Multi-channel impedance detection control method and circuit and transcranial electrical stimulation equipment

Abstract

The invention discloses a multi-channel impedance detection control method and circuit and transcranial electrical stimulation equipment, the multi-channel impedance detection control method is applied to the transcranial electrical stimulation equipment, and comprises the following steps: acquiring waveform signals output to each electrode channel by a controller in the transcranial electrical stimulation equipment; conducting and sampling the waveform signals of the plurality of electrode channels in turn to obtain detection current corresponding to each electrode channel; performing operational amplification on the waveform signal corresponding to each electrode channel to obtain a corresponding constant current source output, and performing turn-on sampling on the constant current source outputs of the plurality of electrode channels in turn according to a sequence of turn-on sampling of the waveform signals of the plurality of electrode channels to obtain an output voltage corresponding to each electrode channel; and obtaining the impedance of the electrode of the electrode channel according to the detection current of each electrode channel and the corresponding output voltage.

Description

Technical Field

[0001] The present invention relates to the technical field of medical equipment, and in particular to a multi-channel impedance detection control method, circuit and transcranial electrical stimulation equipment. Background Art

[0002] Transcranial electrical stimulation (tES) is a safe, tolerable, non-invasive brain stimulation technology. This technology uses two or more electrodes placed on the scalp to allow a weak current to flow through the cerebral cortex, changing the excitation state of neurons and thereby changing the function of certain brain areas. It is effective in treating anxiety, major depression, insomnia, and psychological stress.

[0003] In the prior art, impedance detection is one of the indispensable parts of various transcranial electrical stimulation systems. The greater the impedance, the smaller the actual stimulation power of the human body, and the less obvious the stimulation effect. Only when the impedance between the two electrodes is within a reasonable range can the best treatment effect be achieved. However, the existing transcranial electrical stimulation therapeutic device only supports impedance detection of a single electrode channel. When multiple electrode channels are used, the detection error is large, and it cannot well and in real time reflect the impedance value of each channel electrode during multi-electrode channel treatment. Summary of the invention

[0004] The present invention provides a multi-channel impedance detection control method, circuit and transcranial electrical stimulation device, aiming to solve the problem that the impedance detection error is large when there are multiple electrode channels in the current transcranial electrical stimulation device and the impedance value of each channel electrode during multi-electrode channel treatment cannot be reflected in real time.

[0005] According to one aspect of the present invention, a multi-channel impedance detection control method is provided, which is applied to a transcranial electrical stimulation device, and the multi-channel impedance detection control method comprises:

[0006] Obtaining waveform signals output by a controller in a transcranial electrical stimulation device to each electrode channel;

[0007] The waveform signals of the multiple electrode channels are sampled in turn to obtain the detection current corresponding to each electrode channel;

[0008] Performing operational amplification on the waveform signal corresponding to each electrode channel to obtain the corresponding constant current source output, and conducting and sampling the constant current source outputs of the multiple electrode channels in turn according to the order in which the waveform signals of the multiple electrode channels are conducted, so as to obtain the output voltage corresponding to each electrode channel;

[0009] The impedance of the electrode of each electrode channel is obtained according to the detection current and the corresponding output voltage of the electrode channel.

[0010] A further technical solution is: in the acquisition of the waveform signal outputted by the controller to each electrode channel of the transcranial electrical stimulation device, the method further comprises:

[0011] According to the intensity signal output by the controller in the transcranial electrical stimulation device to multiple electrode channels in real time, the intensity of the waveform signal of the corresponding electrode channel is adjusted to obtain the amplitude-modulated waveform signal.

[0012] A further technical solution is: after obtaining the output voltage corresponding to each electrode channel, it also includes:

[0013] Determining whether the output voltage is less than a preset voltage threshold;

[0014] When the output voltage is less than a preset voltage threshold, the output voltage is amplified to obtain an amplified output voltage.

[0015] According to another aspect of the present invention, a multi-channel impedance detection control circuit is provided, which is applied to a transcranial electrical stimulation device. The multi-channel impedance detection control circuit comprises:

[0016] A fundamental wave receiving unit, connected to the controller of the transcranial electrical stimulation device, and used to receive waveform signals from multiple electrode channels of the controller;

[0017] A first detection unit, comprising a first channel switching sampling circuit, connected to the output end of the fundamental wave receiving unit, and used for conducting and sampling the waveform signals of the plurality of electrode channels in turn to obtain a detection current corresponding to each electrode channel;

[0018] The second detection unit includes a plurality of operational amplifier constant current output circuits and a second channel switching sampling circuit, wherein the input ends of the plurality of operational amplifier constant current output circuits are connected to the output end of the fundamental wave receiving unit, and the output ends thereof are connected to the second channel switching sampling circuit, so that the second channel switching sampling circuit realizes the sampling of the output voltage signals of the plurality of operational amplifier constant current output circuits in turn, thereby collecting the output voltage of the electrode corresponding to each electrode channel of the transcranial electrical stimulation device in each operational amplifier constant current output circuit;

[0019] The output detection unit is connected to the first detection unit and the second detection unit, and is used to obtain the impedance of the electrode of each electrode channel according to the detection current corresponding to each electrode channel and the output voltage.

[0020] Its further technical solution is: the first detection unit also includes an intensity adjustment circuit connected to the controller of the transcranial electrical stimulation device, and the intensity adjustment circuit is also connected between the fundamental wave receiving unit and the first channel switching sampling circuit, including a single-pole multi-throw analog switch, a multi-channel digital potentiometer and a plurality of voltage followers, wherein the single-pole multi-throw analog switch is connected between the output end of the fundamental wave receiving unit and the input end of the multi-channel digital potentiometer, and is used to realize the sampling of waveform signals of multiple electrode channels in turn; the control end of the multi-channel digital potentiometer is also connected to the controller, and is used to receive multiple waveform signals that are turned on in turn and the intensity signals of multiple electrode channels from the controller, and respectively adjust the intensity of the corresponding waveform signals according to the multiple intensity signals to obtain multiple amplitude-modulated waveform signals; the input ends of the multiple voltage followers are respectively connected to the multiple output ends of the multi-channel digital potentiometer, and their output ends are connected to the first channel switching sampling circuit.

[0021] Its further technical solution is: the first detection unit also includes a current loop control circuit, the input end of the current loop control circuit is connected to the output end of the first channel switching sampling circuit, and the output end is connected to the multi-channel digital potentiometer in the intensity adjustment circuit, which is used to adjust the output of the corresponding electrode channel in the intensity adjustment circuit according to the detection current corresponding to each electrode channel.

[0022] A further technical solution is: the second channel switching sampling circuit includes a second multiplexer and a second output operational amplifier, wherein:

[0023] The input end of each operational amplifier constant current output circuit is connected to the output end of one of the voltage followers, and the output end of the operational amplifier constant current output circuit is connected to an input end of the second multiplexer through a resistor voltage divider circuit;

[0024] The inverting input terminal of the second output operational amplifier is connected to the output terminal of the second multiplexer, the non-inverting input terminal thereof is grounded, and the output terminal thereof is connected to the output detection unit.

[0025] Its further technical solution is: the second channel switching sampling circuit also includes a comparator, a second single-pole double-throw analog switch and a third output operational amplifier; wherein,

[0026] The input end of the comparator is connected to the output end of the second output operational amplifier, and is used to determine whether the output voltage is less than a preset voltage threshold;

[0027] The second single-pole double-throw analog switch is connected to the output end of the comparator and the output end of the second output operational amplifier, and the output end of the second single-pole double-throw analog switch is connected to the third output operational amplifier, and is used to be turned on when the output voltage is less than a preset voltage threshold;

[0028] The non-inverting input terminal of the third output operational amplifier is connected to the output terminal of the second single-pole double-throw analog switch, the inverting input terminal thereof is connected to the 60th resistor and one end of the 57th resistor, the output terminal thereof is connected to the other end of the 57th resistor and the output detection unit, and the other end of the 60th resistor is grounded.

[0029] A further technical solution is as follows: the first channel switching sampling circuit includes a first multiplexer and a first output operational amplifier; wherein,

[0030] The input end of the first multiplexer is connected to the output end of the fundamental wave receiving unit, and is used to conduct sampling of the waveform signals of multiple electrode channels in turn;

[0031] The inverting input terminal of the first output operational amplifier is connected to the output terminal of the first multiplexer, the non-inverting input terminal thereof is grounded, and the output terminal of the first output operational amplifier is connected to the output detection unit via a sampling resistor.

[0032] According to another aspect of the present invention, a transcranial electrical stimulation device is also provided, comprising an electrode cap, a controller and the above-mentioned multi-channel impedance detection control circuit, wherein the controller is connected to the electrode channels on the electrode cap and the multi-channel impedance detection control circuit.

[0033] Compared with the prior art, the present invention obtains the waveform signal output by the controller in the transcranial electrical stimulation device to each electrode channel, and performs turn-on sampling on the waveform signals of multiple electrode channels in turn to obtain the detection current corresponding to each electrode channel, and performs operational amplification on the waveform signal corresponding to each electrode channel to obtain the corresponding constant current source output, and performs turn-on sampling on the constant current source outputs of multiple electrode channels in turn according to the order of the waveform signal conduction sampling of the multiple electrode channels to obtain the output voltage corresponding to each electrode channel, and finally obtains the impedance of the electrode of the electrode channel according to the detection current and the corresponding output voltage of each electrode channel. The present invention can perform turn-on sampling on the waveform signals of multiple electrode channels in turn to obtain the detection current, and can also perform turn-on sampling on the constant current source output of the corresponding electrode channel after operational amplification to obtain the corresponding output voltage. According to the detection current obtained by the multiple turn-on sampling and the output voltage of the corresponding electrode channel, the impedance detection of multiple channels can be quickly realized, which is suitable for transcranial electrical stimulation devices with multiple electrode channels, and can support real-time impedance detection of multiple channels, solving the problem that the current detection method only supports the detection of a single channel and does not have real-time performance when detecting multiple channels. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0035] Figure 1 It is a flowchart of a multi-channel impedance detection control method provided by an embodiment of the present invention;

[0036] Figure 2 is a sampling timing diagram when the multi-channel impedance detection control method provided by an embodiment of the present invention is applied;

[0037] Figure 3 It is a schematic diagram of a structural block diagram of a multi-channel impedance detection control circuit provided by an embodiment of the present invention;

[0038] Figure 4 yes Figure 3 A circuit diagram of a fundamental wave receiving unit in the multi-channel impedance detection control circuit shown;

[0039] Figure 5 yes Figure 3 A circuit diagram of an intensity adjustment circuit in a first detection unit of the multi-channel impedance detection control circuit shown;

[0040] Figure 6 yes Figure 3 A circuit diagram of a first channel switching sampling circuit in a first detection unit of a multi-channel impedance detection control circuit;

[0041] Figure 7 yes Figure 3 A circuit diagram of an operational amplifier constant current output circuit in a second detection unit of the multi-channel impedance detection control circuit shown;

[0042] Figure 8 yes Figure 3 A partial circuit diagram of a second channel switching circuit in a second detection unit of the multi-channel impedance detection control circuit shown;

[0043] Fig. 9 yes Figure 3 Another partial circuit diagram of the second channel switching circuit in the second detection unit of the multi-channel impedance detection control circuit is shown. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, operations, elements, components and / or groups thereof.

[0046] It should also be understood that the terms used in this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification of the present invention and the appended claims, the singular forms of "a", "an" and "the" are intended to include the plural forms unless the context clearly indicates otherwise. It should also be further understood that the term "and / or" used in the specification of the present invention and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.

[0047] Reference Figure 1 , Figure 1 The figure is a method flow diagram of a specific embodiment of the multi-channel impedance detection control method of the present invention. The multi-channel impedance detection control method of the present invention is applied to a transcranial electrical stimulation device to realize real-time impedance detection of multiple electrode channels in the transcranial electrical stimulation device. In the embodiment shown in the figure, the multi-channel impedance detection control method includes the following steps:

[0048] S101, obtaining a waveform signal output by a controller in a transcranial electrical stimulation device to each electrode channel.

[0049] In this step, waveform signals of various electrode channels in the transcranial electrical stimulation device are obtained, and the waveform signals are various types of modulated waveforms output by the controller in the transcranial electrical stimulation device.

[0050] S102 , sampling the waveform signals of the plurality of electrode channels in turn to obtain a detection current corresponding to each electrode channel.

[0051] In this step, the waveform signals of multiple electrode channels are sampled in turn to obtain the real-time detection current corresponding to the multiple electrode channels. Figure 2As shown, when the present invention takes turns to conduct sampling, the sampling of the kth electrode channel and the k-1th electrode channel may exist in a protection zone D to prevent the interference signal caused by switching between the electrode channels from affecting the sampling accuracy, wherein k is greater than 1, and the continuous sampling time of each channel is S. Specifically, as shown in the embodiment, four electrode channels are included, CH1, CH2, CH3, and CH4 respectively represent the sampling intervals of the four electrode channels, and W is the sampling interval for one sampling of the transcranial electrical stimulation device.

[0052] Furthermore, there may be a protection zone D at the beginning and end of the sampling interval W to avoid the impact interference introduced by the rising edge of the waveform and the low-level interference of the falling edge.

[0053] Then, the switching time of each electrode channel is: The starting sampling time of each electrode channel is: t k =D+(k-1)S; where

[0054] S103, performing operational amplification on the waveform signal corresponding to each electrode channel to obtain the corresponding constant current source output, and performing turn-on sampling on the constant current source outputs of multiple electrode channels in turn according to the order in which the waveform signals of multiple electrode channels are turned on and sampled, so as to obtain the output voltage corresponding to each electrode channel.

[0055] In this step, the same electrode channel is turned on at the same time when current and voltage are sampled, and current and voltage sampling of the same electrode channel is performed in turn.

[0056] S104, determining whether the output voltage is less than a preset voltage threshold, and amplifying the output voltage when the output voltage is less than the preset voltage threshold to obtain an amplified output voltage.

[0057] In this step, the preset voltage threshold can be 0.3V, and it is determined whether the output voltage is less than 0.3V. When it is less than 0.3V, the output voltage is amplified, and then impedance detection is performed based on the amplification factor, the amplified output voltage and the detection current, so that impedance detection can also be achieved when a small current is output in the transcranial electrical stimulation device. Amplifying the small voltage can also improve the detection accuracy of the small voltage.

[0058] S105 , obtaining the impedance of the electrode of each electrode channel according to the detection current and the corresponding output voltage of the electrode channel.

[0059] S106. According to the intensity signal output by the controller in the transcranial electrical stimulation device to multiple electrode channels in real time, the intensity of the waveform signal of the corresponding electrode channel is adjusted to obtain the amplitude-modulated waveform signal, and then steps S102-S105 are executed.

[0060] In the present invention, the voltage intensity change output to the electrode channel in the transcranial electrical stimulation device can be sensed in real time during detection, and the intensity of the waveform signal of the corresponding electrode channel can be adjusted according to the changed intensity signal, that is, the waveform signal is amplitude modulated to obtain the amplitude modulated waveform signal, so that the amplitude modulated waveform signal is sampled in turn to obtain the real-time detection current, and the amplitude modulated waveform signal is operationally amplified to obtain the corresponding constant current source output, and the constant current source output of the corresponding electrode channel can be turned on in turn to obtain the corresponding output voltage. According to the detection current obtained by multiple rotational conduction samples and the output voltage of the corresponding electrode channel, multi-channel real-time impedance detection can be quickly realized.

[0061] Reference Figures 3 to 9 , Figures 3 to 9A specific embodiment of the multi-channel impedance detection control circuit of the present invention is shown. The multi-channel impedance detection control circuit can be applied to transcranial electrical stimulation devices and other devices to realize real-time impedance detection of multiple electrode channels in the transcranial electrical stimulation device. In the embodiment shown in the accompanying drawings, the multi-channel impedance detection control circuit includes a fundamental wave receiving unit 10, a first detection unit 20, a second detection unit 30 and an output detection unit 40, wherein the fundamental wave receiving unit 10 is connected to the controller of the transcranial electrical stimulation device, and is used to receive waveform signals of multiple electrode channels from the controller; the first detection unit 20 includes an intensity adjustment circuit 21 and a first channel switching sampling circuit 22, the intensity adjustment circuit 21 is connected to the controller of the transcranial electrical stimulation device, and is connected between the fundamental wave receiving unit 10 and the first channel switching sampling circuit 22, and is used to conduct sampling of waveform signals of multiple electrode channels in turn, and adjust the intensity of the corresponding waveform signals according to multiple intensity signals from the controller to obtain multiple amplitude-modulated waveform signals, and the first channel switching sampling circuit 22 is used to realize multiple amplitude-modulated waveform signals. The waveform signal after the turn-on sampling is carried out to obtain the detection current I0 corresponding to each electrode channel; the second detection unit 30 includes a plurality of operational amplifier constant current output circuits 31 and a second channel switching sampling circuit 32, the input ends of the plurality of operational amplifier constant current output circuits 31 are connected to the output end of the intensity adjustment circuit 21, and the output ends thereof are connected to the second channel switching sampling circuit 32, so that the second channel switching sampling circuit 32 realizes the turn-on sampling of the output voltage signals of the plurality of operational amplifier constant current output circuits 31, thereby collecting the output voltage of the electrode corresponding to each electrode channel of the transcranial electrical stimulation device in each operational amplifier constant current output circuit 31; the output detection unit 40 is connected to the first detection unit 20 and the second detection unit 30, and is used to obtain the impedance of the electrode of the electrode channel according to the detection current I0 corresponding to each electrode channel and the output voltage Vout / 0d1V0. In this embodiment, the number of electrode channels is four, and the corresponding operational amplifier constant current output circuit 31 can be set to four. It can be understood that in some other embodiments, the number of the above circuits can also be adjusted according to the number of electrode channels.

[0062] In this embodiment, Figure 4As shown, the fundamental wave receiving unit 10 includes a first single-pole double-throw analog switch U5, which is connected between the controller of the transcranial electrical stimulation device and the first detection unit 20, and is used to be turned on when waveform signals of multiple electrode channels from the controller are received. Preferably, in this embodiment, the model of the first single-pole double-throw analog switch U5 can be TS12A12511DCNR. Based on the above design, the waveform signals of each electrode channel in the transcranial electrical stimulation device can be received, and the waveform signals are various types of modulated waveforms output by the controller in the transcranial electrical stimulation device.

[0063] In some embodiments, Figure 5 As shown, the intensity adjustment circuit 21 includes a single-pole multi-throw analog switch U3, a multi-channel digital potentiometer U20 and four voltage followers (U2A, U2B, U2C, U2D). In this embodiment, the multi-channel digital potentiometer U20 is a four-channel digital potentiometer U20, and the model may be AD5263BRUZ20. Then the single-pole multi-throw analog switch U3 may correspond to a single-pole four-throw analog switch, and the model may be DG201BDY-T1-E3. Among them, the single-pole multi-throw analog switch U3 is connected between the output end of the first single-pole double-throw analog switch U5 and the input end of the multi-channel digital potentiometer U20, and is used to realize the alternating conduction sampling of the waveform signals of the four electrode channels; the control end of the multi-channel digital potentiometer U20 is also connected to the controller, and is used to receive multiple waveform signals that are turned on in turn and the intensity signals of the multiple electrode channels from the controller, and respectively adjust the intensity of the corresponding waveform signals according to the multiple intensity signals to obtain multiple amplitude-modulated waveform signals; the input ends of the four voltage followers (U2A, U2B, U2C, U2D) are respectively connected to the four output ends of the multi-channel digital potentiometer U20, and their output ends are connected to the first channel switching sampling circuit 22, which is used to obtain four independent amplitude-modulated waveform signals, and are also connected to four operational amplifier constant current output circuits 31.

[0064] Specifically, Figure 6As shown, the first channel switching sampling circuit 22 includes a first multiplexer U7 and a first output operational amplifier 222; wherein the input end of the first multiplexer U7 is connected to the output ends of the four voltage followers (U2A, U2B, U2C, U2D), and is used to conduct sampling of the waveform signals of the four electrode channels in turn; the inverting input end of the first output operational amplifier 222 is connected to the output end of the first multiplexer U7, and its inverting input end is grounded, and the output end of the first output operational amplifier 222 is connected to the output detection unit 40 through a sampling resistor RT to transmit the detection current I0 to the output detection unit 40 for calculation. Preferably, in this embodiment, the model of the first multiplexer U7 can be MAX4518ESD+; it can be understood that the sampling time and sampling switching time of each electrode channel when the first detection unit 20 conducts sampling in turn refer to the corresponding description in the above-mentioned multi-channel impedance detection control method, and will not be repeated here.

[0065] Furthermore, the first detection unit 20 also includes a current loop control circuit 23, the input end of the current loop control circuit 23 is connected to the output end of the first channel switching sampling circuit 22, and the output end is connected to the multi-channel digital potentiometer U20 in the intensity adjustment circuit 21, which is used to adjust the output of the corresponding electrode channel in the intensity adjustment circuit 21 according to the detection current I0 corresponding to each electrode channel. Based on the above design, the current loop control circuit 23 can use a control unit (such as MCU, etc.) in combination with software to perform closed-loop regulation on the output current; understandably, the output detection unit 40 can also be implemented by the control unit to complete the impedance calculation.

[0066] Preferably, if Figure 7 As shown, Figure 7 The specific circuit structure diagram of one operational amplifier constant current output circuit 31 is shown in FIG. The input ends of the four operational amplifier constant current output circuits 31 are respectively connected to the output ends of the four voltage followers (U2A, U2B, U2C, U2D). In the embodiment shown in the accompanying drawings, the operational amplifier constant current output circuit 31 is a dual operational amplifier constant current output circuit, including a first operational amplifier U22 and a second operational amplifier U21, and a current setting resistor Rseti1 is connected between the output end of the first operational amplifier U22 and the in-phase input end of the second operational amplifier U21. In this embodiment, the resistance value of the current setting resistor Rseti1 can be 1kΩ, and the ratio of the voltage amplitude of the waveform signal after amplitude modulation to the current setting resistor Rseti1 of 1kΩ is the output current at this time. The operational amplifier constant current output circuit 31 is also connected to a resistor voltage divider circuit 311 to obtain the output voltage (0d1Vout1, 0d1Vout2, 0d1Vout3, 0d1Vout4) of the electrode channel.

[0067] Specifically, Figure 8 and Fig. 9 As shown, the second channel switching sampling circuit 32 includes a second multiplexer U23 and a second output operational amplifier 322, and the model of the second multiplexer U23 is also MAX4518ESD+, wherein the four input terminals of the second multiplexer U23 are respectively connected to the resistor divider circuit 311 at the output terminals of the four operational amplifier constant current output circuits 31, so as to realize the sampling of the waveform signals of the constant current output in the four electrode channels in turn; the inverting input terminal of the second output operational amplifier 322 is connected to the output terminal of the second multiplexer U23, the in-phase input terminal thereof is grounded, and the output terminal thereof is connected to the output detection unit 40, so as to send the processed output voltage od1V0 of each electrode channel to the output detection unit 40 for calculating impedance detection.

[0068] Furthermore, in order to avoid inaccurate sampling values ​​or failure to sample due to too small voltage amplitude, the second channel switching sampling circuit 32 also includes a comparator U10, a second single-pole double-throw analog switch U6 and a third output operational amplifier U25; wherein the input end of the comparator U10 is connected to the output end of the second output operational amplifier 322, for determining whether the output voltage 0d1V0 is less than a preset voltage threshold; the second single-pole double-throw analog switch U6 is connected to the output end of the comparator U10 and the output end of the second output operational amplifier 322, the output end of the second single-pole double-throw analog switch U6 is connected to the third output operational amplifier U25, for being turned on when the output voltage 0d1V0 is less than the preset voltage threshold; the non-inverting input end of the third output operational amplifier U25 is connected to the output end of the second single-pole double-throw analog switch U6, the inverting input end thereof is connected to one end of the sixtieth resistor R60 and the fifty-seventh resistor R57, the output end thereof is connected to the other end of the fifty-seventh resistor R57 and the output detection unit 40, and the other end of the sixtieth resistor R60 is grounded. Based on the above design, the comparator U10 compares the output voltage 0d1V0 with a preset voltage threshold, which can be set to 0.3V, and controls the second single-pole double-throw analog switch U6 according to the comparison result, that is, when the output voltage 0d1V0 is less than 0.3V, the second single-pole double-throw analog switch U6 is turned on to amplify the output voltage 0d1V0 through the third output operational amplifier U25 to obtain the output voltage Vout, for example, it can be amplified by 10 times, and then returned to the original size and provided to the output detection unit 40 for sampling and calculation to realize the sampling of small current voltage.

[0069] It can be understood that the first single-pole double-throw analog switch U5, the single-pole multi-throw analog switch U3, the multi-channel digital potentiometer U20, the first multiplexer U7, the second multiplexer U23, the comparator U10 and the second single-pole double-throw analog switch U6 can be connected to an external controller when working normally to receive an external control signal, an enable signal, a clock signal or a data signal, etc. Figures 4 to 9 For example, receiving PE14-UnipolarON signal, PE15-4CH_EN signal, PD8-5263_RESET signal, PB12-SPI2_CS signal, PB13-SPI2_SCK signal, PB15-SPI2_MOSI signal, PC8-Vin_A0 signal, PC9-Vin_A1 signal, PC6-Vout_A0 signal, PC7-Vout_A1 signal, and when the current loop control circuit 23 is connected to the multi-channel digital potentiometer U20, the PB15-SPI2_MOSI signal can also be sent to the multi-channel digital potentiometer U20 to adjust the output of the corresponding electrode channel in the intensity adjustment circuit 21 according to the detection current I0 corresponding to each electrode channel.

[0070] The present invention can also provide a transcranial electrical stimulation device, including an electrode cap, a controller and the multi-channel impedance detection control circuit described in the above embodiment, wherein the controller is connected to the electrode channel on the electrode cap and the multi-channel impedance detection control circuit. It can be understood that four stimulation electrodes and one common electrode can be distributed on the electrode cap, and the four stimulation electrodes can be placed around the common electrode as the center, and an electrode channel is formed between each stimulation electrode and the common electrode, and the controller and the current loop control circuit 23 are connected to the four stimulation electrodes, and the common electrode is connected to the common ground reference terminal GND of the device.

[0071] It can be understood that when the transcranial electrical stimulation device of this embodiment is used, the power is turned on, the multi-channel impedance detection control circuit works, and the fundamental wave receiving unit 10 receives the waveform signal PA4-WAVE and the real-time intensity signal output from the controller in the transcranial electrical stimulation device to the four electrode channels. After the intensity adjustment circuit 21 is turned on for sampling in turn and the intensity of the corresponding waveform signal PA4-WAVE is adjusted according to the real-time intensity signal, the amplitude-modulated waveform signal is obtained. On the one hand, the amplitude-modulated waveform signals of the four electrode channels are then sampled in turn by the first multiplexer U7 in the first channel switching sampling circuit 22, and then passed through the first output operational amplifier 222 and the sampling resistor RT to obtain the detection current I0; on the other hand, the amplitude-modulated waveform signals of the four electrode channels are respectively After passing through the four operational amplifier constant current output circuits 31, the corresponding constant current source output is obtained, and then the waveform signal of the constant current output is sampled in turn by the second multiplexer U23 in the second channel switching sampling circuit 32, and then the output voltage 0d1V0 is obtained through the second output operational amplifier 322. If the output voltage 0d1V0 is less than 0.3V, the second single-pole double-throw analog switch U6 connected to the second output operational amplifier 322 is turned on to amplify the output voltage 0d1V0 through the third output operational amplifier U25 to obtain the amplified output voltage Vout, thereby realizing the sampling of small current and voltage; finally, the output detection unit 40 calculates the impedance according to the output voltage Vout of the four electrode channels and the corresponding detection current I0, thereby realizing real-time impedance detection.

[0072] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A multi-channel impedance detection control method, applied to a transcranial electrical stimulation device, characterized in that: The multi-channel impedance detection control method comprises: Obtaining waveform signals output by a controller in a transcranial electrical stimulation device to each electrode channel; The waveform signals of the multiple electrode channels are sampled in turn to obtain the detection current corresponding to each electrode channel; Performing operational amplification on the waveform signal corresponding to each electrode channel to obtain the corresponding constant current source output, and conducting and sampling the constant current source outputs of the multiple electrode channels in turn according to the order in which the waveform signals of the multiple electrode channels are conducted, so as to obtain the output voltage corresponding to each electrode channel; The impedance of the electrode of each electrode channel is obtained according to the detection current and the corresponding output voltage of the electrode channel.

2. The multi-channel impedance detection control method according to claim 1, characterized in that: The step of obtaining the waveform signal outputted by the controller to each electrode channel in the transcranial electrical stimulation device further includes: According to the intensity signal output by the controller in the transcranial electrical stimulation device to multiple electrode channels in real time, the intensity of the waveform signal of the corresponding electrode channel is adjusted to obtain the amplitude-modulated waveform signal.

3. The multi-channel impedance detection control method according to claim 1, characterized in that: After obtaining the output voltage corresponding to each electrode channel, the method further includes: Determining whether the output voltage is less than a preset voltage threshold; When the output voltage is less than a preset voltage threshold, the output voltage is amplified to obtain an amplified output voltage.

4. A multi-channel impedance detection control circuit, applied to a transcranial electrical stimulation device, characterized in that: The multi-channel impedance detection control circuit comprises: A fundamental wave receiving unit, connected to the controller of the transcranial electrical stimulation device, and used to receive waveform signals from multiple electrode channels of the controller; A first detection unit, comprising a first channel switching sampling circuit, connected to the output end of the fundamental wave receiving unit, and used for conducting and sampling the waveform signals of the plurality of electrode channels in turn to obtain a detection current corresponding to each electrode channel; The second detection unit includes a plurality of operational amplifier constant current output circuits and a second channel switching sampling circuit, wherein the input ends of the plurality of operational amplifier constant current output circuits are connected to the output end of the fundamental wave receiving unit, and the output ends thereof are connected to the second channel switching sampling circuit, so that the second channel switching sampling circuit realizes the sampling of the output voltage signals of the plurality of operational amplifier constant current output circuits in turn, thereby collecting the output voltage of the electrode corresponding to each electrode channel of the transcranial electrical stimulation device in each operational amplifier constant current output circuit; The output detection unit is connected to the first detection unit and the second detection unit, and is used to obtain the impedance of the electrode of each electrode channel according to the detection current corresponding to each electrode channel and the output voltage.

5. The multi-channel impedance detection control circuit according to claim 4, characterized in that: The first detection unit also includes an intensity adjustment circuit connected to the controller of the transcranial electrical stimulation device, and the intensity adjustment circuit is also connected between the fundamental wave receiving unit and the first channel switching sampling circuit, including a single-pole multi-throw analog switch, a multi-channel digital potentiometer and a plurality of voltage followers, wherein the single-pole multi-throw analog switch is connected between the output end of the fundamental wave receiving unit and the input end of the multi-channel digital potentiometer, and is used to realize the sampling of waveform signals of multiple electrode channels in turn; the control end of the multi-channel digital potentiometer is also connected to the controller, and is used to receive multiple waveform signals that are turned on in turn and intensity signals of multiple electrode channels from the controller, and respectively adjust the intensity of the corresponding waveform signals according to the multiple intensity signals to obtain multiple amplitude-modulated waveform signals; the input ends of the multiple voltage followers are respectively connected to the multiple output ends of the multi-channel digital potentiometer, and their output ends are connected to the first channel switching sampling circuit.

6. The multi-channel impedance detection control circuit according to claim 5, characterized in that: The first detection unit also includes a current loop control circuit, the input end of the current loop control circuit is connected to the output end of the first channel switching sampling circuit, and the output end is connected to the multi-channel digital potentiometer in the intensity adjustment circuit, which is used to adjust the output of the corresponding electrode channel in the intensity adjustment circuit according to the detection current corresponding to each electrode channel.

7. The multi-channel impedance detection control circuit according to claim 5 or 6, characterized in that: The second channel switching sampling circuit includes a second multiplexer and a second output operational amplifier, wherein: The input end of each operational amplifier constant current output circuit is connected to the output end of one of the voltage followers, and the output end of the operational amplifier constant current output circuit is connected to an input end of the second multiplexer through a resistor voltage divider circuit; The inverting input terminal of the second output operational amplifier is connected to the output terminal of the second multiplexer, the non-inverting input terminal thereof is grounded, and the output terminal thereof is connected to the output detection unit.

8. The multi-channel impedance detection control circuit according to claim 7, characterized in that: The second channel switching sampling circuit also includes a comparator, a second single-pole double-throw analog switch and a third output operational amplifier; wherein, The input end of the comparator is connected to the output end of the second output operational amplifier, and is used to determine whether the output voltage is less than a preset voltage threshold; The second single-pole double-throw analog switch is connected to the output end of the comparator and the output end of the second output operational amplifier, and the output end of the second single-pole double-throw analog switch is connected to the third output operational amplifier, and is used to be turned on when the output voltage is less than a preset voltage threshold; The non-inverting input terminal of the third output operational amplifier is connected to the output terminal of the second single-pole double-throw analog switch, the inverting input terminal thereof is connected to the 60th resistor and one end of the 57th resistor, the output terminal thereof is connected to the other end of the 57th resistor and the output detection unit, and the other end of the 60th resistor is grounded.

9. The multi-channel impedance detection control circuit according to claim 4, characterized in that: The first channel switching sampling circuit includes a first multiplexer and a first output operational amplifier; wherein, The input end of the first multiplexer is connected to the output end of the fundamental wave receiving unit, and is used to conduct sampling of waveform signals of multiple electrode channels in turn; The inverting input terminal of the first output operational amplifier is connected to the output terminal of the first multiplexer, the non-inverting input terminal thereof is grounded, and the output terminal of the first output operational amplifier is connected to the output detection unit via a sampling resistor.

10. A transcranial electrical stimulation device, characterized in that: It comprises an electrode cap, a controller and the multi-channel impedance detection control circuit according to any one of claims 4 to 9, wherein the controller is connected to the electrode channels on the electrode cap and the multi-channel impedance detection control circuit.

Images