in particular: each time a pulse of the skin impedance detection signal is transmitted, the feedback signal is detected once, and the average value of the amplitudes of all the pulses of the feedback signal detected between two adjacent pulses of the micro-electric signal is taken as a detection result.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311314207.1A CN117240254A (en) | 2023-10-11 | 2023-10-11 | Pulse signal transmission circuit and pulse signal transmission control method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311314207.1A CN117240254A (en) | 2023-10-11 | 2023-10-11 | Pulse signal transmission circuit and pulse signal transmission control method |
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| Publication Number | Publication Date |
|---|---|
| CN117240254A true CN117240254A (en) | 2023-12-15 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311314207.1A Pending CN117240254A (en) | 2023-10-11 | 2023-10-11 | Pulse signal transmission circuit and pulse signal transmission control method |
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| Country | Link |
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| CN (1) | CN117240254A (en) |
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2023
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