WO2024066999A1

WO2024066999A1 - Electrical stimulator and electrical neutralization protection method for electrical stimulator

Info

Publication number: WO2024066999A1
Application number: PCT/CN2023/117380
Authority: WO
Inventors: 戴聿昌; 庞长林; 姚阳屹; 马芳
Original assignee: 微智医疗器械有限公司
Priority date: 2022-09-30
Filing date: 2023-09-07
Publication date: 2024-04-04
Also published as: CN115445083B; CN115445083A

Abstract

Disclosed are an electrical stimulator and an electrical neutralization protection method for an electrical stimulator. The electrical stimulator comprises N electrodes, a negative phase pulse generation circuit, a first switch, a positive phase pulse generation circuit, a second switch, N third switches, N fourth switches, a leakage current acquisition module, and a control module, wherein N is ≥ 1. N electrical pulse channels are formed between the N electrodes and the negative phase pulse generation circuit or the positive phase pulse generation circuit. One ends of the N third switches are connected to the N electrical pulse channels, respectively, and the other ends are grounded; the N fourth switches connect or disconnect power supply of the N electrical pulse channels, respectively. The control module is used for controlling the fourth switch of a corresponding electrical pulse channel to be disconnected and controlling at least one of the positive phase pulse generation circuit, the second switch, and the third switches.

Description

Electric stimulator and electric neutralization protection method for electric stimulator

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on September 30, 2022, with application number 202211207433.5 and title “Electric Stimulator and Electrical Neutralization Protection Method for Electric Stimulator”, the entire contents of which are incorporated by reference into this application.

Technical Field

The present disclosure relates to the technical field of electronic equipment, and in particular to an electric stimulator and an electric neutralization protection method for the electric stimulator.

Background technique

Electrical stimulators are usually used to improve human functions or treat diseases. The effective signal of the electrical stimulator when working is an electrical pulse signal. According to the requirements of ISO 14708-3 for the electrical neutrality of active implantable medical devices, in addition to the intended function, when in contact with the human body, the implanted part of the active implantable medical device, such as the electrode, should be electrically neutral, and the DC current density of any conductive surface or electrode surface should be ≤0.75μA/ ^mm2 . The electrode part of the electrical stimulator directly contacts the human tissue. When the electrode is in an activated state and emits an electrical stimulation pulse, it is crucial to ensure electrical neutrality for the safety of the patient. However, due to the non-ideal design of the switch in the pulse generator circuit, when the electrode is in an unactivated state, even if the PN junction of the switch in the electrical stimulator is in a cut-off state, there will still be a DC leakage current in the circuit. During the entire life cycle of the electrical stimulator, the aging of the product and the increase in the internal temperature of the device may increase the DC leakage current in the circuit. When the electrode part of the electrical stimulator directly contacts the human tissue, it is crucial to ensure the electrical neutrality of the implanted product for the safety of the patient. Therefore, it is necessary to ensure that the electrical stimulator has safe and effective DC leakage monitoring and protection measures. For protection against DC leakage, the prior art generally adopts a method of setting a capacitor with suitable parameters between each electrode and the pulse generator to isolate the DC leakage current, thereby ensuring the normal operation of the electrical pulse signal while effectively isolating the DC leakage current.

In addition, the electrode part of the electric stimulator is in direct contact with human tissue. When the electrode is in an activated state and emits an electric stimulation pulse, it is crucial to ensure electrical neutrality for the safety of the patient. After the electric stimulator is implanted in a specific area of the human body, the electrode needs to be in direct contact with body fluids for a long time. In the manufacturing process, the electrodes of existing electric stimulators are usually electroplated with platinum ash on the surface of the electrode. The effective single-phase electric pulse signal emitted by the electric stimulator when it is working will cause the platinum ash to produce an electrochemical reaction in the body fluid. When the accumulated voltage on the electrode exceeds a certain limit, the redox reaction of the electrode is violent, and the electrode will be irreversibly consumed, which further puts higher requirements on the charge balancing technology of the electric stimulator. In the prior art, it is usually adopted that after electrical stimulation, a pulse signal with the opposite polarity to the effective pulse signal is emitted to neutralize the accumulated charge on the electrode, so as to achieve the purpose of actively balancing the charge.

In the prior art, the use of a DC blocking capacitor to isolate the DC leakage current is a passive protection method, which cannot automatically monitor the size of the DC leakage current. Therefore, when there is an abnormality in the circuit, it cannot be processed in time, and the safety factor of the product is low. Moreover, when active charge balancing measures are used to neutralize the accumulated charge on the electrode, it cannot be ensured that the accumulated charge on the electrode is completely eliminated to meet the charge balancing requirements.

Summary of the invention

The present disclosure aims to solve at least one of the technical problems existing in the prior art. To this end, one purpose of the present disclosure is to provide an electrical stimulator that can monitor and effectively protect the DC leakage current in the electrical stimulator, and can also eliminate the accumulated charge of the electrode to the greatest extent to ensure that the charge balance meets the requirements.

Another object of the present disclosure is to provide an electrical neutralization protection method for an electrical stimulator.

In order to achieve the above-mentioned purpose, the electric stimulator proposed in the first aspect of the embodiment of the present disclosure includes: N electrodes, wherein N≥1; a negative phase pulse generating circuit and a first switch, wherein the negative phase pulse generating circuit is used to generate a negative phase electrical pulse signal, and the first switch is used to control the connection or disconnection between the negative phase pulse generating circuit and the N electrodes; a positive phase pulse generating circuit and a second switch, wherein the positive phase pulse generating circuit is used to generate a positive phase electrical pulse signal, and the second switch is used to control the connection or disconnection between the positive phase pulse generating circuit and the N electrodes, and N electrical pulse channels are formed between the N electrodes and the negative phase pulse generating circuit or the positive phase pulse generating circuit; N third switches, wherein one end of the N third switches is respectively connected to the N electrical pulse channels, and the other end of the N third switches is grounded; and N fourth switches. The N fourth switches are respectively arranged on the N electric pulse channels to connect or disconnect the power supply of the electric pulse channels; a leakage current acquisition module, the leakage current acquisition module is connected to the N electric pulse channels, and is used to collect the accumulated charge signals in the electric pulse channels; a control module, the control module is connected to the control ends of the N fourth switches, and is also connected to at least one of the control ends of the positive phase pulse generating circuit, the second switch and the third switch, and is used to control the fourth switch of the corresponding electric pulse channel to disconnect when the accumulated charge signal is higher than a preset safety threshold, and when the accumulated charge signal is lower than the preset safety threshold and exceeds the target balanced charge signal range, control the positive phase pulse generating circuit, the second switch and at least one of the third switch according to the accumulated charge signal.

According to the electric stimulator proposed in the embodiment of the present disclosure, the leakage current acquisition module can monitor the DC leakage in N electric pulse channels in real time and actively, and timely disconnect the power supply link of the channel with abnormal leakage current through the fourth switch, so that the electrodes of other channels with normal function continue to be activated and used, thereby effectively extending the service life of the electric stimulator; in addition, the present disclosure can also adjust the waveform of the positive phase pulse and the release time of the passive charge balance according to the accumulated charge signal collected by the leakage current acquisition module, optimize the charge balance effect, and ensure that the accumulated charge voltage remains within the required range of the safety threshold, which is more conducive to ensuring patient safety and further extending the service life of the product electrode.

In some embodiments of the present disclosure, the leakage current acquisition module includes: a switch module, which is used to turn on or off the acquisition of the accumulated charge signal on the corresponding electrical pulse channel; an analog-to-digital conversion circuit, the input end of the analog-to-digital conversion circuit is connected to the switch module, and the output end of the analog-to-digital conversion circuit is connected to the control module, for converting the accumulated charge signal into a digital acquisition signal.

In some embodiments of the present disclosure, the control module includes: a comparator, the input end of the comparator is connected to the output end of the analog-to-digital conversion circuit, and is used to detect when the digital acquisition signal corresponding to the accumulated charge signal is higher than the preset safety signal. A controller is connected to the first output terminal of the comparator, and is used to control the corresponding fourth switch to disconnect according to the cut-off signal, and to control at least one of the positive phase pulse generating circuit, the second switch and the third switch according to the adjustment signal. The controller is also connected to the control terminal of the switch module, and is used to control the switch module to connect or disconnect the collection of the accumulated charge signal of the corresponding electrical pulse channel.

In some embodiments of the present disclosure, the switch module includes: N fifth switches, the N fifth switches are respectively connected to the N electrical pulse channels, and are used to turn on or off the collection of accumulated charge signals on the corresponding connected electrical pulse channels.

In some embodiments of the present disclosure, the electrical stimulator further includes: a prompt module, which is connected to the second output terminal of the comparator and is used to issue an alarm when the digital acquisition signal corresponding to the accumulated charge signal exceeds a preset safety threshold.

In some embodiments of the present disclosure, the electrical stimulator also includes: a sixth switch, which is connected to the positive phase pulse generating circuit and the negative phase pulse generating circuit, and is used to control the overall power supply status of the positive phase pulse generating circuit and the negative phase pulse generating circuit.

In some embodiments of the present disclosure, the analog-to-digital conversion circuit includes an analog-to-digital converter, an input end of the analog-to-digital converter is connected to the switch module, and an output end of the analog-to-digital converter is connected to the control module.

In some embodiments of the present disclosure, the number of the negative phase pulse generating circuit, the first switch, the positive phase pulse generating circuit and the second switch is M, where N is a multiple of M.

In some embodiments of the present disclosure, the preset safety threshold is Vev, and the target balanced charge signal range is (-V _TH , +V _TH ), wherein Vev is greater than +V _TH .

In some embodiments of the present disclosure, the electrical stimulator is a deep brain stimulator, a cortical stimulator, a spinal cord stimulator, a cochlear implant, or a retinal stimulator.

In order to achieve the above-mentioned purpose, the electrical neutralization protection method of the electrical stimulator proposed in the second aspect embodiment of the present disclosure includes the following steps: obtaining the cumulative charge signal in the electric pulse channel formed by connecting N electrodes with a negative phase pulse generating circuit or a positive phase pulse generating circuit; controlling the power supply of the corresponding electric pulse channel to be disconnected when the cumulative charge signal is higher than a preset safety threshold; and when the cumulative charge signal is lower than the preset safety threshold and exceeds the target balanced charge signal range, adjusting at least one of the driving current of the positive phase pulse generating circuit, the connection time of the positive phase pulse generating circuit with the electrode, and the ground discharge time of the electrode according to the cumulative charge signal.

In some embodiments of the present disclosure, at least one of the driving current of the positive phase pulse generating circuit, the connection time of the positive phase pulse generating circuit with the electrode, and the ground discharge time of the electrode is adjusted according to the accumulated charge signal, including: if the accumulated charge signal of the electric pulse channel corresponding to the electrode is positive, then the driving current of the corresponding positive phase driving circuit in the next stimulation cycle is controlled to be reduced and/or the closing time of the second switch is controlled to be shortened, and/or the ground discharge time of the electric pulse channel is increased, wherein the second switch is used to control the connection or disconnection between the positive phase pulse generating circuit and each of the electrodes; if the accumulated charge signal of the electric pulse channel corresponding to the electrode is negative, then the driving current of the corresponding positive phase driving circuit in the next stimulation cycle is controlled to be increased and/or the closing time of the second switch is controlled to be increased, and/or Or increase the ground discharge time of the electric pulse channel.

In some embodiments of the present disclosure, increasing the ground discharge time of the electric pulse channel includes: increasing the closing time of N third switches, wherein one end of the N third switches is respectively connected to the N electric pulse channels, and the other ends of the N third switches are grounded.

In some embodiments of the present disclosure, controlling the driving current of the corresponding positive phase driving circuit to decrease in the next stimulation cycle includes: using a binary successive approximation method to reduce the amplitude of the positive phase electrical pulse signal generated by the positive phase pulse generating circuit by one step. And controlling the driving current of the corresponding positive phase driving circuit to increase in the next stimulation cycle includes: using a binary successive approximation method to increase the amplitude of the positive phase electrical pulse signal generated by the positive phase pulse generating circuit by one step.

Additional aspects and advantages of the present disclosure will be given in part in the following description and in part will be obvious from the following description or learned through practice of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or additional aspects and advantages of the present disclosure will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

FIG1 is a schematic diagram of an electrical stimulator according to an embodiment of the present disclosure;

FIG2 is a schematic diagram of a DC leakage protection technology according to an embodiment of the present disclosure;

FIG3 is a schematic diagram of a charge balancing technique according to an embodiment of the present disclosure;

FIG4 is a schematic diagram of an electrical stimulator according to another embodiment of the present disclosure;

FIG5 is a flow chart of an electrical neutralization protection method for an electrical stimulator according to an embodiment of the present disclosure.

Reference numerals:

Electrical stimulator 100;

N electrodes 1, a negative phase pulse generating circuit 2, a first switch 3, a positive phase pulse generating circuit 4, a second switch 5, N third switches 6, N fourth switches 7, a leakage current acquisition module 8, a control module 9, and a prompt module 10;

Switch module 81, analog-to-digital conversion circuit 82, comparator 91, controller 92;

Electrode 11, electrode 12, electrode 1N, third switch 611, third switch 612, third switch 61N, fourth switch 71, fourth switch 72, fourth switch 7N, fifth switch 811, fifth switch 812, fifth switch 81N, negative phase pulse generating circuit 21, negative phase pulse generating circuit 22, negative phase pulse generating circuit 2M, phase pulse generating circuit 41, positive phase pulse generating circuit 42, positive phase pulse generating circuit 4M, sixth switch P.

Detailed ways

The embodiments described with reference to the accompanying drawings are exemplary, and embodiments of the present disclosure are described in detail below.

The following describes an electrical stimulator according to an embodiment of the present disclosure with reference to FIGS. 1 to 4. In an embodiment of the invention, the electrical stimulator may Electrical stimulators are implantable medical devices. Electrical stimulators implant electrodes into specific areas and send electrical pulses of a certain frequency to stimulate discharges in the affected area, thereby achieving the purpose of improving or treating diseases. Electrical stimulators can specifically be deep brain stimulators, cortical stimulators, spinal cord stimulators, cochlear implants, or retinal stimulators, etc., to achieve corresponding treatments or repairs such as vision, hearing, pain relief, movement disorders, and addiction diseases.

In some embodiments of the present disclosure, FIG1 is a schematic diagram of an electrical stimulator according to an embodiment of the present disclosure. The electrical stimulator 100 includes N electrodes 1, a negative phase pulse generating circuit 2, a first switch 3, a positive phase pulse generating circuit 4, a second switch 5, N third switches 6, N fourth switches 7, a leakage current acquisition module 8 and a control module 9, wherein N ≥ 1. N is preferably a value greater than the number of electrodes of existing electrical stimulator products, such as 64, 128, 256 or other possible values, to form a high-density, multi-electrode electrical stimulator.

Among them, N electrodes 1 are connected to a negative phase pulse generating circuit 2 to form N electric pulse channels, and the negative phase pulse generating module 2 is used to generate a negative phase electric pulse signal, which is an effective stimulation signal, and the N electrodes 1 are used to discharge to activate according to the negative phase electric pulse signal of the negative phase pulse generating circuit 2, and the negative phase electric pulse signal is an effective unidirectional pulse signal. As shown in FIG1 , the N electrodes 1 may include electrode 11, electrode 12…electrode 1N, and when the N electrodes 1 are in an unactivated state, they may discharge to activate according to the negative phase electric pulse signal. The first switch 3 is used to control the connection or disconnection between the negative phase pulse generating circuit 2 and the N electrodes 1.

It is understandable that after the negative phase pulse generating circuit 2 generates a negative phase electrical pulse signal to stimulate the N electrodes 1 to discharge, charge accumulation will occur on the N electrodes 1. In order to ensure the electrical neutrality of the electrode 1, an effective charge balancing technology is required to release or offset the negative phase accumulated charge generated by the negative phase pulse generating circuit 2. Based on this, the electrical stimulator 100 of the embodiment of the present disclosure is also provided with a positive phase pulse generating circuit 4, which is used to generate a positive phase electrical pulse signal, and the positive phase electrical pulse signal can be used to offset the accumulated charge of the negative phase pulse, so as to achieve the purpose of actively balancing the charge. Specifically, N electrical pulse channels are formed between the N electrodes 1 and the positive phase pulse generating circuit 4. The second switch 5 is used to control the connection or disconnection between the positive phase pulse generating circuit 4 and the N electrodes 1.

It is understandable that after the positive phase pulse generating circuit 4 generates a positive phase electrical pulse signal and sends it to the N electrodes 1, and the negative charges accumulated on the N electrodes 1 are offset, it is possible that the accumulated charges on the N electrodes 1 are not completely eliminated, or positive charges are accumulated on the N electrodes 1 after the accumulated negative charges are offset. Therefore, on the basis of the active charge balancing function of the electrical stimulator 100, it is necessary to add a passive charge balancing function.

Based on the above, the electrical stimulator 100 is further provided with N third switches 6, one end of the N third switches 6 is respectively connected to the N electrical pulse channels, and the other end of the N third switches 6 is grounded. As shown in FIG1 , the N third switches 6 may include a third switch 611, a third switch 612…a third switch 61N. When some or all of the N third switches 6 are closed, the corresponding electrical pulse channels are grounded and the accumulated charge is released, thereby achieving the purpose of passive charge balance.

In some embodiments, as shown in FIG1 , the electrical stimulator 100 is further provided with N fourth switches 7, and the N fourth switches 7 may include a fourth switch 71, a fourth switch 72 ... a fourth switch 7N. The N fourth switches 7 are respectively provided on the N electrical pulse channels to connect or disconnect the power supply of the electrical pulse channels. Among them, taking the fourth switch 71 as an example, when the fourth switch 71 is disconnected, the power supply circuit of the electrical pulse channel in which it is located will be disconnected, and the electrode 11 cannot receive the negative phase generated by the negative phase pulse generating circuit 2. The electrical pulse signal and the positive phase electrical pulse signal generated by the positive phase pulse generating circuit 4.

The leakage current acquisition module 8 is connected to the N electric pulse channels and is used to collect the accumulated charge signals in the electric pulse channels. For the unactivated electrodes, due to the non-ideality of the switch design in the circuit, even if the PN junction of the switch is in the cut-off state, there will still be a DC leakage current in the circuit. Therefore, the present disclosure also proposes a DC leakage protection technology, and the leakage current acquisition module 8 can also measure the DC leakage current of the N electric pulse channels by collecting the accumulated charge signals in the N electric pulse channels, so as to achieve the purpose of monitoring the tiny DC leakage current of the semiconductor switch.

The control module 9 is connected to the control ends of N fourth switches, and is also connected to at least one of the control ends of the positive phase pulse generating circuit 4, the second switch 5 and the third switch 6, and is used to control the fourth switch 7 of the corresponding electric pulse channel to disconnect when the accumulated charge signal is higher than a preset safety threshold, and to control at least one of the positive phase pulse generating circuit 4, the second switch 5 and the third switch 6 according to the accumulated charge signal when the accumulated charge signal is lower than the preset safety threshold and exceeds the target balanced charge signal range.

The charge balancing technology and DC leakage protection technology proposed in the present disclosure adopts a cumulative charge voltage monitoring method to monitor the cumulative charge signals on the N electrodes 1. The voltage of the collected cumulative charge can be recorded as V.

Specifically, the preset safety threshold and the target balanced charge signal range can be set according to the electrode capacitance value, the requirement for balancing the accumulated charge, etc. and recorded as Vev and (-V _TH , +V _TH ) respectively, where Vev is greater than +V _TH . It can be understood that when the absolute value of V is greater than Vev, it may affect the service life of the electrode 1 or make the electrode electrical neutrality not meet the requirements. When V is greater than +V _TH or less than -V _TH but its absolute value is less than Vev, it may cause the redox reaction of the electrode 1, but at this time the voltage V of the accumulated charge does not exceed the electrode safety voltage threshold.

When the electrical stimulator 100 is powered on and initialized, the entire system enters the debugging mode, and the leakage current acquisition module 8 performs DC leakage detection on N electrical pulse channels at the same time. If it is detected that V is less than Vev, it enters the normal stimulation mode, otherwise it enters the diagnostic mode. In the diagnostic mode, the leakage current acquisition module 8 performs DC leakage current detection on a single electrode in turn and finds the electrode with leakage. The control module 9 controls the fourth switch 7 on the corresponding electrical pulse channel to disconnect its power supply circuit, and the remaining electrodes with normal leakage detection can continue to be used.

After entering the normal stimulation mode, all activated electrodes are stimulated with normal electric pulses according to the preset stimulation configuration, and all inactivated electrodes are in a floating state. Now, the working principle of the electric stimulator 100 using the DC leakage protection technology according to an embodiment of the present disclosure is described in conjunction with Figures 1 and 2. Figure 2 is a schematic diagram of the DC leakage protection technology according to an embodiment of the present disclosure, wherein the horizontal axis in Figure 2 is time, represented by "t", and the vertical axis is the current amplitude of the electric pulse signal.

Among them, as shown in FIG2, a total stimulation cycle includes a pulse train, a polling monitoring cycle and a passive charge balancing period. A pulse train includes S pulse cycles. For example, the value of S can be set to 1 or 3 or 10, etc., which is not limited here. After each negative phase pulse in a pulse cycle, the positive pulse generating module 4 generates a corresponding positive phase pulse for active charge balancing. The electrical stimulator 100 enters a polling monitoring cycle after executing a pulse train. For example, as shown in FIG2, in the t4 period after the Sth active charge balancing in the Sth pulse cycle, the leakage current acquisition module 8 measures the accumulated charge voltage V of the N electrodes 1 one by one, that is, leakage detection is performed on both the activated electrodes and the inactivated electrodes. When it is detected that the absolute value of V is greater than Vev, the control module 9 controls the interruption of the normal stimulation mode, enters the diagnostic mode, and disables the leakage current. pole and enable leakage detection of normal electrodes.

In the polling monitoring cycle, if it is determined based on the collected accumulated charge signal that the voltage V of the accumulated charge of the N electrodes 1 exceeds the target balanced charge signal range (-V _TH , +V _TH ) but its absolute value is less than Vev, the passive charge balance period, i.e., the t5 period in FIG. 2 , is entered, and the control module 9 controls to increase the discharge duration of the passive charge balance in the t5 period in the stimulation cycle to ensure that the accumulated charge of the electrode is completely released in the stimulation cycle. Furthermore, the control module 9 can also improve the electrical neutrality effect of the charge balance by adjusting the charge amount of the positive phase electrical pulse signal generated by the positive phase pulse generating circuit 4 in the next stimulation cycle and the discharge duration of the passive charge balance.

In some embodiments, the working principle of the charge balancing technology applied by the electrical stimulator 100 of the present embodiment can be described in combination with FIG. 1, FIG. 2 and FIG. 3. FIG. 3 is a schematic diagram of the charge balancing technology according to an embodiment of the present disclosure, wherein the horizontal axis in FIG. 3 is time, represented by "t", and the vertical axis is the current amplitude of the electrical pulse signal, represented by "I". FIG. 3 shows the timing of the charge balancing protection measures within a single stimulation cycle, which includes 1 active charge balancing and 1 passive charge balancing.

Specifically, as shown in FIG3 , the t0 period is the preparation period for normal stimulation of the N electrodes 1, and the first stimulation cycle begins after the t0 period ends. The t1 period is the normal stimulation period, at which the control module 9 controls the second switch 5 and the N third switches 6 to be disconnected and controls the first switch 3 to be closed, the negative phase pulse generating circuit 2 generates a negative phase electric pulse signal, and the N electrodes 1 are activated and discharge. After the stimulation period ends, the t2 period begins, and during the t2 period, the control module 8 controls the first switch 3, the second switch 5 and the N third switches 6 to be disconnected to avoid the overlap of the negative phase electric pulse signal with the active balance signal generated during the t3 period. The t3 period is the period of active charge balance, at which the control module 9 controls the first switch 3 and the N third switches 6 to remain disconnected and controls the second switch 5 to be closed, and the positive phase pulse generating circuit 4 generates a positive phase electric pulse signal to offset the accumulated negative charge on the N electrodes 1 to actively balance the charge. During the t4 period, the control module 9 controls the second switch 5, the first switch 3 and the N third switches 6 to be disconnected, and the accumulated charge signal in the electric pulse channel is collected by the leakage current acquisition module 8. After entering the t5 period, the control module 9 controls the second switch 5 and the first switch 3 to remain in the open state and controls the N third switches 6 to be closed. The accumulated charges on the N electrodes 1 are grounded and released through the N third switches 6, thereby achieving the purpose of passive charge balance.

And, after executing several stimulation cycles such as 2 or 3 or 5 stimulation cycles, insert a long discharge cycle. As shown in Figure 3, during the long discharge cycle time period, the leakage current acquisition module 8 collects the accumulated charge signals on the N electric pulse channels, and the control module 9 controls the N third switches 6 to close, so as to realize the grounding release of the accumulated charges of all electrodes 1 again. This protective measure realizes the DC leakage monitoring and the cumulative charge release of all electrodes 1 in the normal stimulation mode, further ensuring the safety of the patient. In addition, a long discharge cycle can also be used to eliminate the accumulated charge for the unactivated electrodes.

According to the electric stimulator proposed in the embodiment of the present disclosure, the leakage current acquisition module 8 can monitor the DC leakage in the N electric pulse channels in real time and actively, and timely disconnect the power supply link of the leakage current abnormal channel through the fourth switch 7, so that the electrodes of other channels with normal conditions continue to be activated and used, thereby effectively extending the service life of the electric stimulator; in addition, the present disclosure can also adjust the waveform of the positive phase pulse and the release time of the passive charge balance according to the accumulated charge signal collected by the leakage current acquisition module 8, optimize the charge balance effect, ensure that the accumulated charge voltage remains within the required range of the safety threshold, and is more conducive to ensuring patient safety. Further extend the service life of the product electrode.

The disclosed embodiment utilizes the characteristic that the electrode voltage will increase after the DC leakage current accumulates on the electrode for a period of time. Compared with the conventional method of isolating DC leakage with a DC blocking capacitor, the leakage current acquisition module 8 can reduce the circuit volume and improve the system stability.

In some embodiments of the present disclosure, as shown in FIG. 4 , which is a schematic diagram of an electrical stimulator according to another embodiment of the present disclosure, the leakage current acquisition module 8 includes a switch module 81 and an analog-to-digital conversion circuit 82 .

The switch module 81 is used to turn on or off the collection of the accumulated charge signal on the corresponding electric pulse channel. Specifically, the switch module 81 includes N fifth switches, wherein the N fifth switches may include a fifth switch 811, a fifth switch 812 ... a fifth switch 81N. The N fifth switches are respectively connected to the N electric pulse channels, and are used to turn on or off the collection of the accumulated charge signal on the corresponding connected electric pulse channels.

Further, when the electrical stimulator 100 works normally, the control module 9 may control all N fifth switches to be closed simultaneously, or control the fifth switches in the electrical pulse channels corresponding to all activated electrodes 1 to be closed, but the present disclosure is not limited thereto.

In addition, the N fifth switches in the switch module 81 may also be semiconductor switches, which have the characteristics of high sensitivity and fast frequency response.

The input end of the analog-to-digital conversion circuit 82 is connected to the switch module 81, and the output end of the analog-to-digital conversion circuit 82 is connected to the control module 9, for converting the accumulated charge signal into a digital acquisition signal, wherein the analog-to-digital conversion circuit 82 may include an ADC (Analog-to-Digital Converter, analog-to-digital converter or analog-to-digital converter) to realize the conversion of the analog signal into a digital signal. The circuit selection of the analog-to-digital conversion circuit 82 needs to be designed considering the accumulated charge signal (corresponding to the voltage value), the preset safety threshold, the target balanced charge signal range and the sampling accuracy requirements, which are not limited here.

According to the electrical stimulator 100 of the embodiment of the present disclosure, N fifth switches are correspondingly set between the analog-to-digital conversion circuit 82 and the N electrical pulse channels, and the on-off states of the N fifth switches are controlled to monitor the DC leakage and accumulated charge of a single or multiple channels.

In some embodiments of the present disclosure, as shown in Fig. 4, the control module 9 includes a comparator 91 and a controller 92. The input end of the comparator 91 is connected to the output end of the analog-to-digital conversion circuit 82, and is used to output a cut-off signal when the digital acquisition signal corresponding to the accumulated charge signal is higher than a preset safety threshold.

Among them, the comparator 91 is used to compare the acquired cumulative charge signal with the preset safety threshold and the target balanced charge signal range. When it is determined that the absolute value of V is greater than Vev, the DC leakage current is considered to be abnormal and a disconnection signal is output, which may affect the life of the electrode or the safety of electrical neutrality. The controller 92 is connected to the first output end of the comparator 91, and is used to control the corresponding fourth switch 7 to disconnect according to the cut-off signal, that is, interrupt the normal stimulation mode and wait for the control instruction of the peripheral main controller.

Furthermore, the comparator 91 is also used to output an adjustment signal when the digital acquisition signal corresponding to the accumulated charge signal exceeds the target balanced charge signal range, and the controller 92 controls at least one of the positive phase pulse generating circuit 4, the second switch 3 and the third switch 5 according to the adjustment signal.

For example, when the accumulated charge signal V>+ _VTH is detected but the absolute value of V is less than Vev, it means that the positive phase electrical pulse signal The charge amount of the positive phase electric pulse signal is greater than the charge amount of the negative phase electric pulse signal, and the comparator 91 outputs an adjustment signal to the controller 92 to control the reduction of the charge amount of the positive phase electric pulse signal generated by the positive phase pulse generating circuit 4 in the subsequent stimulation cycle. For example, the binary division method can be used to control the amplitude of the positive phase electric pulse signal in the time period t3 in Figure 3 to be reduced by one step, so that the charge amount of the positive phase electric pulse signal is closer to the charge amount of the negative phase electric pulse signal.

For another example, when it is detected that the accumulated charge signal V is less than -V _TH but the absolute value of V is less than Vev, it means that the charge amount of the positive phase electric pulse signal is less than the charge amount of the negative phase electric pulse signal. The comparator 91 outputs an adjustment signal to the controller 92 to control the increase of the charge amount of the positive phase electric pulse signal generated by the positive phase pulse generating circuit 4 in the subsequent stimulation cycle. For example, the binary division method can be used to control the amplitude of the positive phase electric pulse signal in the time period t3 in Figure 3 to increase by one step, so that the charge amount of the positive phase electric pulse signal is closer to the charge amount of the negative phase electric pulse signal, so as to better neutralize the charge amount of the negative phase electric pulse signal and optimize the active charge balancing effect.

For another example, when the accumulated charge signal -V _TH ＜V＜+V _TH is detected, that is, the digital sampling signal of the accumulated charge signal V is within the target balanced charge signal range (-V _TH , +V _TH ), which means that the charge amount of the positive phase electrical pulse signal is closer to the charge amount of the negative phase electrical pulse signal. At this time, the controller 92 controls the charge amount of the positive phase electrical pulse signal generated by the positive phase pulse generating circuit 4 in the subsequent stimulation cycle to remain unchanged.

Furthermore, the controller 92 can also reasonably extend the time of passive charge balance in the current stimulation cycle while adjusting the charge amount of the positive phase electrical pulse signal, such as extending the t5 period in FIG. 3, that is, increasing the closing time of the N third switches 6, to ensure that the accumulated charges on the N electrodes 1 have enough time to be released, and further ensure that the ideal charge balance effect is achieved. This continues until, during the stimulation cycle of the channel, the comparator 91 determines that V satisfies -V _TH <V <+V _TH based on the detected accumulated charge signal V, the N electrodes 1 continue to be stimulated using the adjusted current amplitude of the positive phase electrical pulse signal and the passive charge balance discharge time configuration parameters, and the electrical stimulator 100 restores the discharge time of the passive charge balance to the default setting.

In other embodiments, as shown in FIG. 4 , the controller 92 is also connected to the control end of the switch module 81 to control the switch module 81 to connect or disconnect the collection of the accumulated charge signal of the corresponding electric pulse channel.

In some embodiments of the present disclosure, the electrical stimulator 100 also includes a prompt module 10. The prompt module 10 is connected to the second output terminal of the comparator 91, and is used to issue an alarm when the digital acquisition signal corresponding to the accumulated charge signal exceeds a preset safety threshold. Among them, if the absolute value of the detected V is greater than Vev, it may affect the life of the electrode or the safety of electrical neutrality. Therefore, in this case, the controller 92 controls the interruption of the normal stimulation mode, and the prompt module 10 also issues an alarm in time. Furthermore, the prompt module 10 can also specifically prompt the user which specific electrical pulse channel has an abnormal voltage V of the accumulated charge of the electrode.

In some embodiments of the present disclosure, as shown in FIG. 4 , the electrical stimulator 100 further includes a sixth switch P, which is connected to the positive phase pulse generating circuit 4 and the negative phase pulse generating circuit 2, and is used to control the overall power supply status of the positive phase pulse generating circuit 4 and the negative phase pulse generating circuit 2. The sixth switch P can cut off the power as a whole under preset circumstances to ensure the safety of product use.

In some embodiments of the present disclosure, the analog-to-digital conversion circuit 82 includes an analog-to-digital converter, the input end of the analog-to-digital converter is connected to the switch module 81, and the output end of the analog-to-digital converter is connected to the control module 9. This embodiment can simultaneously monitor the DC leakage and the voltage V of the accumulated charge of N electrodes 1 through an analog-to-digital converter, which can save Save system power consumption and significantly reduce hardware costs.

Alternatively, as an optional embodiment, the analog-to-digital conversion circuit 82 includes N analog-to-digital converters or less than N analog-to-digital converters (in this case, one analog-to-digital converter may correspond to multiple electrodes), which can also achieve the technical effects of the present disclosure.

In some embodiments of the present disclosure, the number of negative phase pulse generating circuits 2 is M, wherein the M negative phase pulse generating circuits may include negative phase pulse generating circuit 21, negative phase pulse generating circuit 22…negative phase pulse generating circuit 2M, and each negative phase pulse generating circuit is connected to a first switch 3. The number of positive phase pulse generating circuits 4 is M, wherein the M positive phase pulse generating circuits may include positive phase pulse generating circuit 41, positive phase pulse generating circuit 42…positive phase pulse generating circuit 4M, and each positive phase pulse generating circuit is connected to a second switch 5.

Wherein, N is a multiple (including one) of M. That is, one negative phase pulse generating circuit 2 or one positive phase pulse generating circuit can be connected to one or more electrodes at the same time.

In some embodiments of the present disclosure, an electrical neutralization protection method for an electrical stimulator is also proposed. As shown in Figure 5, it is a flow chart of the electrical neutralization protection method for an electrical stimulator according to an embodiment of the present disclosure, wherein the electrical neutralization protection method for an electrical stimulator includes at least the following steps S1-S3, which are specifically as follows.

S1, obtaining the accumulated charge signal in the electric pulse channel formed by connecting N electrodes to a negative phase pulse generating circuit or a positive phase pulse generating circuit.

In some embodiments, the accumulated charge signal is collected by the leakage current acquisition module in the above embodiment, and the leakage current acquisition module can monitor and confirm the actual accumulated charge on the electrode surface after charge balance in real time to ensure that the ideal charge balance effect is achieved. In addition, the leakage current acquisition module can also measure the DC leakage current of N electrical pulse channels to achieve the purpose of monitoring the tiny DC leakage current of the semiconductor switch.

S2, when the accumulated charge signal is higher than a preset safety threshold, the power supply of the corresponding electric pulse channel is controlled to be disconnected.

When it is determined that the accumulated charge signal is higher than the preset safety threshold, the electrical stimulator enters the diagnostic mode. In the diagnostic mode, the leakage current acquisition module performs DC leakage current detection on individual electrodes in turn and finds the electrode with leakage. The control module controls to disconnect the power supply circuit of the corresponding electrical pulse channel, while the remaining electrodes with normal leakage detection can continue to be used.

S3, when the accumulated charge signal is lower than the preset safety threshold and exceeds the target balance charge signal range, at least one of the driving current of the positive phase pulse generating circuit, the connection time of the positive phase pulse generating circuit with the electrode, and the ground discharge time of the electrode is adjusted according to the accumulated charge signal.

Among them, if the accumulated charge signal of the electric pulse channel corresponding to the electrode is positive, that is, the charge amount of the positive phase electric pulse signal generated by the positive phase pulse generating circuit is greater than the charge amount of the negative phase electric pulse signal generated by the negative phase pulse generating circuit, then the driving current of the corresponding positive phase driving circuit in the next stimulation cycle is controlled to decrease. For example, the amplitude of the positive phase electric pulse signal in the t3 period in Figure 3 can be controlled to decrease by one step by using a binary division successive approximation method, so that the charge amount of the positive phase electric pulse signal is closer to the charge amount of the negative phase electric pulse signal. And/or, the closing time of the second switch is controlled to be shortened, and/or the ground discharge time of the electric pulse channel is increased. For example, the t5 period in Figure 3 is extended, that is, the closing time of N third switches is increased to ensure that the accumulated charge on the N electrodes has enough time to complete the release, and further ensure that the ideal charge balance effect is achieved.

If the accumulated charge signal of the electric pulse channel corresponding to the electrode is a negative value, that is, the charge amount of the positive phase electric pulse signal generated by the positive phase pulse generating circuit is less than the charge amount of the negative phase electric pulse signal generated by the negative phase pulse generating circuit, then the driving current of the corresponding positive phase driving circuit in the next stimulation cycle is controlled to increase. For example, the amplitude of the positive phase electric pulse signal in the t3 period in Figure 3 can be controlled to increase by one step by using a binary division successive approximation method, so that the charge amount of the positive phase electric pulse signal is closer to the charge amount of the negative phase electric pulse signal. And/or, the closing time of the second switch is controlled to increase, and/or the ground discharge time of the electric pulse channel is increased. For example, the t5 period in Figure 3 is extended, that is, the closing time of N third switches is increased to ensure that the accumulated charge on the N electrodes has enough time to complete the release, and further ensure that the ideal charge balance effect is achieved.

Other structures and operations of the electrical stimulator 100 according to the embodiment of the present disclosure are known to those skilled in the art and will not be described in detail here.

Although embodiments of the present disclosure have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present disclosure, the scope of which is defined by the claims and their equivalents.

Claims

An electrical stimulator, comprising:

N electrodes, where N ≥ 1;

A negative phase pulse generating circuit, wherein the negative phase pulse generating circuit is used to generate a negative phase electrical pulse signal;

A first switch, the first switch is used to control the connection or disconnection between the negative phase pulse generating circuit and each of the electrodes;

A positive phase pulse generating circuit, wherein the positive phase pulse generating circuit is used to generate a positive phase electrical pulse signal,

A second switch, the second switch is used to control the connection or disconnection between the positive phase pulse generating circuit and each of the electrodes, so that N electrical pulse channels are formed between the N electrodes and the negative phase pulse generating circuit or the positive phase pulse generating circuit;

N third switches, one end of each of the N third switches is connected to the N electrical pulse channels respectively, and the other end of each of the N third switches is grounded;

N fourth switches, wherein the N fourth switches are respectively arranged on the N electrical pulse channels to connect or disconnect the power supply of the electrical pulse channels;

A leakage current collection module, the leakage current collection module is connected to the N electrical pulse channels and is used to collect accumulated charge signals in the electrical pulse channels; and

A control module, wherein the control module is connected to the control ends of the N fourth switches and is simultaneously connected to at least one of the control ends of the positive phase pulse generating circuit, the second switch and the third switch, and is used to control the fourth switch of the corresponding electric pulse channel to be disconnected when the accumulated charge signal is higher than a preset safety threshold, and to control the positive phase pulse generating circuit, the second switch and at least one of the third switch according to the accumulated charge signal when the accumulated charge signal is lower than the preset safety threshold and exceeds the target balanced charge signal range.
The electrical stimulator according to claim 1, characterized in that the leakage current acquisition module comprises:

A switch module, the switch module is used to turn on or off the collection of the accumulated charge signal on the corresponding electric pulse channel; and

An analog-to-digital conversion circuit, wherein the input end of the analog-to-digital conversion circuit is connected to the switch module, and the output end of the analog-to-digital conversion circuit is connected to the control module, is used to convert the accumulated charge signal into a digital acquisition signal.
The electrical stimulator according to claim 2, characterized in that the control module comprises:

a comparator, wherein the input end of the comparator is connected to the output end of the analog-to-digital conversion circuit, and is used to output a cut-off signal when the digital acquisition signal corresponding to the accumulated charge signal is higher than the preset safety threshold, and to output an adjustment signal when the digital acquisition signal corresponding to the accumulated charge signal exceeds the target balanced charge signal range; and

a controller connected to the first output terminal of the comparator, configured to control the corresponding fourth switch to be disconnected according to the cut-off signal, and to control at least one of the positive phase pulse generating circuit, the second switch and the third switch according to the adjustment signal,

Wherein, the controller is also connected to the control end of the switch module, and is used to control the switch module to connect or disconnect the collection of the accumulated charge signal of the corresponding electric pulse channel.
The electrical stimulator according to claim 2 or 3, characterized in that the switch module comprises:

N fifth switches, the N fifth switches are respectively connected to the N electrical pulse channels, and are used to turn on or off the collection of accumulated charge signals on the corresponding connected electrical pulse channels.
The electrical stimulator according to claim 3, characterized in that the electrical stimulator further comprises:

A prompt module is connected to the second output terminal of the comparator and is used to issue an alarm when the digital acquisition signal corresponding to the accumulated charge signal exceeds a preset safety threshold.
The electrical stimulator according to any one of claims 1 to 5, characterized in that the electrical stimulator further comprises:

A sixth switch, wherein the sixth switch is connected to the positive phase pulse generating circuit and the negative phase pulse generating circuit, and is used to control the overall power supply state of the positive phase pulse generating circuit and the negative phase pulse generating circuit.
The electrical stimulator according to any one of claims 2 to 5, characterized in that

The analog-to-digital conversion circuit includes an analog-to-digital converter, an input end of the analog-to-digital converter is connected to the switch module, and an output end of the analog-to-digital converter is connected to the control module.
The electrical stimulator according to any one of claims 1 to 7, characterized in that

The number of the negative phase pulse generating circuit, the first switch, the positive phase pulse generating circuit and the second switch is M, where N is a multiple of M.
The electrical stimulator according to any one of claims 1-8, characterized in that the preset safety threshold is Vev, and the target balanced charge signal range is (-V TH , +V TH ), wherein Vev is greater than +V TH .
The electrical stimulator according to any one of claims 1 to 9 is characterized in that the electrical stimulator is a deep brain stimulator, a cortical stimulator, a spinal cord stimulator, a cochlear implant or a retinal stimulator.
An electrical neutralization protection method for an electrical stimulator, characterized in that it comprises the following steps:

Acquiring a cumulative charge signal in an electric pulse channel formed by connecting N electrodes to a negative phase pulse generating circuit or a positive phase pulse generating circuit;

When the accumulated charge signal is higher than a preset safety threshold, controlling the power supply of the corresponding electric pulse channel to be disconnected; and

When the accumulated charge signal is lower than the preset safety threshold and exceeds the target balanced charge signal range, at least one of the driving current of the positive phase pulse generating circuit, the connection time of the positive phase pulse generating circuit to the electrode, and the ground discharge time to the electrode is adjusted according to the accumulated charge signal.
The electrical neutralization protection method according to claim 11 is characterized in that adjusting at least one of the driving current of the positive phase pulse generating circuit, the connection time between the positive phase pulse generating circuit and the electrode, and the ground discharge time to the electrode according to the accumulated charge signal comprises:

If the accumulated charge signal of the electric pulse channel corresponding to the electrode is positive, the driving current of the corresponding positive phase driving circuit in the next stimulation cycle is controlled to be reduced and/or the closing time of the second switch is controlled to be shortened, and/or the ground discharge time of the electric pulse channel is increased, wherein the second switch is used to control the connection between the positive phase pulse generating circuit and each of the electrodes. connect or disconnect;

If the accumulated charge signal of the electric pulse channel corresponding to the electrode is negative, the driving current of the corresponding positive phase driving circuit in the next stimulation cycle is controlled to increase and/or the closing time of the second switch is controlled to increase, and/or the ground discharge time of the electric pulse channel is increased.
The electrical neutralization protection method according to claim 12, characterized in that increasing the ground discharge duration of the electrical pulse channel comprises:

The closing time of N third switches is increased, wherein one end of the N third switches is respectively connected to the N electrical pulse channels, and the other ends of the N third switches are grounded.
The electrical neutralization protection method according to claim 12 or 13 is characterized in that controlling the driving current of the corresponding positive phase driving circuit in the next stimulation cycle to decrease comprises: using a binary successive approximation method to reduce the amplitude of the positive phase electrical pulse signal generated by the positive phase pulse generating circuit by one step; and

Controlling the increase of the driving current of the corresponding positive phase driving circuit in the next stimulation cycle includes: using a binary successive approximation method to increase the amplitude of the positive phase electrical pulse signal generated by the positive phase pulse generating circuit by one step.