Electrical stimulation circuit and medical equipment

Abstract

The utility model provides an electrical stimulation circuit and medical equipment, and the electrical stimulation circuit comprises a timer which is used for timing to a first trigger time and a second trigger time; the pulse width modulator is connected with the timer, generates a first pulse signal under the condition of the first trigger time, and generates a second pulse signal under the condition of the second trigger time; the driving circuit is connected with the pulse width modulator, the first pulse signal outputs a first stimulation current through the driving circuit, the second pulse signal outputs a second stimulation current through the driving circuit, and the first stimulation current and the second stimulation current are opposite in direction; the stimulation electrode is connected with the driving circuit, the stimulation electrode is in contact with a plurality of stimulation positions and is used for randomly outputting a first stimulation current and a second stimulation current to any stimulation position, and the nervous system of the user can be prevented from adapting to the stimulation mode and denying the treatment effect; meanwhile, the dosage of charges conveyed to the body of the patient can be accurately controlled, and charge balance is ensured, so that safety is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of medical devices, in particular to an electrical stimulation circuit and a medical device. Background Art

[0002] Essential tremor is a common neurological disorder characterized by involuntary rhythmic oscillations in various parts of the body (especially the hands and arms), severely impairing the patient's daily activities and quality of life. Current treatment options, including medications and invasive surgeries, often have limited efficacy or pose significant risks and side effects. Therefore, there is an urgent need for innovative and non-invasive methods to address essential tremor.

[0003] Current medical devices can stimulate nerves by outputting stimulating currents through defibrillators to relieve essential tremor. However, the stimulating signals of current defibrillators can only control the presence or absence, unable to achieve dynamic smooth control and accurately control the output of stimulating signals, resulting in poor user experience. Moreover, existing defibrillators use fixed stimulation patterns to regularly stimulate fixed positions, and the human nervous system may adapt to the stimulation pattern, causing the stimulating action to fail to exert its relieving and therapeutic effects. Summary of the Utility Model

[0004] Embodiments of the utility model provide an electrical stimulation circuit and a medical device to solve the problems existing in the related art. The technical solutions are as follows:

[0005] In a first aspect, embodiments of the utility model provide an electrical stimulation circuit, including:

[0006] A timer for timing to a first trigger time and a second trigger time;

[0007] A pulse width modulator connected to the timer for generating a first pulse signal at the first trigger time and a second pulse signal at the second trigger time;

[0008] A drive circuit connected to the pulse width modulator. The first pulse signal outputs a first stimulating current through the drive circuit, and the second pulse signal outputs a second stimulating current through the drive circuit. The first stimulating current and the second stimulating current are in opposite directions;

[0009] Stimulating electrodes connected to the drive circuit. The stimulating electrodes are in contact with multiple stimulating positions for randomly outputting the first stimulating current and the second stimulating current to any one of the stimulating positions.

[0010] In an embodiment, it further includes:

[0011] A voltage / level converter, whose input terminal is connected to the pulse width modulator, and whose output terminal is connected to the drive circuit, is used to perform voltage / level conversion on the first pulse signal and the second pulse signal and output them to the drive circuit.

[0012] In one embodiment, the drive circuit includes four transistors, and the four transistors are combined to form an H-bridge circuit, and the load of the H-bridge circuit is connected to the stimulation electrode.

[0013] In one embodiment, the H-bridge circuit includes a first NMOS transistor, a second NMOS transistor, a first PMOS transistor, and a second PMOS transistor. The source electrodes of the first PMOS transistor and the second PMOS transistor are connected to each other and connected to the power supply. The gate electrodes of the first PMOS transistor and the second PMOS transistor are both connected to the same voltage / level converter. The drain electrodes of the first PMOS transistor and the second PMOS transistor are respectively connected to the positive and negative poles of the stimulation electrode; the drain electrode of the first PMOS transistor is connected to the drain electrode of the first NMOS transistor, the drain electrode of the second PMOS transistor is connected to the drain electrode of the second NMOS transistor, the gate electrodes of the first NMOS transistor and the second NMOS transistor are connected to another voltage / level converter, and the source electrodes of the first NMOS transistor and the second NMOS transistor are connected to each other and grounded through a constant current driver.

[0014] In one embodiment, when the first PMOS transistor and the second PMOS transistor are in the on state, the stimulation current flows to the stimulation electrode to neutralize the voltage difference between the two stimulation electrodes.

[0015] In one embodiment, when the first PMOS transistor and the second PMOS transistor are both in the on state, the stimulation current flows through the first PMOS transistor and the first NMOS transistor to the constant current driver, and then flows to the ground.

[0016] In one embodiment, when the first PMOS transistor, the second PMOS transistor, and the first NMOS transistor are all in the on state, the first PMOS transistor is turned off, and the stimulation current flows to the stimulation electrode.

[0017] In one embodiment, the stimulation positions include the corresponding positions of the radial nerve, the median nerve, and the ulnar nerve.

[0018] In one embodiment, it further includes:

[0019] A microcontroller, which is built-in with a timer and a pulse width modulator;

[0020] A DC / DC boost regulator, whose feedback branch is connected to a digital-to-analog converter, and the digital-to-analog converter is connected to a microcontroller for modifying the power supply voltage according to the required output current.

[0021] In a second aspect, an embodiment of the present invention provides a medical device including the electrical stimulation circuit as described above.

[0022] The advantages or beneficial effects in the above technical solutions at least include:

[0023] The present invention can make the stimulation pattern become random, randomly outputting the corresponding stimulation current to any stimulation position, which can prevent the user's nervous system from adapting to the stimulation pattern and negating the treatment effect; secondly, the present invention precisely generates the first stimulation current and the second stimulation current through precise timing. The first stimulation current and the second stimulation current respectively correspond to the stimulation in the first stage and the second stage, which can precisely control the charge dose delivered to the patient's body and also ensure charge balance to ensure safety.

[0024] The above summary is only for the purpose of the specification and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features of the present invention will be readily apparent by referring to the drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In the drawings, unless otherwise specified, the same reference numerals throughout the several views denote the same or similar components or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in accordance with the present invention and should not be regarded as limiting the scope of the present invention.

[0026] Figure 1 is a circuit schematic diagram of the electrical stimulation circuit of the present invention;

[0027] Figure 2 is a schematic diagram of three stages of the stimulation pulse of the present invention;

[0028] Figure 3 is a schematic diagram of adjusting the output current of the H-bridge circuit in each stage of the present invention;

[0029] Figure 4 is a schematic diagram of the H-bridge circuit conduction in the t1 - t2 period of the present invention;

[0030] Figure 5 is a schematic diagram of the H-bridge circuit conduction in the t2 - t3 period of the present invention;

[0031] Figure 6Schematic diagram of the H-bridge circuit conduction during the t3-t4 period of the present utility model;

[0032] Figure 7 Schematic diagram of the circuit during the process of monitoring the actual output current of the present utility model;

[0033] Figure 8 Schematic diagram of the fault detection process of the present utility model;

[0034] Figure 9 Schematic diagram of the circuit connection of the DC / DC boost regulator of the present utility model;

[0035] Figure 10 Schematic diagram showing that the high-voltage power supply can be increased or decreased in real time according to the value of the output current of the present utility model. Detailed implementation manners

[0036] In the following, only some exemplary embodiments are simply described. As those skilled in the art can recognize, the described embodiments can be modified in various different ways without departing from the spirit or scope of the present utility model. Therefore, the drawings and descriptions are considered to be exemplary in nature rather than restrictive.

[0037] This embodiment provides an electrical stimulation circuit, which can be applied to wearable medical devices, aiming to provide targeted electrical stimulation to the radial nerve, median nerve, and ulnar nerve located in the wrist area, so as to relieve tremors in the long term by optimizing the transmission of peripheral nerve stimulation. At the same time, it improves the effectiveness and personalization of the treatment of essential tremor, providing a promising solution for patients seeking to improve symptom management and quality of life.

[0038] As Figure 1 shown, an electrical stimulation circuit of this embodiment includes a microcontroller, a voltage / level converter, a drive circuit, and stimulation electrodes. The input / output (I / O) pins of the microcontroller are connected to the voltage / level converter and then to the drive circuit. The load of the drive circuit is connected to the stimulation electrodes, and the stimulation electrodes are used to contact the specified stimulation positions in the human body. By controlling the logic of the transistors in the drive circuit through the microcontroller, a stimulation current is generated. Among them, the stimulation positions include the corresponding positions of the radial nerve, the corresponding positions of the median nerve, and the corresponding positions of the ulnar nerve.

[0039] In this embodiment, for the voltage / level converter, its input end is connected to the pulse width modulator, and its output end is connected to the drive circuit. The voltage / level converter is used to convert the low-voltage pulse signal generated by the microcontroller into a signal suitable for driving the gates of the transistors in the above drive circuit.

[0040] The microcontroller may be built-in with a pulse width modulator and a timer. The timer is connected to the pulse width modulator through a peripheral interconnect module PPI. By timing with the timer, once the timer is triggered, a cascading effect will automatically activate all relevant modules at predefined and precise time intervals. For example, it activates the pulse width modulator to adjust the amplitude or frequency of the output signal, controls the switching state of the transistors in the drive circuit connected to the microcontroller, and then generates a corresponding stimulation current.

[0041] In this embodiment, the timer is used for timing. After the timer is started, it begins to count. When the timer counts to the first trigger time, it triggers the pulse width modulator to generate a first pulse signal. When the timer counts to the second trigger time, it triggers the pulse width modulator to generate a second pulse signal. Among them, the first pulse signal and the second pulse signal are used to control the on and off times of the transistors in the drive circuit, so as to accurately change the direction and magnitude of the current in the drive circuit.

[0042] The first pulse signal outputs a first stimulation current after passing through the drive circuit, and the second pulse signal outputs a second stimulation current after passing through the drive circuit. The first stimulation current and the second stimulation current are in opposite directions. The stimulation electrode is connected to the output end of the drive circuit, and both the first stimulation current and the second stimulation current act on the designated position of the human body through the stimulation electrode to achieve the effect of electrical stimulation.

[0043] In this embodiment, the stimulation electrode can be pre-contacted with multiple designated stimulation positions on the human body. The stimulation positions involve three nerves, namely the radial nerve, the median nerve, and the ulnar nerve. The stimulation mode of the stimulation electrode is set to a random mode, that is, within each cycle (after the output of the first stimulation current and the second stimulation current is completed, it is one cycle), the state of the stimulation pulse output by the stimulation electrode corresponding to one nerve switches to the stimulation pulse output by the stimulation electrode corresponding to another nerve. This switching action is called a stimulation position switch. Before the stimulation position switch occurs, the stimulation electrode corresponding to the current nerve is controlled to output a designated stimulation pulse, and the order of this stimulation position switch is random.

[0044] At the same time, the stimulation parameters corresponding to a single stimulation pulse also randomly vary within a specified range, making the output stimulation current also have randomness. Randomness may help prevent the user's nervous system from adapting to the stimulation mode and negating the treatment effect.

[0045] Among them, the first stimulation current and the second stimulation current are in opposite directions and equal in magnitude. Outputting the corresponding stimulation current to any nerve position in the random mode can be understood as, for example, if there are four electrodes A, B, C, and D, the first stimulation current can be output from A to B, and the second stimulation current from B to A; or the first stimulation current can be output from A to C, and the second stimulation current from C to A, and so on.

[0046] The stimulation parameters include current amplitude, pulse interval / stimulation frequency, and pulse width, etc. Each stimulation parameter can have a fixed value or a random value. The random current amplitude is uniformly distributed within a specified range with an average value, and the average value determines the average charge dose delivered to the patient's body. The range can be adjusted, but the upper limit always remains below the maximum tolerance threshold. For example, the amplitude may vary between 3.5 mA and 4.5 mA, with an average value of 4.0 mA, and the charge dose provided by this mode is equivalent to that of a fixed 4.0 mA mode.

[0047] The random pulse interval follows a uniform distribution within a specified range and has an average value, which determines the average charge dose delivered to the patient's body. For example, the pulse interval can range from 2 ms to 18 ms, with an average value of 10 ms, and the charge dose provided by this mode is equivalent to that of a fixed 100 Hz mode.

[0048] The random pulse width follows a uniform distribution within a specified range, with the mean being the average value, and this average value affects the duration of electrical stimulation of the patient's body. For example, the pulse width can range from 250 us to 350 us, with an average value of 300 us.

[0049] The stimulation location of the stimulation electrode involves switching between three nerves (radial nerve, median nerve, ulnar nerve). In each cycle, the device controls the stimulation electrode corresponding to the current nerve to output a series of stimulation pulses before switching the stimulation location, and the order of switching the stimulation location is random, which helps prevent the user's nervous system from adapting to the stimulation pattern and negating the treatment effect. The number of pulses in each cycle is uniformly distributed within a specified range and has an average value, and the average value determines the switching frequency and the amount of charge allocated to the stimulation electrode corresponding to this specific nerve. For example, the stimulation electrode corresponding to the radial nerve can be controlled to output 5 - 15 pulses (average value of 10 pulses), the stimulation electrode corresponding to the median nerve can be controlled to output 5 - 15 pulses (average value of 10 pulses), and the stimulation electrode corresponding to the ulnar nerve can be controlled to output 2 - 8 pulses (average value of 5 pulses). This mode distributes 40%, 40%, and 20% of the charge to the stimulation electrode corresponding to the radial nerve, the stimulation electrode corresponding to the median nerve, and the stimulation electrode corresponding to the ulnar nerve, respectively. Assuming an average pulse interval of 10 ms, the equivalent switching frequency is 4 Hz (250 ms).

[0050] Among them, a pseudo - random generator can be used to create a random pattern, and the initial random seed can be shuffled when the device is powered on, and the resulting pseudo - random pattern is imperceptible to the human body.

[0051] In this embodiment, the drive circuit is an H-bridge circuit. The drive circuit includes four transistors, and the four transistors are combined to form an H-bridge circuit. The load of the H-bridge circuit is connected to the positive and negative electrodes of the stimulation electrode. Specifically, the H-bridge circuit includes a first NMOS transistor, a second NMOS transistor, a first PMOS transistor, and a second PMOS transistor. The source electrodes of the first PMOS transistor and the second PMOS transistor are connected and connected to the power supply. The gate electrodes of the first PMOS transistor and the second PMOS transistor are both connected to the same voltage / level converter. The drain electrodes of the first PMOS transistor and the second PMOS transistor are respectively connected to the positive and negative electrodes of the stimulation electrode; the drain electrode of the first PMOS transistor is connected to the drain electrode of the first NMOS transistor, and the drain electrode of the second PMOS transistor is connected to the drain electrode of the second NMOS transistor. The gate electrodes of the first NMOS transistor and the second NMOS transistor are connected to another voltage / level converter. The source electrodes of the first NMOS transistor and the second NMOS transistor are connected and grounded through a constant current driver. The H-bridge circuit can invert the voltage / current reverse of the load connected thereto.

[0052] As Figure 2 shown, the stimulation electrode of this embodiment outputs a first stimulation current and a second stimulation current, corresponding to three stages of the stimulation pulse in one cycle, including a first stage, a neutral phase, and a second stage. The first stage starts when the timer starts timing and reaches the first trigger time CC0, and the second stage starts at the second trigger time CC2. Specifically, when the timer reaches these CC0–CC3 moments:

[0053] +(CC0): The first stage starts: The timer triggers the PWM1 task through the PPI. PWM1 controls 4 transistors to generate the first phase. The pulse width is controlled by PWM, with a precision of 62.5 ns at a 16 MHz clock.

[0054] +(CC1) Midpoint of the first phase: The timer triggers the analog-to-digital converter ADC to sample the output current of the first phase.

[0055] +(CC2): The second stage starts: The timer triggers the PWM2 task through the PPI. PWM2 controls 4 transistors to generate the second phase. The pulse width is controlled by PWM, with a precision of 62.5 ns at a 16 MHz clock.

[0056] +(CC3) Midpoint of the second phase: The timer triggers the analog-to-digital converter ADC to sample the output current of the second phase.

[0057] The above analog-to-digital converter ADC is connected to a timer through a peripheral interconnect module and is used to collect the intermediate voltage of the first stimulation current when the timer counts to the first acquisition time CC1, and to collect the intermediate voltage of the second stimulation current when the timer counts to the second acquisition time CC3. The analog-to-digital converter samples the voltage between two pulses and converts the reading into current through the following formula: IOUT = VOUT / RREF; if the difference between the measured output current and the required current is greater than the fault threshold, a fault is detected.

[0058] In order to solve the problem of current overshoot during the activation of the stimulation pulse in this embodiment, the control of all four transistors in the H-bridge circuit is coordinated at each stage of the stimulation pulse generation, which is different from the traditional practice of only using two transistors. Combined Figures 3 to 6 As shown, the specific control method is as follows:

[0059] At time t1 in the first stage: Turn on two PMOSs, that is, both the first PMOS transistor and the second PMOS transistor are in the conducting state to neutralize any voltage difference between the two electrodes. This step generates a very short surge current (<100 ns).

[0060] At time t2 in the first stage: Based on the control at time t1, turn on an NMOS to start the stimulation current. That is, on the basis of turning on the first PMOS transistor and the second PMOS transistor, turn on the first NMOS transistor. The stimulation current does not flow through the electrode. Instead, it directly flows to the constant current driver.

[0061] At time t3 in the first stage: Based on the control at time t2, turn off the first PMOS transistor about 200 ns after turning on the first NMOS transistor to redirect the stimulation current to the stimulation electrode. This marks the start of the first stage of stimulation. This strategy can minimize the unnecessary spikes in the output current that appear on the electrode.

[0062] At time t4 in the first stage: Turn off all PMOSs and NMOSs to end the stimulation in the first stage.

[0063] Combined Figure 3 As shown, at times t5, t6, t7, and t8, the corresponding control programs are executed to generate the stimulation in the second stage.

[0064] The above times t1 to t4 correspond to the first stage of the stimulation pulse, times t4 to t5 correspond to the neutral phase, and times t5 to t8 correspond to the second stage of the stimulation pulse.

[0065] The beneficial effects of this embodiment are:

[0066] High-precision timing: Achieving a timing accuracy with a pulse width less than 1 us in two-phase, neutral-phase, and current measurements is crucial for delivering an accurate dose of charge and ensuring charge balance between the two phases of a biphasic stimulation pulse.

[0067] Robust operation: The timing accuracy is not affected by the microcontroller load. Once started, all modules trigger in a seamless domino effect without relying on continuous monitoring by the main microcontroller.

[0068] Real-time current monitoring: Facilitates measuring the actual output current at precise time intervals during pulse generation, enabling detection of errors in stimulation delivery, such as electrode disconnect or impaired electrode-skin interface, thereby enhancing safety and effectiveness.

[0069] Eliminating current overshoot: A novel switching method effectively eliminates current surges without additional hardware, thus minimizing complexity.

[0070] The working principle of an electrical stimulation circuit is as follows:

[0071] Step S1: Obtain the stimulation requirement and activate the timer according to the stimulation requirement;

[0072] The stimulation requirement can be initiated by a user who needs to use a stimulation electrode for electrical stimulation. After activating the timer, the timer starts timing.

[0073] Step S2: Generate a first stimulation current by the microcontroller when the timer counts to the first trigger time;

[0074] Step S3: Generate a second stimulation current by the microcontroller when the timer counts to the second trigger time; The first stimulation current and the second stimulation current are in opposite directions;

[0075] The generation of the first stimulation current and the second stimulation current has randomness. Specifically:

[0076] Randomly set each pulse parameter based on a preset specified range. The pulse parameters include current amplitude, pulse interval, and pulse width;

[0077] Generate the first stimulation current and the second stimulation current based on the pulse parameters.

[0078] Step S4: Randomly switch the stimulation position and make the stimulation electrode output the first stimulation current and the second stimulation current to the stimulation position. Incorporating randomization / randomness into the stimulation pattern while still delivering the required dose of charge helps prevent the user's nervous system from adapting to the stimulation pattern and negating the therapeutic effect.

[0079] In this embodiment, in order to monitor the actual output current, such as Figure 7As shown, collect the intermediate voltage of the first stimulation current and the intermediate voltage of the second stimulation current; perform current calculations on the intermediate voltage of the first stimulation current and the intermediate voltage of the second stimulation current respectively according to the formula IOUT = VOUT / RREF to obtain the first-stage stimulation current and the second-stage stimulation current;

[0080] Compare the first-stage stimulation current and the second-stage stimulation current with a preset target current respectively. When the difference between the first-stage stimulation current and the target current is greater than the fault threshold, and / or the difference between the second-stage stimulation current and the target current is greater than the fault threshold, generate a fault signal to trigger a fault event.

[0081] Among them, the fault threshold is proportional to the required output current. For example, the fault threshold for an output current of 0.3 mA is set to + / -0.1 mA, while the fault threshold for an output current of 10 mA is set to + / -0.2 mA.

[0082] In this embodiment, the actual output current of each stimulation pulse is measured by measuring the voltage across the reference resistor RREF during the pulse generation process, and the measurement is performed at the midpoints of the first stage and the second stage (as described above), and the results are averaged. The goal is to continuously monitor the real-time output current in order to respond promptly to potential fault situations. These faults usually occur when the electrode-skin interface is damaged, thus hindering the stimulator's ability to provide the expected stimulation current. This mechanism can protect the user from potential electric shocks in case of a fault.

[0083] To enhance the robustness of fault detection and prevent false alarms, refer to Figure 8 As shown, the electrical stimulation method further includes:

[0084] Each channel of the electrical stimulation circuit is equipped with an error counter. In the case of a fault event, generate an increment signal and send it to the counter to increase the counter count; in the case of no fault event, generate a decrement signal and send it to the counter to decrease the counter count;

[0085] When the count value of the counter exceeds a preset threshold, generate a stop instruction, and the stop instruction is used to control the stimulation electrode to stop outputting the stimulation current. When a fault event occurs, the counter increments; otherwise, it decrements; when the counter exceeds the specified preset threshold, a fault will be detected. For example, when the preset threshold is 10 fault events, it takes about 100 milliseconds and 10 pulses to detect a fault.

[0086] When a fault is detected, it is designated for handling; the stimulation circuit executes an immediate stop command to immediately stop the electrical stimulation to prevent potential user injury. However, a recovery attempt will be made, that is, a test pulse of a preset amplitude is generated every second, which can be a test pulse with an amplitude of 0.3 mA, to separately evaluate the channel connection. Determine whether the output current of the stimulation electrode matches the test pulse. If it matches, it means that the channel being tested has recovered. If the output current of the stimulation electrode is significantly different from the test pulse, it means that the channel being tested has not recovered.

[0087] If all channels have been successfully recovered, normal stimulation is resumed, and any parameter updates made during the recovery period are retained, so that the stimulation electrode outputs the first stimulation current and the second stimulation current again. However, after five attempts fail, the fault is designated as confirmed. Then, the device terminates the stimulation session and notifies the user through the LED indicator and the application.

[0088] In some embodiments, the power supply voltage can also be adjusted according to the required output current. Assuming that the stimulator only needs to generate a low output current, the high-voltage power supply can be reduced; similarly, when the stimulator needs to generate a high output current, the high-voltage power supply can be increased accordingly, so as to achieve the effect of an adaptive high-voltage power supply. Specifically:

[0089] By adding a DC / DC boost regulator to the stimulation circuit and adding a digital-to-analog converter (DAC) to the feedback branch of the DC / DC boost regulator to modify the high-voltage generator circuit, as Figure 9 shown. Among them, the DAC is controlled by a microcontroller (MCU). By adjusting VTUNE, the value of VOUT can be adjusted according to the following formula: VOUT = VTUNE + (VFB - VTUNE)(R1 + R2) / R1.

[0090] Among them, VFB is a fixed-value feedback voltage specified by the DC / DC boost regulator, and R1 and R2 are both reference resistors.

[0091] When VTUNE = 0, then VOUT = VFB(R1 + R2) / R1, which is the highest value that the electrical stimulation circuit can generate. When VTUNE = VFB, then VOUT = VTUNE, which is the minimum value.

[0092] As Figure 10 shown, according to the value of the output current, the high-voltage power supply can be increased or decreased in real time.

[0093] The above-mentioned adaptive solution has two advantages: First, adjusting the high-voltage power supply as needed can significantly reduce power consumption; although the electrical stimulation circuit is designed to generate a maximum of 10 mA at a 100V power supply, in most cases, the user does not need the maximum stimulation current; if the user only needs 5 mA, the high-voltage power supply can be reduced to 80V, which can significantly reduce power consumption and extend battery life.

[0094] Second, reducing the high-voltage power supply helps to more easily detect current faults; if the electrode interface is slightly damaged, the reduced high-voltage power supply can more easily detect current faults.

[0095] Another embodiment of the present utility model further provides a medical device, which includes the electrical stimulation circuit as described above. For the corresponding circuit modules and functions in the medical device of the embodiment of the present utility model, reference can be made to the corresponding descriptions in the above-mentioned electrical stimulation circuit, and details are not described herein again.

[0096] In the description of this specification, the descriptions with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present utility model. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0097] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" can explicitly or implicitly include at least one of these features. In the description of the present utility model, "a plurality" means two or more, unless otherwise specifically defined.

[0098] As described above, the above are only the specific embodiments of the present utility model, but the protection scope of the present utility model is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present utility model can easily think of various changes or substitutions, and these should all be covered within the protection scope of the present utility model. Therefore, the protection scope of the present utility model should be subject to the protection scope of the claims.

Claims

1. An electrical stimulation circuit, characterized in that: include: A timer, used for timing to a first trigger time and a second trigger time; a pulse width modulator, connected to the timer, for generating a first pulse signal at the first trigger time and generating a second pulse signal at the second trigger time; A driving circuit connected to the pulse width modulator, wherein the first pulse signal outputs a first stimulation current through the driving circuit, and the second pulse signal outputs a second stimulation current through the driving circuit, and the first stimulation current is in the opposite direction to the second stimulation current; A stimulation electrode is connected to the driving circuit, and the stimulation electrode contacts a plurality of stimulation positions, and is used to randomly output the first stimulation current and the second stimulation current to any stimulation position.

2. The electrical stimulation circuit according to claim 1, characterized in that: Also includes: A voltage / level converter, whose input end is connected to the pulse width modulator and whose output end is connected to the drive circuit, is used for performing voltage / level conversion on the first pulse signal and the second pulse signal and outputting them to the drive circuit.

3. The electrical stimulation circuit according to claim 2, characterized in that: The driving circuit includes four transistors, which are combined to form an H-bridge circuit, and the load of the H-bridge circuit is connected to the stimulation electrode.

4. The electrical stimulation circuit according to claim 3, characterized in that: The H-bridge circuit includes a first NMOS transistor, a second NMOS transistor, a first PMOS transistor and a second PMOS transistor, the source of the first PMOS transistor is connected to the source of the second PMOS transistor and is connected to a power supply, the gate of the first PMOS transistor and the gate of the second PMOS transistor are both connected to the same voltage / level converter, the drain of the first PMOS transistor and the drain of the second PMOS transistor are respectively connected to the positive and negative poles of the stimulation electrode; the drain of the first PMOS transistor is connected to the drain of the first NMOS transistor, the drain of the second PMOS transistor is connected to the drain of the second NMOS transistor, the gate of the first NMOS transistor and the gate of the second NMOS transistor are connected to another voltage / level converter, the source of the first NMOS transistor is connected to the source of the second NMOS transistor and is grounded after a constant current driver.

5. The electrical stimulation circuit according to claim 4, characterized in that: When the first PMOS transistor and the second PMOS transistor are turned on, the stimulation current flows to the stimulation electrode to neutralize the voltage difference between the two stimulation electrodes.

6. The electrical stimulation circuit according to claim 5, characterized in that: When the first PMOS transistor and the second PMOS transistor are both in the on state, the stimulation current flows through the first PMOS transistor and the first NMOS transistor to the constant current driver, and then flows to the ground.

7. The electrical stimulation circuit according to claim 6, characterized in that: When the first PMOS transistor, the second PMOS transistor, and the first NMOS transistor are all in the on state, the first PMOS transistor is turned off, and the stimulation current flows to the stimulation electrode.

8. The electrical stimulation circuit according to claim 1, characterized in that: The stimulation positions include the corresponding position of the radial nerve, the corresponding position of the median nerve and the corresponding position of the ulnar nerve.

9. The electrical stimulation circuit according to claim 1, characterized in that: Also includes: A microcontroller having the timer and the pulse width modulator built therein; A DC / DC boost regulator has a feedback branch connected to a digital-to-analog converter, which is connected to the microcontroller and is used to modify the power supply voltage according to the required output current.

10. A medical device, characterized in that: It comprises the electrical stimulation circuit as claimed in any one of claims 1 to 9.

Images