A differential output current source circuit and a time-domain coherent electrical stimulation method

Abstract

The present invention provides a differential output current source circuit and a time-domain coherent electrical stimulation method, wherein the circuit comprises a common-phase output circuit and an inverting output circuit respectively used to convert an input high-frequency analog voltage signal into a constant high-frequency analog positive current signal and a high-frequency analog negative current signal, wherein the common-phase output circuit and the inverting output circuit both comprise a Howland circuit and two voltage followers, wherein the common-phase input terminal of the Howland circuit of the common-phase output circuit receives a voltage signal, and the output terminal of the Howland circuit of the common-phase output circuit outputs a positive current signal; the inverting input terminal of the Howland circuit of the inverting output circuit receives a voltage signal, and the output terminal of the Howland circuit of the inverting output circuit outputs a negative current signal; and the two voltage followers are connected to the Howland circuit by being respectively arranged in a feedback loop at the common-phase input terminal and the inverting input terminal of the Howland circuit. The present invention converts a high-frequency analog voltage signal into a high-frequency analog current signal and ensures that the current is outputted constantly under the conditions of high frequency and load variation.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic circuits, and in particular to a differential output current source circuit and a time-domain coherent electrical stimulation method. Background Art

[0002] Time-domain coherent electrical stimulation is a non-invasive neuromodulation technology that transmits two high-frequency electric fields to the brain through electrodes placed on the scalp. The two high-frequency electric fields interfere with each other in the deep brain to produce a low-frequency oscillating envelope electric field, thereby regulating the neural activity in the deep area of ​​the human brain. It can be used to treat neurological diseases such as Parkinson's disease and Alzheimer's disease. In traditional electrical stimulators, a voltage-controlled current source is used to output current to the electrode. The output is a single-ended mode, that is, one electrode in a channel outputs a constant current, and the output of the other electrode is connected to the ground in the circuit. Time-domain coherent electrical stimulation is different from traditional electrical stimulators. It requires at least two channels of current sources to output simultaneously. If the output of each stimulation channel is a single-ended mode, then there will be multiple electrodes connected to the ground. At this time, the current output from one channel can return through the ground electrodes of other channels, resulting in an envelope waveform near the ground electrode, causing serious current crosstalk between channels. In addition, parameters such as waveform, current amplitude, frequency and phase are important factors in regulating the therapeutic effect of time-domain coherent electrical stimulation. Whether these parameters can be accurately output from the hardware circuit mainly depends on the current source circuit.

[0003] Therefore, it is necessary to provide a current source circuit for time-domain coherent electrical stimulation. Summary of the invention

[0004] In view of this, an embodiment of the present invention provides a differential output current source circuit and a time-domain coherent electrical stimulation method to eliminate or improve one or more defects existing in the prior art.

[0005] One aspect of the present invention provides a differential output current source circuit, the circuit comprising: a common-phase output circuit for converting an input high-frequency analog voltage signal into a constant high-frequency analog positive current signal and an inverting output circuit for converting an input high-frequency analog voltage signal into a constant high-frequency analog negative current signal, the common-phase output circuit and the inverting output circuit both comprising a Howland circuit and two voltage followers,

[0006] The in-phase input terminal of the Howland circuit of the in-phase output circuit is used to receive an input high-frequency analog voltage signal, and the output terminal of the Howland circuit of the in-phase output circuit is used to output a constant high-frequency analog positive current signal;

[0007] The inverting input end of the Howland circuit of the inverting output circuit is used to receive an input high-frequency analog voltage signal, and the output end of the Howland circuit of the inverting output circuit is used to output a constant high-frequency analog negative current signal;

[0008] The two voltage followers are connected to the Howland circuit by being respectively arranged in feedback loops at the non-inverting input terminal and the inverting input terminal of the Howland circuit.

[0009] In some embodiments of the present invention, the Howland circuit of the in-phase output circuit comprises: a first operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor and a fifth resistor,

[0010] The first end of the first resistor is used to receive the input high-frequency analog voltage signal, and the second end of the first resistor is connected to the in-phase input end of the first operational amplifier and the first end of the third resistor;

[0011] The first end of the second resistor is used for grounding, and the second end of the second resistor is connected to the inverting input end of the first operational amplifier and the first end of the fourth resistor;

[0012] The non-inverting input terminal of the first operational amplifier is connected to the first end of the third resistor, the inverting input terminal of the first operational amplifier is connected to the first end of the fourth resistor, and the output terminal of the first operational amplifier is connected to the first end of the fifth resistor;

[0013] The second end of the third resistor and the second end of the fourth resistor are respectively used to receive the feedback voltage output by the feedback loop of the non-inverting input terminal and the inverting input terminal of the first operational amplifier;

[0014] The second end of the fifth resistor is used to output a constant high-frequency analog positive current signal.

[0015] In some embodiments of the present invention, the two voltage followers of the in-phase output circuit are a first voltage follower and a second voltage follower.

[0016] The first voltage follower comprises a second operational amplifier, a non-inverting input terminal of the second operational amplifier is connected to the output terminal of the first operational amplifier and the first end of the fifth resistor, an inverting input terminal of the second operational amplifier is connected to the output terminal of the second operational amplifier and the second end of the third resistor, and the output terminal of the second operational amplifier is connected to the second end of the third resistor;

[0017] The second voltage follower includes a third operational amplifier, the non-inverting input terminal of the third operational amplifier is connected to the second end of the fifth resistor, the inverting input terminal of the third operational amplifier is connected to the output terminal of the third operational amplifier and the second end of the fourth resistor, and the output terminal of the third operational amplifier is connected to the second end of the fourth resistor.

[0018] In some embodiments of the present invention, the first operational amplifier, the second operational amplifier and the third operational amplifier are all powered by dual power supplies.

[0019] In some embodiments of the present invention, the first resistor and the second resistor have equal resistance values, and the third resistor and the fourth resistor have equal resistance values;

[0020] The output current of the in-phase output circuit is the product of the quotient of the voltage value of the input high-frequency analog voltage signal and the resistance value of the fifth resistor and the ratio of the resistance values ​​of the third resistor to the first resistor, or the product of the quotient of the voltage value of the input high-frequency analog voltage signal and the resistance value of the fifth resistor and the ratio of the resistance values ​​of the fourth resistor to the second resistor.

[0021] In some embodiments of the present invention, the Howland circuit of the inverting output circuit includes: a fourth operational amplifier, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor and a tenth resistor,

[0022] The first end of the seventh resistor is used to receive the input high-frequency analog voltage signal, and the second end of the seventh resistor is connected to the inverting input end of the fourth operational amplifier and the first end of the ninth resistor;

[0023] The first end of the sixth resistor is used for grounding, and the second end of the sixth resistor is connected to the in-phase input end of the fourth operational amplifier and the first end of the eighth resistor;

[0024] The non-inverting input terminal of the fourth operational amplifier is connected to the first end of the eighth resistor, the inverting input terminal of the fourth operational amplifier is connected to the first end of the ninth resistor, and the output terminal of the fourth operational amplifier is connected to the first end of the tenth resistor;

[0025] The second end of the eighth resistor and the second end of the ninth resistor are respectively used to receive the feedback voltage output by the feedback loop of the non-inverting input terminal and the inverting input terminal of the fourth operational amplifier;

[0026] The second end of the tenth resistor is used to output a constant high-frequency analog negative current signal.

[0027] In some embodiments of the present invention, the two voltage followers of the inverting output circuit are a third voltage follower and a fourth voltage follower.

[0028] The third voltage follower comprises a fifth operational amplifier, a non-inverting input terminal of the fifth operational amplifier is connected to the output terminal of the fourth operational amplifier and the first terminal of the tenth resistor, an inverting input terminal of the fifth operational amplifier is connected to the output terminal of the fifth operational amplifier and the second terminal of the eighth resistor, and the output terminal of the fifth operational amplifier is connected to the second terminal of the eighth resistor;

[0029] The fourth voltage follower includes a sixth operational amplifier, the non-inverting input terminal of the sixth operational amplifier is connected to the second end of the tenth resistor, the inverting input terminal of the sixth operational amplifier is connected to the output terminal of the sixth operational amplifier and the second end of the ninth resistor, and the output terminal of the sixth operational amplifier is connected to the second end of the ninth resistor.

[0030] In some embodiments of the present invention, the fourth operational amplifier, the fifth operational amplifier and the sixth operational amplifier are all powered by dual power supplies.

[0031] In some embodiments of the present invention, the sixth resistor and the seventh resistor have the same resistance value, and the eighth resistor and the ninth resistor have the same resistance value;

[0032] The output current of the inverting output circuit is the negative value of the product of the quotient of the voltage value of the input high-frequency analog voltage signal and the resistance value of the tenth resistor and the ratio of the resistance values ​​of the eighth resistor to the sixth resistor, or the negative value of the product of the quotient of the voltage value of the input high-frequency analog voltage signal and the resistance value of the tenth resistor and the ratio of the resistance values ​​of the ninth resistor to the seventh resistor.

[0033] Another aspect of the present invention provides a time-domain coherent electrical stimulation method, which uses the differential output current source circuit as described above as each time-domain coherent electrical stimulation channel to perform the time-domain coherent electrical stimulation method, and the in-phase output circuit and the inverting output circuit in the differential output current source circuit are both connected to the electrodes.

[0034] The differential output current source circuit and the time-domain coherent electrical stimulation method of the present invention, when the high-frequency analog voltage signal enters the differential output current source circuit, the differential output current source circuit divides the high-frequency analog voltage signal into two signals, one of which is transmitted to the same-phase output circuit through the same-phase input end of the Howland circuit of the input same-phase output circuit, and the same-phase output circuit converts the input high-frequency analog voltage signal into a constant high-frequency analog positive current signal and outputs it from the output end of the Howland circuit of the same-phase output circuit, and the other is transmitted to the reverse output circuit through the reverse input end of the Howland circuit of the input reverse output circuit, and the reverse output circuit converts the input high-frequency analog voltage signal into a constant high-frequency analog negative current signal and outputs it from the output end of the Howland circuit of the reverse output circuit. Among them, the feedback loops of the same-phase input end and the reverse input end of the Howland circuit in the same-phase and reverse output circuits of the differential output current source circuit are respectively added with voltage followers, so that all positive current signals and negative current signals output from the output end of the Howland circuit in the two output currents flow into the human brain load. Since the load of the human brain is constantly changing, compared with the traditional Howland current source circuit, the output mode of the differential output current source circuit is differential output, which can convert high-frequency analog voltage signals into high-frequency analog current signals, and can ensure that the current signal is constantly output under the conditions of high frequency and constantly changing load required by time-domain coherent electrical stimulation, that is, the output current signal is not affected by changes in human body load.

[0035] Additional advantages, purposes, and features of the present invention will be described in part in the following description, and will become apparent to those skilled in the art after studying the following, or may be learned from the practice of the present invention. The purposes and other advantages of the present invention may be achieved and obtained by the structures specifically indicated in the specification and the accompanying drawings.

[0036] Those skilled in the art will appreciate that the objectives and advantages that can be achieved with the present invention are not limited to the above specific description, and the above and other objectives that can be achieved by the present invention will be more clearly understood from the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The drawings described herein are used to provide a further understanding of the present invention, constitute a part of this application, and do not constitute a limitation of the present invention.

[0038] Figure 1 Schematic diagram of the working principle of a differential output current source circuit in one embodiment of the present invention.

[0039] Figure 2Schematic diagram of a specific circuit structure of a differential output current source circuit in one embodiment of the present invention;

[0040] Figure 3 The figure is a schematic diagram of current signal waveforms output by the in-phase output circuit and the inverting output circuit of the differential output current source circuit in one embodiment of the present invention. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments and the accompanying drawings. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0042] It should also be noted that, in order to avoid obscuring the present invention due to unnecessary details, only structures and / or processing steps closely related to the solutions according to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0043] It should be emphasized that the term “include / comprises” when used herein refers to the presence of features, elements, steps or components, but does not exclude the presence or addition of one or more other features, elements, steps or components.

[0044] It should also be noted that, unless otherwise specified, the term “connection” herein may refer not only to a direct connection but also to an indirect connection involving an intermediate.

[0045] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the accompanying drawings, the same reference numerals represent the same or similar components, or the same or similar steps.

[0046] The embodiments of the present invention provide a differential output current source circuit and a time-domain coherent electrical stimulation method that can be used for time-domain coherent electrical stimulation. By adjusting the output waveform, current amplitude, frequency, phase and other parameters of the differential output current source circuit, an envelope waveform can be formed at a specified location deep in the human brain, and the generation of an envelope waveform near the electrode or other locations can be prevented. This can avoid the serious current crosstalk generated when multiple electrical stimulation channels are used in traditional electrical stimulation methods, and can effectively ensure the treatment effect of time-domain coherent electrical stimulation.

[0047] Figure 1 and Figure 2 The following are respectively a schematic diagram of the working principle and a schematic diagram of the specific structure of a differential output current source circuit in one embodiment of the present invention. Figure 1 and Figure 2As shown, a differential output current source circuit in this embodiment can be used for time-domain coherent electrical stimulation, including: a common-phase output circuit for converting an input high-frequency analog voltage signal into a constant high-frequency analog positive current signal and an inverting output circuit for converting an input high-frequency analog voltage signal into a constant high-frequency analog negative current signal. The common-phase output circuit and the inverting output circuit both include a Howland circuit and two voltage followers connected to the Howland circuit, wherein the common-phase input terminal of the Howland circuit of the common-phase output circuit is used to receive the input high-frequency analog voltage signal, and the output terminal of the Howland circuit of the common-phase output circuit is used to output a constant high-frequency analog positive current signal; the inverting input terminal of the Howland circuit of the inverting output circuit is used to receive the input high-frequency analog voltage signal, and the output terminal of the Howland circuit of the inverting output circuit is used to output a constant high-frequency analog negative current signal; the two voltage followers in the two output circuits are respectively arranged in the feedback loops of the common-phase input terminal and the inverting input terminal of the Howland circuit.

[0048] Specifically, if Figure 1 As shown, when the high-frequency analog voltage signal Vin enters the above-mentioned differential output current source circuit, the differential output current source circuit divides the high-frequency analog voltage signal Vin into two signals, one of which is transmitted to the same-phase output circuit through the same-phase input terminal of the Howland circuit of the input same-phase output circuit, and the same-phase output circuit converts the input high-frequency analog voltage signal into a constant high-frequency analog positive current signal I + The high-frequency analog voltage signal Vin is transmitted to the inverting output circuit through the inverting input terminal of the Howland circuit of the inverting output circuit, and the inverting output circuit converts the input high-frequency analog voltage signal into a constant high-frequency analog negative current signal I - And outputted from the output end of the Howland circuit of the inverting output circuit. Among them, the feedback loops of the in-phase input end and the inverting input end of the Howland circuit in the in-phase and inverting output circuits of the differential output current source circuit are respectively added with voltage followers, so that all positive current signals and negative current signals outputted from the output end of the Howland circuit in the two output currents flow into the human brain load. Since the human brain load is constantly changing, compared with the traditional Howland current source circuit, the output mode of the differential output current source circuit is differential output, which can convert high-frequency analog voltage signals into high-frequency analog current signals, and can ensure that the current signal is constantly output under the conditions of high frequency and constantly changing load required by time-domain coherent electrical stimulation, that is, the output current signal is not affected by changes in human body load.

[0049] In one embodiment of the present invention, Figure 2 As shown, the Howland circuit of the in-phase output circuit includes: a first operational amplifier U1, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4 and a fifth resistor R5, wherein the first end of the first resistor R1 is used to receive the input high-frequency analog voltage signal, and the second end of the first resistor R1 is connected to the in-phase input end of the first operational amplifier U1 and the first end of the third resistor R3; the first end of the second resistor R2 is used to be grounded, and the second end of the second resistor R2 is connected to the inverting input end of the first operational amplifier U1 and the first end of the fourth resistor R4; the in-phase input end of the first operational amplifier U1 is connected to the first end of the third resistor R3, the inverting input end of the first operational amplifier U1 is connected to the first end of the fourth resistor R4, and the output end of the first operational amplifier U1 is connected to the first end of the fifth resistor R5; the second end of the third resistor R3 and the second end of the fourth resistor R4 are respectively used to receive the feedback voltage output by the feedback loop of the in-phase input end and the inverting input end of the first operational amplifier U1; the second end of the fifth resistor R5 is used to output a constant high-frequency analog positive current signal.

[0050] In one embodiment of the present invention, Figure 1 and Figure 2 As shown, the two voltage followers of the in-phase output circuit are a first voltage follower and a second voltage follower, the first voltage follower includes a second operational amplifier U2, the in-phase input terminal of the second operational amplifier U2 is connected to the output terminal of the first operational amplifier U1 and the first end of the fifth resistor R5, the inverting input terminal of the second operational amplifier U2 is connected to the output terminal of the second operational amplifier U2 and the second end of the third resistor R3, and the output terminal of the second operational amplifier U2 is connected to the second end of the third resistor R3; the second voltage follower includes a third operational amplifier U3, the in-phase input terminal of the third operational amplifier U3 is connected to the second end of the fifth resistor R5, the inverting input terminal of the third operational amplifier U3 is connected to the output terminal of the third operational amplifier U3 and the second end of the fourth resistor R4, and the output terminal of the third operational amplifier U3 is connected to the second end of the fourth resistor R4.

[0051] In this embodiment, by respectively adding a first voltage follower and a second voltage follower to the feedback loops of the non-inverting input terminal and the inverting input terminal of the first operational amplifier U1 of the non-inverting output circuit, that is, connecting the first voltage follower (the second operational amplifier U2 with the inverting input terminal and the output terminal short-circuited) between the second end of the third resistor R3 and the first end of the fifth resistor R5, and connecting the second voltage follower (the third operational amplifier U3 with the inverting input terminal and the output terminal short-circuited) between the second end of the fourth resistor R4 and the second end of the fifth resistor R5, all currents passing through the fifth resistor R5 can flow into the human brain load, ensuring constant output of current under high frequency and constantly changing load conditions.

[0052] In one embodiment of the present invention, the power supply modes of the first operational amplifier U1, the second operational amplifier U2 and the third operational amplifier U3 are all dual power supply. Specifically, in the selection of the first operational amplifier U1, the second operational amplifier U2 and the third operational amplifier U3, operational amplifiers of the same model with low input bias current, high gain bandwidth product GBP and high slew rate SR are selected, which is conducive to the differential output current source circuit of this embodiment to convert high-frequency analog voltage signals into high-frequency analog current signals, and can ensure that the current signal is output constantly under the high frequency required by time-domain coherent electrical stimulation and the conditions of constantly changing loads. For example, the models of the first operational amplifier U1, the second operational amplifier U2 and the third operational amplifier U3 are all OPA197, that is, Figure 2 The corresponding V+ is connected to +16V voltage, and V- is connected to -16V voltage, which has a better effect.

[0053] In one embodiment of the present invention, the resistance values ​​of the first resistor R1 and the second resistor R2 are equal, and the resistance values ​​of the third resistor R3 and the fourth resistor R4 are equal. Under this condition, the high-frequency analog positive current signal I output by the in-phase output circuit is + The product of the quotient of the voltage value Vin of the input high-frequency analog voltage signal and the resistance value of the fifth resistor R5 and the ratio of the resistance values ​​of the third resistor R3 and the first resistor R1, or the product of the quotient of the voltage value Vin of the input high-frequency analog voltage signal and the resistance value of the fifth resistor R5 and the ratio of the resistance values ​​of the fourth resistor R4 and the second resistor R2, that is, Among them, r1, r2, r3, r4 and r5 represent the resistance values ​​of the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4 and the fifth resistor R5 respectively. The waveform of the current signal is as follows: Figure 3 It has been verified that when the resistance values ​​of the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4 are equal, the signal output is more stable. For example, the resistance values ​​of the first resistor R1 , the second resistor R2 , the third resistor R3 and the fourth resistor R4 are all 10 kilo-ohms, and the resistance value of the fifth resistor R5 is 100 ohms, which has a better effect.

[0054] In one embodiment of the present invention, Figure 2 As shown, the Howland circuit of the inverting output circuit includes: a fourth operational amplifier U4, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9 and a tenth resistor R10, the first end of the seventh resistor R7 is used to receive the input high-frequency analog voltage signal, the second end of the seventh resistor R7 is connected to the inverting input end of the fourth operational amplifier U4 and the first end of the ninth resistor R9; the first end of the sixth resistor R6 is used to be grounded, the second end of the sixth resistor R6 is connected to the non-inverting input end of the fourth operational amplifier U4, the eighth resistor R7 and the ninth resistor R9. The first end of R8 is connected; the non-inverting input end of the fourth operational amplifier U4 is connected to the first end of the eighth resistor R8, the inverting input end of the fourth operational amplifier U4 is connected to the first end of the ninth resistor R9, and the output end of the fourth operational amplifier U4 is connected to the first end of the tenth resistor R10; the second end of the eighth resistor R8 and the second end of the ninth resistor R9 are respectively used to receive the feedback voltage output by the feedback loop of the non-inverting input end and the inverting input end of the fourth operational amplifier U4; the second end of the tenth resistor R10 is used to output a constant high-frequency analog negative current signal.

[0055] In one embodiment of the present invention, Figure 1 and Figure 2 As shown, the two voltage followers of the inverting output circuit are a third voltage follower and a fourth voltage follower, the third voltage follower includes a fifth operational amplifier U5, the in-phase input terminal of the fifth operational amplifier U5 is connected to the output terminal of the fourth operational amplifier U4 and the first end of the tenth resistor R10, the inverting input terminal of the fifth operational amplifier U5 is connected to the output terminal of the fifth operational amplifier U5 and the second end of the eighth resistor R8, and the output terminal of the fifth operational amplifier U5 is connected to the second end of the eighth resistor R8; the fourth voltage follower includes a sixth operational amplifier U6, the in-phase input terminal of the sixth operational amplifier U6 is connected to the second end of the tenth resistor R10, the inverting input terminal of the sixth operational amplifier U6 is connected to the output terminal of the sixth operational amplifier U6 and the second end of the ninth resistor R9, and the output terminal of the sixth operational amplifier U6 is connected to the second end of the ninth resistor R9.

[0056] In this embodiment, by respectively adding a third voltage follower and a fourth voltage follower to the feedback loops of the non-inverting input terminal and the inverting input terminal of the fourth operational amplifier U4 of the inverting output circuit, that is, connecting the third voltage follower (the fifth operational amplifier U5 with the inverting input terminal and the output terminal short-circuited) between the second end of the eighth resistor R8 and the first end of the tenth resistor R10, and connecting the fourth voltage follower (the sixth operational amplifier U6 with the inverting input terminal and the output terminal short-circuited) between the second end of the ninth resistor R9 and the second end of the tenth resistor R10, all currents passing through the tenth resistor R10 can flow into the human brain load, ensuring constant output of current under high frequency and changing load conditions.

[0057] In one embodiment of the present invention, the power supply modes of the fourth operational amplifier U4, the fifth operational amplifier U5 and the sixth operational amplifier U6 are all dual power supply. Specifically, in the selection of the fourth operational amplifier U4, the fifth operational amplifier U5 and the sixth operational amplifier U6, operational amplifiers of the same model with low input bias current, high gain bandwidth product GBP and high slew rate SR are selected, which is beneficial for the differential output current source circuit of this embodiment to convert high-frequency analog voltage signals into high-frequency analog current signals, and can ensure that the current signal is output constantly under the conditions of high frequency and constantly changing load required by time-domain coherent electrical stimulation. For example, the models of the fourth operational amplifier U4, the fifth operational amplifier U5 and the sixth operational amplifier U6 are all OPA197, that is, Figure 2 The corresponding V+ is connected to +16V voltage, and V- is connected to -16V voltage, which has a better effect.

[0058] In one embodiment of the present invention, the sixth resistor R6 and the seventh resistor R7 have the same resistance value, and the eighth resistor R8 and the ninth resistor R9 have the same resistance value. Under this condition, the high-frequency analog negative current signal I output by the inverting output circuit is - The product of the quotient of the voltage value Vin of the input high-frequency analog voltage signal and the resistance value of the tenth resistor R10 and the ratio of the resistance values ​​of the eighth resistor R8 to the sixth resistor R6 takes a negative value, or the product of the quotient of the voltage value Vin of the input high-frequency analog voltage signal and the resistance value of the tenth resistor R10 and the ratio of the resistance values ​​of the ninth resistor R9 to the seventh resistor R7 takes a negative value, that is, Among them, r6, r7, r8, r9 and r10 represent the resistance values ​​of the sixth resistor R6, the seventh resistor R7, the eighth resistor R8, the ninth resistor R9 and the tenth resistor R10 respectively. The waveform of the current signal is as follows: Figure 3 It has been verified that when the resistance values ​​of the sixth resistor R6, the seventh resistor R7, the eighth resistor R8 and the ninth resistor R9 are all equal, the signal output is more stable. For example, the sixth resistor R6, the seventh resistor R7, the eighth resistor R8 and the ninth resistor R9 all have resistance values ​​of 10 kilo-ohms, and the tenth resistor R10 has a resistance value of 100 ohms, which has a better effect.

[0059] It can be seen that the differential output current source circuit of the embodiment of the present invention mainly forms a current source circuit structure of a differential output mode by combining a Howland current source circuit structure and a voltage follower structure, and the entire circuit is only composed of an operational amplifier and a resistor device, which is simple and reliable.

[0060] On the other hand, an embodiment of the present invention also provides a time-domain coherent electrical stimulation method, which uses the differential output current source circuit as described above as each time-domain coherent electrical stimulation channel to perform the time-domain coherent electrical stimulation method, and the in-phase output circuit and the inverting output circuit in the differential output current source circuit are both connected to the electrodes.

[0061] Since the time-domain coherent electrical stimulation method requires at least two time-domain coherent electrical stimulation channels to be executed, each of which is composed of the aforementioned differential output current source circuit, that is, composed of the same-phase output circuit and the opposite-phase output circuit of the differential output current source circuit, the output of each stimulation channel is a differential output mode, and the same-phase output circuit and the opposite-phase output circuit in the circuit are both connected to one electrode. This can avoid the problem of multiple electrodes being connected to the ground due to the simultaneous output of current sources of multiple stimulation channels achieved through single-ended output of traditional electrical stimulation methods, thereby causing an envelope waveform to be generated near the ground electrode, resulting in serious current crosstalk between channels.

[0062] It should be understood by those skilled in the art that the exemplary components, systems and methods described in conjunction with the embodiments disclosed herein can be implemented in hardware, software or a combination of the two. Whether it is performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention. When implemented in hardware, it can be, for example, an electronic circuit, an application specific integrated circuit (ASIC), appropriate firmware, a plug-in, a function card, etc. When implemented in software, the elements of the present invention are programs or code segments used to perform the required tasks. The program or code segment can be stored in a machine-readable medium, or transmitted on a transmission medium or a communication link via a data signal carried in a carrier.

[0063] It should be clear that the present invention is not limited to the specific configuration and processing described above and shown in the figures. For the sake of simplicity, a detailed description of the known method is omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications and additions, or change the order between the steps after understanding the spirit of the present invention.

[0064] In the present invention, features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, and / or combined with or replace features of other embodiments.

[0065] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the embodiments of the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A differential output current source circuit, characterized in that: The circuit comprises: a common-phase output circuit for converting an input high-frequency analog voltage signal into a constant high-frequency analog positive current signal and an inverting output circuit for converting an input high-frequency analog voltage signal into a constant high-frequency analog negative current signal, wherein the common-phase output circuit and the inverting output circuit both comprise a Holland circuit and two voltage followers. The in-phase input end of the Holland circuit of the in-phase output circuit is used to receive an input high-frequency analog voltage signal, and the output end of the Holland circuit of the in-phase output circuit is used to output a constant high-frequency analog positive current signal; The inverting input end of the Holland circuit of the inverting output circuit is used to receive an input high-frequency analog voltage signal, and the output end of the Holland circuit of the inverting output circuit is used to output a constant high-frequency analog negative current signal; The two voltage followers are connected to the Howland circuit via feedback loops respectively arranged at the in-phase input terminal and the inverting input terminal of the Howland circuit.

2. The differential output current source circuit according to claim 1, characterized in that: The Holland circuit of the in-phase output circuit comprises: a first operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor and a fifth resistor, The first end of the first resistor is used to receive the input high-frequency analog voltage signal, and the second end of the first resistor is connected to the in-phase input end of the first operational amplifier and the first end of the third resistor; The first end of the second resistor is used for grounding, and the second end of the second resistor is connected to the inverting input end of the first operational amplifier and the first end of the fourth resistor; The non-inverting input terminal of the first operational amplifier is connected to the first end of the third resistor, the inverting input terminal of the first operational amplifier is connected to the first end of the fourth resistor, and the output terminal of the first operational amplifier is connected to the first end of the fifth resistor; The second end of the third resistor and the second end of the fourth resistor are respectively used to receive the feedback voltage output by the feedback loop of the non-inverting input terminal and the inverting input terminal of the first operational amplifier; The second end of the fifth resistor is used to output a constant high-frequency analog positive current signal.

3. The differential output current source circuit according to claim 2, characterized in that: The two voltage followers of the in-phase output circuit are a first voltage follower and a second voltage follower. The first voltage follower comprises a second operational amplifier, a non-inverting input terminal of the second operational amplifier is connected to the output terminal of the first operational amplifier and the first end of the fifth resistor, an inverting input terminal of the second operational amplifier is connected to the output terminal of the second operational amplifier and the second end of the third resistor, and the output terminal of the second operational amplifier is connected to the second end of the third resistor; The second voltage follower includes a third operational amplifier, the non-inverting input terminal of the third operational amplifier is connected to the second end of the fifth resistor, the inverting input terminal of the third operational amplifier is connected to the output terminal of the third operational amplifier and the second end of the fourth resistor, and the output terminal of the third operational amplifier is connected to the second end of the fourth resistor.

4. The differential output current source circuit according to claim 3, characterized in that: The first operational amplifier, the second operational amplifier and the third operational amplifier are all powered by dual power supplies.

5. The differential output current source circuit according to claim 2, characterized in that: The resistance values ​​of the first resistor and the second resistor are equal, and the resistance values ​​of the third resistor and the fourth resistor are equal; The output current of the in-phase output circuit is the product of the quotient of the voltage value of the input high-frequency analog voltage signal and the resistance value of the fifth resistor and the ratio of the resistance values ​​of the third resistor to the first resistor, or the product of the quotient of the voltage value of the input high-frequency analog voltage signal and the resistance value of the fifth resistor and the ratio of the resistance values ​​of the fourth resistor to the second resistor.

6. The differential output current source circuit according to claim 1, characterized in that: The Howland circuit of the inverting output circuit comprises: a fourth operational amplifier, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor and a tenth resistor, The first end of the seventh resistor is used to receive the input high-frequency analog voltage signal, and the second end of the seventh resistor is connected to the inverting input end of the fourth operational amplifier and the first end of the ninth resistor; The first end of the sixth resistor is used for grounding, and the second end of the sixth resistor is connected to the in-phase input end of the fourth operational amplifier and the first end of the eighth resistor; The non-inverting input terminal of the fourth operational amplifier is connected to the first end of the eighth resistor, the inverting input terminal of the fourth operational amplifier is connected to the first end of the ninth resistor, and the output terminal of the fourth operational amplifier is connected to the first end of the tenth resistor; The second end of the eighth resistor and the second end of the ninth resistor are respectively used to receive the feedback voltage output by the feedback loop of the non-inverting input terminal and the inverting input terminal of the fourth operational amplifier; The second end of the tenth resistor is used to output a constant high-frequency analog negative current signal.

7. The differential output current source circuit according to claim 6, characterized in that: The two voltage followers of the inverting output circuit are a third voltage follower and a fourth voltage follower. The third voltage follower comprises a fifth operational amplifier, a non-inverting input terminal of the fifth operational amplifier is connected to the output terminal of the fourth operational amplifier and the first terminal of the tenth resistor, an inverting input terminal of the fifth operational amplifier is connected to the output terminal of the fifth operational amplifier and the second terminal of the eighth resistor, and the output terminal of the fifth operational amplifier is connected to the second terminal of the eighth resistor; The fourth voltage follower includes a sixth operational amplifier, the non-inverting input terminal of the sixth operational amplifier is connected to the second end of the tenth resistor, the inverting input terminal of the sixth operational amplifier is connected to the output terminal of the sixth operational amplifier and the second end of the ninth resistor, and the output terminal of the sixth operational amplifier is connected to the second end of the ninth resistor.

8. The differential output current source circuit according to claim 7, characterized in that: The fourth operational amplifier, the fifth operational amplifier and the sixth operational amplifier are all powered by dual power supplies.

9. The differential output current source circuit according to claim 6, characterized in that: The sixth resistor and the seventh resistor have the same resistance value, and the eighth resistor and the ninth resistor have the same resistance value; The output current of the inverting output circuit is the negative value of the product of the quotient of the voltage value of the input high-frequency analog voltage signal and the resistance value of the tenth resistor and the ratio of the resistance values ​​of the eighth resistor to the sixth resistor, or the negative value of the product of the quotient of the voltage value of the input high-frequency analog voltage signal and the resistance value of the tenth resistor and the ratio of the resistance values ​​of the ninth resistor to the seventh resistor.

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