Stimulation generation protection circuit for transcranial electrical stimulation

Abstract

The embodiment of the invention provides a stimulation generation protection circuit for transcranial electrical stimulation. The stimulation generation protection circuit comprises an ESD protection circuit, a current switching detection circuit, a separation detection circuit and a constant current source type stimulation generation circuit. By integrating the anti-static module, damage of static electricity to the circuit can be effectively inhibited, and normal work of internal elements is guaranteed; an output value identification unit is designed to monitor an output signal in real time and accurately judge whether the output signal exceeds a set value or not, so that protection measures are taken in time; and a load detection module is constructed, so that the connection and working state of the load can be accurately sensed. Therefore, multiple protection of the circuit is realized, the reliability, safety and adaptability of the circuit in a complex working environment are improved, and a powerful guarantee is provided for stable operation of related electronic equipment.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of medical electronics, in particular to a stimulation generation protection circuit for transcranial electrical stimulation. BACKGROUND

[0002] In the medical field, traditional therapies such as drug treatment, surgical intervention and physical rehabilitation training have significant limitations: drug treatment can easily cause systemic side effects and has limited effect on non-organic lesions such as nerve function repair, surgical intervention is traumatic, has a long recovery period and is difficult to precisely control deep tissues, and physical rehabilitation relies on the active cooperation of patients and has a low functional recovery efficiency. Electrical stimulation therapy directly acts on nerves, muscles or tissues through an external current or electric field, with the advantages of non-invasiveness or minimally invasive, targeted regulation, few side effects, suitable for refractory diseases and immediate adjustability, and has become an important supplement to non-drug and non-surgical treatment. However, traditional transcranial electrical stimulation (such as tDCS, tACS) has problems such as insufficient penetration depth, low spatial resolution and difficulty in deep regulation, making it difficult to act on deep nuclei such as thalamus and basal ganglia, and has limited effect on diseases involving deep brain regions. Transcranial time-interference stimulation therapy (tTIS) emerged in this background, which applies two high-frequency alternating currents to the scalp, uses the frequency difference to form a low-frequency interference electric field in the deep brain, and realizes the targeted regulation of deep nerves. Compared with traditional transcranial electrical stimulation, it has the advantages of precise regulation of deep brain regions, high spatial resolution, higher safety, expanded application range and non-invasive deep replacement, and can be used for Parkinson's disease, depression and other deep brain region-related diseases, and does not require surgical implantation of electrodes, making it more acceptable to patients. In tTIS, a constant current source has significant advantages over a constant voltage source as a stimulation output: due to individual differences and dynamic changes in the impedance of the scalp and skull, a constant current source can maintain a constant output current, ensuring stable stimulation parameters and avoiding abnormal interference electric fields caused by impedance fluctuations, ensuring consistent results; it can accurately control the current amplitude ratio and frequency difference of the two channels to ensure that the deep interference electric field precisely meets the needs of the target brain region; by presetting the maximum current limit, the constant current source can avoid sudden increases in current caused by sudden changes in load impedance, improving safety; at the same time, it can adapt to the impedance differences of different patients without frequent adjustments, and has better individual adaptability, providing stable, accurate and safe current output for tTIS, which is a key technical support for targeted regulation of deep brain regions.

[0003] In the field of electronic circuit technology, especially in the application of related circuits involving intermediate frequency stimulation, the technical bottleneck of existing protection circuits is increasingly prominent. On the one hand, the static electricity protection design of traditional circuits mostly uses passive protection elements such as voltage-dependent resistors, but such solutions are prone to parasitic capacitance in high-frequency signal transmission scenarios, leading to signal distortion, and the static electricity discharge efficiency is limited, which cannot meet the increasing industrial demand for ESD standards, especially in fields such as semiconductor manufacturing and medical electronics that are sensitive to static electricity, where circuit failure caused by static electricity breakdown occurs frequently.

[0004] On the other hand, there is a common problem of response delay in current output value control links. Existing circuits mostly rely on the simple combination of comparators and reference sources to identify output overcurrent or overvoltage, but when transient spikes occur in the output signal, the sampling rate of traditional detection circuits is difficult to match, often leading to delayed protection action, and thus causing major medical accidents. At the same time, load detection technology still remains at the level of simple current sampling or impedance matching judgment, and cannot monitor the dynamic changes of the load in real time. In the case of load short circuit, open circuit or nonlinear switching, there is a lack of effective early warning and protection mechanism, which seriously restricts the reliability and intelligent level of the stimulation circuit system.

[0005] In summary, the existing stimulation circuit has obvious deficiencies in penetration depth, spatial resolution, safety, and deep regulation. In the design of protection circuits, there are obvious deficiencies in the efficiency of static electricity protection, the real-time identification of output overvalue, and the accuracy of load detection. Therefore, an integrated and intelligent stimulation protection circuit design is needed to solve the above problems. SUMMARY

[0006] In view of the above problems, a stimulation generation protection circuit for transcranial electrical stimulation is provided to overcome the above problems or at least partially solve the above problems, comprising: an ESD protection circuit, a current switching detection circuit, a disengagement detection circuit, and a constant current source type stimulation generation circuit, wherein: The ESD protection circuit is composed of an input port, a resistor, a diode group, a capacitor, and an inductor, and is used to guide the static electricity to the ground; The current switching detection circuit includes a relay, an operational amplifier, and an ADC acquisition chip, and is used for double-loop switching and real-time current monitoring; The disengagement detection circuit is connected to the GPIO port to feedback the load state through optical coupling isolation input and output; The constant current source type stimulation generation circuit is composed of a current source, a switching switch, a power supply, and an output port, and is used to generate controllable stimulation current.

[0007] Optionally, the ESD protection circuit includes an input port STMU1, an input port STMU0, a resistor R39, a resistor R40, a diode D12, a diode D13, a diode D14, a diode D15, a capacitor C45, a capacitor C46, an inductor L3, an inductor L4, an output port BOOST_OUT, and a ground terminal HVSS; wherein: Left side: the input port STMU1 is connected to one end of the resistor R39, the anode of the diode D12 is connected to the STMU1-R39 line, the cathode of the diode D12 is connected to one end of the capacitor C45 and one end of the inductor L3, the other end of the capacitor C45 is grounded HVSS, the other end of the inductor L3 is connected to the anode of the diode D13, the cathode of the diode D13 is connected to the output port BOOST_OUT, and the output port BOOST_OUT also serves as a connection point of the protected circuit; Right side: the input port STMU0 is connected to one end of the resistor R40, the anode of the diode D14 is connected to the STMU0-R40 line, the cathode of the diode D14 is connected to one end of the capacitor C46 and one end of the inductor L4, the other end of the capacitor C46 is grounded HVSS, the other end of the inductor L4 is connected to the anode of the diode D15, and the cathode of the diode D15 is connected to the output port BOOST_OUT; the right side and the left side together constitute a protection structure for the protected circuit.

[0008] Optionally, the current switching detection circuit includes a relay K2, an operational amplifier U22, an ADC acquisition chip U27, and an output interface U19, wherein: Relay part K2: the current output port STMU1_1 is connected to pin 3 of the relay K2, the switching interface STMU1_2 is connected to pin 2 of the relay K2, the switching interface STMU1_3 is connected to pin 4 of the relay K2, the current output port STMU1_1 is connected to pin 5 of the operational amplifier U22, and the diode D31 is connected in parallel with the relay K2; Operational amplifier U22 part: one end of the resistor (R45) of pin 4 of the operational amplifier U22 is connected to pin 3 of the operational amplifier U22, pin 3 of the operational amplifier U22 is connected to the ADC_5V power supply, pin 2 of the operational amplifier U22 is grounded, pin 1 of the operational amplifier U22 is connected to the REF_2V5 reference voltage, and pin 6 of the operational amplifier U22 outputs an amplified signal; The pin 3 of the ADC acquisition chip U27 is connected with the voltage signal line OUT1, the pin 4 of the ADC acquisition chip U27 is connected with the voltage signal line OUT2, the pin 5 of the ADC acquisition chip U27 is connected with the voltage signal line OUT3, and the pin 6 of the ADC acquisition chip U27 is connected with the voltage signal line OUT4, which are used for respectively collecting voltage signals; the pins 9 and 10 of the ADC acquisition chip U27 are connected with the single-chip microcomputer through the I2C bus, the VDD pin of the ADC acquisition chip U27 is connected with the ADC_5V power supply, and the GND pin of the ADC acquisition chip U27 is grounded; The output interface U19 is used for connecting the electrode sheet and delivering the current to the patient's body.

[0009] Optionally, the current switching detection circuit further comprises resistors R45, R49, R59, R62, R63, R64, R65 and R67, which are used for voltage division, current limiting and filtering of the circuit.

[0010] Optionally, in the current switching detection circuit, the relay K2 is switched to the non-patient circuit first, and then switched to the patient circuit after the ADC acquisition chip U27 confirms that the current is normal, wherein the switching control signal JDQ_1 of the relay K2 is driven through the triode Q6.

[0011] Optionally, the disengagement detection circuit comprises a current input part, a core detection part and an output part, wherein: The current input part comprises input ports STMU0_1 and STMU0_2, and the input ports STMU0_1 and STMU0_2 are connected in series with a circuit comprising a resistor R28 and a diode D8, wherein the resistor R28 and the diode D8 are connected in parallel. The core detection part comprises an optocoupler U13, the optocoupler U13 is connected with the current input part through a pin 1 and a pin 2, a pin 3 of the optocoupler U13 is grounded HVSS, and a pin 4 of the optocoupler U13 is connected to a power supply S5V through a resistor R26. The output part comprises that the pin 4 of the optocoupler U13 is connected to a GPIO15 port through a resistor R29, and is connected in parallel with a capacitor C30 to ground.

[0012] Optionally, the GPIO15 port is used for outputting the detected signal to an external processor, and triggering a power reduction output when the external processor detects that the level change rate exceeds a predetermined threshold.

[0013] Optionally, the ground end HVSS of the ESD protection circuit and the ground end DVSS of the current switching detection circuit are isolated through a magnetic bead.

[0014] Optionally, the data packet transmitted to the single-chip microcomputer through the I2C bus contains a time stamp, which is used to associate the timing relationship between the current anomaly and the load state change.

[0015] Optionally, in the case that the high-level duration of the disengagement detection circuit output is greater than the preset time, and / or the current switching detection circuit identifies that the current value exceeds the safety threshold, the stimulation output is cut off and an audible and visual alarm is performed.

[0016] The embodiment of the present application provides a stimulation generation protection circuit for transcranial electrical stimulation, which comprises an ESD protection circuit, a current switching detection circuit, a disengagement detection circuit and a constant current source type stimulation generation circuit, wherein: the ESD protection circuit is composed of an input port, a resistor, a diode group, a capacitor and an inductor, and is used for guiding electrostatic charge to a ground terminal; the current switching detection circuit comprises a relay, an operational amplifier and an ADC acquisition chip, and is used for double-loop switching and real-time current monitoring; the disengagement detection circuit is isolated on the input and output sides through an optical coupler, and is connected with a GPIO port to feed back a load state; and the constant current source type stimulation generation circuit is composed of a current source, a switching switch, a power supply and an output port, and is used for generating a controllable stimulation current. The circuit can effectively inhibit the damage of static electricity to the circuit and protect the normal work of internal elements through the integrated anti-static module; the output value identification unit can be designed to realize real-time monitoring of the output signal and accurate judgment of whether the output signal exceeds the set value, so that protection measures can be taken in time; and the load detection module can be constructed to accurately perceive the connection and working state of the load. Therefore, multiple protections of the circuit are realized, the reliability, safety and adaptability of the circuit in a complex working environment are improved, and a strong guarantee is provided for the stable operation of related electronic equipment. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the present application, the following will briefly introduce the drawings needed to be used in the description of the present application. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0018] Fig. 1 is a system architecture diagram of a stimulation generation protection circuit for transcranial electrical stimulation provided by the embodiment of the present application; Fig. 2 is a stimulation generation protection circuit diagram for transcranial electrical stimulation provided by the embodiment of the present application; Fig. 3 is a constant current source type stimulation generation circuit diagram provided by the embodiment of the present application. DETAILED DESCRIPTION

[0019] In order to make the above objectives, characteristics and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0020] Referring to Figs. 1-2 , a stimulation generation protection circuit architecture diagram and circuit diagram for transcranial electrical stimulation are shown, which can also be used for intermediate frequency stimulation. The stimulation generation protection circuit can be applied to but not limited to mouse cranial four-channel stimulation electrodes, and can also be applied to eight-channel, sixteen-channel and thirty-two-channel stimulation electrodes.

[0021] Specifically, the stimulation generation protection circuit includes the following four circuits: ESD protection circuit, current switching detection circuit, disengagement detection circuit and constant current source type stimulation generation circuit, wherein: The ESD protection circuit is composed of an input port, a resistor, a diode group, a capacitor and an inductor, and is used to guide electrostatic charge to the ground end; The current switching detection circuit includes a relay, an operational amplifier and an ADC acquisition chip, and is used for double-loop switching and real-time current monitoring; The disengagement detection circuit is connected to the GPIO port to feedback the load state through optical coupling isolation input and output sides; The constant current source type stimulation generation circuit is composed of a current source, a switching switch, a power supply and an output port, and is used to generate controllable stimulation current.

[0022] Specifically, the ESD protection circuit can include an input port STMU1, an input port STMU0, a resistor R39, a resistor R40, a diode D12, a diode D13, a diode D14, a diode D15, a capacitor C45, a capacitor C46, an inductor L3, an inductor L4, an output port BOOST_OUT and a ground end HVSS.

[0023] In the embodiments of the present application, the above-mentioned related electronic elements can be connected in the following way: Left side: the input port STMU1 is connected to one end of the resistor R39, the anode of the diode D12 is connected to the STMU1-R39 line, the cathode of the diode D12 is connected to one end of the capacitor C45 and one end of the inductor L3, the other end of the capacitor C45 is grounded HVSS, the other end of the inductor L3 is connected to the anode of the diode D13, the cathode of the diode D13 is connected to the output port BOOST_OUT, and the output port BOOST_OUT also serves as the connection point of the protected circuit.

[0024] Right side: input port STMU0 is connected to one end of resistor R40, the anode of diode D14 is connected to the STMU0-R40 line, the cathode of diode D14 is connected to one end of capacitor C46 and one end of inductor L4, the other end of capacitor C46 is connected to ground HVSS, the other end of inductor L4 is connected to the anode of diode D15, the cathode of diode D15 is connected to output port BOOST_OUT; the right side and the left side together constitute a protection structure for the protected circuit.

[0025] In the embodiment of the application, diodes D12 to D15 constitute an electrostatic discharge (ESD) protection front end. The core characteristic of these diodes is their unidirectional conductivity. In the normal working state of the circuit, the voltage polarity applied across these diodes causes them to be reverse biased, so they present a high-impedance cut-off state. This cut-off state has little effect on the normal signal transmission path in the circuit, ensuring that the signal can pass through this area with low loss and no distortion, maintaining the core function of the circuit.

[0026] However, when a sudden and high-energy ESD event occurs, the ESD pulse usually generates a sharp peak far exceeding the normal working voltage in a short time. At this time, the voltage polarity or amplitude applied to diodes D12-D15 changes, quickly breaking through the reverse bias state, causing the diodes to enter a low-impedance conduction state. Once conduction occurs, they can provide a low-resistance discharge path for transient high-voltage and high-current electrostatic charges, guiding them to the designated ground HVSS. This process is short in duration, effectively discharging the ESD before it damages the circuit components, thus actively protecting the subsequent circuit.

[0027] In order to further improve the overall ESD robustness and suppress high-frequency transient interference, capacitors C45 and C46 and inductors L3 and L4 are integrated into the circuit. The main role of capacitors C45 and C46 is to absorb and buffer the high-frequency transient energy contained in the ESD pulse. According to the characteristics of the capacitor, when the ESD causes a voltage mutation, the capacitor will absorb the current and temporarily store part of the charge energy in its electric field, thereby smoothing the voltage peak, reducing the rise rate and peak value of the transient voltage, and reducing the direct impact on the subsequent circuit.

[0028] At the same time, inductors L3 and L4 connected in series in the signal path or power path can suppress the transient current change rate caused by the ESD event according to the inductance characteristics. When the current increases sharply, the inductance will generate a reverse electromotive force to hinder the current mutation, limiting the peak value and rise speed of the current.

[0029] Through the synergistic effect of capacitance and inductance, the transient high voltage and large current generated by electrostatic discharge are effectively blocked from entering the subsequent circuit, protecting sensitive components in the circuit from static damage and improving the tolerance of the device in an electrostatic environment. Reducing the impact of static interference on circuit signal transmission, ensuring the accuracy and stability of signal transmission, avoiding signal distortion, error code and other problems caused by static interference. Reduce the impact and damage of static on components, prolong the service life of electronic components in the circuit, and reduce the maintenance and replacement cost of the device due to component damage.

[0030] In the embodiment of the application, the current switching detection circuit can include a relay K2, an operational amplifier U22, an ADC acquisition chip U27 and an output interface U19, wherein: The relay part K2 part: the current output port STMU1_1 is connected to pin 3 of the relay K2, the switching interface STMU1_2 is connected to pin 2 of the relay K2, the switching interface STMU1_3 is connected to pin 4 of the relay K2, and the current output port STMU1_1 is connected to pin 5 of the operational amplifier U22 to provide one of the input signals for the operational amplifier. The diode D31 is connected in parallel with the relay K2 for protecting the circuit from the back electromotive force generated when the relay is powered off.

[0031] The operational amplifier U22 part: one end of the resistor R45 is connected to pin 4 of the operational amplifier U22, pin 3 of the operational amplifier U22 is connected to the ADC_5V power supply, pin 2 of the operational amplifier U22 is grounded, pin 1 of the operational amplifier U22 is connected to the REF_2V5 reference voltage, and pin 6 of the operational amplifier U22 outputs the amplified signal to the subsequent circuit, which can provide high-precision input; The ADC acquisition chip U27 part: pin 3 of the ADC acquisition chip U27 is connected to the voltage signal line OUT1, pin 4 of the ADC acquisition chip U27 is connected to the voltage signal line OUT2, pin 5 of the ADC acquisition chip U27 is connected to the voltage signal line OUT3, pin 6 of the ADC acquisition chip U27 is connected to the voltage signal line OUT4, and the pins are used to respectively collect voltage signals; pin 9 and pin 10 of the ADC acquisition chip U27 are connected to the single-chip microcomputer through the I2C bus, the VDD pin of the ADC acquisition chip U27 is connected to the ADC_5V power supply, and the GND pin of the ADC acquisition chip U27 is grounded. The ADDR pin and the ALERT / RDY pin can be connected according to the function of the chip; The output interface U19 is used to connect the electrode sheet to deliver current to the patient's body.

[0032] In the current switching detection circuit, the relay K2 can be switched to the non-patient circuit first, and then switched to the patient circuit after confirming that the current is normal through the ADC acquisition chip U27, which can effectively avoid the initial current impact, wherein the switching control signal JDQ_1 of the relay K2 is driven through the transistor Q6.

[0033] It can be understood that the current switching detection circuit builds a real-time current monitoring system through the efficient cooperation of the operational amplifier and the ADC acquisition chip: the operational amplifier accurately amplifies the voltage signal of the output end STMU1_1, and the ADC acquisition chip further converts the voltage into current data to realize dynamic monitoring and capture abnormal conditions such as overcurrent, undercurrent and transient peak in time.

[0034] In the embodiment of the application, in order to improve the medical safety level, the relay K2 adopts a double-circuit switching mechanism, that is, when the device is started, the current is first guided to the non-patient circuit, and then automatically switched to the patient treatment circuit after confirming that the current value is within the preset safety threshold through the ADC chip, thereby avoiding the risk of initial current impact.

[0035] Further, the ADC acquisition chip realizes data interaction with the single-chip microcomputer through the I2C bus, and this protocol has the advantages of few occupied pins, strong anti-interference performance and low transmission error rate, thereby simplifying the system integration complexity.

[0036] In the embodiment of the application, the data packet transmitted to the single-chip microcomputer through the I2C bus can contain a time stamp, which is used to associate the time sequence relationship between the current abnormality and the load state change.

[0037] For example, when the time stamp shows that the load is disconnected (GPIO15 high level) earlier than the current drop, it is determined that the electrode is actively removed, and only a gentle alarm is triggered; if the current drop is earlier than the load disconnection signal, it is determined that the wire is internally broken, and an emergency stop is triggered and a hardware fault code is marked.

[0038] In the embodiment of the application, the current switching detection circuit further comprises resistors R45, R49, R59, R62, R63, R64, R65 and R67 for voltage division, current limiting and filtering of the circuit.

[0039] It can be understood that the resistors arranged in the circuit can form a composite anti-noise barrier with the filtering capacitor to suppress common-mode interference and ripple noise, ensure that a higher current monitoring accuracy can be maintained in a strong electromagnetic environment, and meet the core requirements of the medical safety standard for current control.

[0040] In the embodiment of the application, the disconnection detection circuit comprises a current input part, a core detection part and an output part, wherein: The current input part includes input port STMU0_1 and input port STMU0_2, which are connected in series with a circuit composed of resistor R28 and diode D8, wherein resistor R28 and diode D8 are connected in parallel. It can be understood that this connection can protect and preprocess the input signal to some extent, resistor R28 plays a current limiting role, and diode D8 can be used to prevent reverse flow of the signal and the like.

[0041] The core detection part includes optocoupler U13, which is connected to the current input part through pin 1 and pin 2, pin 3 of optocoupler U13 is grounded HVSS, and pin 4 of optocoupler U13 is connected to power supply S5V through resistor R26 to provide working voltage for the optocoupler. It can be understood that optocoupler U13 plays a role of electrical isolation and signal transmission, and couples the input side signal to the output side through optical signal.

[0042] The output part includes pin 4 of optocoupler U13 connected to GPIO15 port through resistor R29, and connected to ground in parallel with capacitor C30. Capacitor C30 can play a role of filtering and stabilizing the output signal, and resistor R29 plays a role of current limiting and signal matching. The GPIO15 port can output the detected signal to an external control unit or processor and the like for subsequent judgment and processing.

[0043] For example, the GPIO15 port can output the detected signal to an external processor, and trigger a power reduction output when the external processor detects that the rate of change of the level exceeds a predetermined threshold.

[0044] In actual application, when the electrode sheet is partially detached due to patient movement, the GPIO15 port captures that the rate of change of the level exceeds a predetermined threshold, and the processor determines that it is "progressive detachment", and the stimulation power can be linearly reduced from 80mA to 25mA (for example) within 3 pulse periods, the device screen pops up an orange warning "unstable electrode contact", and the power is automatically charged after the contact is restored. This process ensures treatment continuity and avoids the risk of treatment interruption caused by traditional emergency stop scheme.

[0045] It can be understood that the input side driving current of optocoupler U13 changes dynamically with the load impedance, and the output side conduction state corresponds to the load state: when the load is normal, the optocoupler is turned on, and the GPIO15 port outputs low level; when the load is disconnected, the optocoupler is cut off, and the GPIO15 port outputs high level; when the load is short-circuited, the optocoupler is saturated, and the GPIO15 port outputs low level and current exceeds threshold. Real-time monitoring of dynamic changes of the load can be achieved.

[0046] The disengagement detection circuit adopts an optical coupler U13 to realize electrical isolation between the input side and the output side, effectively blocks the influence of electrical interference and overvoltage on the output side circuit and equipment on the input side, significantly improves the stability and reliability of the circuit, and is especially suitable for occasions with high electrical safety requirements; at the same time, through the reasonable cooperation design of resistors, diodes and other elements, the circuit can sensitively detect the change of the input signal, so as to timely and accurately judge whether there is disengagement; in addition, the setting of the capacitor C30 and the optimized overall circuit layout endow the circuit with good anti-interference ability, ensuring that it can work stably even in a complex electromagnetic environment, effectively reducing the probability of false detection.

[0047] In the embodiment of the application, in the case that the disengagement detection circuit output high level duration is greater than the preset time, and / or the current switching detection circuit identifies that the current value exceeds the safety threshold, the stimulation output can also be cut off and an audible and light alarm can be performed, so that the occurrence of a medical accident can be further avoided.

[0048] In addition, the ground end HVSS of the ESD protection circuit and the ground end DVSS of the current switching detection circuit are isolated by a magnetic bead.

[0049] It can be understood that the magnetic bead presents near-zero impedance to direct current and low-frequency signals, which can ensure that the potentials of the two grounds are balanced and the stability of the circuit reference is maintained; at the same time, it presents high impedance to high-frequency noise, which can strongly block the propagation of interference to the circuit. The electrostatic energy release and signal detection accuracy can be realized on a single PCB, which significantly improves the safety and reliability of medical equipment in a complex electromagnetic environment.

[0050] As shown in Fig. 3 The embodiment of the application also provides a constant current source type stimulation generation circuit.

[0051] The constant current source type stimulation generation circuit can be used to generate a controllable stimulation current, and the highest stimulation current corresponding to 45V voltage can be output, and the core thereof is composed of a current source U29, U30 (built-in 8-bit DAC), switching switches SW2-SW5, power supply and output ports VDD, VSS, STMU0, STMU1.

[0052] Specifically, U29 and U30 are integrated DAC constant current source core components, and the current source is built-in 8-bit DAC. The DAC can convert the digital control signal into an analog control quantity, and then change the current source output current size. Based on the 8-bit DAC, 255 kinds of gear outputs can be realized, combined with circuit configuration, 8 step values are actually formed, with 33uA as the basic step (33uA, 66uA, 99uA, 132uA, 165uA, 198uA, 231uA, 264uA), and the highest can realize 264*255=67320uA of stimulation output. The output waveform includes but is not limited to rectangular wave, triangular wave, sine wave, and can realize transcranial time interference stimulation with multi-channel output stimulation, meet the stimulation current precision demand of multiple scene, and also meet the stimulation needs of different scenes. Switches SW2 and SW3 are respectively connected in series between U29, U30 and the branch of the intermediate output node (connecting STMU1, STMU0); SW4 and SW5 are respectively connected in series between the intermediate output node and VSS (ground). VDD provides working voltage for the circuit, supports the highest 45V voltage related output demand, and VSS is used as a ground potential reference to build a current loop potential reference.

[0053] Further, the built-in 8-bit DAC constant current source can realize small step (33uA as the basis) and multi-gear (255 gears) current regulation, and can realize fine stimulation of cells / tissues in bioelectric stimulation, and guarantee the accuracy of treatment. The DAC controlled by digital signal can adapt to various digital signal input scenes and can flexibly respond to different treatment instructions. The switch network composed of SW2-SW5 makes the current path have diversified configuration capability. It supports the conventional single constant current output mode, and can also realize complex circuit design through switch combination.

[0054] It should be noted that the stimulation generation protection circuit for transcranial electrical stimulation provided by the embodiment of the present application can include but is not limited to four circuit channels of ESD protection circuit, current switching detection circuit, disengagement detection circuit and constant current source stimulation generation circuit. Those skilled in the art can increase other circuit channels on the basis of the present application according to actual needs.

[0055] The embodiment of the present application provides a stimulation generation protection circuit for transcranial electrical stimulation, which comprises an ESD protection circuit, a current switching detection circuit, a disengagement detection circuit and a constant current source stimulation generation circuit, wherein: the ESD protection circuit is composed of an input port, a resistor, a diode group, a capacitor and an inductor, and is used for guiding electrostatic charge to a ground terminal; the current switching detection circuit comprises a relay, an operational amplifier and an ADC acquisition chip, and is used for double-loop switching and real-time current monitoring; the disengagement detection circuit is isolated on the input and output sides through an optical coupling, and is connected with a GPIO port to feed back a load state; the constant current source type stimulation generation circuit is composed of a current source, a switching switch, a power supply and an output port; and is used for generating a controllable stimulation current. The circuit can effectively inhibit the damage of static electricity to the circuit and protect the normal work of internal elements by integrating an anti-static module; an output value identification unit is designed, which can monitor an output signal in real time and accurately judge whether the output signal exceeds a set value, so that protection measures can be taken in time; a load detection module is constructed, which can accurately perceive the connection and working state of a load. Therefore, multiple protections of the circuit are realized, the reliability, safety and adaptability of the circuit in a complex working environment are improved, and a strong guarantee is provided for the stable operation of related electronic equipment.

[0056] The above describes a stimulation generation protection circuit for transcranial electrical stimulation in detail, and the principle and implementation mode of the present application are described by applying specific examples in the present article; the above embodiment is only used for helping to understand the method and core idea of the present application; meanwhile, according to the idea of the present application, the specific implementation mode and application range will be changed by those skilled in the art; in conclusion, the content of the specification should not be understood as the limitation of the present application.

Claims

1. A stimulation generation protection circuit for transcranial electrical stimulation, characterized in that, include: The circuit includes an ESD protection circuit, a current switching detection circuit, a disconnection detection circuit, and a constant current source stimulation generation circuit, among which: The ESD protection circuit consists of an input port, resistors, diodes, capacitors, and inductors, and is used to guide electrostatic charge to the ground terminal. The current switching detection circuit includes a relay, an operational amplifier, and an ADC acquisition chip, and is used for dual-loop switching and real-time current monitoring. The disconnection detection circuit isolates the input and output sides via optocouplers and connects to a GPIO port to feedback the load status. The constant current source stimulation generating circuit consists of a current source, a switching switch, a power supply, and an output port; it is used to generate a controllable stimulation current.

2. The stimulation generation protection circuit for transcranial electrical stimulation according to claim 1, characterized in that, The ESD protection circuit includes input port STMU1, input port STMU0, resistor R39, resistor R40, diode D12, diode D13, diode D14, diode D15, capacitor C45, capacitor C46, ​​inductor L3, inductor L4, output port BOOST_OUT, and ground terminal HVSS; wherein: Left side: Input port STMU1 is connected to one end of resistor R39, the anode of diode D12 is connected to the STMU1-R39 line, the cathode of diode D12 is connected to one end of capacitor C45 and one end of inductor L3, the other end of capacitor C45 is grounded to HVSS, the other end of inductor L3 is connected to the anode of diode D13, and the cathode of diode D13 is connected to output port BOOST_OUT. At the same time, output port BOOST_OUT also serves as the connection point of the protected circuit. Right side: Input port STMU0 is connected to one end of resistor R40, the anode of diode D14 is connected to the STMU0-R40 line, the cathode of diode D14 is connected to one end of capacitor C46 and one end of inductor L4, the other end of capacitor C46 is grounded to HVSS, the other end of inductor L4 is connected to the anode of diode D15, and the cathode of diode D15 is connected to output port BOOST_OUT; the right side and the left side together form a protective structure for the protected circuit.

3. The stimulation generation protection circuit for transcranial electrical stimulation according to claim 2, characterized in that, The current switching detection circuit includes a relay K2, an operational amplifier U22, an ADC acquisition chip U27, and an output interface U19, wherein: Relay section K2: Current output port STMU1_1 is connected to pin 3 of relay K2, switching interface STMU1_2 is connected to pin 2 of relay K2, switching interface STMU1_3 is connected to pin 4 of relay K2, and at the same time, current output port STMU1_1 is connected to pin 5 of operational amplifier U22, and diode D31 is connected in parallel with relay K2; Operational amplifier U22 section: Pin 4 of operational amplifier U22 is connected to one end of resistor R45, pin 3 of operational amplifier U22 is connected to ADC_5V power supply, pin 2 of operational amplifier U22 is grounded, pin 1 of operational amplifier U22 is connected to REF_2V5 reference voltage, and pin 6 of operational amplifier U22 outputs the amplified signal. ADC acquisition chip U27 section: Pin 3 of ADC acquisition chip U27 is connected to voltage signal line OUT1, pin 4 is connected to voltage signal line OUT2, pin 5 is connected to voltage signal line OUT3, and pin 6 is connected to voltage signal line OUT4, used to acquire voltage signals respectively; pins 9 and 10 of ADC acquisition chip U27 are connected to the microcontroller via I2C bus; the VDD pin of ADC acquisition chip U27 is connected to the ADC_5V power supply, and the GND pin of ADC acquisition chip U27 is grounded; The output interface U19 is used to connect electrode pads and deliver current to the patient's body.

4. The stimulation generation protection circuit for transcranial electrical stimulation according to claim 3, characterized in that, The current switching detection circuit is also equipped with resistors R45, R49, R59, R62, R63, R64, R65, and R67 for voltage division, current limiting, and filtering.

5. A stimulation generation protection circuit for transcranial electrical stimulation according to claim 4, characterized in that, In the current switching detection circuit, relay K2 is first switched to the non-patient circuit. After the current is confirmed to be normal by the ADC acquisition chip U27, relay K2 is then switched to the patient circuit. The switching control signal JDQ_1 of relay K2 is driven by transistor Q6.

6. A stimulation generation protection circuit for transcranial electrical stimulation according to claim 5, characterized in that, The disconnection detection circuit includes a current input section, a core detection section, and an output section, wherein: The current input section includes input port STMU0_1 and input port STMU0_2. Input port STMU0_1 and input port STMU0_2 are connected in series with a circuit consisting of resistor R28v and diode D8, wherein resistor R28 and diode D8 are connected in parallel. The core detection part includes an optocoupler U13, which is connected to the current input part through pin 1 and pin 2. Pin 3 of the optocoupler U13 is grounded to HVSS, and pin 4 of the optocoupler U13 is connected to the power supply S5V through resistor R26. The output section includes pin 4 of the optocoupler U13, which is connected to the GPIO15 port via resistor R29, and grounded in parallel with capacitor C30.

7. A stimulation generation protection circuit for transcranial electrical stimulation according to claim 6, characterized in that, The GPIO15 port is used to output the detected signal to an external processor. When the external processor detects that the rate of change of the level exceeds a predetermined threshold, it triggers a power reduction output.

8. A stimulation generation protection circuit for transcranial electrical stimulation according to claim 7, characterized in that, The ground terminal HVSS of the ESD protection circuit is isolated from the ground terminal DVSS of the current switching detection circuit by a ferrite bead.

9. A stimulation generation protection circuit for transcranial electrical stimulation according to claim 8, characterized in that, The data packets transmitted to the microcontroller via the I2C bus contain timestamps, which are used to correlate the timing relationship between current anomalies and load state changes.

10. A stimulation generation protection circuit for transcranial electrical stimulation according to claim 1 or 9, characterized in that, If the high-level output of the disconnection detection circuit lasts for a longer than a preset time, and / or the current switching detection circuit detects that the current value exceeds the safety threshold, the stimulation output is cut off and an audible and visual alarm is triggered.

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