Electric tactile feedback circuit, intelligent wearable device and control method thereof

Abstract

The invention discloses an electric tactile feedback circuit, intelligent wearable equipment and a control method thereof, and belongs to the technical field of virtual reality interaction. The electric tactile feedback circuit comprises a power module, a control module, a booster circuit, a current limiting circuit, a stimulation waveform generation module and an electrode array. The boost circuit is connected with the power supply module and the control module and is used for boosting the initial voltage input by the power supply module to a predetermined voltage. The current limiting circuit is respectively connected with the booster circuit and the stimulation waveform generation module and is used for limiting the input current input into the stimulation waveform generation module within a specified current threshold value; the stimulation waveform generation module is connected with the control module and the electrode array and used for generating and outputting a composite alternating current stimulation signal to the electrode array so as to generate electric tactile feedback, and the composite alternating current stimulation signal comprises a pair of alternating current stimulation signals with opposite phases. The technical problem that an existing electric tactile feedback scheme has large potential safety hazards is solved.

Description

Technical Field

[0001] The present application relates to the field of virtual reality interaction technology, and in particular to an electric tactile feedback circuit, a smart wearable device and a control method thereof. Background Art

[0002] Virtual reality interaction technology, as a rapidly developing technology field in recent years, has greatly enriched the user experience. In the pursuit of a more realistic and intuitive interactive experience, electrotactile feedback technology, as an important sensory simulation method, has received widespread attention and research.

[0003] In the current electrotactile feedback scheme, the electrical stimulation technology used is usually divided into two modes: constant voltage stimulation and constant current stimulation. However, given the non-constancy of the human body load, the constant voltage stimulation mode is prone to cause user discomfort due to charge accumulation, such as a strong tingling sensation. At the same time, even in the constant current stimulation mode, existing schemes generally use higher voltage levels, such as ±100V alternating voltage signals or directly use up to 300V DC pulse stimulation to meet the needs of tactile perception. Therefore, the existing electrotactile feedback scheme has a large safety hazard.

[0004] The above contents are only used to assist in understanding the technical solution of the present application and do not constitute an admission that the above contents are prior art. Summary of the invention The main purpose of the present application is to provide an electrotactile feedback circuit, a smart wearable device and a control method thereof, aiming to solve the technical problem that existing electrotactile feedback solutions have major safety hazards.

[0005] To achieve the above-mentioned purpose, the present application proposes an electrotactile feedback circuit, which includes a power supply module, a control module, a boost circuit, a current limiting circuit, a stimulation waveform generation module and an electrode array; The boost circuit is connected to the power module and the control module respectively, and is used to boost the initial voltage input by the power module to a predetermined voltage; The current limiting circuit is connected to the boost circuit and the stimulation waveform generating module respectively, and is used to limit the input current of the stimulation waveform generating module to within a specified current threshold; The stimulation waveform generation module is connected to the control module and the electrode array respectively, and is used to generate and output a composite AC stimulation signal to the electrode array to generate electrotactile feedback, wherein the composite AC stimulation signal includes a pair of anti-phase AC stimulation signals.

[0006] In one embodiment, the boost circuit includes a boost transistor, a boost inductor, a boost diode and a boost capacitor; One end of the boost inductor is connected to the positive electrode of the power module, and the other end of the boost inductor is connected to the drain of the boost transistor and the input end of the boost diode respectively; The input end of the boost diode is connected to the current limiting circuit and one end of the boost capacitor respectively; The other end of the boost capacitor is connected to the negative pole of the power module; The gate of the boost transistor is connected to the control module, and the source of the boost transistor is grounded, so as to control the boost transistor to be turned on or off in response to a control signal of the control module.

[0007] In one embodiment, the current limiting circuit is composed of two current limiting sub-circuits, the stimulation waveform generation module is composed of two stimulation waveform generation units, and the electrode array is composed of two groups of electrode pairs; One end of the current limiting subcircuit is connected to the boost circuit, the other end of the current limiting subcircuit is connected to one end of the stimulation waveform generating unit, and the other end of the stimulation waveform generating unit is connected to the electrode pair; The control module is connected to the two stimulation waveform generating units respectively, and is used to control the two stimulation waveform generating units to generate AC stimulation signals respectively, wherein the AC stimulation signals generated by the two stimulation waveform generating units have opposite phases to form a composite AC stimulation signal.

[0008] In one embodiment, the current limiting subcircuit includes a precision voltage regulator, a current limiting transistor, a first current limiting resistor, and a second current limiting resistor; The collector of the current limiting transistor and one end of the first current limiting resistor are commonly connected to the boost circuit; The base of the current limiting transistor is respectively connected to the other end of the first current limiting resistor and the output end of the precision voltage stabilizing source; The emitter of the current limiting transistor is respectively connected to one end of the second current limiting power supply and the reference end of the precision voltage stabilizing source; The input end of the precision voltage-stabilizing source and the other end of the second current-limiting resistor are commonly connected to the stimulation waveform generating module.

[0009] In one embodiment, the current limiting sub-circuit further includes a single-pole multi-throw switch, and the second current limiting resistor includes at least two current limiting sub-resistors; The moving contact of the single-pole multi-throw switch is respectively connected to the emitter of the current limiting transistor and the reference end of the precision voltage regulator; Each static contact of the single-pole multi-throw switch is connected to a current limiting resistor respectively.

[0010] In one embodiment, the stimulation waveform generation unit includes a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, and a sixth transistor; The collector of the first transistor is connected to the current limiting subcircuit and the collector of the second transistor respectively; The base of the first transistor is connected to one end of the first resistor, and the emitter of the first transistor is connected to the anode of the electrode pair and the collector of the third transistor respectively; The other end of the first resistor is connected to the collector of the fifth transistor, the base of the fifth transistor is connected to the control module, and the emitter of the fifth transistor is grounded; The base of the second transistor is connected to one end of the second resistor, and the emitter of the second transistor is connected to the cathode of the electrode pair and the collector of the fourth transistor respectively; The other end of the second resistor is connected to the collector of the sixth transistor, the base of the sixth transistor is connected to the control module, and the emitter of the sixth transistor is grounded; The base of the third transistor is connected to one end of the third resistor, and the other end of the third resistor is connected to the control module; The base of the fourth transistor is connected to one end of the fourth resistor, and the other end of the fourth resistor is connected to the control module; An emitter of the third transistor and an emitter of the fourth transistor are commonly grounded.

[0011] In one embodiment, the stimulation waveform generation unit further includes a fifth resistor and a sixth resistor; One end of the fifth resistor is connected to the current limiting subcircuit and the collector of the first transistor respectively, and the other end of the fifth resistor is connected to the base of the first transistor and one end of the first resistor respectively; One end of the sixth resistor is connected to the current limiting subcircuit and the collector of the second transistor respectively, and the other end of the sixth resistor is connected to the base of the second transistor and one end of the second resistor respectively.

[0012] In one embodiment, the stimulation waveform generation unit further includes a seventh resistor and an eighth resistor; One end of the seventh resistor is connected to the other end of the first resistor and the collector of the fifth transistor respectively, and the other end of the seventh resistor is connected to the emitter and the anode of the first transistor respectively; One end of the eighth resistor is connected to the other end of the second resistor and the collector of the sixth transistor respectively, and the other end of the eighth resistor is connected to the emitter and cathode of the second transistor respectively.

[0013] In one embodiment, the electrotactile feedback circuit further includes a voltage sampling circuit and a current sampling circuit; The voltage sampling circuit is connected in parallel with the current limiting circuit, and the voltage sampling circuit is connected to the control module to transmit the collected circuit voltage to the control module; The stimulation waveform generation module is connected in series with the sampling resistor and then grounded. The current sampling circuit is connected to the control module to transmit the collected circuit current to the control module.

[0014] In addition, to achieve the above objectives, the present application also proposes a smart wearable device, which includes the above-mentioned electrotactile feedback circuit.

[0015] In one embodiment, the electrode array in the electrotactile feedback circuit of the smart wearable device is composed of two groups of electrode pairs, and the electrode pairs include circular or rectangular paired electrodes.

[0016] In addition, to achieve the above purpose, the present application also proposes a control method applied to the above smart wearable device, including: Controlling the smart wearable device to output a predetermined reference stimulation signal from the electrode array, and receiving an adjusted tactile pattern fed back in response to the predetermined reference stimulation signal; According to the current amplitude and waveform parameters corresponding to the adjusted tactile mode, the smart wearable device is controlled to output a composite AC stimulation signal from the electrode array.

[0017] In one embodiment, the control method further includes: Monitoring the electric tactile feedback circuit to obtain the circuit voltage and circuit current of the electric tactile feedback current; When the circuit voltage exceeds a predetermined safety voltage, or the circuit current exceeds a predetermined safety current, the electric tactile feedback circuit is controlled to be disconnected.

[0018] In one embodiment, after the step of monitoring the electric tactile feedback circuit to obtain the circuit voltage and circuit current of the electric tactile feedback current, the method includes: The current skin impedance is calculated based on the circuit voltage and the circuit current; According to the current skin impedance, the waveform of the AC stimulation signal in the composite AC stimulation signal is adjusted.

[0019] One or more technical solutions proposed in this application have at least the following technical effects: The present application proposes an electrotactile feedback circuit. The electrotactile feedback circuit includes a power module, a control module, a boost circuit, a current limiting circuit, a stimulation waveform generation module and an electrode array; the boost circuit is respectively connected to the power module and the control module, and is used to boost the initial voltage input by the power module to a predetermined voltage; the current limiting circuit is respectively connected to the boost circuit and the stimulation waveform generation module, and is used to limit the input current of the stimulation waveform generation module within a specified current threshold; the stimulation waveform generation module is respectively connected to the control module and the electrode array, and is used to generate and output a composite AC stimulation signal to the electrode array to generate electrotactile feedback. Therefore, the present application can limit the voltage and current flowing into the skin from the source through voltage limiting and current limiting processing, thereby reducing safety hazards. On the other hand, a composite AC stimulation signal consisting of a pair of anti-phase AC stimulation signals is generated by the stimulation waveform generation module and transmitted to the electrode array to stimulate the user's skin. By virtue of the superposition effect of this pair of anti-phase AC stimulation signals in space and time, and the characteristic that nerve fibers are more sensitive to changes in current direction, the stimulation efficiency and nerve responsiveness are improved. While ensuring the tactile effect, the maximum voltage required for the circuit can be greatly reduced again, effectively reducing the safety hazards caused by charge accumulation, dielectric breakdown and other phenomena in existing electrotactile feedback schemes. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0022] Figure 1 This is a circuit structure diagram of the first embodiment of the electric tactile feedback circuit of the present application; Figure 2 A waveform diagram of an AC stimulation signal according to an embodiment of the present application; Figure 3 This is a schematic diagram of the equivalent impedance of human skin during electrical stimulation; Figure 4 A schematic diagram of a waveform of a composite AC stimulation signal involved in an embodiment of the present application; Figure 5 A circuit structure diagram of a boost circuit according to an embodiment of the present application; Figure 6 This is a circuit structure diagram of a second embodiment of the electric tactile feedback circuit of the present application; Figure 7A circuit structure diagram of an embodiment of a current limiting subcircuit according to an embodiment of the present application; Figure 8 A circuit structure diagram of another embodiment of a current limiting subcircuit involved in an embodiment of the present application; Fig. 9 A circuit structure diagram of a stimulation waveform generating unit according to an embodiment of the present application; Fig.10 A circuit structure diagram of a third embodiment of the electric tactile feedback circuit of the present application; Fig.11 This is a circuit structure diagram of a fourth embodiment of the electric tactile feedback circuit of the present application; Fig.12 A schematic diagram of the structure of an electrode array involved in an embodiment of the present application; Fig.13 Another schematic diagram of the structure of the electrode array involved in the embodiment of the present application; Fig.14 This is a flow chart of a control method for a smart wearable device of the present application.

[0023] Description of Figure Numbers: 10. Power module; 20. Control module; 30. Boost circuit; Qu, boost transistor; Lu, boost inductor; Du, boost diode; Cu, boost capacitor; 40. current limiting circuit; 41. current limiting sub-circuit; TL, precision voltage source; Qi, current limiting transistor; Ri1, first current limiting resistor; Ri2, second current limiting resistor; Sw, single-pole multi-throw switch; Rcl, current limiting sub-resistor; 50. Stimulation waveform generation module; 51. Stimulation waveform generation unit; Q1. First transistor; Q2. Second transistor; Q3. Third transistor; Q4. Fourth transistor; Q5. Fifth transistor; Q6. Sixth transistor; R1. First resistor; R2. Second resistor; R3. Third resistor; R4. Fourth resistor; R5. Fifth resistor; R6. Sixth resistor; R7. Seventh resistor; R8. Eighth resistor; 60. electrode array; 61. electrode pair; 70. Voltage sampling circuit; 80. Current sampling circuit; Rs, sampling resistor.

[0024] The purpose, features and advantages of this application will be further described in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0026] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0027] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in the field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0028] In order to better understand the technical solution of the present application, a detailed description will be given below in conjunction with the accompanying drawings and specific implementation methods.

[0029] The main solution of the embodiment of the present application is: the electrotactile feedback circuit includes a power module, a control module, a boost circuit, a current limiting circuit, a stimulation waveform generating module and an electrode array; the boost circuit is respectively connected to the power module and the control module, and is used to boost the initial voltage input by the power module to a predetermined voltage; the current limiting circuit is respectively connected to the boost circuit and the stimulation waveform generating module, and is used to limit the input current of the stimulation waveform generating module within a specified current threshold; the stimulation waveform generating module is respectively connected to the control module and the electrode array, and is used to generate and output a composite AC stimulation signal to the electrode array to generate electrotactile feedback, wherein the composite AC stimulation signal includes a pair of anti-phase AC stimulation signals.

[0030] In the current electrotactile feedback scheme, the electrical stimulation technology used is usually divided into two modes: constant voltage stimulation and constant current stimulation. However, given the non-constancy of the human body load, the constant voltage stimulation mode is prone to cause user discomfort due to charge accumulation, such as a strong tingling sensation. At the same time, even in the constant current stimulation mode, due to the different skin conditions of different people, some people do need a very high voltage to produce a sense of touch. In order to make the stimulation universal for different groups of people, existing schemes generally use higher voltage levels, such as ±100V alternating voltage signals or directly use up to 300V DC pulse stimulation to meet the needs of tactile perception. Therefore, the existing electrotactile feedback scheme has a large safety hazard.

[0031] The present application provides a solution. On the one hand, the present application can limit the voltage and current flowing into the skin from the source through voltage limiting and current limiting processing, thereby reducing safety hazards. On the other hand, a composite AC stimulation signal consisting of a pair of reversed AC stimulation signals is generated by the stimulation waveform generation module and transmitted to the electrode array to stimulate the user's skin. With the help of the superposition effect of this pair of reversed AC stimulation signals in space and time, and the characteristics of nerve fibers being more sensitive to changes in the direction of current, the efficiency of stimulation and the responsiveness of nerves are improved, thereby ensuring the tactile effect and greatly reducing the maximum voltage required by the circuit again, effectively reducing the safety hazards caused by charge accumulation, dielectric breakdown and other phenomena in the existing electrotactile feedback scheme.

[0032] Based on this, the present application proposes an electric tactile feedback circuit.

[0033] See also Figure 1 In one embodiment of the electric tactile feedback circuit of the present application, the electric tactile feedback circuit includes a power module 10, a control module 20, a boost circuit 30, a current limiting circuit 40, a stimulation waveform generation module 50 and an electrode array 60; The boost circuit 30 is connected to the power module 10 and the control module 20 respectively, and is used to boost the initial voltage input by the power module 10 to a predetermined voltage; The current limiting circuit 40 is connected to the boost circuit 30 and the stimulation waveform generating module 50 respectively, and is used to limit the input current of the stimulation waveform generating module 50 to within a specified current threshold; The stimulation waveform generation module 50 is connected to the control module 20 and the electrode array 60 respectively, and is used to generate and output a composite AC stimulation signal to the electrode array 60 to generate electrotactile feedback, wherein the composite AC stimulation signal includes a pair of anti-phase AC stimulation signals.

[0034] It should be noted that the predetermined voltage is a voltage value within a preset safe voltage range, and illustratively, the preset safe voltage range may be less than 36 V. The specified current threshold is a preset maximum current value flowing into the stimulation waveform generation module 50, such as 3 mA, 5 mA, 10 mA, etc.

[0035] It should also be noted that the composite AC stimulation signal includes a pair of anti-phase AC stimulation signals, wherein each AC stimulation signal is composed of positive and negative pulses connected together without interval, and the phase difference between the two AC stimulation signals is 180°. Figure 2 As shown, Figure 2 The waveform diagram of the AC stimulation signal involved in the embodiment of the present application. The AC stimulation signal can be determined by the six pulse parameters of pre-stimulation delay D, pulse width W, pulse period P, pulse amplitude I, the number of pulses NPB that trigger tactile sensation each time, and tactile sensation generation period T. It can be understood that the present embodiment can generate composite AC stimulation signals with different tactile sensations and targeted adaptation to different groups of people by adjusting these six pulse parameters. It can be understood that the present embodiment can provide several groups of AC stimulation signals corresponding to different pulse parameters for user selection. Of course, the user's set pulse parameters are obtained to generate an AC stimulation signal of the corresponding waveform.

[0036] In this embodiment, the electrotactile feedback circuit includes a power module 10, a control module 20, a boost circuit 30, a current limiting circuit 40, a stimulation waveform generation module 50 and an electrode array 60. The power module 10 is used to supply power to the components in the electrotactile feedback circuit that need to be powered, such as the boost module 30 and the control module 20. The boost circuit 30 is connected to the power module 10 and the control module 20, respectively, and boosts the initial voltage input by the power module 10 to a predetermined voltage indicated by the control module 20. The current limiting circuit 40 is connected to the boost circuit 30 and the stimulation waveform generation module 50, respectively, and limits the input current of the stimulation waveform generation module 50 to a specified current threshold indicated by the control module 20, thereby limiting the voltage and current flowing into the skin from the source through voltage limiting and current limiting processing, thereby reducing safety hazards. The stimulation waveform generation module 50 is connected to the control module 20, and the stimulation waveform generation module 50 is connected to the electrode array 60. Therefore, after receiving the control signal of the control module 20, the stimulation waveform generation module 50 can generate and output the corresponding composite AC stimulation signal to the electrode array 60, so as to electrically stimulate the user's skin through the electrode array 60 to generate tactile feedback, wherein the composite AC stimulation signal includes a pair of anti-phase AC stimulation signals. Figure 3 As shown, Figure 3 This is a schematic diagram of the equivalent impedance of human skin during electrical stimulation. It can be seen that the electrode-skin interface is equivalent to a series resistor R 电极 and capacitor C 电极, while the stratum corneum of the human skin is equivalent to a resistor Rp and a capacitor Cp in parallel, and the deep tissue of the human skin is equivalent to a resistor Rd. Therefore, due to the capacitance effect between the electrode and the human skin and the capacitance effect of the human skin itself, high-frequency AC signals can more easily penetrate the human skin and stimulate the nerves. However, if only a single AC signal is used as a stimulation signal, due to the different skin conditions of different people, in order to make the stimulation universal for different people, it is necessary to ensure that the voltage of this AC signal has a high dynamic range. Generally speaking, the maximum voltage is about 50V. Although the voltage dynamic range has been greatly reduced compared to the existing DC pulses of several hundred volts, this maximum voltage still belongs to the high voltage range, and there are still certain safety hazards. The present embodiment uses a pair of anti-phase AC stimulation signals to form a composite AC stimulation signal for electrotactile feedback, such as Figure 4 As shown, Figure 4 The waveform diagram of the composite AC stimulation signal involved in the embodiment of the present application, the dotted line in the figure is one AC stimulation signal in the composite AC stimulation signal, the solid line is another AC stimulation signal in the composite AC stimulation signal, and the phase difference between the two AC stimulation signals is 180°. It has been confirmed through experiments that this composite AC stimulation signal can significantly reduce the maximum voltage required by the circuit again while ensuring the tactile effect, generally speaking, it can be no more than 36V. Therefore, on the one hand, this embodiment can limit the voltage and current flowing into the skin from the source through voltage limiting and current limiting processing, thereby reducing safety hazards. On the other hand, a composite AC stimulation signal consisting of a pair of reversed AC stimulation signals is generated by the stimulation waveform generation module and transmitted to the electrode array to stimulate the user's skin. With the help of the superposition effect of this pair of reversed AC stimulation signals in space and time, and the characteristics of nerve fibers being more sensitive to changes in the direction of current, the efficiency of stimulation and the responsiveness of nerves are improved, thereby ensuring the tactile effect and greatly reducing the maximum voltage required by the circuit again, effectively reducing the safety hazards caused by charge accumulation, dielectric breakdown and other phenomena in the existing electrotactile feedback scheme.

[0037] like Figure 5 As shown, Figure 5 is a circuit structure diagram of a boost circuit involved in an embodiment of the present application, wherein the boost circuit 30 includes a boost transistor Qu, a boost inductor Lu, a boost diode Du and a boost capacitor Cu; One end of the boost inductor Lu is connected to the positive electrode of the power module 10, and the other end of the boost inductor Lu is connected to the drain of the boost transistor Qu and the input end of the boost diode Du respectively; The input end of the boost diode Du is connected to the current limiting circuit 40 and one end of the boost capacitor Cu respectively; The other end of the boost capacitor Cu is connected to the negative electrode of the power module 10; The gate of the boost transistor Qu is connected to the control module 20 , and the source of the boost transistor Qu is grounded, so as to control the boost transistor Qu to be turned on or off in response to a control signal of the control module 20 .

[0038] It should be noted that the inductance value of the boost inductor Lu and the capacitance value of the boost capacitor Cu are selected according to the predetermined voltage.

[0039] In this embodiment, one end of the boost inductor Lu is connected to the positive electrode of the power module 10, and the other end of the boost inductor Lu is respectively connected to the drain of the boost transistor Qu and the input end of the boost diode Du; the input end of the boost diode Du is respectively connected to the current limiting circuit 40 and one end of the boost capacitor Cu; the other end of the boost capacitor Cu is connected to the negative electrode of the power module 10; the gate of the boost transistor Qu is connected to the control module 20, and the source of the boost transistor Qu is grounded, which is used to control the boost transistor Qu to be turned on or off in response to the control signal of the control module 20. The control module 20 can control the boost transistor Qu to be turned on or off through a PWM signal, so that the boost inductor Lu and the boost capacitor Cu are charged and discharged, thereby controlling the voltage amplitude of the output voltage (i.e., VDD in the figure) of the boost circuit 30. For the electrotactile feedback circuit, controlling the voltage amplitude of VDD is equivalent to indirectly controlling the current amplitude input to the human body, thereby realizing the pulse amplitude I in the waveform parameter of the AC stimulation signal. In addition, the boost circuit 30 does not have the ability to output large current. During operation, the boost circuit 30 first quickly raises the voltage and then maintains it at the peak voltage state. When the stimulation waveform generation module 50 starts to generate a composite AC stimulation signal, the boost inductor Lu and the boost capacitor Cu discharge energy, and the voltage gradually decreases. At this time, the control module 20 disconnects by controlling the boost transistor Qu, and the boost circuit 30 is no longer grounded, and the voltage is raised until the predetermined voltage is reached. If a sudden large current discharge occurs during the output of the composite AC stimulation signal, the energy of the boost inductor Lu and the boost capacitor Cu will be quickly consumed, resulting in a rapid decrease in voltage, exceeding the boost voltage capability of the boost circuit 30. At this time, the boost circuit 30 can only output low voltage and low current. Since the total amount of electricity that can be discharged is determined after the boost inductor Lu and the boost capacitor Cu are selected, the process of raising the voltage is to replenish energy into the boost inductor Lu and the boost capacitor Cu, but the speed of raising the voltage (i.e., the speed of replenishing energy) is controlled by the control module 20 to control the boost transistor Qu to turn on or off. Therefore, in this embodiment, the ability of the boost circuit 30 to discharge discharge, i.e., the ability to output current, can be limited by selecting the boost inductor Lu and the boost capacitor Cu according to a predetermined voltage, so that the large current can only exist for a moment and will not pose a threat to the human body, thereby improving the safety of the entire electric tactile feedback circuit. Since the total amount of electricity that can be output by the electric tactile feedback circuit in this embodiment is limited by the capacity of the boost inductor Lu and the boost capacitor Cu, the total amount of electricity that flows into the skin can be limited from the source, further reducing safety hazards.

[0040] like Figure 6 As shown, the current limiting circuit 40 is composed of two current limiting sub-circuits 41, the stimulation waveform generation module 50 is composed of two stimulation waveform generation units 51, and the electrode array 60 is composed of two groups of electrode pairs 61; One end of the current limiting subcircuit 41 is connected to the boost circuit 30, the other end of the current limiting subcircuit 41 is connected to one end of the stimulation waveform generating unit 51, and the other end of the stimulation waveform generating unit 51 is connected to the electrode pair 61; The control module 20 is connected to the two stimulation waveform generating units 51 respectively, and is used to control the two stimulation waveform generating units 51 to generate AC stimulation signals respectively, wherein the AC stimulation signals generated by the two stimulation waveform generating units 51 have opposite phases to constitute a composite AC stimulation signal.

[0041] In this embodiment, the current limiting circuit 40 is composed of two current limiting sub-circuits 41, the stimulation waveform generation module 50 is composed of two stimulation waveform generation units 51, and the electrode array 60 is composed of two groups of electrode pairs 61. One end of the current limiting sub-circuit 41 is connected to the boost circuit 30, the other end of the current limiting sub-circuit 41 is connected to one end of the stimulation waveform generation unit 51, and the other end of the stimulation waveform generation unit 51 is connected to the electrode pair 61; the control module 20 is respectively connected to the two stimulation waveform generation units 51, and is used to control the two stimulation waveform generation units 51 to generate AC stimulation signals respectively, wherein the AC stimulation signals generated by the two stimulation waveform generation units 51 are opposite in phase, forming a composite AC stimulation signal. Thus, the two current limiting sub-circuits 41 are connected in parallel with the boost circuit 30, and then connected to different stimulation waveform generation units 51 and different electrode pairs 61 respectively. Thus, the independent operation of the two different stimulation waveform generation units 51 is realized through the independent current limiting sub-circuit 41, which improves the independence and stability of the two output AC stimulation signals.

[0042] In addition, it is understandable that the present embodiment can also increase the number of electrodes in the electrode pair 61 through a multiplexer. For example, since the human body can distinguish the existence of a sensing interval between two electrical stimulations (generally at least 25 ms), the electrodes in different electrode pairs 61 can be turned on in time periods within the sensing interval by means of a multiplexer in a time-division control manner, thereby equivalently achieving simultaneous electrical stimulation of multiple electrodes.

[0043] like Figure 7 As shown, Figure 7 4 is a circuit structure diagram of an embodiment of a current limiting sub-circuit according to an embodiment of the present application. The current limiting sub-circuit 41 includes a precision voltage regulator TL, a current limiting transistor Qi, a first current limiting resistor Ri1 and a second current limiting resistor Ri2; The collector of the current limiting transistor Qi and one end of the first current limiting resistor Ri1 are commonly connected to the boost circuit 30; The base of the current limiting transistor Qi is connected to the other end of the first current limiting resistor Ri1 and the output end of the precision voltage stabilizing source TL respectively; The emitter of the current limiting transistor Qi is respectively connected to one end of the second current limiting power supply and the reference end of the precision voltage stabilizing source TL; The input end of the precision voltage regulator TL and the other end of the second current limiting resistor Ri2 are commonly connected to the stimulation waveform generating module 50 .

[0044] In this embodiment, the precision voltage regulator TL is used to provide a stable and controllable power supply. The collector of the current limiting transistor Qi and one end of the first current limiting resistor Ri1 are connected to the boost circuit 30, the base of the current limiting transistor Qi is connected to the other end of the first current limiting resistor Ri1 and the output end of the precision voltage regulator TL, the emitter of the current limiting transistor Qi is connected to one end of the second current limiting power supply and the reference end of the precision voltage regulator TL, and the input end of the precision voltage regulator TL and the other end of the second current limiting resistor Ri2 are connected to the stimulation waveform generation module 50. The current limiting capability of the current limiting sub-circuit 41 is mainly determined by the second current limiting resistor Ri2. The maximum current that can pass through the current limiting sub-circuit 41 (i.e., the specified current threshold) is Iout = V ref / R+I KA , V ref IKA is the reference voltage of the precision voltage regulator TL, and IKA is the reference current flowing through the precision voltage regulator TL. The current limiting subcircuit is directly connected in series to the current input terminal of the stimulation waveform generating unit 51, that is, the power current of the power module 10 must first pass through the current limiting subcircuit 41 before it can flow through the stimulation waveform generating unit 51 and then enter the human skin through the electrode array 60. In this process, the power current will be limited by the current limiting subcircuit 41 before flowing into the human body, and in this embodiment, the current limiting subcircuit 41 is a pure hardware circuit, that is, it is not directly controlled by the control module 20, so even if the control module 20 fails, it will not affect the current limiting ability of the current limiting subcircuit 41, thereby effectively avoiding the safety hazards caused by large currents.

[0045] like Figure 8 As shown, Figure 8 4 is a circuit structure diagram of another embodiment of the current limiting sub-circuit involved in the embodiment of the present application, the current limiting sub-circuit 41 further includes a single-pole multi-throw switch Sw, and the second current limiting resistor Ri2 includes at least two current limiting sub-resistors Rcl; The moving contact of the single-pole multi-throw switch Sw is connected to the emitter of the current limiting transistor Qi and the reference end of the precision voltage regulator source TL respectively; Each static contact of the single-pole multi-throw switch Sw is connected to the current limiting resistor Rcl respectively.

[0046] Since different people have different skin conditions and different sensitivities, in order to facilitate the adjustment of the size of the specified current threshold. In this embodiment, the current limiting sub-circuit 41 also includes a single-pole multi-throw switch Sw, and the second current limiting resistor Ri2 includes at least two current limiting sub-resistors Rcl; the moving contact of the single-pole multi-throw switch Sw is respectively connected to the emitter of the current limiting transistor Qi and the reference end of the precision voltage regulator TL; and each static contact of the single-pole multi-throw switch Sw is respectively connected to the current limiting sub-resistor Rcl. The resistance value of each current limiting sub-resistor Rcl is different. Figure 8 The current limiting sub-resistor Rcl includes a current limiting sub-resistor Rcl1, a current limiting sub-resistor Rcl2 and a current limiting sub-resistor Rcl3. For example, in this embodiment, the single-pole multi-throw switch Sw is controlled, and after the moving contact of the single-pole multi-throw switch Sw contacts the static contact connected to the current limiting sub-resistor Rcl1, the resistance value of the second current limiting resistor Ri2 is the resistance value of the current limiting sub-resistor Rcl1. For example, experiments have found that a current of 3mA will cause a strong tactile sensation for most people. Taking into account the differences between different groups of people, in this embodiment, the specified current threshold can be set to three adjustable gears through the circuit structure of this embodiment, which are 3mA, 5mA, and 10mA. Here, the single-pole multi-throw switch Sw can adopt a manual shift switch or an electric shift switch. Therefore, in this embodiment, the switching of different resistance values ​​of the second current limiting resistor Ri2 can be realized by controlling the single-pole multi-throw switch Sw, thereby changing the current limiting capacity of the current limiting sub-circuit 41.

[0047] like Fig. 9 As shown, the stimulation waveform generating unit 51 includes a first transistor Q1, a second transistor Q2, a third transistor Q3, a fourth transistor Q4, a fifth transistor Q5 and a sixth transistor Q6; The collector of the first transistor Q1 is connected to the current limiting sub-circuit 41 and the collector of the second transistor Q2 respectively; The base of the first transistor Q1 is connected to one end of the first resistor R1, and the emitter of the first transistor Q1 is connected to the anode A in the electrode pair 61 and the collector of the third transistor Q3 respectively; The other end of the first resistor R1 is connected to the collector of the fifth transistor Q5, the base of the fifth transistor Q5 is connected to the control module 20, and the emitter of the fifth transistor Q5 is grounded; The base of the second transistor Q2 is connected to one end of the second resistor R2, and the emitter of the second transistor Q2 is connected to the cathode C in the electrode pair 61 and the collector of the fourth transistor Q4 respectively; The other end of the second resistor R2 is connected to the collector of the sixth transistor Q6, the base of the sixth transistor Q6 is connected to the control module 20, and the emitter of the sixth transistor Q6 is grounded; The base of the third transistor Q3 is connected to one end of the third resistor R3, and the other end of the third resistor R3 is connected to the control module 20; The base of the fourth transistor Q4 is connected to one end of the fourth resistor R4, and the other end of the fourth resistor R4 is connected to the control module 20; The emitter of the third transistor Q3 and the emitter of the fourth transistor Q4 are commonly grounded.

[0048] It should be noted that the first transistor Q1 and the second transistor Q2 are PNP (P-type, N-type, P-type, consisting of a P-type semiconductor region sandwiched between two N-type semiconductor regions) transistors, and the third transistor Q3, the fourth transistor Q4, the fifth transistor Q5 and the sixth transistor Q6 are NPN (N-type, P-type, N-type, consisting of an N-type semiconductor region sandwiched between two P-type semiconductor regions) transistors.

[0049] The stimulation waveform generating unit 51 includes an H-bridge circuit, wherein one stimulation waveform generating unit 51 generates a reference AC stimulation signal through the H-bridge circuit, and the other stimulation waveform generating unit 51 simultaneously generates an AC stimulation signal with the same waveform but a phase difference of 180° through the H-bridge circuit. As mentioned above, among the six waveform parameters of the AC stimulation signal, the five waveform parameters of the delay D before stimulation, the pulse width W, the pulse period P, the number of pulses NPB for each tactile triggering, and the tactile generation period T are adjusted by the control module 20 through the PWM (Pulse Width Modulation) signal to control the stimulation waveform generating unit 51.

[0050] In this embodiment, the collector of the first transistor Q1 is connected to the current limiting subcircuit 41 and the collector of the second transistor Q2 respectively; the base of the first transistor Q1 is connected to one end of the first resistor R1, and the emitter of the first transistor Q1 is connected to the anode A in the electrode pair 61 and the collector of the third transistor Q3 respectively; the other end of the first resistor R1 is connected to the collector of the fifth transistor Q5, the base of the fifth transistor Q5 is connected to the control module 20, and the emitter of the fifth transistor Q5 is grounded. Thus, the control module 20 controls the conduction and disconnection of the fifth transistor Q5 through the PWM signal, so as to realize the grounding or non-grounding of the base of the first transistor Q1, so as to control the conduction and disconnection of the first transistor Q1. The base of the second transistor Q2 is connected to one end of the second resistor R2, and the emitter of the second transistor Q2 is connected to the cathode C in the electrode pair 61 and the collector of the fourth transistor Q4 respectively; the other end of the second resistor R2 is connected to the collector of the sixth transistor Q6, the base of the sixth transistor Q6 is connected to the control module 20, and the emitter of the sixth transistor Q6 is grounded. Therefore, the control module 20 also controls the on and off of the sixth transistor Q6 through the PWM signal, so as to realize the grounding or disconnection of the base of the second transistor Q2, so as to control the on and off of the second transistor Q2.

[0051] The base of the third transistor Q3 is connected to one end of the third resistor R3, and the other end of the third resistor R3 is connected to the control module 20; the base of the fourth transistor Q4 is connected to one end of the fourth resistor R4, and the other end of the fourth resistor R4 is connected to the control module 20; the emitter of the third transistor Q3 and the emitter of the fourth transistor Q4 are grounded together.

[0052] Therefore, this embodiment achieves the reversal of the voltage direction by controlling the on and off of the first transistor Q1 , the second transistor Q2 , the third transistor Q3 , and the fourth transistor Q4 .

[0053] In some embodiments, the stimulation waveform generation unit 51 further includes a fifth resistor R5 and a sixth resistor R6; One end of the fifth resistor R5 is connected to the current limiting sub-circuit 41 and the collector of the first transistor Q1 respectively, and the other end of the fifth resistor R5 is connected to the base of the first transistor Q1 and one end of the first resistor R1 respectively; One end of the sixth resistor R6 is connected to the current limiting sub-circuit 41 and the collector of the second transistor Q2 , and the other end of the sixth resistor R6 is connected to the base of the second transistor Q2 and one end of the second resistor R2 .

[0054] In this embodiment, one end of the fifth resistor R5 is connected to the current limiting subcircuit 41 and the collector of the first transistor Q1, respectively, and the other end of the fifth resistor R5 is connected to the base of the first transistor Q1 and one end of the first resistor R1, respectively; one end of the sixth resistor R6 is connected to the current limiting subcircuit 41 and the collector of the second transistor Q2, respectively, and the other end of the sixth resistor R6 is connected to the base of the second transistor Q2 and one end of the second resistor R2, respectively. Therefore, compared with the conventional H-bridge circuit, this embodiment adds two pull-up resistors, the fifth resistor R5 and the sixth resistor R6, to ensure that the first transistor Q1 and the second transistor Q2 are completely turned off when not in use, which can further improve the circuit safety and circuit stability.

[0055] In some embodiments, the stimulation waveform generation unit 51 further includes a seventh resistor R7 and an eighth resistor R8; One end of the seventh resistor R7 is connected to the other end of the first resistor R1 and the collector of the fifth transistor Q5, and the other end of the seventh resistor R7 is connected to the emitter and the anode A of the first transistor Q1, respectively. One end of the eighth resistor R8 is connected to the other end of the second resistor R2 and the collector of the sixth transistor Q6 respectively, and the other end of the eighth resistor R8 is connected to the emitter and the cathode C of the second transistor Q2 respectively.

[0056] In this embodiment, one end of the seventh resistor R7 is connected to the other end of the first resistor R1 and the collector of the fifth transistor Q5, respectively, and the other end of the seventh resistor R7 is connected to the emitter and anode A of the first transistor Q1, respectively; one end of the eighth resistor R8 is connected to the other end of the second resistor R2 and the collector of the sixth transistor Q6, respectively, and the other end of the eighth resistor R8 is connected to the emitter and cathode C of the second transistor Q2, respectively. Therefore, compared with the conventional H-bridge circuit, this embodiment adds the seventh resistor R7 and the eighth resistor R8 as a discharge path, which can eliminate the residual voltage of the transistor, thereby improving the response speed of the stimulation waveform generation unit 51, reducing the loss, and also improving the circuit stability of the stimulation waveform generation unit 51.

[0057] like Fig.10 As shown, the electric tactile feedback circuit also includes a voltage sampling circuit 70 and a current sampling circuit 80; The voltage sampling circuit 70 is connected in parallel with the current limiting circuit 40 , and the voltage sampling circuit 70 is connected with the control module 20 , and is used to transmit the collected circuit voltage to the control module 20 ; The stimulation waveform generation module 50 is connected in series with the sampling resistor Rs and then grounded. The current sampling circuit 80 is connected in parallel with the sampling resistor Rs. The current sampling circuit 80 is connected to the control module 20 for transmitting the collected circuit current to the control module 20 .

[0058] In this embodiment, the voltage sampling circuit 70 is connected in parallel with the current limiting circuit 40, and the voltage sampling circuit 70 is connected to the control module 20, and is used to transmit the collected circuit voltage to the control module 20; the stimulation waveform generation module 50 is connected in series with the sampling resistor Rs and then grounded, and the current sampling circuit 80 is connected in parallel with the sampling resistor Rs, and the current sampling circuit 80 is connected to the control module 20, and is used to transmit the collected circuit current to the control module 20. In this way, the circuit voltage and circuit current in the input stimulation waveform generation module 50 can be collected to realize the voltage and current monitoring of the electric tactile feedback circuit. Fig.11 , the voltage sampling circuit 70 can be connected in parallel with the current limiting sub-circuit 41, and the voltage sampling circuit 70 is connected to the control module 20 to transmit the collected circuit voltage to the control module 20. The emitter of the third transistor Q3 and the emitter of the fourth transistor Q4 in the two stimulation waveform generating units 51 are connected in series with the sampling resistor Rs and then grounded, the current sampling circuit 80 is connected in parallel with the sampling resistor Rs, and the current sampling circuit 80 is connected to the control module 20 to transmit the collected circuit current to the control module 20. It can be understood that the control module 20 can directly cut off the electrotactile feedback circuit when it detects that the circuit voltage exceeds the predetermined safety voltage, or the circuit current exceeds the predetermined safety current. The control module 20 can also calculate the current skin impedance based on the circuit voltage and the circuit current, and then adjust the waveform of the AC stimulation signal in the composite AC stimulation signal according to the current skin impedance.

[0059] In addition, an embodiment of the present application further provides a smart wearable device, which includes the above-mentioned electric tactile feedback circuit. Exemplarily, the smart wearable device can be a wearable device with tactile feedback, such as a smart bracelet, a smart watch, etc.

[0060] In some embodiments, the electrode array in the electrotactile feedback circuit of the smart wearable device is composed of two groups of electrode pairs, and the electrode pairs include circular or rectangular paired electrodes.

[0061] Since the electrotactile feedback circuit of this embodiment needs to output two anti-phase AC stimulation signals as a composite AC stimulation signal, the electrode array is composed of two groups of electrode pairs, and each group of electrode pairs is used to output an AC stimulation signal. Each group of electrode pairs is composed of paired electrodes, that is, at least one pair of anodes and cathodes. For example, each group of electrode pairs includes an anode and a cathode. Fig.12 and Fig.13 As shown, the circular anodes A and cathodes C in the two sets of electrode pairs can be placed alternately, and the rectangular anodes A and cathodes C in the two sets of electrode pairs can also be placed side by side. It can be understood that the shape and distribution of the anodes A and cathodes C can be adjusted according to specific needs.

[0062] In addition, if Fig.14 As shown, the present application also proposes a control method for a smart wearable device, which is applied to the above smart wearable device, and the control method includes: Step S10, controlling the smart wearable device to output a predetermined reference stimulation signal from the electrode array, and receiving an adjusted tactile pattern fed back in response to the predetermined reference stimulation signal; Step S20, controlling the smart wearable device to output a composite AC stimulation signal from the electrode array according to the current amplitude and waveform parameters corresponding to the adjusted tactile mode.

[0063] It should be noted that the predetermined reference stimulation signal is a stimulation signal that is preset as a reference tactile sensation. Exemplarily, the predetermined reference stimulation signal is a stimulation signal with the weakest current amplitude and a default waveform.

[0064] After the user puts on the smart wearable device, the electrode array on the smart wearable device is in close contact with the user's human skin in parts such as fingers, palms or wrists. After receiving the start command, the smart wearable device is controlled to drive the electric tactile feedback circuit to output a predetermined reference stimulation signal from the electrode array. Then, after the user feels the tactile sensation under the predetermined reference stimulation signal, the tactile amplitude gear can be adjusted so that the smart wearable device adjusts the current amplitude of the output predetermined reference stimulation signal to change the tactile intensity. The user can also adjust the waveform parameters of the predetermined reference stimulation signal so that the smart wearable device adjusts the waveform of the output predetermined reference stimulation signal to change the tactile sensation. Then, the tactile amplitude gear and waveform parameters selected by the user can be used as the adjusted tactile mode for the feedback of the predetermined reference stimulation signal. Then, according to the current amplitude and waveform parameters corresponding to the adjusted tactile mode, the smart wearable device is controlled to output a composite AC stimulation signal from the electrode array.

[0065] This embodiment controls the smart wearable device to output a predetermined reference stimulation signal from the electrode array, and receives the adjusted tactile pattern fed back for the predetermined reference stimulation signal; and then controls the smart wearable device to output a composite AC stimulation signal from the electrode array according to the current amplitude and waveform parameters corresponding to the adjusted tactile pattern. Therefore, the tactile intensity and tactile feeling brought by the composite AC stimulation signal finally output by this embodiment are more in line with the personalized needs of the user.

[0066] In some embodiments, the control method further comprises: Step S30, monitoring the electric tactile feedback circuit to obtain the circuit voltage and circuit current of the electric tactile feedback current; Step S40, when the circuit voltage exceeds a predetermined safety voltage, or the circuit current exceeds a predetermined safety current, the electric tactile feedback circuit is controlled to be disconnected.

[0067] It should be noted that the predetermined safety voltage is a voltage value preset within the safety range for the human body, and the predetermined safety current is a current value preset within the safety range for the human body.

[0068] This embodiment monitors the electric tactile feedback circuit through the voltage sampling circuit and the current sampling circuit in the electric tactile feedback circuit to obtain the circuit voltage and circuit current of the electric tactile feedback current. Then, the circuit voltage and circuit current are judged, and when the circuit voltage exceeds the predetermined safety voltage, or the circuit current exceeds the predetermined safety current, the electric tactile feedback circuit is controlled to be disconnected. This embodiment further improves the safety of the use of the smart wearable device by monitoring the electric tactile feedback circuit in real time and timely cutting off the electric tactile feedback circuit when high voltage and high current are detected.

[0069] In some embodiments, after step S30, the method includes: Step S50, calculating the current skin impedance according to the circuit voltage and the circuit current; Step S60, adjusting the waveform of the AC stimulation signal in the composite AC stimulation signal according to the current skin impedance.

[0070] This embodiment can use the quotient of the circuit voltage and the circuit current as the current skin impedance, and then this embodiment can proportionally scale the waveform of the AC stimulation signal in the composite AC stimulation signal according to the current skin impedance. Exemplarily, this embodiment can proportionally scale the waveform of the AC stimulation signal at the previous moment according to the impedance difference between the current skin impedance and the historical skin impedance at the previous moment. This embodiment can also proportionally scale the waveform of the benchmark AC stimulation signal according to the impedance difference between the current skin impedance and the benchmark skin impedance. Among them, the scaling factor of the proportional scaling is determined according to the impedance difference, and the scaling factor is positively correlated with the impedance difference.

[0071] This embodiment calculates the current skin impedance according to the circuit voltage and the circuit current, and adjusts the waveform of the AC stimulation signal in the composite AC stimulation signal according to the current skin impedance. Therefore, this embodiment adjusts the waveform of the composite AC stimulation signal in real time according to the skin condition, thereby reducing the impact of sweating, fan, air conditioning, etc. on the user's tactile feedback.

[0072] The above are only some embodiments of the present application, and are not intended to limit the patent scope of the present application. All equivalent structural changes made using the contents of the present application specification and drawings under the technical concept of the present application, or direct / indirect application in other related technical fields are included in the patent protection scope of the present application.

Claims

1. An electric tactile feedback circuit, characterized in that: The electrotactile feedback circuit includes a power module, a control module, a boost circuit, a current limiting circuit, a stimulation waveform generation module and an electrode array; The boost circuit is connected to the power module and the control module respectively, and is used to boost the initial voltage input by the power module to a predetermined voltage; The current limiting circuit is connected to the boost circuit and the stimulation waveform generating module respectively, and is used to limit the input current of the stimulation waveform generating module to within a specified current threshold; The stimulation waveform generation module is connected to the control module and the electrode array respectively, and is used to generate and output a composite AC stimulation signal to the electrode array to generate electrotactile feedback, wherein the composite AC stimulation signal includes a pair of anti-phase AC stimulation signals.

2. The electrotactile feedback circuit according to claim 1, wherein: The boost circuit includes a boost transistor, a boost inductor, a boost diode and a boost capacitor; One end of the boost inductor is connected to the positive electrode of the power module, and the other end of the boost inductor is connected to the drain of the boost transistor and the input end of the boost diode respectively; The input end of the boost diode is connected to the current limiting circuit and one end of the boost capacitor respectively; The other end of the boost capacitor is connected to the negative electrode of the power module; The gate of the boost transistor is connected to the control module, and the source of the boost transistor is grounded, so as to control the boost transistor to be turned on or off in response to a control signal of the control module.

3. The electric tactile feedback circuit according to claim 1, characterized in that: The current limiting circuit is composed of two current limiting sub-circuits, the stimulation waveform generation module is composed of two stimulation waveform generation units, and the electrode array is composed of two groups of electrode pairs; One end of the current limiting subcircuit is connected to the boost circuit, the other end of the current limiting subcircuit is connected to one end of the stimulation waveform generating unit, and the other end of the stimulation waveform generating unit is connected to the electrode pair; The control module is connected to two stimulation waveform generating units respectively, and is used to control the two stimulation waveform generating units to generate AC stimulation signals respectively, wherein the AC stimulation signals generated by the two stimulation waveform generating units have opposite phases and constitute the composite AC stimulation signal.

4. The electric tactile feedback circuit according to claim 3, characterized in that: The current limiting subcircuit includes a precision voltage stabilizing source, a current limiting transistor, a first current limiting resistor and a second current limiting resistor; The collector of the current limiting transistor and one end of the first current limiting resistor are commonly connected to the boost circuit; The base of the current limiting transistor is respectively connected to the other end of the first current limiting resistor and the output end of the precision voltage stabilizing source; The emitter of the current limiting transistor is respectively connected to one end of the second current limiting power supply and the reference end of the precision voltage stabilizing source; The input end of the precision voltage-stabilizing source and the other end of the second current-limiting resistor are commonly connected to the stimulation waveform generating module.

5. The electric tactile feedback circuit according to claim 4, characterized in that: The current limiting sub-circuit further includes a single-pole multi-throw switch, and the second current limiting resistor includes at least two current limiting sub-resistors; The moving contact of the single-pole multi-throw switch is respectively connected to the emitter of the current limiting transistor and the reference end of the precision voltage stabilizing source; Each static contact of the single-pole multi-throw switch is connected to the current limiting resistor respectively.

6. The electric tactile feedback circuit according to claim 3, characterized in that: The stimulation waveform generating unit includes a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor and a sixth transistor; The collector of the first transistor is connected to the current limiting subcircuit and the collector of the second transistor respectively; The base of the first transistor is connected to one end of the first resistor, and the emitter of the first transistor is connected to the anode of the electrode pair and the collector of the third transistor respectively; The other end of the first resistor is connected to the collector of the fifth transistor, the base of the fifth transistor is connected to the control module, and the emitter of the fifth transistor is grounded; The base of the second transistor is connected to one end of the second resistor, and the emitter of the second transistor is connected to the cathode of the electrode pair and the collector of the fourth transistor respectively; The other end of the second resistor is connected to the collector of the sixth transistor, the base of the sixth transistor is connected to the control module, and the emitter of the sixth transistor is grounded; The base of the third transistor is connected to one end of a third resistor, and the other end of the third resistor is connected to the control module; The base of the fourth transistor is connected to one end of a fourth resistor, and the other end of the fourth resistor is connected to the control module; An emitter of the third transistor and an emitter of the fourth transistor are commonly grounded.

7. The electric tactile feedback circuit according to claim 6, characterized in that: The stimulation waveform generating unit further includes a fifth resistor and a sixth resistor; One end of the fifth resistor is connected to the current limiting subcircuit and the collector of the first transistor respectively, and the other end of the fifth resistor is connected to the base of the first transistor and one end of the first resistor respectively; One end of the sixth resistor is connected to the current limiting subcircuit and the collector of the second transistor respectively, and the other end of the sixth resistor is connected to the base of the second transistor and one end of the second resistor respectively.

8. The electric tactile feedback circuit according to claim 6, characterized in that: The stimulation waveform generating unit further includes a seventh resistor and an eighth resistor; One end of the seventh resistor is connected to the other end of the first resistor and the collector of the fifth transistor respectively, and the other end of the seventh resistor is connected to the emitter of the first transistor and the anode respectively; One end of the eighth resistor is connected to the other end of the second resistor and the collector of the sixth transistor respectively, and the other end of the eighth resistor is connected to the emitter of the second transistor and the cathode respectively.

9. The electric tactile feedback circuit according to any one of claims 1 to 8, characterized in that: The electrotactile feedback circuit also includes a voltage sampling circuit and a current sampling circuit; The voltage sampling circuit is connected in parallel with the current limiting circuit, and the voltage sampling circuit is connected to the control module, and is used to transmit the collected circuit voltage to the control module; The stimulation waveform generation module is connected in series with the sampling resistor and then grounded, the current sampling circuit is connected in parallel with the sampling resistor, and the current sampling circuit is connected to the control module for transmitting the collected circuit current to the control module.

10. A smart wearable device, characterized in that: The smart wearable device comprises the electrotactile feedback circuit as claimed in any one of claims 1 to 9.

11. The smart wearable device according to claim 10, characterized in that: The electrode array in the electric tactile feedback circuit of the smart wearable device is composed of two groups of electrode pairs, and the electrode pairs include circular or rectangular paired electrodes.

12. A control method for a smart wearable device, characterized in that: Applied to the smart wearable device according to any one of claims 10 to 11, the control method comprises: Controlling the smart wearable device to output a predetermined reference stimulation signal from the electrode array, and receiving an adjusted tactile pattern fed back to the predetermined reference stimulation signal; The intelligent wearable device is controlled to output a composite AC stimulation signal from the electrode array according to the current amplitude and waveform parameters corresponding to the adjusted tactile mode.

13. The control method of the smart wearable device according to claim 12, characterized in that: The control method further comprises: Monitoring the electrotactile feedback circuit to obtain a circuit voltage and a circuit current of the electrotactile feedback current; When the circuit voltage exceeds a predetermined safety voltage, or the circuit current exceeds a predetermined safety current, the electric tactile feedback circuit is controlled to be disconnected.

14. The control method of the smart wearable device according to claim 13, characterized in that: After the step of monitoring the electrotactile feedback circuit to obtain the circuit voltage and circuit current of the electrotactile feedback current, the method further comprises: Calculate the current skin impedance according to the circuit voltage and the circuit current; According to the current skin impedance, the waveform of the AC stimulation signal in the composite AC stimulation signal is adjusted.

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