Constant current electrical stimulator and method of controlling the same

Abstract

The application discloses a control method of a constant-current electric stimulator, the constant-current electric stimulator comprising an H-bridge circuit, a high-voltage power supply and a constant-current source control module connected in series to a low-side branch of the H-bridge circuit; the control method outputs bidirectional symmetrical constant-current pulses to an electrode load by means of the H-bridge circuit, and controls two high-side switches to be simultaneously turned on before and after each commutation, so that two output nodes are at the same potential via the high-voltage power supply to neutralize the potential across the electrode load, or switches the output state of the constant-current source control module before and after the establishment of a constant-current path. The application further discloses a constant-current electric stimulator. The control method of the constant-current electric stimulator disclosed by the application can eliminate overshoot when the constant current is switched on, and improve the stability and use safety of the output pulse.

Description

Technical Field

[0001] This invention relates to the field of electrical stimulators, and in particular to constant current electrical stimulators and their control methods. Background Technology

[0002] Currently, electrical stimulators typically use H-bridge circuits to output pulses to the load to stimulate it. However, the pulse output methods of existing electrical stimulators still have room for improvement in terms of the stability of the output pulses and the safety of use.

[0003] Therefore, it is desirable to provide an improved control method. The background description is provided solely for understanding the relevant techniques in this field and is not intended as an admission of prior art. Summary of the Invention

[0004] The present invention aims to provide a solution that at least partially solves the above-mentioned problems.

[0005] In a first aspect, embodiments of the present invention provide a control method for a constant current electrical stimulator, the constant current electrical stimulator including an H-bridge circuit, a high-voltage power supply, and a constant current source control module. The H-bridge circuit includes a first high-side switch and a second high-side switch located on the high-side branch, and a first low-side switch and a second low-side switch located on the low-side branch. A first output node is formed between the first high-side switch and the first low-side switch, and a second output node is formed between the second high-side switch and the second low-side switch. The first output node and the second output node are used to connect to the two ends of the electrode load, respectively. The high-voltage power supply is used to provide high-voltage power to the high-side branch of the H-bridge circuit, and the constant current source control module is connected in series to the low-side branch of the H-bridge circuit. The control method includes periodically performing the following steps: The first high-side switch and the second high-side switch are simultaneously turned on, and the first low-side switch and the second low-side switch are simultaneously turned off, in order to neutralize the potential at both ends of the electrode load. When the potential across the electrode load is neutralized, the second low-side switch is turned on to establish a first current path from the high-voltage power supply through the second high-side switch and the second low-side switch to the constant current source control module. After establishing the first current path, the second high-side switch is controlled to open, so that the current flows from the high-voltage power supply through the first high-side switch, the first output node, the electrode load, the second output node and the second low-side switch to the constant current source control module, so as to generate a first constant current pulse flowing through the electrode load in the first direction; At the end of the first constant current pulse, the second low-side switch is controlled to open and the second high-side switch is turned on again, so that the first high-side switch and the second high-side switch are turned on at the same time and the first low-side switch and the second low-side switch are turned off at the same time, so as to neutralize the potential at both ends of the electrode load again. When the potential across the electrode load is neutralized again, the first low-side switch is turned on to establish a second current path from the high-voltage power supply through the first high-side switch and the first low-side switch to the constant current source control module. After establishing the second current path, the first high-side switch is controlled to open, so that the current flows from the high-voltage power supply through the second high-side switch, the second output node, the electrode load, the first output node and the first low-side switch to the constant current source control module, so as to generate a second constant current pulse flowing through the electrode load in a second direction, wherein the second direction is opposite to the first direction.

[0006] In some embodiments, controlling the first high-side switch and the second high-side switch to be simultaneously turned on includes: Apply a conduction level to the first high-side switch and the second high-side switch respectively, so that the conduction state of the first high-side switch and the second high-side switch is maintained for a preset neutralization time, so that the voltage difference across the electrode load meets the preset neutralization condition.

[0007] In some embodiments, the periodic execution step of the control method further includes: At the end of the second constant current pulse, the first low-side switch is turned off and the first high-side switch is turned on again, so that the first high-side switch and the second high-side switch are turned on simultaneously and the first low-side switch and the second low-side switch are turned off simultaneously.

[0008] In a second aspect, embodiments of the present invention provide a control method for a constant current electrical stimulator. The constant current electrical stimulator includes an H-bridge circuit, a high-voltage power supply, and a controllable constant current source control module. The H-bridge circuit includes a first high-side switch and a second high-side switch located on the high-side branch, and a first low-side switch and a second low-side switch located on the low-side branch. A first output node is formed between the first high-side switch and the first low-side switch, and a second output node is formed between the second high-side switch and the second low-side switch. The first output node and the second output node are used to connect to the two ends of the electrode load, respectively. The high-voltage power supply is used to provide high-voltage power to the high-side branch of the H-bridge circuit, and the controllable constant current source control module is connected in series in the low-side branch of the H-bridge circuit. The controllable constant current source control module has a first working state and a second working state. In the first working state, the controllable constant current source control module stops outputting current. In the second working state, the controllable constant current source control module outputs a set constant current. The control method includes the following steps, which are performed periodically: When the controllable constant current source control module is in the first working state, the first high-side switch and the second low-side switch are turned on to establish a first current path from the high voltage power supply through the first high-side switch, the first output node, the electrode load, the second output node and the second low-side switch to the controllable constant current source control module. After establishing the first current path, the controllable constant current source control module is switched from the first working state to the second working state, so that the set constant current output by the controllable constant current source control module flows through the electrode load through the first current path to generate a first constant current pulse flowing through the electrode load in the first direction. When the first constant current pulse ends, the controllable constant current source control module is controlled to switch from the second working state to the first working state, and the first high-side switch and the second low-side switch are controlled to disconnect. While keeping the controllable constant current source control module in the first working state, control the second high-side switch and the first low-side switch to be turned on, so as to establish a second current path from the high voltage power supply through the second high-side switch, the second output node, the electrode load, the first output node and the first low-side switch to the controllable constant current source control module; After establishing the second current path, the controllable constant current source control module is switched from the first working state to the second working state, so that the set constant current output by the controllable constant current source control module flows through the electrode load through the second current path to generate a second constant current pulse flowing through the electrode load in a second direction, which is opposite to the first direction. At the end of the second constant current pulse, the controllable constant current source control module is controlled to switch from the second working state to the first working state, and the second high-side switch and the first low-side switch are controlled to disconnect.

[0009] In some embodiments, the controllable constant current source control module includes a voltage-controlled constant current source, which is configured to adjust the output current according to the control voltage; The first operating state is achieved by applying a zero-current control voltage to the voltage-controlled constant current source, wherein the zero-current control voltage makes the output current of the voltage-controlled constant current source zero; The second operating state is achieved by applying a constant current control voltage to the voltage-controlled constant current source, wherein the constant current control voltage causes the voltage-controlled constant current source to output the set constant current.

[0010] In some embodiments, the constant current stimulator further includes a DAC module configured to output the zero current control voltage and the constant current control voltage, and the controllable constant current source control module configured to adjust the output current according to the zero current control voltage or the constant current control voltage.

[0011] In some embodiments, the controllable constant current source control module includes a voltage-controlled constant current source with a negative feedback loop, the voltage-controlled constant current source being configured to adjust the output current according to a set voltage and current feedback signal; The first operating state is achieved by clamping the feedback input terminal in the negative feedback loop, wherein when the feedback input terminal is clamped, the voltage-controlled constant current source stops outputting current; The second operating state is achieved by releasing the clamp on the feedback input terminal, wherein when the feedback input terminal is released from clamping, the voltage-controlled constant current source outputs the set constant current according to the set voltage.

[0012] In some embodiments, the negative feedback loop includes an operational amplifier and a controlled device. The output terminal of the operational amplifier is connected to the control terminal of the controlled device. The feedback input terminal is the inverting input terminal of the operational amplifier. The feedback input terminal is connected to the control pin of the controllable constant current source control module via a clamping diode. The first operating state is achieved by switching the control pin to the first level, turning on the clamping diode and clamping the feedback input terminal, so that the operational amplifier stops outputting drive signals to the controlled device. The second operating state is achieved by switching the control pin to the second level, turning off the clamping diode and releasing the clamp on the feedback input terminal, so that the operational amplifier drives the controlled device to output the set constant current according to the set voltage and the current feedback signal.

[0013] In some embodiments, the negative feedback loop further includes a sampling resistor, the first terminal of the controlled device is connected to the low-side branch of the H-bridge circuit, the second terminal is connected to the reference potential terminal via the sampling resistor, the non-inverting input terminal of the operational amplifier receives a set voltage, and the inverting input terminal of the operational amplifier is connected to the connection node between the controlled device and the sampling resistor; In the second operating state, the current flowing through the controlled device flows through the sampling resistor and forms the current feedback signal at the connection node.

[0014] In some embodiments, controlling the controllable constant current source control module to switch from the second operating state to the first operating state, and controlling the first high-side switch and the second low-side switch to disconnect, includes: The switching and disconnecting actions are executed in either the first or second preset order. The first preset sequence is to perform the switching action first, and then perform the disconnection action; The second preset sequence is to first perform the disconnection action and then perform the switching action; And / or The controllable constant current source control module switching from the second operating state to the first operating state, and controlling the second high-side switch and the first low-side switch to disconnect, includes: Perform switching and disconnecting actions according to the third or fourth preset sequence; The third preset sequence is to perform the switching action first, and then perform the disconnection action; The fourth preset sequence is to first perform the disconnection action and then perform the switching action.

[0015] In some embodiments, the first high-side switch, the second high-side switch, the first low-side switch, and the second low-side switch are selected from one or more of a field-effect transistor, a bipolar transistor, an insulated-gate bipolar transistor, an analog switch, or an optocoupler switch.

[0016] In some embodiments, the constant current pulse in the first direction and the constant current pulse in the second direction have the same pulse width and the same current amplitude, so that the net charge of the electrode load is zero in a complete pulse cycle.

[0017] In some embodiments, the electrode load includes a capacitive load formed by the contact between the electrode and human skin.

[0018] In a third aspect, embodiments of the present invention provide a constant current electrical stimulator, which may include: The H-bridge circuit includes a first high-side switch and a second high-side switch located in the high-side branch, and a first low-side switch and a second low-side switch located in the low-side branch. A first output node is formed between the first high-side switch and the first low-side switch, and a second output node is formed between the second high-side switch and the second low-side switch. The first output node and the second output node are used to connect to the two ends of the electrode load, respectively. A high-voltage power supply is configured to provide high-voltage power to the high-side branch of the H-bridge circuit. A constant current source control module is connected in series in the low-side branch of the H-bridge circuit; The controller is configured to perform the control method as described in any one of claims 1 to 13 to output bidirectional constant current pulses to the electrode load.

[0019] In some embodiments, the constant current source control module includes a voltage-controlled constant current source, and the constant current electrical stimulator further includes a DAC module; The DAC module is configured to output zero-current control voltage and constant-current control voltage; The constant current source control module is configured to stop outputting current according to the zero current control voltage and output a set constant current according to the constant current control voltage.

[0020] In some embodiments, the constant current stimulator further includes a constant current source control module, which includes a voltage-controlled constant current source with a negative feedback loop, the negative feedback loop including an operational amplifier, a controlled device, and a clamping diode; The output terminal of the operational amplifier is connected to the control terminal of the controlled device, and the inverting input terminal of the operational amplifier serves as the feedback input terminal. The feedback input terminal is connected to the control pin of the constant current source control module via the clamping diode. The constant current source control module is configured to switch between stopping the output current and outputting a set constant current by switching the level of the control pin to turn the clamping diode on or off.

[0021] In a fourth aspect, embodiments of the present invention provide an electronic device, including: a processor and a memory storing a computer program, the processor being configured to implement the method as described in the first or second aspect when executing the computer program.

[0022] In a fifth aspect, embodiments of the present invention provide a program product including a computer program, wherein the computer program, when executed by a processor, implements the method as described in the first or second aspect.

[0023] In a sixth aspect, embodiments of the present invention provide a storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the method as described in the first or second aspect.

[0024] The control method for the constant current electrical stimulator provided in this invention utilizes the simultaneous activation of the first and second high-side switches before and after each switching, ensuring that the first and second output nodes are at the same potential via a high-voltage power supply, thereby neutralizing the potential across the electrode load. By ensuring that the electrode load is at the same potential via a high-voltage power supply before and after switching, this method can dissipate residual differential charge on the electrode load, preventing residual charge from the previous pulse from affecting the waveform of subsequent pulses. This solves the technical problem that residual differential charge on the electrode load is not properly dissipated during switching of H-bridge bidirectional pulses, thus affecting the stability and safety of the output pulses.

[0025] This invention also provides another control method for a constant current electrostimulator, which constructs the constant current source control module as a controllable constant current source. The controllable constant current source has a first operating state where the output current is stopped and a second operating state where a set constant current is output. The control method is achieved by first turning on the diagonally opposite high-side switch and low-side switch of the controllable constant current source in the first operating state to establish a current path. After the current path is established, the controllable constant current source is switched to the second operating state to output a constant current pulse to the electrode load through the current path. At the end of each constant current pulse, the controllable constant current source is switched back to the first operating state and then the corresponding high-side switch and low-side switch are turned off. By ensuring that the controllable constant current source is in a state of stopping current output when each switch is turned on or off, the switches of the H-bridge circuit are turned on and off under conditions of zero or near-zero current. This scheme can reduce the overshoot during closing and turning off, and also obtain a stable and symmetrical bidirectional constant current pulse. This solves the technical problem that during the process of applying bidirectional constant current pulses to the electrode load, the switches of the H-bridge circuit are easily turned on and off under current conditions, which can easily generate overshoot during closing and turning off, thus affecting the stability of the output pulse and the safety of use.

[0026] Other optional features and technical effects of the embodiments of the present invention are partly described below and partly apparent from reading this document. Attached Figure Description

[0027] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The elements shown are not limited to the scale shown in the drawings, and the same or similar reference numerals in the drawings denote the same or similar elements, wherein: Figure 1 An exemplary block diagram of a constant current electrical stimulator according to an embodiment of the present invention is shown; Figure 2 This diagram shows the H-bridge circuit structure when the constant current source control module is placed in the low-side branch. Figure 3 This diagram shows the H-bridge circuit structure when the constant current source control module is placed in the high-side branch. Figure 4 A schematic diagram of the current path when the H-bridge circuit outputs a first constant current pulse along a first direction according to an embodiment of the present invention is shown. Figure 5 A schematic diagram of the current path when the H-bridge circuit outputs a second constant current pulse along the second direction according to an embodiment of the present invention is shown. Figure 6 A schematic diagram of an exemplary bidirectional pulse output voltage waveform is shown. Figure 7 A schematic diagram of the bidirectional pulse output current waveform according to an embodiment of the present invention is shown; Figure 8 A schematic flowchart of a control method for a constant current electrostimulator according to an embodiment of the present invention is shown; Figure 9 A schematic diagram of the switching states and current paths of the control method steps for the constant current electrical stimulator according to the first embodiment is shown. Figure 10 A schematic diagram of the switching states and current paths of the control method steps for the constant current electrical stimulator according to the first embodiment is shown. Figure 11 A schematic diagram of the switching states and current paths of the control method steps for the constant current electrical stimulator according to the first embodiment is shown. Figure 12 A schematic diagram of the switching states and current paths of the control method steps for the constant current electrical stimulator according to the first embodiment is shown. Figure 13 A schematic diagram of the switching states and current paths of the control method steps for the constant current electrical stimulator according to the first embodiment is shown. Figure 14 A schematic diagram of the switching states and current paths of the control method steps for the constant current electrical stimulator according to the first embodiment is shown. Figure 15 A schematic diagram of the switching states and current paths of the control method steps for the constant current electrical stimulator according to the first embodiment is shown. Figure 16 A schematic flowchart of a control method for a constant current electrostimulator according to an embodiment of the present invention is shown; Figure 17 A schematic diagram of the switching states and current paths of the control method steps for the constant current electrical stimulator according to the second embodiment is shown. Figure 18 A schematic diagram of the switching states and current paths of the control method steps for the constant current electrical stimulator according to the second embodiment is shown. Figure 19 A schematic diagram of the switching states and current paths of the control method steps for the constant current electrical stimulator according to the second embodiment is shown. Figure 20 A schematic diagram of the switching states and current paths of the control method steps for the constant current electrical stimulator according to the second embodiment is shown. Figure 21 An exemplary circuit diagram of a voltage-controlled constant current source with a negative feedback loop according to a third embodiment is shown; Figure 22 A schematic diagram of the switching states and current paths of the control method steps for a constant current electrical stimulator according to the third embodiment is shown. Figure 23 A schematic diagram of the switching states and current paths of the control method steps for a constant current electrical stimulator according to the third embodiment is shown. Figure 24 A schematic diagram of the switching states and current paths of the control method steps for a constant current electrical stimulator according to the third embodiment is shown. Figure 25 A schematic diagram of the switching states and current paths of the control method steps for a constant current electrical stimulator according to the third embodiment is shown. Figure 26 An exemplary structural diagram of an electronic device that can implement the method according to embodiments of the present invention is shown. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings. Here, the illustrative embodiments and descriptions of this invention are used to explain the invention, but are not intended to limit the invention.

[0029] As previously mentioned, electrical stimulators typically deliver pulses to the electrode load via an H-bridge circuit. By way of explanation, and not limitation, if only a single-polarity pulse is applied to the electrode load, charge will gradually accumulate on the equivalent capacitance of the electrode load, potentially leading to nerve damage. Therefore, it is desirable to deliver bidirectional, symmetrical pulses to the electrode load.

[0030] However, in some known H-bridge bidirectional pulse output methods, the residual differential charge on the electrode load may not be properly discharged during commutation; and at the instant the switch is turned on, if the constant current source is already in output mode, a closing overshoot may occur on the electrode load. Both the residual differential charge and the closing overshoot can affect the stability and safety of the output pulse.

[0031] To address this issue, this invention provides a constant current electrical stimulator and its control method. Before and after each switching operation, the corresponding switch is controlled to bring the two output nodes to the same potential via a high-voltage power supply, thereby neutralizing the potential at both ends of the electrode load. Alternatively, the output state of the constant current source is switched before and after the constant current path is established, thereby dissipating residual differential charge, eliminating closing overshoot, improving waveform stability and safety of use, and thus effectively alleviating or overcoming the aforementioned problems.

[0032] Therefore, this invention provides a control method for a constant current electrical stimulator and a corresponding constant current electrical stimulator. The specific implementation method is described in detail below with reference to the accompanying drawings.

[0033] In some embodiments of the present invention, reference is made to Figure 1The constant current electrical stimulator may include a controller, a DAC module, an H-bridge circuit, a high-voltage power supply, and a constant current source control module. In this embodiment, the controller may be configured to output an H-bridge control signal for controlling the on / off state of each switch in the H-bridge circuit, and a stimulation current setting signal for setting the output state of the constant current source control module. In some embodiments, the controller may be implemented by a microcontroller, for example. The high-voltage power supply provides high-voltage power to the high-side branch of the H-bridge circuit; the constant current source control module is connected in series to the low-side branch of the H-bridge circuit for setting a constant current flowing through the electrode load; the DAC module is connected to the controller for providing a control voltage to the constant current source control module. The H-bridge circuit has a first output node and a second output node for connecting the two ends of the electrode load, respectively, to output bidirectional constant current pulses to the electrode load under the control of the controller. As an explanation and not a limitation, the electrode load may be a capacitive load formed in contact with human skin (see reference). Figure 3 (The load on human skin is characterized by a capacitor C and a resistor R connected in parallel).

[0034] In some embodiments of the present invention, reference is made to Figure 2 The H-bridge circuit may include a first high-side switch Q1 and a second high-side switch Q2 located in the high-side branch, and a first low-side switch Q3 and a second low-side switch Q4 located in the low-side branch. In this embodiment, a first output node is formed between the first high-side switch Q1 and the first low-side switch Q3, and a second output node is formed between the second high-side switch Q2 and the second low-side switch Q4. The first and second output nodes are used to connect to the two ends of the electrode load, respectively. The other ends of the first high-side switch Q1 and the second high-side switch Q2 are connected to a high-voltage power supply, and the other ends of the first low-side switch Q3 and the second low-side switch Q4 are connected to a constant current source control module. The constant current source control module is connected in series between the low-side branch and the reference potential terminal.

[0035] In this embodiment, the constant current source control module is located on the low-side branch of the H-bridge circuit (i.e., the side closest to the reference potential). By way of explanation and not limitation, placing the constant current source control module on the low side facilitates precise control of the constant current by operational amplifiers (compared to the difficulty in precisely controlling the constant current on the high side), and also allows the neutralization method described later—"to bring the two output nodes to the same potential via the high-voltage power supply to neutralize the potential across the electrode load"—to be valid; this neutralization method requires that there is no constant current source between the electrode load and the high-voltage power supply. In an alternative embodiment, the reference... Figure 3 The constant current source control module can also be placed on the high-side branch of the H-bridge circuit (i.e., the side closer to the high-voltage power supply). By way of illustration and not limitation, although the (H-bridge) control method described in the embodiments of the present invention is preferably applicable to... Figure 2 The constant current source control module shown is configured in the low-side branch architecture of the H-bridge circuit. However, the (H-bridge) control method of this embodiment can be combined with or implemented in, for example... Figure 3The constant current source control module shown can also be placed in the high-side branch of the H-bridge circuit, and the resulting solution also falls within the scope of this invention. For the sake of simplicity, the (H-bridge) control method described in this embodiment will be described in conjunction with the architecture where the constant current source control module is placed in the low-side branch of the H-bridge circuit.

[0036] In some embodiments, the first high-side switch Q1, the second high-side switch Q2, the first low-side switch Q3, and the second low-side switch Q4 may be selected from one or more of a field-effect transistor, a bipolar transistor, an insulated-gate bipolar transistor, an analog switch, or an optocoupler switch. Optionally, when switching between high-side and low-side switches (e.g., first turning off a low-side switch and then turning on a high-side switch of the same bridge arm), a dead zone may be reserved to avoid instantaneous shoot-through between the high-side and low-side switches of the same bridge arm.

[0037] In some embodiments of the present invention, the constant current source control module may include a controllable constant current source, such as a voltage-controlled constant current source, configured to adjust the output current according to a control voltage. In some embodiments, the voltage-controlled constant current source may have a first operating state and a second operating state, wherein the output current is stopped in the first operating state and a set constant current is output in the second operating state. By way of explanation and not limitation, the first and second operating states of the voltage-controlled constant current source can be implemented by a variety of different specific architectures, such as an implementation based on control voltage adjustment (control voltage type) and an implementation based on negative feedback loop clamping (negative feedback clamping type). The specific hardware structure and control process will be further described in conjunction with the accompanying drawings in the embodiments described later.

[0038] In some embodiments of the invention, the high-voltage power supply is configured to provide a boosted high-voltage power supply to the high-side branch of the H-bridge circuit. By way of explanation and not limitation, the high-voltage power supply may include a boost circuit to raise a lower battery voltage to a higher voltage suitable for electrical stimulation.

[0039] As previously mentioned, the H-bridge circuit, under the control of the controller, alternately outputs bidirectional constant current pulses to the electrode load. Among them, the reference... Figure 4 When the first high-side switch Q1 and the second low-side switch Q4 are turned on, and the second high-side switch Q2 and the first low-side switch Q3 are turned off, current flows from the high-voltage power supply through the first high-side switch Q1, the first output node, the electrode load, the second output node, and the second low-side switch Q4 to the constant current source control module, thereby applying a first constant current pulse along the first direction to the electrode load. (Reference) Figure 5 When the second high-side switch Q2 and the first low-side switch Q3 are turned on, and the first high-side switch Q1 and the second low-side switch Q4 are turned off, the current flows from the high-voltage power supply through the second high-side switch Q2, the second output node, the electrode load, the first output node and the first low-side switch Q3 to the constant current source control module, thereby applying a second constant current pulse along the second direction to the electrode load, the second direction being opposite to the first direction.

[0040] However, as an explanation rather than a limitation, since the electrode load is a capacitive load formed by the contact between the electrode and human skin, if a constant voltage control method is used through an H-bridge circuit, for example, by directly controlling the application of the aforementioned bidirectional pulses to this capacitive electrode load—for example, by controlling the first high-side switch Q1 and the second low-side switch Q4 to conduct to generate a positive pulse, and controlling the second high-side switch Q2 and the first low-side switch Q3 to conduct to generate a symmetrical negative pulse—then at the instant each switch is turned on and the voltage is suddenly applied to the electrode load, the equivalent capacitance of the electrode load will be rapidly charged, introducing a large transient current. This will cause a significant overshoot in the output waveform at the beginning edge of each pulse. Figure 6 As shown. Figure 6 The diagram schematically illustrates an exemplary bidirectional pulse output voltage waveform in this scenario, where the spikes at the leading edges of each pulse characterize the aforementioned overshoot. This overshoot causes the actual stimulation applied to the electrode load to deviate from the set value during the pulse initiation phase, reducing the constant current accuracy. Furthermore, it also affects the stability and safety of the output pulse.

[0041] To eliminate or reduce the aforementioned overshoot, the control method for the constant current electrostimulator provided in this embodiment of the invention can employ the neutralization potential method (described later) and the soft-start / stop method for switching the controllable constant current source control module. This involves neutralizing the potential across the electrode load before and after each switching operation to discharge any residual differential charge, or switching the output state of the constant current source control module before and after the establishment of the constant current path, causing the switches in the H-bridge circuit to operate under zero or near-zero current conditions. In this way, the constant current no longer generates the aforementioned transient overshoot when it is applied to the electrode load, but instead quickly establishes and stabilizes at the set constant current value, thereby improving the current waveform on the electrode load to the desired state. Figure 7 As shown. Figure 7 The diagram schematically illustrates a bidirectional pulsed output current waveform according to an embodiment of the present invention, which presents as a bidirectional constant current pulse with a flat top and positive and negative symmetry. By way of explanation and not limitation, relative to... Figure 6 The waveform exhibits significant overshoot at the pulse leading edge. Figure 7 The overshoot in the waveform is eliminated or significantly reduced, and the output bidirectional constant current pulse is more stable and symmetrical, thereby improving the stability of the stimulation waveform and the safety of use.

[0042] Accordingly, in some embodiments of the present invention, a control method for a constant current electrical stimulator is proposed, more specifically, an H-bridge circuit control method. Figure 8 A flowchart illustrating the control method of the constant current electrical stimulator is shown. Figures 9 to 15 The states of each switch in the H-bridge circuit and the current path in each step of the specific embodiment of the control method (first embodiment) are schematically shown (arrows in the figure indicate the direction of current flow).

[0043] like Figure 8 As shown, the control method for this constant current electrical stimulator may include the following steps performed periodically: S810 controls the first high-side switch and the second high-side switch to be turned on simultaneously, and the first low-side switch and the second low-side switch to be turned off simultaneously, so as to neutralize the potential at both ends of the electrode load.

[0044] In the first embodiment, reference Figure 9 S810 may include: applying a conduction level to the first high-side switch Q1 and the second high-side switch Q2 respectively, so that the conduction state of the first high-side switch Q1 and the second high-side switch Q2 is maintained for a preset neutralization time, so that the voltage difference across the electrode load meets the preset neutralization condition. As an explanation, and not a limitation, the preset neutralization time should not be less than the time required for the voltage difference across the electrode load to decay to the preset neutralization condition (e.g., the two output nodes tend to be at the same potential, or the residual differential voltage is lower than a preset level), and its typical value can be associated with the RC time constant equivalent to the electrode load. In some specific embodiments, when the first high-side switch Q1 and the second high-side switch Q2 are simultaneously turned on, and both low-side switches are turned off, the first output node and the second output node are at the same potential via the high-voltage power supply, thereby causing the two ends of the electrode load to tend to be at the same potential, discharging the residual differential charge on it, and achieving potential neutralization. This avoids the charge remaining on the capacitance equivalent to the electrode load from the previous pulse from affecting the subsequent pulse waveform.

[0045] S820 controls the second low-side switch to turn on when the potential across the electrode load is neutralized, so as to establish a first current path from the high-voltage power supply through the second high-side switch and the second low-side switch to the constant current source control module.

[0046] In this first embodiment, reference Figure 10 At this time, with the second high-side switch Q2 still conducting, the second low-side switch Q4 is turned on, and current flows from the high-voltage power supply through the second high-side switch Q2 and the second low-side switch Q4 to the constant current source control module. At this point, this first current path does not flow through the electrode load. Explained, and not limited to, this allows a constant current to be established first in the same bridge arm path that does not flow through the electrode load, enabling the output current of the constant current source control module to stabilize beforehand, thereby avoiding closing overshoot when the current is subsequently switched to the electrode load.

[0047] S830, after establishing the first current path, controls the second high-side switch to open, so that the current flows from the high-voltage power supply through the first high-side switch, the first output node, the electrode load, the second output node and the second low-side switch to the constant current source control module, so as to generate the first constant current pulse flowing through the electrode load in the first direction.

[0048] In this first embodiment, reference Figure 11After the second high-side switch Q2 is disconnected, the constant current that has stabilized in the previous step can be switched onto the electrode load, thus flowing through the electrode load in the first direction (from the first output node to the second output node), forming the first constant current pulse. Since the current is already stable before being switched onto the electrode load, there is essentially no overshoot on the electrode load at the moment of switching, thereby obtaining, for example... Figure 7 The smooth pulse shown.

[0049] S840, at the end of the first constant current pulse, controls the second low-side switch to open and the second high-side switch to turn on again, so that the first high-side switch and the second high-side switch are turned on simultaneously and the first low-side switch and the second low-side switch are turned off simultaneously, so as to neutralize the potential at both ends of the electrode load again.

[0050] In this first embodiment, reference Figure 12 In this step, after the first constant current pulse ends, the H-bridge circuit is restored to a neutral state where the two high-side switches are on and the two low-side switches are off. This allows the first and second output nodes to be brought back to the same potential via the high-voltage power supply, discharging the charge on the electrode load. Explained, this prepares for the subsequent generation of a smooth constant current pulse in the opposite direction.

[0051] S850, with the potential across the electrode load neutralized again, controls the first low-side switch to turn on, so as to establish a second current path from the high-voltage power supply through the first high-side switch and the first low-side switch to the constant current source control module.

[0052] In this first embodiment, reference Figure 13 Similar to step S820, at this time, the first high-side switch Q1 is still on and the first low-side switch Q3 is on. The current flows from the high-voltage power supply through the first high-side switch Q1 and the first low-side switch Q3 to the constant current source control module. This second current path also does not flow through the electrode load, so that the output current of the constant current source control module reaches stability first, thereby avoiding the overshoot when the current is switched into the electrode load.

[0053] S860, after establishing the second current path, controls the first high-side switch to open, so that the current flows from the high-voltage power supply through the second high-side switch, the second output node, the electrode load, the first output node and the first low-side switch to the constant current source control module, so as to generate a second constant current pulse flowing through the electrode load in the second direction.

[0054] The second direction is opposite to the first direction.

[0055] In this first embodiment, reference Figure 14After the first high-side switch Q1 is disconnected, the stabilized constant current is switched into the electrode load and flows through the electrode load in the second direction (from the second output node to the first output node), forming a second constant current pulse opposite to the direction of the first constant current pulse. In some embodiments, the first and second constant current pulses may have the same pulse width and current amplitude, thereby making the net charge of the electrode load approach zero within a complete pulse cycle, achieving active charge balance. Similarly, and as mentioned above, since the current is already stable before being switched into the electrode load, there is essentially no overshoot on the electrode load at the moment of switching in, thereby achieving, for example... Figure 7 The smooth pulse shown.

[0056] In a further embodiment, the control method may further include a periodic step S870: S870, at the end of the second constant current pulse, controls the first low-side switch to open and the first high-side switch to turn on again, so that the first high-side switch and the second high-side switch are turned on at the same time, and the first low-side switch Q3 and the second low-side switch Q4 are turned off at the same time.

[0057] In this first embodiment, reference Figure 15 In step S870, after the second constant current pulse ends, the H-bridge circuit is reset to the state where the two high-side switches are on and the two low-side switches are off. Explained, but not limited to, this allows for the re-neutralization of the electrode load at the end of the current cycle. Alternatively, this operation allows the neutralization step (starting step) of S810 in each cycle, starting from the second pulse cycle, to be continued by step S870 (ending step) of the previous cycle. Furthermore, at the end of the operation (when there are no more subsequent cycles), step S870 also ensures that the electrode load remains in a neutralized state, preventing residual charge from remaining for an extended period.

[0058] Therefore, the above-described (H-bridge) control method of this invention, by neutralizing the potential at both ends of the electrode load before and after each switching and by establishing a stable constant current in the same bridge arm path that does not flow through the electrode load before switching it into the electrode load, not only releases the residual differential charge on the electrode load during switching, but also eliminates the closing overshoot when the constant current is switched into the electrode load, thereby obtaining a stable and symmetrical bidirectional constant current pulse, which is beneficial to improving the stability of the stimulation waveform and reducing the risk of damage to the human body.

[0059] In some embodiments of the present invention, reference is made to Figure 16 The constant current stimulator can also perform another (H-bridge circuit) control method. In this control method, the constant current source control module is constructed as a controllable constant current source, which has a first operating state and a second operating state: in the first operating state, the controllable constant current source stops outputting current; in the second operating state, the controllable constant current source outputs a set constant current.

[0060] refer to Figure 16 The control method includes the following steps, which are performed periodically: S1610, when the controllable constant current source is in the first working state, controls the first high-side switch and the second low-side switch to be turned on, so as to establish a first current path from the high-voltage power supply through the first high-side switch, the first output node, the electrode load, the second output node and the second low-side switch to the controllable constant current source.

[0061] In some embodiments, step S1610 can be performed by first turning on the first high-side switch Q1 and the second low-side switch Q4, which are diagonally opposite each other, to establish a first current path through the electrode load, provided that the controllable constant current source has stopped outputting current (i.e., the first operating state). Since the controllable constant current source has not yet output current at this time, the first high-side switch Q1 and the second low-side switch Q4 are turned on under zero current conditions, thereby avoiding overshoot caused by closing the circuit when current is present. Thus, soft start can be achieved by first turning on the switches under zero current conditions and then switching on the constant current after the path is established.

[0062] S1620, after establishing the first current path, the controllable constant current source is switched from the first working state to the second working state, so that the set constant current output by the controllable constant current source flows through the electrode load through the first current path to generate the first constant current pulse flowing through the electrode load in the first direction.

[0063] In some embodiments, after each switch in the first current path is turned on at zero current (or equivalent zero current), the controllable constant current source is switched from stopping output to outputting a set constant current. This set constant current flows through the electrode load in a first direction (from the first output node to the second output node), thereby smoothly forming the first constant current pulse. As an explanation, and not a limitation, since the current is gradually applied by the controllable constant current source after the path is established, there is essentially no closing overshoot on the electrode load.

[0064] S1630, at the end of the first constant current pulse, control the controllable constant current source to switch from the second working state to the first working state, and control the first high-side switch and the second low-side switch to disconnect.

[0065] In some embodiments, at the end of the first constant current pulse, by causing the controllable constant current source to stop outputting current and disconnecting the first high-side switch Q1 and the second low-side switch Q4, the switches are opened under zero current or near-zero current conditions, thereby achieving soft stop and reducing turn-off overshoot.

[0066] In some embodiments, step S1630 can be performed in a preset order.

[0067] In some embodiments, step S1630 may execute a switching action and a disconnection action in a first preset order, wherein the first preset order is to execute the switching action first and then the disconnection action.

[0068] In some other embodiments, step S1630 may execute the switching action and the disconnection action in a second preset order, wherein the second preset order is to execute the disconnection action first and then the switching action.

[0069] S1640, while keeping the controllable constant current source in the first working state, controls the second high-side switch and the first low-side switch to be turned on, so as to establish a second current path from the high voltage power supply through the second high-side switch, the second output node, the electrode load, the first output node and the first low-side switch Q3 to the controllable constant current source.

[0070] In some embodiments, similar to step S1610, step S1640 can, when the controllable constant current source stops outputting current, turn on the second high-side switch Q2 and the first low-side switch Q3, which are arranged diagonally, to establish a second current path in the opposite direction through the electrode load. Thus, soft-start can be achieved by first turning on the switches at zero current and then switching on the constant current after the path is established.

[0071] S1650, after establishing the second current path, controls the controllable constant current source to switch from the first working state to the second working state, so that the set constant current output by the controllable constant current source flows through the electrode load through the second current path to generate a second constant current pulse flowing through the electrode load in the second direction.

[0072] The second direction is opposite to the first direction.

[0073] In some embodiments, similar to step S1620, after switching the controllable constant current source to the second operating state, the constant current can be set to flow through the electrode load in a second direction (from the second output node to the first output node) to form a second constant current pulse opposite to the direction of the first constant current pulse. In some embodiments, the first constant current pulse and the second constant current pulse can have the same pulse width and current amplitude, so that the net charge of the electrode load approaches zero in a complete pulse cycle, thereby achieving active charge balance.

[0074] S1660, at the end of the second constant current pulse, control the controllable constant current source to switch from the second working state to the first working state, and control the second high-side switch and the first low-side switch to disconnect.

[0075] In some embodiments, similar to S1630, at the end of the second constant current pulse, the controllable constant current source can be stopped from outputting current and the second high-side switch Q2 and the first low-side switch Q3 can be disconnected under zero current or near-zero current conditions, thereby achieving soft stop and reducing turn-off overshoot.

[0076] In some embodiments, step S1660 can be performed in a preset order.

[0077] In some embodiments, step S1660 may execute the switching action and the disconnection action in a third preset order, wherein the third preset order is to execute the switching action first and then the disconnection action.

[0078] In some embodiments, step S1660 may execute the switching action and the disconnection action in a fourth preset order, wherein the fourth preset order is to execute the disconnection action first and then the switching action.

[0079] Therefore, the control method described in this embodiment of the invention utilizes a soft-start mechanism where, when the output current is stopped (first operating state), the diagonal switches are first turned on, and after the current path is established, the output set constant current is switched on (second operating state). It also employs a soft-stop mechanism where, at the end of the pulse, the output current is first stopped, and then the corresponding switch is turned off. This ensures that the switches in the H-bridge circuit are turned on and off under zero or near-zero current conditions, thereby reducing closing and closing overshoot and achieving the desired result. Figure 7 The smooth bidirectional constant current pulse shown.

[0080] In the embodiments of the present invention, it should be noted that the above-mentioned architecture for stopping the controllable constant current source from outputting current or outputting a set constant current in the first working state is not limited to making its physical output current absolutely zero, but also includes preventing the controllable constant current source from providing an effective constant current output for forming a constant current pulse to the H-bridge circuit through enable control, clamping control, feedback intervention, etc.

[0081] In some embodiments, the controllable constant current source described above has different specific implementation methods, such as implementation based on control voltage regulation and implementation based on negative feedback loop clamping. The corresponding soft start-stop control and its switching state and current path will be described below in conjunction with the accompanying drawings.

[0082] refer to Figures 17 to 20 This demonstrates what can be achieved. Figure 16The diagram illustrates the switching states and current paths of each step in the second embodiment of the control method. In this second embodiment, the controllable constant current source can be configured as a voltage-controlled constant current source, which is configured to adjust the output current according to a control voltage. In this second embodiment, the first operating state of the voltage-controlled constant current source is achieved by applying a zero-current control voltage to the voltage-controlled constant current source, wherein the zero-current control voltage makes the output current of the voltage-controlled constant current source zero; the second operating state is achieved by applying a constant current control voltage to the voltage-controlled constant current source, wherein the constant current control voltage causes the voltage-controlled constant current source to output the set constant current.

[0083] In some embodiments, the constant current electrical stimulator may further include a DAC module configured to output the zero-current control voltage and the constant current control voltage, thereby controlling the voltage-controlled constant current source to switch between a first operating state and a second operating state by a controller. In some embodiments, the control voltage may be output by the controller via a digital-to-analog converter. In other embodiments, the control voltage may also be obtained by low-pass filtering of a pulse width modulation signal output by the controller; both fall within the scope of this invention.

[0084] refer to Figures 17 to 20 The steps of the soft start-stop method in the second embodiment can be specifically implemented as follows.

[0085] In this second embodiment, in conjunction with reference to Figure 17 First, the zero-current control voltage can be applied to the voltage-controlled constant current source to make its output current zero (corresponding to the first operating state). Under this condition, the first high-side switch Q1 and the second low-side switch Q4 are turned on to establish a first current path from the high-voltage power supply through the first high-side switch Q1, the first output node, the electrode load, the second output node, and the second low-side switch Q4 to the voltage-controlled constant current source. After the first current path is established, the constant current control voltage is applied to the voltage-controlled constant current source (corresponding to the second operating state) so that the set constant current output by the voltage-controlled constant current source flows through the electrode load through the first current path, generating a first constant current pulse flowing through the electrode load in the first direction. As an explanation and not a limitation, since the voltage-controlled constant current source has zero output current when the first high-side switch Q1 and the second low-side switch Q4 are turned on, the switches are turned on under zero current conditions to avoid overshoot during closing. The constant current control voltage is applied after the first current path is established so that the set constant current is smoothly switched into the electrode load.

[0086] Continue to refer to Figure 18At the end of the first constant current pulse, the zero-current control voltage is applied to the voltage-controlled constant current source to make its output current zero, and the first high-side switch Q1 and the second low-side switch Q4 are disconnected. For illustrative purposes, but not limiting, applying the zero-current control voltage first to stop the voltage-controlled constant current source from outputting current, and then disconnecting the first high-side switch Q1 and the second low-side switch Q4, allows the switches to open under zero-current conditions, achieving a soft stop.

[0087] Continue to refer to Figure 19 While maintaining the zero-current control voltage (output current is zero) applied to the voltage-controlled constant current source, the second high-side switch Q2 and the first low-side switch Q3 are turned on to establish a second current path from the high-voltage power supply through the second high-side switch Q2, the second output node, the electrode load, the first output node, and the first low-side switch Q3 to the voltage-controlled constant current source. After establishing the second current path, the constant current control voltage is applied to the voltage-controlled constant current source, causing the set constant current output by the voltage-controlled constant current source to flow through the electrode load via the second current path, generating a second constant current pulse flowing through the electrode load in a second direction, which is opposite to the first direction.

[0088] Continue to refer to Figure 20 At the end of the second constant current pulse, the zero current control voltage is applied to the voltage-controlled constant current source to make its output current zero, and the second high-side switch Q2 and the first low-side switch Q3 are disconnected.

[0089] In this embodiment, the state switching action can be achieved by applying the zero-current control voltage or the constant-current control voltage to the voltage-controlled constant current source. Accordingly, at the end of the first constant current pulse or the second constant current pulse, the switching from the second state to the first state can be achieved by applying the zero-current control voltage to the voltage-controlled constant current source.

[0090] Therefore, this embodiment switches the output state of the voltage-controlled constant current source by applying a zero-current control voltage or a constant-current control voltage, and achieves soft start-stop by coordinating the switching on and off of the switch under zero current conditions, thus obtaining the desired output state. Figure 7 The stable bidirectional constant current pulse shown; and since the control voltage can be generated by the controller through digital-to-analog conversion or pulse width modulation filtering, no special components are required, which helps to reduce costs.

[0091] refer to Figures 21 to 25 This demonstrates what can be achieved. Figure 16 The diagram illustrates the switching states and current paths of each step in the third embodiment of the control method. In this third embodiment, the controllable constant current source can be constructed as a voltage-controlled constant current source with a negative feedback loop, such as... Figure 21 As shown.

[0092] In this third embodiment, reference Figure 21The negative feedback loop may include operational amplifier U1 and controlled devices. For example... Figure 21 As shown, the controlled device may include a transistor VT. The non-inverting input of operational amplifier U1 receives a set voltage. (Reference) Figure 21 The set voltage can be provided by the DAC input V1, and the set voltage at the DAC input V1 can be generated by the aforementioned DAC module. The output of operational amplifier U1 is connected to the control terminal (base) of a controlled device such as transistor VT via base resistor R2. The first terminal (e.g., collector) of the controlled device such as transistor VT is connected to the low-side branch of the H-bridge circuit, and the second terminal (e.g., emitter) of the controlled device such as transistor VT is connected to the reference potential terminal via sampling resistor R1. Figure 21 The first terminal of the controlled device, such as transistor VT, is connected to the high-voltage power supply terminal VCC via resistor R4, which characterizes the electrode load, to illustrate the path of the constant current flowing through the electrode load. As mentioned earlier, in a constant-current electrostimulator, the first terminal of the controlled device, such as transistor VT, can be connected to the low-side branch of an H-bridge circuit, and then connected to the high-voltage power supply via the H-bridge circuit and the electrode load. The inverting input terminal of operational amplifier U1 is connected to the connection node between the controlled device, such as transistor VT, and the sampling resistor R1 via feedback resistor R3. Operational amplifier U1 is powered by power supply terminal VDD.

[0093] Continue to refer to Figure 21 When the voltage-controlled constant current source outputs current, the current flowing through the controlled device, such as transistor VT, flows through the sampling resistor R1, and a current feedback signal is formed at the connection node between the controlled device, such as transistor VT, and the sampling resistor R1. Operational amplifier U1 drives the controlled device, such as transistor VT, according to the set voltage at its non-inverting input and the current feedback signal fed back to its inverting input via feedback resistor R3, so that the current flowing through the controlled device, such as transistor VT, stabilizes at the constant current value set by the set voltage. Thus, the current flowing through the electrode load is determined by the set voltage and the sampling resistor R1, and is basically unaffected by changes in the electrode load impedance, which is beneficial for obtaining high-precision constant current output.

[0094] In this third embodiment, the negative feedback loop may further include a clamping diode D, and the inverting input terminal of the operational amplifier U1 is connected to the control pin of the controllable constant current source control module (reference) via the clamping diode D. Figure 21(This control pin is denoted by V2). The first operating state of the voltage-controlled constant current source (stop output current) is achieved by switching the control pin V2 to a first level. In this first level, the clamping diode D is turned on and clamps the inverting input terminal, causing the operational amplifier U1 to stop outputting a drive signal to the controlled device, such as the transistor VT, thereby stopping the voltage-controlled constant current source from outputting current. The second operating state (output set constant current) is achieved by switching the control pin V2 to a second level. In this second level, the clamping diode D is turned off and releases the clamp on the inverting input terminal, allowing the operational amplifier U1 to drive the controlled device, such as the transistor VT, to output the set constant current according to the set voltage and the current feedback signal.

[0095] In this embodiment, the specific high and low values ​​of the first and second levels, and the connection polarity of the anode / cathode of the clamping diode D relative to the control pin V2 and the inverting input terminal, can be selected as needed. It is sufficient to ensure that the clamping diode D is conducting to clamp the inverting input terminal when the control pin V2 is at the first level, and is reverse-biased when it is at the second level. For example, in one implementation, the anode of the clamping diode D is connected to the control pin V2, and the cathode is connected to the inverting input terminal, with the first level being high and the second level being low; in another implementation, the anode of the clamping diode D is connected to the inverting input terminal, and the cathode is connected to the control pin V2, with the first level being low and the second level being high. Both of these fall within the scope of this invention.

[0096] Continue to refer to Figures 22 to 25 The steps of the soft start-stop method in the third embodiment can be specifically implemented as follows.

[0097] In this third embodiment, in conjunction with reference to Figure 22 When the control pin is switched to the first level to clamp the inverting input terminal, causing the voltage-controlled constant current source to stop outputting current (corresponding to the first operating state), the first high-side switch Q1 and the second low-side switch Q4 are turned on to establish a first current path from the high-voltage power supply through the first high-side switch Q1, the first output node, the electrode load, the second output node, and the second low-side switch Q4 to the voltage-controlled constant current source. After establishing the first current path, the control pin is switched to the second level to release the clamp, causing the operational amplifier U1 to drive the controlled device to output the set constant current (corresponding to the second operating state). The set constant current flows through the electrode load via the first current path, generating a first constant current pulse flowing through the electrode load in the first direction.

[0098] Here, when the first high-side switch Q1 and the second low-side switch Q4 are turned on, the control pin is at the first level and the inverting input terminal is clamped, causing the voltage-controlled constant current source to stop outputting current. Therefore, the switch is turned on under zero current conditions to avoid overshoot during closing. After the first current path is established, the control pin is switched to the second level and the clamping is released, so that the set constant current is smoothly switched into the electrode load.

[0099] Continue to refer to Figure 23 At the end of the first constant current pulse, the control pin is switched to the first level (clamping the inverting input terminal to stop the voltage-controlled constant current source from outputting current), and the first high-side switch Q1 and the second low-side switch Q4 are disconnected. In some embodiments, the control pin can be switched to the first level first to stop the voltage-controlled constant current source from outputting current, and then the first high-side switch Q1 and the second low-side switch Q4 can be disconnected under zero current conditions, achieving soft stop. In another embodiment, the above operation can be reversed.

[0100] Continue to refer to Figure 24 While keeping the control pin at the first level (when the voltage-controlled constant current source stops outputting current), the second high-side switch Q2 and the first low-side switch Q3 are turned on to establish a second current path from the high-voltage power supply through the second high-side switch Q2, the second output node, the electrode load, the first output node, and the first low-side switch Q3 to the voltage-controlled constant current source. After establishing the second current path, the control pin is switched to the second level to release the clamp, allowing the set constant current output by the voltage-controlled constant current source to flow through the electrode load via the second current path, generating a second constant current pulse flowing through the electrode load in a second direction, which is opposite to the first direction.

[0101] Continue to refer to Figure 25 At the end of the second constant current pulse, the control pin is switched to the first level (clamping the inverting input terminal to stop the voltage-controlled constant current source from outputting current), and the second high-side switch Q2 and the first low-side switch Q3 are disconnected.

[0102] In this embodiment, the state switching action can be achieved by switching the control pin to the first level (to clamp the inverting input terminal and stop the voltage-controlled constant current source from outputting current). Accordingly, at the end of the first or second constant current pulse, the switching from the second state to the first state can be achieved by switching the control pin to the first level.

[0103] Therefore, this embodiment switches the output state of the voltage-controlled constant current source by clamping and declamping the inverting input of the operational amplifier. Combined with the switching on and off at zero current, soft start-stop is achieved. Furthermore, the negative feedback loop formed by the operational amplifier, the controlled device, and the sampling resistor stabilizes the current flowing through the electrode load at a set value, making it largely unaffected by changes in the electrode load impedance, thus obtaining... Figure 7 The smooth bidirectional constant current pulse shown.

[0104] Accordingly, embodiments of the present invention also provide a constant current electrical stimulator that can implement the aforementioned control method.

[0105] In summary, the constant current electrical stimulator and its control method of the present invention output bidirectional symmetrical constant current pulses to the electrode load through an H-bridge circuit, so that the net charge of the electrode load approaches zero within a complete pulse cycle, thus avoiding the risk of nerve damage caused by the charge accumulation of unipolar pulses.

[0106] Furthermore, in some embodiments, such as the first embodiment, the first high-side switch and the second high-side switch can be simultaneously turned on before and after each switching, so that the first output node and the second output node are at the same potential via the high-voltage power supply, thereby neutralizing the potential at both ends of the electrode load and discharging the residual differential charge on it; and by first establishing a stable constant current on the same bridge arm path that does not flow through the electrode load, and then disconnecting the corresponding high-side switch to cut the current into the electrode load, the closing overshoot when the constant current is cut in is eliminated, thereby obtaining a smooth and symmetrical bidirectional constant current pulse, improving the stability of the stimulation waveform and the safety of use.

[0107] Alternatively, in some embodiments, such as the second and third embodiments, the controllable constant current source can first turn on the diagonal high-side and low-side switches when the output current is stopped, and then switch to the output set constant current after the current path is established. Also, the output current can be stopped first and then the corresponding switches can be turned off at the end of the pulse, so that the switches of the H-bridge circuit are turned on and off under zero current or near-zero current conditions, thereby reducing the overshoot of closing and turning off. The second embodiment switches its output state by applying a zero current control voltage or a constant current control voltage to the voltage-controlled constant current source. The third embodiment switches its output state by clamping and declamping the inverting input terminal of the operational amplifier.

[0108] Therefore, the embodiments of the present invention improve the stability of the stimulation waveform and the safety of use by coordinating the control timing of the H-bridge and the output state of the constant current source.

[0109] In some embodiments of the present invention, an electronic device is also provided, which includes a processor and a memory storing a computer program, the processor being configured to implement the method of any embodiment of the present invention when running the computer program.

[0110] Figure 26 A schematic diagram is shown of a method or electronic device 2600 that can be used to implement embodiments of the present invention. In some embodiments, the number of electronic devices may be more or less than the number shown. In some embodiments, it can be implemented using a single or multiple electronic devices. It can also be implemented using cloud or distributed electronic devices in some embodiments.

[0111] like Figure 26 As shown, the electronic device 2600 includes a processor 2601 and a memory 2602. The processor executes programs stored in the memory, which, when executed by a computer, can implement the methods, steps, or functions described in the above embodiments. The processor 2601 may include various types of processors, such as a central processing unit (CPU), a graphics processing unit (GPU), a neural network processor (NPU), a digital signal processor (DSP), etc. The processor 2601 and the memory 2602 are interconnected via a bus 2603. Input / output (I / O) interfaces may also be connected to the bus 2603. The systems, devices, modules, or units illustrated in the above embodiments can be implemented by a computer or its associated components.

[0112] Although not shown, in this embodiment of the invention, a program product is provided, including a computer program that, when executed by a processor, implements the method of any embodiment of the invention.

[0113] Although not shown, in an embodiment of the invention, a storage medium is provided storing a computer program configured to be run to implement the method of any embodiment of the invention.

[0114] Storage media in embodiments of the present invention include articles that are permanent and non-permanent, removable and non-removable, capable of storing information by any method or technology. Examples of storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transfer medium that can be used to store information accessible by a computing device.

[0115] The methods, programs, systems, apparatuses, etc., in embodiments of the present invention can be executed or implemented in one or more networked computers, or practiced in a distributed computing environment. In the embodiments of this specification, in these distributed computing environments, tasks can be performed by remote processing devices connected via a communication network.

[0116] Those skilled in the art will understand that the embodiments described in this specification can be provided as methods, systems, or computer program products. Therefore, those skilled in the art will realize that the functional modules / units or controllers and related method steps described in the above embodiments can be implemented in software, hardware, or a combination of both.

[0117] Unless explicitly stated otherwise, the actions or steps of the methods and procedures described in the embodiments of the present invention do not necessarily have to be performed in a specific order and can still achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0118] This document describes several embodiments of the present invention; however, for the sake of brevity, the descriptions of the embodiments are not exhaustive, and identical or similar features or parts between the embodiments may be omitted. In this document, "one embodiment," "some embodiments," "example," "specific example," or "some examples" refers to embodiments applicable to at least one, but not all, of the present invention. The above terms do not necessarily refer to the same embodiments or examples. Without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described herein, as well as the features of the different embodiments or examples.

[0119] The exemplary systems and methods of the present invention have been specifically shown and described with reference to the above embodiments, which are merely examples of the best mode for implementing the systems and methods. Those skilled in the art will understand that various changes can be made to the embodiments of the systems and methods described herein without departing from the spirit and scope of the invention as defined in the appended claims when implementing the systems and / or methods.

Claims

1. A control method for a constant current electrical stimulator, characterized in that, The constant current electrical stimulator includes an H-bridge circuit, a high-voltage power supply, and a constant current source control module. The H-bridge circuit includes a first high-side switch and a second high-side switch located on the high-side branch, and a first low-side switch and a second low-side switch located on the low-side branch. A first output node is formed between the first high-side switch and the first low-side switch, and a second output node is formed between the second high-side switch and the second low-side switch. The first output node and the second output node are used to connect to the two ends of the electrode load, respectively. The high-voltage power supply is used to provide high-voltage power to the high-side branch of the H-bridge circuit, and the constant current source control module is connected in series to the low-side branch of the H-bridge circuit. The control method includes periodically performing the following steps: The first high-side switch and the second high-side switch are simultaneously turned on, and the first low-side switch and the second low-side switch are simultaneously turned off, in order to neutralize the potential at both ends of the electrode load. When the potential across the electrode load is neutralized, the second low-side switch is turned on to establish a first current path from the high-voltage power supply through the second high-side switch and the second low-side switch to the constant current source control module. After establishing the first current path, the second high-side switch is controlled to open, so that the current flows from the high-voltage power supply through the first high-side switch, the first output node, the electrode load, the second output node and the second low-side switch to the constant current source control module, so as to generate a first constant current pulse flowing through the electrode load in the first direction; At the end of the first constant current pulse, the second low-side switch is controlled to open and the second high-side switch is turned on again, so that the first high-side switch and the second high-side switch are turned on at the same time and the first low-side switch and the second low-side switch are turned off at the same time, so as to neutralize the potential at both ends of the electrode load again. When the potential across the electrode load is neutralized again, the first low-side switch is turned on to establish a second current path from the high-voltage power supply through the first high-side switch and the first low-side switch to the constant current source control module. After establishing the second current path, the first high-side switch is controlled to open, so that the current flows from the high-voltage power supply through the second high-side switch, the second output node, the electrode load, the first output node and the first low-side switch to the constant current source control module, so as to generate a second constant current pulse flowing through the electrode load in a second direction, wherein the second direction is opposite to the first direction.

2. The method according to claim 1, characterized in that, The control of simultaneously turning on the first high-side switch and the second high-side switch includes: Apply a conduction level to the first high-side switch and the second high-side switch respectively, so that the conduction state of the first high-side switch and the second high-side switch is maintained for a preset neutralization time, so that the voltage difference across the electrode load meets the preset neutralization condition.

3. The method according to claim 1, characterized in that, The periodic execution steps of the control method further include: At the end of the second constant current pulse, the first low-side switch is turned off and the first high-side switch is turned on again, so that the first high-side switch and the second high-side switch are turned on simultaneously and the first low-side switch and the second low-side switch are turned off simultaneously.

4. A control method for a constant current electrical stimulator, characterized in that, The constant current stimulator includes an H-bridge circuit, a high-voltage power supply, and a controllable constant current source control module. The H-bridge circuit includes a first high-side switch and a second high-side switch located on the high-side branch, and a first low-side switch and a second low-side switch located on the low-side branch. A first output node is formed between the first high-side switch and the first low-side switch, and a second output node is formed between the second high-side switch and the second low-side switch. The first output node and the second output node are used to connect to the two ends of the electrode load, respectively. The high-voltage power supply is used to provide high-voltage power to the high-side branch of the H-bridge circuit, and the controllable constant current source control module is connected in series to the low-side branch of the H-bridge circuit. The controllable constant current source control module has a first working state and a second working state. In the first working state, the controllable constant current source control module stops outputting current. In the second working state, the controllable constant current source control module outputs a set constant current. The control method includes the following steps, which are performed periodically: When the controllable constant current source control module is in the first working state, the first high-side switch and the second low-side switch are turned on to establish a first current path from the high voltage power supply through the first high-side switch, the first output node, the electrode load, the second output node and the second low-side switch to the controllable constant current source control module. After establishing the first current path, the controllable constant current source control module is switched from the first working state to the second working state, so that the set constant current output by the controllable constant current source control module flows through the electrode load through the first current path to generate a first constant current pulse flowing through the electrode load in the first direction. When the first constant current pulse ends, the controllable constant current source control module is controlled to switch from the second working state to the first working state, and the first high-side switch and the second low-side switch are controlled to disconnect. While keeping the controllable constant current source control module in the first working state, control the second high-side switch and the first low-side switch to be turned on, so as to establish a second current path from the high voltage power supply through the second high-side switch, the second output node, the electrode load, the first output node and the first low-side switch to the controllable constant current source control module; After establishing the second current path, the controllable constant current source control module is switched from the first working state to the second working state, so that the set constant current output by the controllable constant current source control module flows through the electrode load through the second current path to generate a second constant current pulse flowing through the electrode load in a second direction, which is opposite to the first direction. At the end of the second constant current pulse, the controllable constant current source control module is controlled to switch from the second working state to the first working state, and the second high-side switch and the first low-side switch are controlled to disconnect.

5. The control method according to claim 4, characterized in that, The controllable constant current source control module includes a voltage-controlled constant current source, which is configured to adjust the output current according to the control voltage. The first operating state is achieved by applying a zero-current control voltage to the voltage-controlled constant current source, wherein the zero-current control voltage makes the output current of the voltage-controlled constant current source zero; The second operating state is achieved by applying a constant current control voltage to the voltage-controlled constant current source, wherein the constant current control voltage causes the voltage-controlled constant current source to output the set constant current.

6. The control method according to claim 5, characterized in that, The constant current electrical stimulator also includes a DAC module, which is configured to output the zero current control voltage and the constant current control voltage. The controllable constant current source control module is configured to adjust the output current according to the zero current control voltage or the constant current control voltage.

7. The control method according to claim 4, characterized in that, The controllable constant current source control module includes a voltage-controlled constant current source with a negative feedback loop, wherein the voltage-controlled constant current source is configured to adjust the output current according to the set voltage and current feedback signal; The first operating state is achieved by clamping the feedback input terminal in the negative feedback loop, wherein when the feedback input terminal is clamped, the voltage-controlled constant current source stops outputting current; The second operating state is achieved by releasing the clamp on the feedback input terminal, wherein when the feedback input terminal is released from clamping, the voltage-controlled constant current source outputs the set constant current according to the set voltage.

8. The control method according to claim 7, characterized in that, The negative feedback loop includes an operational amplifier and a controlled device. The output terminal of the operational amplifier is connected to the control terminal of the controlled device. The feedback input terminal is the inverting input terminal of the operational amplifier. The feedback input terminal is connected to the control pin of the controllable constant current source control module via a clamping diode. The first operating state is achieved by switching the control pin to the first level, turning on the clamping diode and clamping the feedback input terminal, so that the operational amplifier stops outputting drive signals to the controlled device. The second operating state is achieved by switching the control pin to the second level, turning off the clamping diode and releasing the clamp on the feedback input terminal, so that the operational amplifier drives the controlled device to output the set constant current according to the set voltage and the current feedback signal.

9. The control method according to claim 8, characterized in that, The negative feedback loop also includes a sampling resistor. The first end of the controlled device is connected to the low-side branch of the H-bridge circuit, and the second end is connected to the reference potential terminal through the sampling resistor. The non-inverting input terminal of the operational amplifier receives the set voltage, and the inverting input terminal of the operational amplifier is connected to the connection node between the controlled device and the sampling resistor. In the second operating state, the current flowing through the controlled device flows through the sampling resistor and forms the current feedback signal at the connection node.

10. The control method according to claim 4, characterized in that, The controllable constant current source control module switching from the second operating state to the first operating state, and controlling the first high-side switch and the second low-side switch to disconnect, includes: The switching and disconnecting actions are executed in either the first or second preset order. The first preset sequence is to perform the switching action first, and then perform the disconnection action; The second preset sequence is to first perform the disconnection action and then perform the switching action; And / or The controllable constant current source control module switching from the second operating state to the first operating state, and controlling the second high-side switch and the first low-side switch to disconnect, includes: Perform switching and disconnecting actions according to the third or fourth preset sequence; The third preset sequence is to perform the switching action first, and then perform the disconnection action; The fourth preset sequence is to first perform the disconnection action and then perform the switching action.

11. The method according to claim 1 or 4, characterized in that, The first high-side switch, the second high-side switch, the first low-side switch, and the second low-side switch are selected from one or more of field-effect transistors, bipolar transistors, insulated-gate bipolar transistors, analog switches, or optocouplers.

12. The method according to claim 1 or 4, characterized in that, The constant current pulse in the first direction and the constant current pulse in the second direction have the same pulse width and the same current amplitude, so that the net charge of the electrode load is zero in a complete pulse cycle.

13. The method according to claim 1 or 4, characterized in that, The electrode load includes the capacitive load formed when the electrode comes into contact with human skin.

14. A constant current electrical stimulator, characterized in that, include: The H-bridge circuit includes a first high-side switch and a second high-side switch located in the high-side branch, and a first low-side switch and a second low-side switch located in the low-side branch. A first output node is formed between the first high-side switch and the first low-side switch, and a second output node is formed between the second high-side switch and the second low-side switch. The first output node and the second output node are used to connect to the two ends of the electrode load, respectively. A high-voltage power supply is configured to provide high-voltage power to the high-side branch of the H-bridge circuit. A constant current source control module is connected in series in the low-side branch of the H-bridge circuit; The controller is configured to perform the control method as described in any one of claims 1 to 13 to output bidirectional constant current pulses to the electrode load.

15. The constant current electrical stimulator according to claim 14, characterized in that, The constant current source control module includes a voltage-controlled constant current source, and the constant current electrical stimulator also includes a DAC module; The DAC module is configured to output zero-current control voltage and constant-current control voltage; The constant current source control module is configured to stop outputting current according to the zero current control voltage and output a set constant current according to the constant current control voltage.

16. The constant current electrical stimulator according to claim 14, characterized in that, The constant current electrical stimulator also includes a constant current source control module, which includes a voltage-controlled constant current source with a negative feedback loop, the negative feedback loop including an operational amplifier, a controlled device, and a clamping diode; The output terminal of the operational amplifier is connected to the control terminal of the controlled device, and the inverting input terminal of the operational amplifier serves as the feedback input terminal. The feedback input terminal is connected to the control pin of the constant current source control module via the clamping diode. The constant current source control module is configured to switch between stopping the output current and outputting a set constant current by switching the level of the control pin to turn the clamping diode on or off.

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