Constant-current electrical stimulation system with impedance monitoring function and use method of constant-current electrical stimulation system

Abstract

The invention discloses a constant-current electrical stimulation system with impedance monitoring and a use method thereof. The system comprises a main control unit, a digital isolator, a voltage-controlled constant current source circuit, a current acquisition circuit, an impedance detection circuit, a main power supply circuit, a power supply isolation module, a secondary power supply circuit, a booster circuit, an interaction host and the like which are connected in order. Safe and reliable pulse electrical stimulation output with adjustable parameters is provided, human tissue impedance and real-time current during stimulation are monitored in real time, an interaction host can display related information, and a user is warned when impedance or current is abnormal, so that accurate and safe electrical stimulation is realized.

Description

Technical Field

[0001] The present invention relates to the field of physical therapy equipment, and in particular to a constant current electrical stimulation system with impedance monitoring and a method of using the same. Background Art

[0002] In the fields of biomedical engineering and physical therapy, electrical stimulation systems are widely used for pain control, muscle stimulation, and neuromodulation. For example, in vagus nerve monitoring, they are primarily used in conjunction with electromyography and evoked potential devices to assess nerve integrity and locate possible lesions and injuries. Traditional constant-current electrical stimulation systems provide a constant current output to ensure consistent and effective treatment or diagnosis.

[0003] However, due to individual differences in tissue impedance and changes during treatment due to swelling, temperature, or other physiological factors, a fixed current output and its accompanying compliance voltage will not achieve the optimal stimulation effect, resulting in inconsistent stimulation intensity or side effects. Furthermore, the lack of real-time monitoring and adjustment capabilities makes it impossible for traditional systems to determine whether the stimulation effect is achieving the desired effect based on dynamic bioimpedance. Furthermore, this uncertainty in constant current stimulation can lead to high voltages and localized burning, resulting in a lack of safety and accuracy in treatment or diagnostic results.

[0004] At present, although some technologies have been proposed on the market to improve electrical stimulation systems, such as automatically adjusting the current intensity through preset programs, these methods often do not take into account the changes in bioimpedance in actual applications.

[0005] CN 107252525 A discloses a multi-channel electrical stimulation device based on electromyographic feedback. It proposes to obtain electromyographic data through electromyographic acquisition, then evaluate the muscle health status. After completing data acquisition and analysis, the host computer configures the frequency, pulse width, amplitude, and channel information of the stimulation current without removing the cuff. The configuration information is sent to the electromyographic signal acquisition / electrical stimulation output device via wired or Bluetooth, which switches it to the electrical stimulation mode. The cuff is used to stimulate and treat muscle groups with unsatisfactory electromyographic data. The electrical stimulation of each channel is time-sharing, and one channel stimulation output is performed at a certain moment. However, this design is mainly used to detect and obtain muscle status, and the muscle health status is determined by electromyographic data, and then the treatment area is determined. However, this solution still cannot prevent the occurrence of local burning caused by impedance changes during electrical stimulation.

[0006] CN106955104A discloses a human body load impedance detection device and method for an electrical stimulation therapy device, and discloses a solution for adjusting the output current by detecting the human body load impedance. However, the above solutions all use ADC to collect voltage and then convert the impedance. It is inevitable that the impedance conversion must be achieved through a single electrical stimulation and then subsequent adjustments must be made. Therefore, it is impossible to avoid the damage caused by the first electrical stimulation. Moreover, its function is relatively simple, and it can only adjust the current size, but not other parameters. This has limited accuracy, safety, and patient comfort for treatment or diagnosis.

[0007] CN114984452A discloses an electrical stimulation device capable of time interference, which adjusts the output current by detecting the load impedance of the human body. However, its circuit architecture is relatively complex, requiring the setting of more calculation links, and the measurement accuracy is not very high.

[0008] Therefore, it is necessary to develop an electrical stimulation system that can monitor impedance in real time and adjust the current intensity, pulse width, and stimulation frequency as needed to improve the accuracy, safety, and comfort of treatment or diagnosis. Summary of the Invention

[0009] The purpose of the present invention is to provide a constant current electrical stimulation system with impedance monitoring and a method for using the same. The system provides safe and reliable pulsed electrical stimulation output with adjustable parameters, and monitors human tissue impedance in real time, as well as the real-time current when stimulation occurs. The interactive host will display relevant information and alert the user when an abnormal impedance or current condition occurs, thereby achieving accurate and safe electrical stimulation. Specifically, the output of the electrical stimulation system of the present invention can adjust the current intensity, pulse width, and stimulation frequency as needed to improve the accuracy, safety, and comfort of treatment or diagnosis.

[0010] The present invention is achieved through the following technical solutions: Figure 1 Shown: A constant current electrical stimulation system with impedance monitoring and a method of using the same, comprising

[0011] The main control unit 3 is a microcontroller used to execute control logic, data acquisition and communication protocol processing;

[0012] A digital isolator 6 is connected to the main control unit 3;

[0013] The voltage-controlled constant current source circuit 101 is connected to the digital isolator 6, receives the stimulation signal from the main control unit 3 and generates a stimulation signal, outputting an electrical stimulation output current to the human tissue;

[0014] The current acquisition circuit 102 is connected to the digital isolator 6. When the electrical stimulation current occurs, it collects the analog stimulation current from the human tissue and converts it into digital information to feed back to the main control unit 3.

[0015] The impedance detection circuit 103 is connected to the digital isolator 6, collects the AC excitation signal by applying it to the human tissue, measures the voltage division signal and converts the analog stimulation current into digital information, and feeds the voltage division signal and the digital information of the analog stimulation current back to the main control unit 3;

[0016] The voltage-controlled constant current source circuit 101, the current acquisition circuit 102, and the impedance detection circuit 103 together constitute the stimulation unit 10;

[0017] The main power supply circuit 4 is connected to the main control unit 3 to step down and stabilize the voltage;

[0018] The power isolation module 5 is connected to the main power circuit 4 and is used to reduce the voltage of the main power circuit 4;

[0019] A secondary power supply circuit 7 is connected to the power isolation module 5 and is also connected to the stimulation unit 10 to supply power to the stimulation unit 10;

[0020] a boost circuit 8 connected to the secondary power circuit 7 and serving as a voltage source for the constant current electrical stimulation output current; and

[0021] The interactive host 1 is connected to the main control unit 3 through the communication circuit 2, and is used to exchange data with the main control unit 3 and display information including but not limited to the current setting intensity, the real-time intensity of the stimulation current, and the impedance value.

[0022] A method for using a constant current electrical stimulation system with impedance monitoring comprises the following steps

[0023] Step 1: Start the device. The main control unit 3 controls the impedance detection circuit 103 to perform impedance detection of human tissue. If the impedance detection is abnormal, the main control unit 3 will feedback to the main control unit 3, and the main control unit 3 will send an instruction to the interactive host 1. The interactive host 1 will issue a warning and prompt whether to continue or pause. If the impedance detection is normal, the main control unit 3 will feedback to the main control unit 3 and proceed to step 2.

[0024] Step 2: After receiving the signal indicating that the impedance detection is normal, the main control unit 3 sends a secondary signal data to the voltage-controlled constant current source circuit 101, and the voltage-controlled constant current source circuit 101 outputs an electrical stimulation output current;

[0025] Step 3: The main control unit 3 sends a stimulation current detection signal to the current acquisition circuit 102, and the current acquisition circuit 102 performs stimulation current detection and feeds back the detected stimulation current to the main control unit 3;

[0026] In step 4, the main control unit 3 compares the stimulation current output in step 2 with the stimulation current fed back in step 3 to determine whether the current is normal. If the current is abnormal, the main control unit 3 sends a feedback to the main control unit 3, and the main control unit 3 sends a command to the interactive host 1. The interactive host 1 issues a warning and prompts whether to continue or pause. If the current detection is normal, the main control unit 3 sends a feedback to the main control unit 3 and proceeds to step 5.

[0027] In step 5, the main control unit 3 controls the impedance detection circuit 103 to perform impedance detection of human tissue. If the impedance detection is abnormal, the main control unit 3 is fed back to the main control unit 3, and the main control unit 3 sends an instruction to the interactive host 1, which issues an alarm. If the impedance detection is normal, the next stimulation signal data point is processed to determine whether stimulation is to be performed. If stimulation is to be performed, steps 1-5 are repeated; if stimulation is not to be performed, step 6 is performed.

[0028] Step 6: The interactive host 1 displays "continue" or "pause" to interact with the user.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] By monitoring the patient's impedance changes in real time, the present invention can promptly stop and alert the user if the current stimulation environment is affected by impedance, thereby reducing the safety and misjudgment risks that may occur during electrical stimulation treatment or diagnosis, providing patients with a safer and more effective solution. Constant current control also ensures the consistency, accuracy, and convenience of electrical stimulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0032] Figure 2 This is the circuit diagram of the stimulation unit in the present invention

[0033] Figure 3 1 is a circuit diagram of the main power supply circuit in the present invention;

[0034] Figure 4 is a circuit diagram of the secondary power supply circuit in the present invention;

[0035] Figure 5 is a circuit diagram of the boost circuit in the present invention;

[0036] Figure 6 Flowchart of the present invention. DETAILED DESCRIPTION

[0037] The present invention is described in detail below with reference to the accompanying drawings:

[0038] like Figure 1 、 2Shown: A constant current electrical stimulation system with impedance monitoring and a method of using the same, comprising

[0039] The main control unit 3 is a microcontroller used to execute control logic, data acquisition and communication protocol processing; specifically, the main control unit adopts a microcontroller (MCU) based on the ARM Cortex-M core architecture, AVR core architecture, PIC core architecture, 8051 core architecture, etc.

[0040] The digital isolator 6 is connected to the main control unit 3; the digital isolator 6 here is a digital isolator based on capacitive coupling technology, or a digital communication isolation chip, or an optical coupling isolation chip.

[0041] The voltage-controlled constant current source circuit 101 is connected to the digital isolator 6, receives the stimulation signal from the main control unit 3 and generates a stimulation signal, outputting an electrical stimulation output current to the human tissue;

[0042] The current acquisition circuit 102 is connected to the digital isolator 6. When the electrical stimulation current occurs, it collects the analog stimulation current from the human tissue and converts it into digital information to feed back to the main control unit 3.

[0043] The impedance detection circuit 103 is connected to the digital isolator 6, collects the AC excitation signal by applying it to the human tissue, measures the voltage division signal and converts the analog stimulation current into digital information, and feeds the voltage division signal and the digital information of the analog stimulation current back to the main control unit 3;

[0044] The voltage-controlled constant current source circuit 101, the current acquisition circuit 102, and the impedance detection circuit 103 together constitute the stimulation unit 10;

[0045] The main power supply circuit 4 is connected to the main control unit 3 to step down and stabilize the voltage;

[0046] The power isolation module 5 is connected to the main power circuit 4 and is used to step down the voltage of the main power circuit 4. The power isolation module 5 is an isolated DC-DC converter with an isolation withstand voltage of 4kVdc, which meets the power isolation withstand voltage requirements of floating circuits in medical equipment.

[0047] A secondary power supply circuit 7 is connected to the power isolation module 5 and is also connected to the stimulation unit 10 to supply power to the stimulation unit 10;

[0048] a boost circuit 8 connected to the secondary power circuit 7 and serving as a voltage source for the constant current electrical stimulation output current; and

[0049] The interactive host 1 is connected to the main control unit 3 through the communication circuit 2, and is used to exchange data with the main control unit 3 and display information including but not limited to the current setting intensity, the real-time intensity of the stimulation current, and the impedance value.

[0050] Specifically, the interactive host exchanges data with the main control unit through the communication circuit, and the interactive interface displays the connection position with the human tissue under different surgical procedures. The system can adapt to different electrodes. Needle electrodes, patch electrodes or spiral electrodes can be selected as needed. The two electrodes connected to the human tissue are connected to the constant current electrical stimulation interface to form a current loop. The current intensity, pulse width and stimulation frequency can be adjusted according to different modes. The electromyographic signal waveform generated by the human muscle due to nerve electrical stimulation is fed back to the interactive host to diagnose the function of the nerve or muscle. The display and warning content include but are not limited to the current setting intensity, the real-time intensity of the stimulation current, and the impedance value.

[0051] Specifically, somatosensory evoked potentials (SSEPs) used in cerebrovascular surgery, peripheral nerve repair surgery, and spinal cord surgery require a stimulation intensity of 15-30 mA (pulse width 0.1–0.3 ms, frequency 2–5 Hz). Alternatively, for cranial nerve monitoring, facial nerve monitoring, and recurrent laryngeal and vagus nerve monitoring during thyroid surgery, the stimulation intensity is 0.05–5 mA (pulse width 0.1–0.2 ms, frequency 1–4 Hz).

[0052] Take a specific case as an example:

[0053] During thyroidectomy, recurrent laryngeal nerve monitoring is performed using a monopolar or bipolar stimulating electrode placed in contact with the recurrent laryngeal nerve, a needle recording electrode inserted into the thyroarytenoid or cricothyroid muscle, and a ground electrode applied to the shoulder or anterior chest. The current intensity is set to 0.5–1.0 mA, the pulse width to 100–200 µs, and the frequency to 4 Hz.

[0054] During acoustic neuroma surgery, a monopolar or bipolar stimulating electrode is used to contact the exposed facial nerve or cochlear nerve. At the same time, a needle recording electrode is inserted into the orbicularis oculi, orbicularis oris, trapezius, and other muscles. The ground electrode is attached to the forehead or the contralateral shoulder. The current intensity is set to 0.2–0.5 mA (increased gradually according to the degree of nerve exposure, not exceeding 1.5 mA), the pulse width is 100–200 µs, and the frequency is 4–6 Hz.

[0055] During neck dissection, a monopolar or bipolar stimulating electrode is placed in contact with the accessory nerve, brachial plexus, or phrenic nerve. Simultaneously, a needle recording electrode is inserted into the trapezius muscle, diaphragm, or hypothenar muscle of the hand. A ground electrode is attached to the ipsilateral shoulder or contralateral chest. Parameters should be adjusted based on nerve depth and surrounding tissue: for superficial nerves (such as the accessory nerve), the initial current is 0.3–0.8 mA; for deep nerves (such as the brachial plexus), the current can be set to 1.0–2.0 mA. Pulse width should be maintained at 100–200 µs and a frequency of 4–6 Hz.

[0056] The voltage-controlled constant current source circuit 101 includes a digital-to-analog conversion module DAC, an operational amplifier U1, a transistor Q1, and a constant current resistor R1; the output of the digital-to-analog conversion module DAC is connected to the positive input terminal of the operational amplifier U1, and the negative input terminal is connected to the emitter of the transistor Q1. The output terminal of the operational amplifier U1 is connected to the base of the transistor Q1, the emitter of the transistor Q1 is connected to the constant current resistor R1, the other end of the constant current resistor R1 is connected to GND, and the collector of the transistor is connected to the impedance detection circuit 103.

[0057] Generally speaking, the output current of electrical stimulation is adjustable from 0-30mA in 0.01mA steps, the pulse width is adjustable from 50-250us in 50us steps, and the output frequency is adjustable from 1-10Hz in 1Hz steps. The typical human body impedance in electrical stimulation applications ranges from 100Ω to 1kΩ. The impedance alarm threshold set here is 3kΩ (because the boost circuit outputs a maximum of 100V. To ensure that the constant current setting can meet 30mA, the impedance threshold is set to 3kΩ).

[0058] The current acquisition circuit 102 includes a current detection operational amplifier U2, a shunt resistor Rs, and an analog-to-digital conversion module ADC; the output voltage V1 of the boost circuit 8 is connected to one end of the shunt resistor Rs, and the other end of the shunt resistor Rs is connected to the impedance detection circuit 103; the positive and negative input terminals of the current detection operational amplifier U2 are respectively connected to the two ends of the shunt resistor, and the output of the current detection operational amplifier U2 is connected to the analog-to-digital conversion module ADC;

[0059] When the electrical stimulation current occurs, the current passing through the shunt resistor Rs passes through the circuit detection operational amplifier U2 to amplify the voltage at both ends of it, and then the analog-to-digital conversion module ADC collects the analog stimulation current information and converts the analog stimulation current information into digital information through analog-to-digital conversion. The information is transferred to the main control unit 3 through the digital isolator 6 for display and signal comparison.

[0060] The impedance detection circuit 103 includes a capacitor C1, a capacitor C2, a resistor RL, a resistor R2, a resistor R3, a solid-state relay Q2, a solid-state relay Q3, a solid-state relay Q4, and a hybrid bio-impedance detection chip AFE;

[0061] The negative pole of the input side of the solid-state relay Q3 is connected to the control pin 2 of the main control unit 3, and the positive pole of the input side of the solid-state relay Q3 is connected to the voltage V2; the negative pole of the output side of the solid-state relay Q3 is connected to the positive pole of the output side of the solid-state relay Q2; the positive pole of the output side of the solid-state relay Q3 is connected to one end of the hybrid bioimpedance detection chip AFE through the capacitor C1 and the resistor R2; the other end of the hybrid bioimpedance detection chip AFE is connected to the positive pole of the output side of the solid-state relay Q4 through the resistor R3 and the capacitor C2, the positive pole of the input side of the solid-state relay Q4 is connected to the voltage V2, and the negative pole of the input side of the solid-state relay Q4 is connected to the voltage V2. Connect to the control pin 2 of the main control unit 3, the output negative electrode of the solid-state relay Q4 is connected to the output positive electrode of the solid-state relay Q2 via the resistor RL; the input positive electrode of the solid-state relay Q2 is connected to the voltage V2, and the input negative electrode of the solid-state relay Q2 is connected to the control pin 1 of the main control unit 3; the output negative electrode of the solid-state relay Q4 is connected to the transistor collector of the voltage-controlled constant current source circuit 101; the output negative electrode of the solid-state relay Q4 is connected to the transistor collector of the voltage-controlled constant current source circuit 101; the output positive electrode of the solid-state relay Q4 is connected to the other end of the shunt resistor Rs of the current acquisition circuit 102;

[0062] Solid-state relays Q2, Q3, and Q4 all control their on / off switching via MCU signals transmitted via digital signal isolation. When MCU control pin 2 is low, the system enters impedance detection mode, turning on solid-state relays Q4 and Q3. The AC excitation signal flows through resistor R2 and capacitor C1, through load RL, and then returns to the AFE via capacitor C2 and resistor R3. The AFE converts the current signal into a voltage signal via an integrated operational amplifier. The signal is then collected and calculated using the ADC. This impedance data is then transmitted to the MCU via digital signal isolation for display and evaluation. When MCU control pin 1 is low, solid-state relay Q2 turns on, entering electrical stimulation mode.

[0063] Regarding display and judgment: Before electrical stimulation, impedance is checked. If the impedance value is less than 3kΩ, it meets the requirements (because the maximum output of the boost circuit is 100V, the impedance threshold is set to 3kΩ to meet the constant current setting of 30mA). Then electrical stimulation begins. However, at this time, the stimulation lead may fall off or become unstable. Therefore, the current value is checked in real time to determine whether it meets the set value. If it does not meet the requirements, a warning prompt is displayed to re-enter the impedance monitoring. After each stimulation, the impedance test is repeated to ensure that the lead connection is normal. This cycle is used to perform regular electrical stimulation.

[0064] like Figure 3 As shown: the main power supply circuit 4 is a circuit including a BUCK step-down topology circuit, a low-dropout linear regulator and an output filter capacitor C5;

[0065] The BUCK step-down topology circuit is a DC-DC converter with integrated MOSFET, a freewheeling diode D1, an energy storage inductor L1, an input filter capacitor C3, and an output filter capacitor C4;

[0066] In the buck topology circuit, the positive electrode of the input filter capacitor C3 is connected to the input voltage terminal V0, and the negative electrode of the input filter capacitor C3 is connected to the reference ground Gnd. The input terminal of the DC-DC converter is connected to the input voltage terminal V0, and the output terminal of the DC-DC converter is connected to the cathode of the freewheeling diode D1 and one end of the energy storage inductor L1. The anode of the freewheeling diode D1 is connected to the reference ground Gnd. The other end of the energy storage inductor L1 is connected to the anode of the output filter capacitor C4, and the cathode of the output filter capacitor C4 is connected to the reference ground Gnd. The anode of the output filter capacitor C4 is connected back to the feedback input pin FB of the DC-DC converter and the voltage V3. The feedback output pin of the DC-DC converter is connected to the reference ground Gnd.

[0067] The input end of the low-voltage dropout linear regulator LDO is connected to the anode of the output filter capacitor C4, and the output end of the low-voltage dropout linear regulator is connected to the anode of the output filter capacitor C5 and the voltage V4 to store energy and filter;

[0068] The cathode of the filter capacitor C5 is connected to the cathode of the output filter capacitor C4.

[0069] like Figure 4 As shown: the secondary power supply circuit 7 includes a BUCK step-down topology circuit and a charge pump voltage inverter;

[0070] The BUCK step-down topology circuit is a circuit comprising a DC-DC converter with integrated MOSFET, a freewheeling diode D2, an energy storage inductor L2, an output filter capacitor C6, and an input filter capacitor C7;

[0071] In the buck topology circuit, the positive electrode of input filter capacitor C6 is connected to the input voltage terminal V0iso, and the negative electrode of input filter capacitor C6 is connected to the reference ground Gndiso. The input terminal of the DC-DC converter is connected to the input voltage terminal V0iso, and the output terminal of the DC-DC converter is connected to the cathode of freewheeling diode D2 and one end of energy storage inductor L2. The anode of freewheeling diode D2 is connected to the reference ground Gndiso. The other end of energy storage inductor L2 is connected to the anode of output filter capacitor C7, and the cathode of output filter capacitor C7 is connected to the reference ground Gndiso. The anode of output filter capacitor C7 is connected back to the feedback input pin FB of the DC-DC converter and voltage V2. The feedback output pin of the DC-DC converter is connected to the reference ground Gndiso.

[0072] The input end of the charge pump voltage inverter is connected to the anode of the output filter capacitor C7, and the output end of the charge pump voltage inverter is connected to the anode of the output filter capacitor C8 and the voltage V5;

[0073] The cathode of the filter capacitor C8 is connected to the cathode of the output filter capacitor C7.

[0074] like Figure 5 As shown: the boost circuit 8 is a Boost topology circuit consisting of a DC-DC converter with an integrated MOSFET, a voltage regulator diode D3, an energy storage inductor L3, an input capacitor C9, an input capacitor C10, a resistor R4 and a resistor R5;

[0075] The positive electrode of input capacitor C9 is connected to voltage terminal V0iso, the negative electrode of input capacitor C9 is connected to reference ground Gndiso, the input terminal of the DC-DC converter is connected to voltage terminal V0iso, one end of the energy storage inductor is connected to voltage terminal V0iso, and the other end of the energy storage inductor is connected to the SW switch node of the DC-DC converter and the anode of the Zener diode; the cathode of the Zener diode is connected to the anode of output capacitor C10, and the cathode of output capacitor C10 is connected to reference ground Gndiso. The anode of output voltage C10 is connected to resistors R4 and R5 to form a voltage divider output, which is connected to the feedback input terminal of the DC-DC converter; the output value of the boost voltage is set by the resistance ratio of these two resistors;

[0076] The feedback output pin of the DC-DC converter is connected to the reference ground Gndiso; the anode of the output voltage C10 is also connected to the voltage V1.

[0077] like Figure 6 A method for using a constant current electrical stimulation system with impedance monitoring is shown, comprising the following steps:

[0078] Step 1: Start the device. The main control unit 3 controls the impedance detection circuit 103 to perform impedance detection of human tissue. If the impedance detection is abnormal, the main control unit 3 will feedback to the main control unit 3, and the main control unit 3 will send an instruction to the interactive host 1. The interactive host 1 will issue a warning and prompt whether to continue or pause. If the impedance detection is normal, the main control unit 3 will feedback to the main control unit 3 and proceed to step 2.

[0079] Step 2: After receiving the signal indicating that the impedance detection is normal, the main control unit 3 sends a secondary signal data to the voltage-controlled constant current source circuit 101, and the voltage-controlled constant current source circuit 101 outputs an electrical stimulation output current;

[0080] Step 3: The main control unit 3 sends a stimulation current detection signal to the current acquisition circuit 102, and the current acquisition circuit 102 performs stimulation current detection and feeds back the detected stimulation current to the main control unit 3;

[0081] In step 4, the main control unit 3 compares the stimulation current output in step 2 with the stimulation current fed back in step 3 to determine whether the current is normal. If the current is abnormal, the main control unit 3 sends a feedback to the main control unit 3, and the main control unit 3 sends a command to the interactive host 1. The interactive host 1 issues a warning and prompts whether to continue or pause. If the current detection is normal, the main control unit 3 sends a feedback to the main control unit 3 and proceeds to step 5.

[0082] In step 5, the main control unit 3 controls the impedance detection circuit 103 to perform impedance detection of human tissue. If the impedance detection is abnormal, the main control unit 3 is fed back to the main control unit 3, and the main control unit 3 sends an instruction to the interactive host 1, which issues an alarm. If the impedance detection is normal, the next stimulation signal data point is processed to determine whether stimulation is to be performed. If stimulation is to be performed, steps 1-5 are repeated; if stimulation is not to be performed, step 6 is performed.

[0083] Step 6: The interactive host 1 displays "continue" or "pause" to interact with the user. The user actively operates to start the next stimulation or pause.

[0084] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent replacements for some of the technical features therein. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A constant current electrical stimulation system with impedance monitoring and a method for using the same, characterized in that: include The main control unit (3) is a microcontroller used to execute control logic, data acquisition and communication protocol processing; A digital isolator (6) connected to the main control unit (3); A voltage-controlled constant current source circuit (101) is connected to the digital isolator (6), receives a stimulation signal from the main control unit (3), generates a stimulation signal, and outputs an electrical stimulation output current to human tissue; The current collection circuit (102) is connected to the digital isolator (6), and when the electrical stimulation current occurs, it collects the analog stimulation current from the human tissue and converts it into digital information to feed back to the main control unit (3); The impedance detection circuit (103) is connected to the digital isolator (6), collects the AC excitation signal applied to the human tissue, measures the voltage division signal and converts the analog stimulation current into digital information, and feeds back the voltage division signal and the digital information of the analog stimulation current to the main control unit (3); The voltage-controlled constant current source circuit (101), the current acquisition circuit (102), and the impedance detection circuit (103) together constitute a stimulation unit (10); A main power supply circuit (4) is connected to the main control unit (3) to step down and stabilize the voltage; A power isolation module (5) is connected to the main power circuit (4) and is used to reduce the voltage of the main power circuit (4); A secondary power supply circuit (7) is connected to the power isolation module (5) and is also connected to the stimulation unit (10) to supply power to the stimulation unit (10); A boost circuit (8) connected to the secondary power circuit (7) as a voltage source for the constant current electrical stimulation output current; and The interactive host (1) is connected to the main control unit (3) via a communication circuit (2) and is used to exchange data with the main control unit (3) and display information including but not limited to current setting intensity, real-time intensity of stimulation current, and impedance value.

2. The constant current electrical stimulation system with impedance monitoring according to claim 1, characterized in that: The voltage-controlled constant current source circuit (101) includes a digital-to-analog conversion module DAC, an operational amplifier U1, a transistor Q1, and a constant current resistor R1; the output of the digital-to-analog conversion module DAC is connected to the positive input terminal of the operational amplifier U1, the negative input terminal is connected to the emitter of the transistor Q1, the output terminal of the operational amplifier U1 is connected to the base of the transistor Q1, the emitter of the transistor Q1 is connected to the constant current resistor R1, the other end of the constant current resistor R1 is connected to GND, and the collector of the transistor is connected to the impedance detection circuit (103).

3. The constant current electrical stimulation system with impedance monitoring according to claim 1, characterized in that: The current acquisition circuit (102) includes a current detection operational amplifier U2, a shunt resistor Rs, and an analog-to-digital conversion module ADC; the output voltage V1 of the boost circuit (8) is connected to one end of the shunt resistor Rs, and the other end of the shunt resistor Rs is connected to the impedance detection circuit (103); the positive and negative input ends of the current detection operational amplifier U2 are respectively connected to the two ends of the shunt resistor, and the output of the current detection operational amplifier U2 is connected to the analog-to-digital conversion module ADC; When the electrical stimulation current occurs, the current passing through the shunt resistor Rs passes through the circuit detection operational amplifier U2 to amplify the voltage at both ends of the shunt resistor Rs, and then the analog stimulation current information is collected by the analog-to-digital conversion module ADC and converted into digital information through analog-to-digital conversion. The information is then transferred to the main control unit (3) through the digital isolator (6) for display and signal comparison.

4. The constant current electrical stimulation system with impedance monitoring according to claim 1, characterized in that: The impedance detection circuit (103) includes a capacitor C1, a capacitor C2, a resistor RL, a resistor R2, a resistor R3, a solid-state relay Q2, a solid-state relay Q3, a solid-state relay Q4, and a hybrid bioimpedance detection chip AFE; The negative pole of the input side of the solid-state relay Q3 is connected to the control pin 2 of the main control unit (3), and the positive pole of the input side of the solid-state relay Q3 is connected to the voltage V2; the negative pole of the output side of the solid-state relay Q3 is connected to the positive pole of the output side of the solid-state relay Q2; the positive pole of the output side of the solid-state relay Q3 is connected to one end of the hybrid bio-impedance detection chip AFE through the capacitor C1 and the resistor R2; the other end of the hybrid bio-impedance detection chip AFE is connected to the positive pole of the output side of the solid-state relay Q4 through the resistor R3 and the capacitor C2, the positive pole of the input side of the solid-state relay Q4 is connected to the voltage V2, and the negative pole of the input side of the solid-state relay Q4 is connected to the main control unit (3). The negative electrode of the output side of the solid-state relay Q4 is connected to the positive electrode of the output side of the solid-state relay Q2 via the resistor RL; the positive electrode of the input side of the solid-state relay Q2 is connected to the voltage V2, and the negative electrode of the input side of the solid-state relay Q2 is connected to the control pin 1 of the main control unit (3); the negative electrode of the output side of the solid-state relay Q4 is connected to the transistor collector of the voltage-controlled constant current source circuit (101); the negative electrode of the output side of the solid-state relay Q4 is connected to the transistor collector of the voltage-controlled constant current source circuit (101); the positive electrode of the output side of the solid-state relay Q4 is connected to the other end of the shunt resistor Rs of the current acquisition circuit (102); Solid-state relays Q2, Q3, and Q4 all control their on / off switching via MCU signals transmitted via digital signal isolation. When MCU control pin 2 is low, the system enters impedance detection mode, turning on solid-state relays Q4 and Q3. The AC excitation signal flows through resistor R2 and capacitor C1, through load RL, and then returns to the AFE via capacitor C2 and resistor R3. The AFE converts the current signal into a voltage signal via an integrated operational amplifier. The signal is then collected and calculated using the ADC. This impedance data is then transmitted to the MCU via digital signal isolation for display and evaluation. When MCU control pin 1 is low, solid-state relay Q2 turns on, entering electrical stimulation mode.

5. The constant current electrical stimulation system with impedance monitoring according to claim 1, characterized in that: The main power supply circuit (4) is a circuit including a BUCK step-down topology circuit, a low voltage drop linear regulator and an output filter capacitor C5; The BUCK step-down topology circuit is a DC-DC converter with integrated MOSFET, a freewheeling diode D1, an energy storage inductor L1, an input filter capacitor C3, and an output filter capacitor C4; In the buck topology circuit, the positive electrode of the input filter capacitor C3 is connected to the input voltage terminal V0, and the negative electrode of the input filter capacitor C3 is connected to the reference ground Gnd. The input terminal of the DC-DC converter is connected to the input voltage terminal V0, and the output terminal of the DC-DC converter is connected to the cathode of the freewheeling diode D1 and one end of the energy storage inductor L1. The anode of the freewheeling diode D1 is connected to the reference ground Gnd. The other end of the energy storage inductor L1 is connected to the anode of the output filter capacitor C4, and the cathode of the output filter capacitor C4 is connected to the reference ground Gnd. The anode of the output filter capacitor C4 is connected back to the feedback input pin FB of the DC-DC converter and the voltage V3. The feedback output pin of the DC-DC converter is connected to the reference ground Gnd. The input end of the low-voltage dropout linear regulator LDO is connected to the anode of the output filter capacitor C4, and the output end of the low-voltage dropout linear regulator is connected to the anode of the output filter capacitor C5 and the voltage V4 to store energy and filter; The cathode of the filter capacitor C5 is connected to the cathode of the output filter capacitor C4.

6. The constant current electrical stimulation system with impedance monitoring according to claim 1, characterized in that: The secondary power supply circuit (7) includes a BUCK step-down topology circuit and a charge pump voltage inverter; The BUCK step-down topology circuit is a circuit comprising a DC-DC converter with integrated MOSFET, a freewheeling diode D2, an energy storage inductor L2, an output filter capacitor C6, and an input filter capacitor C7; In the buck topology circuit, the positive electrode of input filter capacitor C6 is connected to the input voltage terminal V0iso, and the negative electrode of input filter capacitor C6 is connected to the reference ground Gndiso. The input terminal of the DC-DC converter is connected to the input voltage terminal V0iso, and the output terminal of the DC-DC converter is connected to the cathode of freewheeling diode D2 and one end of energy storage inductor L2. The anode of freewheeling diode D2 is connected to the reference ground Gndiso. The other end of energy storage inductor L2 is connected to the anode of output filter capacitor C7, and the cathode of output filter capacitor C7 is connected to the reference ground Gndiso. The anode of output filter capacitor C7 is connected back to the feedback input pin FB of the DC-DC converter and voltage V2. The feedback output pin of the DC-DC converter is connected to the reference ground Gndiso. The input end of the charge pump voltage inverter is connected to the anode of the output filter capacitor C7, and the output end of the charge pump voltage inverter is connected to the anode of the output filter capacitor C8 and the voltage V5; The cathode of the filter capacitor C8 is connected to the cathode of the output filter capacitor C7.

7. The constant current electrical stimulation system with impedance monitoring according to claim 1, characterized in that: The boost circuit (8) is a Boost topology circuit consisting of a DC-DC converter with an integrated MOSFET, a voltage regulator diode D3, an energy storage inductor L3, an input capacitor C9, an input capacitor C10, a resistor R4, and a resistor R5; The positive electrode of input capacitor C9 is connected to voltage terminal V0iso, the negative electrode of input capacitor C9 is connected to reference ground Gndiso, the input terminal of the DC-DC converter is connected to voltage terminal V0iso, one end of the energy storage inductor is connected to voltage terminal V0iso, and the other end of the energy storage inductor is connected to the SW switch node of the DC-DC converter and the anode of the Zener diode; the cathode of the Zener diode is connected to the anode of output capacitor C10, and the cathode of output capacitor C10 is connected to reference ground Gndiso. The anode of output voltage C10 is connected to resistors R4 and R5 to form a voltage divider output, which is connected to the feedback input terminal of the DC-DC converter; the output value of the boost voltage is set by the resistance ratio of these two resistors; The feedback output pin of the C-DC converter is connected to the reference ground Gndiso; the anode of the output voltage C10 is also connected to the voltage V1.

8. A method for using the constant current electrical stimulation system with impedance monitoring according to any one of claims 1 to 7, characterized in that: Includes the following steps Step 1, start the device, the main control unit (3) controls the impedance detection circuit (103) to perform impedance detection of human tissue, if the impedance detection is abnormal, the main control unit (3) is fed back to the main control unit (3), and the main control unit (3) sends an instruction to the interactive host (1), and the interactive host (1) issues a warning and prompts whether to continue or pause; if the impedance detection is normal, the main control unit (3) is fed back to the main control unit (3) and step 2 is performed; Step 2: After receiving the signal indicating that the impedance detection is normal, the main control unit (3) sends a secondary signal data to the voltage-controlled constant current source circuit (101), and the voltage-controlled constant current source circuit (101) outputs an electrical stimulation output current; Step 3, the main control unit (3) sends a stimulation current detection signal to the current acquisition circuit (102), and the current acquisition circuit (102) performs stimulation current detection and feeds back the detected stimulation current to the main control unit (3); In step 4, the main control unit (3) compares the stimulation current output in step 2 with the stimulation current fed back in step 3 to determine whether the current is normal. If the current is abnormal, the feedback is sent to the main control unit (3), and the main control unit (3) sends an instruction to the interactive host (1). The interactive host (1) issues a warning and prompts whether to continue or pause. If the current detection is normal, the feedback is sent to the main control unit (3) and step 5 is performed. In step 5, the main control unit (3) controls the impedance detection circuit (103) to perform impedance detection of human tissue. If the impedance detection is abnormal, the main control unit (3) is fed back to the main control unit (3), and the main control unit (3) sends an instruction to the interactive host (1), and the interactive host (1) issues an alarm. If the impedance detection is normal, the next stimulation signal data point is performed to determine whether stimulation is performed. If stimulation is performed, steps 1-5 are repeated; if stimulation is not performed, step 6 is performed. Step 6: The interactive host (1) displays "continue" or "pause" to interact with the user.

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