Implantable medical device and wireless energy transmission method

Abstract

The present application provides an implantable medical device and a wireless energy transmission method, wherein the receiving coil of the implantable medical device receives the energy sent by the transmitting coil of the transmitting end and outputs an AC voltage, the rectifier circuit converts the AC voltage into a DC voltage, and the load balancing circuit generates a pulse width modulation PWM wave according to the DC voltage and a preset voltage threshold, and the PWM wave is used to control the DC voltage provided to the load. The supply of the DC voltage of the load is dynamically controlled by generating a PWM wave, and the load consumes energy to discharge when the DC voltage is provided to the load, and the discharge is stopped when the DC voltage is not provided to the load, so that the DC voltage output by the rectifier circuit can be adjusted to stabilize within a preset range, so that the AC voltage output by the receiving coil will also tend to be stable, thereby avoiding the occurrence of erroneous demodulation data output in the implantable medical device based on coil pair coupling communication, and improving the effectiveness and accuracy of communication.

Description

Technical Field

[0001] The present application relates to the technical field of wireless energy transmission, and in particular to an implantable medical device and a wireless energy transmission method. Background Art

[0002] There are two ways to power implantable medical devices: one is battery power, including disposable batteries and rechargeable batteries, and the other is battery-free power. Rechargeable battery and battery-free implantable medical devices often use coil pair coupling to transmit power from the external transmitter to the implant receiving end, which is rectified by the rectifier circuit and supplied to the battery management unit or application circuit. The transmitting coil of the transmitter and the receiving coil of the implantable medical device form a coil pair.

[0003] When the coil pair is used for both wireless energy transmission and communication, the load change of the rectifier circuit of the implantable medical device will affect the communication quality between the coil pairs, especially when the load has both static low power consumption and transient high current demand. For example, implantable medical devices such as spinal cord nerve stimulators and micro peripheral nerve stimulators have low static power consumption, but large current demand during stimulation output, causing the load behind the rectifier circuit to change significantly within a certain period, thereby affecting the effectiveness and accuracy of communication. Summary of the invention

[0004] In view of this, the present application provides an implantable medical device and a wireless energy transmission method to solve the deficiencies in the related art.

[0005] In a first aspect of the present application, an implantable medical device is provided, comprising:

[0006] The receiving coil is used to receive the energy sent by the sending coil at the sending end and output an AC voltage;

[0007] A rectifier circuit, used for converting the AC voltage into a DC voltage;

[0008] The load balancing circuit is used to generate a pulse width modulation (PWM) wave according to the DC voltage and a preset voltage threshold, and the PWM wave is used to control the DC voltage provided to the load.

[0009] According to one embodiment of the present application, the load balancing circuit includes:

[0010] A voltage dividing circuit, used for dividing the DC voltage to generate a target DC voltage;

[0011] An analog-to-digital converter (ADC) acquisition circuit is used to sample and perform analog-to-digital conversion on the target DC voltage to generate a digital signal corresponding to the target DC voltage;

[0012] The microcontroller unit MCU is used to receive the digital signal corresponding to the target DC voltage and generate a PWM wave according to the DC voltage and the preset voltage threshold.

[0013] According to one embodiment of the present application, the load balancing circuit includes:

[0014] A switch circuit, wherein a control end of the switch circuit receives the PWM wave and is turned on when the PWM wave is at a high level to provide the DC voltage to the load.

[0015] According to an embodiment of the present application, the switch circuit includes an NMOS tube, the load is connected between the drain of the NMOS tube and the DC output end of the rectifier circuit, and the NMOS tube is specifically used for:

[0016] The gate of the NMOS tube receives the PWM wave, and the NMOS tube is turned on when the PWM wave is at a high level to provide the DC voltage to the load.

[0017] According to one embodiment of the present application, the load balancing circuit is specifically used for:

[0018] The frequency and duty cycle of the PWM wave are determined according to a comparison result between the DC voltage and the preset voltage threshold.

[0019] In a second aspect of the present application, a wireless energy transmission method is provided, which is applied to an implantable medical device, wherein the implantable medical device comprises: a receiving coil, a rectifier circuit and a load balancing circuit, and the method comprises:

[0020] The receiving coil receives energy sent by the sending coil at the sending end and outputs an AC voltage;

[0021] The rectifier circuit converts the AC voltage into a DC voltage;

[0022] The load balancing circuit generates a pulse width modulation (PWM) wave according to the DC voltage and a preset voltage threshold, and the PWM wave is used to control the DC voltage provided to the load.

[0023] According to one embodiment of the present application, the load balancing circuit includes a voltage divider circuit, an analog-to-digital converter ADC acquisition circuit and a microcontroller unit MCU, and the method further includes:

[0024] The voltage divider circuit divides the DC voltage to generate a target DC voltage;

[0025] The ADC acquisition circuit samples and performs analog-to-digital conversion on the target DC voltage to generate a digital signal corresponding to the target DC voltage;

[0026] The MCU receives a digital signal corresponding to the target DC voltage, and generates a PWM wave according to the DC voltage and the preset voltage threshold.

[0027] According to an embodiment of the present application, the load balancing circuit includes a switch circuit, and the method further includes:

[0028] The control end of the switch circuit receives the PWM wave and is turned on when the PWM wave is at a high level to provide the DC voltage to the load.

[0029] According to an embodiment of the present application, the switch circuit includes an NMOS tube, the load is connected between the drain of the NMOS tube and the DC output end of the rectifier circuit; the control end of the switch circuit receives the PWM wave and is turned on when the PWM wave is at a high level, including:

[0030] The gate of the NMOS tube receives the PWM wave, and the NMOS tube is turned on when the PWM wave is at a high level.

[0031] According to an embodiment of the present application, generating a PWM wave according to the DC voltage and the preset voltage threshold includes:

[0032] The frequency and duty cycle of the PWM wave are determined according to a comparison result between the DC voltage and the preset voltage threshold.

[0033] It can be seen from the above technical solution that the receiving coil of the implantable medical device receives the energy sent by the transmitting coil of the transmitting end and outputs an AC voltage. The rectifier circuit converts the AC voltage into a DC voltage. The load balancing circuit generates a PWM wave according to the DC voltage and a preset voltage threshold. The PWM wave is used to control the DC voltage provided to the load. The supply of the DC voltage of the load is dynamically controlled by generating a PWM wave. When the rectified DC voltage is provided to the load, the load is discharged, and when the rectified DC voltage is not provided to the load, the discharge is stopped. Thus, the DC voltage output by the rectifier circuit can be adjusted to be stable within a preset range, so that the AC voltage output by the receiving coil will also tend to be stable, thereby avoiding the occurrence of erroneous demodulation data output in the implantable medical device based on coil pair coupling communication, thereby improving the effectiveness and accuracy of communication.

[0034] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a structural schematic diagram of an implantable medical device provided in an embodiment of the present application;

[0036] Figure 2 is a schematic diagram of a resistor voltage divider circuit provided in an embodiment of the present application;

[0037] Figure 3 is a schematic diagram of a capacitor voltage divider circuit provided in an embodiment of the present application;

[0038] Figure 4 is a structural diagram of an in vitro transmitting end provided in an embodiment of the present application;

[0039] Figure 5 It is a flowchart of a wireless energy transmission method provided in an embodiment of the present application;

[0040] Figure 6 It is a structural schematic diagram of an implantable medical device provided in another embodiment of the present application. DETAILED DESCRIPTION

[0041] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0042] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The singular forms "a", "said" and "the" used in this application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0043] In order to enable those skilled in the art to better understand the technical solutions provided by the embodiments of the present application and to make the above-mentioned purposes, features and advantages of the embodiments of the present application more obvious and understandable, the technical solutions in the embodiments of the present application are further described in detail below in conjunction with the accompanying drawings.

[0044] Rechargeable battery and battery-free implantable medical devices often use coil pair coupling to transmit power from the transmitter to the implant receiving end, where the transmitter coil and the receiver coil of the implantable medical device form a coil pair. However, when the coil pair is used for both wireless energy transmission and communication, if the load after the rectifier circuit of the implantable medical device changes significantly, the communication quality between the coil pairs will be affected.

[0045] For example, the current of the application circuit after the rectifier circuit of the implantable medical device is 0.1mA under static power consumption, and this current is continuous. When the application circuit performs stimulation output, the stimulation output current is 4mA, the pulse width is 1ms, and the cycle is 10ms. In this way, in a 10ms cycle, there is a large current of 1ms and a small current of 9ms. During the 1ms stimulation output time, because a large current needs to pass, the load is in a low resistance state. Under the static power consumption of 9ms, because the current passing is small, the load is in a high resistance state. That is to say, the load after the rectifier circuit changes significantly within a certain period, and this load change will affect the effectiveness and accuracy of wireless communication based on the coupling of the coil pair of the implantable medical device.

[0046] The voltage fluctuation of the neurostimulator can easily interfere with the output waveform of the electrical stimulation, affecting the therapeutic effect of the electrical stimulation output of the neurostimulator. In addition, the bit errors caused by the reduced accuracy of communication make it impossible to obtain the working status of the neurostimulator in time. For neurostimulators implanted in the human body and with high requirements for electrical stimulation accuracy, this situation will cause great safety hazards to users.

[0047] In view of this, an embodiment of the present application discloses an implantable medical device, which dynamically controls the supply of DC voltage to the load by generating PWM waves through a load balancing circuit in the implantable medical device. When the rectified DC voltage is provided to the load, current flows through the load, and discharges through the load to consume the rectified electric energy. When the rectified DC voltage is not provided to the load, no current flows through the load, and the discharge stops and the rectified electric energy is not consumed. Therefore, the DC voltage output by the rectifier circuit can be adjusted to stabilize within a preset range, thereby ensuring the therapeutic effect of the electrical stimulation output of the neurostimulator. At the same time, since the DC voltage output by the rectifier circuit can be stabilized within a preset range, the AC voltage output by the receiving coil will also tend to be stable, thereby avoiding erroneous demodulation data output of the implantable medical device based on coil-pair coupling communication, thereby improving the effectiveness and accuracy of communication. When the effectiveness and accuracy of communication are improved, the above-mentioned bit error situations can be reduced, thereby improving the performance and reliability of the neurostimulator.

[0048] like Figure 1 As shown, Figure 1 It is a structural schematic diagram of an implantable medical device provided in an embodiment of the present application.

[0049] In the embodiments of the present application, an implantable medical device may be a medical device that is fully or partially inserted into the human body through surgery or other medical means, and is left in the human body for a long time or temporarily after the surgery. The implantable medical device may be used to treat, repair or replace damaged tissues, organs or functions of the human body.

[0050] The embodiments of the present application do not specifically limit the type of implantable medical devices. For example, implantable medical devices may include neurostimulators (such as spinal cord neurostimulators, micro peripheral nerve stimulators, etc.), cardiac defibrillators, etc.

[0051] like Figure 1 As shown, the implantable medical device may include a receiving coil 110 , a rectifying circuit 120 and a load balancing circuit 130 .

[0052] The following is a detailed explanation of each part of the implantable medical device.

[0053] 1. The receiving coil 110 is used to receive energy sent by the transmitting coil at the transmitting end and output an AC voltage.

[0054] In an embodiment of the present application, the implantable medical device can perform wireless energy transmission and wireless communication with an external transmitting end based on the coupling of a coil pair, where the coil pair includes a receiving coil 110 of the implantable medical device and a transmitting coil of the transmitting end. The receiving coil 110 can receive energy sent by the transmitting coil of the transmitting end and output an AC voltage.

[0055] Exemplarily, the receiving coil 110 and the transmitting coil of the transmitting end may include a resonant coil, a micro-spiral coil or other customized coils, and the embodiments of the present application do not specifically limit the types of the receiving coil 110 and the transmitting coil of the transmitting end.

[0056] In some embodiments, the transmitting end can apply an AC voltage signal to the transmitting coil. The change in the voltage waveform causes the current in the transmitting coil to change accordingly, and the changing current will generate a changing magnetic field in space. This changing magnetic field can propagate to the surrounding space in the form of electromagnetic waves. The receiving coil 110 senses the change in the magnetic field in the surrounding space and outputs an AC voltage.

[0057] In some embodiments, the implantable medical device also includes a resonant circuit. After the receiving coil 110 receives the energy sent by the transmitting coil at the transmitting end and outputs an AC voltage, the AC voltage is transmitted to the resonant circuit. The resonant circuit can adjust and optimize the frequency of the AC voltage to ensure that it matches the resonant frequency of the receiving coil 110, thereby improving the energy conversion efficiency.

[0058] In some embodiments, the implantable medical device also includes an impedance matching circuit. The AC voltage processed by the resonant circuit will be further transmitted to the impedance matching circuit. The impedance matching circuit can adjust and optimize the impedance characteristics of the circuit to ensure that the input impedance of the implantable medical device matches the characteristic impedance of the transmission line, thereby reducing energy reflection and loss during transmission, thereby further improving the energy conversion efficiency and stability of the overall system.

[0059] 2. The rectifier circuit 120 is used to convert the AC voltage into a DC voltage.

[0060] The rectifier circuit 120 is used to rectify the AC voltage output by the receiving coil 110 , and convert the AC voltage with periodic positive and negative changes into a DC voltage with a single direction.

[0061] Exemplarily, the rectifier circuit 120 may include a half-wave rectifier circuit, a full-wave rectifier circuit (such as a bridge rectifier), etc.

[0062] In some embodiments, the implantable medical device further includes a filter circuit, which can smooth the pulsating DC voltage output by the rectifier circuit 120 and reduce the ripple in the voltage (ie, the AC component in the voltage), thereby providing a more stable DC voltage output.

[0063] In some embodiments, the implantable medical device also includes a decoupling capacitor, which can smooth the pulsating DC voltage output by the rectifier circuit 120, reduce the ripple in the voltage, and store the electrical energy rectified by the rectifier circuit 120. The decoupling capacitor can be connected in parallel with the DC output end of the rectifier circuit 120.

[0064] 3. The load balancing circuit 130 is used to generate a pulse width modulation PWM wave according to the DC voltage and a preset voltage threshold, and the PWM wave is used to control the DC voltage provided to the load.

[0065] PWM (Pulse Width Modulation) is a periodic signal consisting of a series of high-level (usually 1 or logic high) and low-level (usually 0 or logic low) pulses. The frequency of a PWM wave refers to the number of times the signal changes from high level to low level and then back to high level within 1 second, indicating the number of periodic changes per second. The duty cycle of a PWM wave refers to the ratio of the high-level time to the entire cycle time within a pulse cycle, and the unit is % (0%~100%).

[0066] In an embodiment of the present application, the load balancing circuit 130 generates a PWM wave based on the DC voltage and a preset voltage threshold, and the PWM wave is used to control the DC voltage provided to the load. When the DC voltage output by the rectifier circuit 120 is provided to the load, current flows through the load, thereby consuming the rectified electric energy. When the DC voltage output by the rectifier circuit 120 is not provided to the load, no current flows through the load, and the rectified electric energy is not consumed, thereby adjusting the DC voltage output by the rectifier circuit 120.

[0067] In some embodiments, the implantable medical device can communicate with an external transmitting end based on the coupling of the coil pair to negotiate and determine the above-mentioned preset voltage threshold.

[0068] In some embodiments, the load balancing circuit 130 is specifically used for:

[0069] The frequency and duty cycle of the PWM wave are determined according to a comparison result between the DC voltage output by the rectifier circuit 120 and a preset voltage threshold.

[0070] Exemplarily, if the DC voltage output by the rectifier circuit 120 is greater than a preset voltage threshold, a PWM wave with a first frequency and a first duty cycle can be generated; if the DC voltage output by the rectifier circuit 120 is less than or equal to the preset voltage threshold, a PWM wave with a second frequency and a second duty cycle can be generated, wherein the first frequency is greater than the second frequency, and the first duty cycle is greater than the second duty cycle.

[0071] For example, the preset voltage threshold is 5V. When the DC voltage output by the rectifier circuit 120 is 7V, a PWM wave with a frequency of 500Hz (first frequency) and a duty cycle of 90% (first duty cycle) can be generated, which means that at a frequency of 500Hz, 90% of the time in each cycle is for the DC voltage output by the rectifier circuit 120 to be provided to the load. When the DC voltage output by the rectifier circuit 120 is 4.8V, a PWM wave with a frequency of 250Hz (second frequency) and a duty cycle of 5% (second duty cycle) can be generated, which means that at a frequency of 250Hz, only 5% of the time in each cycle is for the DC voltage output by the rectifier circuit 120 to be provided to the load.

[0072] In some embodiments, if the DC voltage output by the rectifier circuit 120 is greater than a preset voltage threshold, and the difference between the DC voltage and the preset voltage threshold is greater than the preset threshold, a PWM wave with a third frequency and a third duty cycle can be generated, wherein the third frequency is greater than the first frequency, and the third duty cycle is greater than the first duty cycle.

[0073] In an embodiment of the present application, the frequency and duty cycle of the PWM wave can be determined based on the comparison result between the DC voltage and the preset voltage threshold. When the DC voltage output by the rectifier circuit 120 is greater than the preset voltage threshold, the load can consume the rectified electric energy frequently and for a long time, thereby effectively reducing the DC voltage output by the rectifier circuit 120. When the DC voltage output by the rectifier circuit 120 is less than or equal to the preset voltage threshold, the number of times and time for which the rectified DC voltage is provided to the load is small, which has little impact on the DC voltage output by the rectifier circuit 120, so that the DC voltage output by the rectifier circuit 120 is stable within the preset range, thereby improving the stability of the rectified DC voltage.

[0074] In some embodiments, the load balancing circuit 130 includes a switch circuit, and a control terminal of the switch circuit can receive a PWM wave. When the PWM wave is at a high level, the switch circuit is turned on to provide the rectified DC voltage to the load; when the PWM wave is at a low level, the switch circuit is turned off and does not provide the rectified DC voltage to the load.

[0075] In some embodiments, the switch circuit may include an NMOS tube, and a load is connected between the drain of the NMOS tube and the DC output terminal of the rectifier circuit 120. The on / off of the NMOS tube can control the on / off of the circuit in which the DC voltage output by the rectifier circuit 120 is discharged (energy consumed) through the load.

[0076] The gate of the NMOS tube can receive a PWM wave. The NMOS tube is turned on when the PWM wave is at a high level, so that the circuit for discharging the DC voltage output by the rectifier circuit 120 through the load is turned on, thereby providing the DC voltage output by the rectifier circuit 120 to the load; the NMOS tube is cut off when the PWM wave is at a low level, so that the circuit for discharging the DC voltage output by the rectifier circuit 120 through the load is disconnected, thereby not providing the DC voltage output by the rectifier circuit 120 to the load.

[0077] In an embodiment of the present application, a PWM wave is generated to dynamically control the supply of DC voltage to the load. When the rectified DC voltage is provided to the load, discharge is performed through the load, that is, the rectified electric energy is consumed by the load, and discharge is stopped when the rectified DC voltage is not provided to the load. The DC voltage output by the rectifier circuit can be adjusted to be stable within a preset range, so that the AC voltage output by the receiving coil will also tend to be stable, thereby avoiding erroneous demodulation data output of implantable medical devices based on coil-pair coupling communication, thereby improving the effectiveness and accuracy of communication.

[0078] In some embodiments, the load balancing circuit 130 may include a voltage divider circuit, an analog-to-digital converter ADC acquisition circuit, and a microcontroller unit MCU.

[0079] About the voltage divider circuit:

[0080] Since the DC voltage output by the rectifier circuit 120 may not meet the working requirements of subsequent circuits or devices, for example, the DC voltage output by the rectifier circuit 120 is 5V, and the ADC acquisition circuit usually has a specific input voltage range (such as 0 to 1.8V), the DC voltage output by the rectifier circuit 120 can be transmitted to a voltage divider circuit, and the voltage divider circuit can be used to divide the DC voltage output by the rectifier circuit 120 to generate a target DC voltage.

[0081] Exemplarily, the voltage divider circuit may include a resistor voltage divider circuit or a capacitor voltage divider circuit. In actual circuit applications, the type of voltage divider circuit can be selected according to demand. Resistor voltage dividers are commonly used in circuits built with discrete components, while capacitor voltage dividers are more commonly used inside integrated circuits.

[0082] like Figure 2 As shown, Figure 2 Schematic diagram of a resistor voltage divider circuit provided in an embodiment of the present application. Figure 2 In FIG. 1 , V_ACDC is the DC voltage output by the rectifier circuit 120 , R1 and R2 are two resistor elements for voltage division, and their resistance values ​​are 900 kilo-ohms and 100 kilo-ohms, respectively, and VADC_R is the target DC voltage output by the resistor voltage divider circuit.

[0083] like Figure 3 As shown, Figure 3 Schematic diagram of a capacitor voltage divider circuit provided in an embodiment of the present application. Figure 3 In FIG. 1 , V_ACDC is the DC voltage output by the rectifier circuit 120 , C1 and C2 are two capacitor elements for voltage division, and their capacitances are 900 pF and 100 pF respectively, and VADC_C is the target DC voltage output by the capacitor voltage divider circuit.

[0084] About ADC acquisition circuit:

[0085] The ADC acquisition circuit can be used to sample and perform analog-to-digital conversion on the target DC voltage to generate a digital signal corresponding to the target DC voltage.

[0086] The ADC acquisition circuit can measure the target DC voltage at a certain sampling frequency and convert the measured value into digital form for MCU to analyze and control.

[0087] About MCU:

[0088] The MCU can be used to receive a digital signal corresponding to the target DC voltage, and generate a PWM wave according to the DC voltage and the preset voltage threshold.

[0089] In some embodiments, the MCU may determine the frequency and duty cycle of the PWM wave according to a comparison result between the DC voltage output by the rectifier circuit 120 and a preset voltage threshold.

[0090] Exemplarily, if the DC voltage output by the rectifier circuit 120 is greater than a preset voltage threshold, a PWM wave with a first frequency and a first duty cycle can be generated; if the DC voltage output by the rectifier circuit 120 is less than or equal to the preset voltage threshold, a PWM wave with a second frequency and a second duty cycle can be generated, wherein the first frequency is greater than the second frequency, and the first duty cycle is greater than the second duty cycle.

[0091] In some embodiments, the MCU includes a storage unit for storing a preset PWM algorithm. The MCU determines the frequency and duty cycle of the PWM wave based on the comparison result between the DC voltage output by the rectifier circuit 120 and the preset voltage threshold and the above PWM algorithm.

[0092] In an embodiment of the present application, the DC voltage output by the rectifier circuit is divided by the voltage divider circuit in the load balancing circuit to generate a target DC voltage, the ADC acquisition circuit samples and performs analog-to-digital conversion on the target DC voltage to generate a digital signal corresponding to the target DC voltage, the MCU receives the digital signal corresponding to the target DC voltage, and generates a PWM wave according to the DC voltage and the preset voltage threshold, thereby dynamically controlling the supply of the DC voltage to the load by generating the PWM wave, and discharging through the load when the rectified DC voltage is provided to the load, that is, the rectified electric energy is consumed by the load, and discharging is stopped when the rectified DC voltage is not provided to the load, so that the DC voltage output by the rectifier circuit can be adjusted to be stable within a preset range, so that the AC voltage output by the receiving coil will also tend to be stable, thereby avoiding erroneous demodulation data output of implantable medical devices based on coil-pair coupling communication, thereby improving the effectiveness and accuracy of communication.

[0093] like Figure 4 As shown, Figure 4 It is a structural schematic diagram of an extracorporeal transmitting end provided in an embodiment of the present application, which may include a DC power supply circuit 410, a power amplifier 420, a signal modulation circuit 430, a high-frequency clock circuit 440, a signal demodulation circuit 450, a main control unit 460 and a resonant transmitting coil 470.

[0094] The DC power supply circuit 410 can provide a DC voltage, and the DC voltage outputted by the DC power supply circuit 410 is adjustable. The adjustable voltage is outputted to the power amplifier 420 , so that the output power of the power amplifier 420 can be adjusted.

[0095] The signal modulation circuit 430 receives the high-frequency clock pulse generated by the high-frequency clock circuit 440 . The signal modulation circuit 430 can adjust the high-frequency clock pulse and then transmit the adjusted high-frequency clock pulse to the power amplifier 420 , thereby achieving a small range adjustment of the output power of the power amplifier 420 .

[0096] The power amplifier 420 amplifies the input signal according to the adjustment of the pulse width of the high-frequency clock pulse by the signal modulation circuit 430 and the DC voltage provided by the DC power supply circuit 410, and then transmits it to the resonant transmitting coil 470, and finally presents an amplitude shift keying (ASK) modulated voltage waveform on the resonant transmitting coil 470, and the modulation depth can be determined by the pulse width of the high-frequency clock pulse and the DC voltage.

[0097] When the ASK modulated voltage waveform is applied to the resonant transmitting coil 470, the change in the voltage waveform causes the current in the resonant transmitting coil 470 to change accordingly, and the changing current will generate a changing magnetic field in space. This changing magnetic field can propagate to the surrounding space in the form of electromagnetic waves, thereby realizing wireless energy transmission or signal transmission.

[0098] The resonant transmitting coil 470 can receive the communication signals sent by the implantable medical device and transmit the communication signals to the signal demodulation circuit 450. The signal demodulation circuit 450 demodulates the communication signals, extracts the target information, and transmits the target information to the main control unit 460 for further analysis and processing.

[0099] In an embodiment of the present application, the implantable medical device can perform wireless energy transmission and wireless communication with an external transmitting end based on the coupling of the coil pair.

[0100] like Figure 5 As shown, Figure 5 The present invention provides a flow chart of a wireless energy transmission method provided in an embodiment of the present invention. The wireless energy transmission method is applied to an implantable medical device, and the implantable medical device includes: a receiving coil, a rectifier circuit and a load balancing circuit.

[0101] The wireless energy transmission method may include the following steps:

[0102] S501: The receiving coil receives energy sent by the sending coil of the sending end and outputs an AC voltage;

[0103] S502: The rectifier circuit converts the AC voltage into a DC voltage;

[0104] S503: The load balancing circuit generates a pulse width modulation (PWM) wave according to the DC voltage and a preset voltage threshold, where the PWM wave is used to control the DC voltage provided to the load.

[0105] About the load balancing circuit in S503:

[0106] In some embodiments, the load balancing circuit may include a voltage divider circuit, an analog-to-digital converter ADC acquisition circuit, and a microcontroller unit MCU.

[0107] The voltage divider circuit divides the DC voltage to generate a target DC voltage;

[0108] The ADC acquisition circuit samples and performs analog-to-digital conversion on the target DC voltage to generate a digital signal corresponding to the target DC voltage;

[0109] The MCU receives a digital signal corresponding to the target DC voltage, and generates a PWM wave according to the DC voltage and the preset voltage threshold.

[0110] In some embodiments, the load balancing circuit may include a switching circuit.

[0111] The control end of the switch circuit receives the PWM wave and is turned on when the PWM wave is at a high level to provide the DC voltage to the load.

[0112] In some embodiments, the switch circuit includes an NMOS tube, and the load is connected between the drain of the NMOS tube and the DC output end of the rectifier circuit;

[0113] The control end of the switch circuit receives the PWM wave and is turned on when the PWM wave is at a high level, comprising:

[0114] The gate of the NMOS tube receives the PWM wave, and the NMOS tube is turned on when the PWM wave is at a high level.

[0115] In some embodiments, the load balancing circuit may determine the frequency and duty cycle of the PWM wave according to a comparison result between the DC voltage and the preset voltage threshold.

[0116] The implementation process of each step in the above-mentioned wireless energy transmission method is specifically described in the implementation process of the functions and effects of the corresponding parts in the above-mentioned implantable medical device, which will not be repeated here.

[0117] like Figure 6 As shown, Figure 6 6 is a schematic diagram of the structure of an implantable medical device provided by another embodiment of the present application. The implantable medical device may include: a resonant receiving coil 610, a rectifier circuit 620, a voltage divider circuit 630, an ADC acquisition circuit 640, an MCU 650, a reverse modulation circuit 660, a signal demodulation circuit 670, a load 680 and an NMOS switch circuit 690.

[0118] The implantable medical device also includes an electrical stimulation module (not shown in the figure). The electrical stimulation module has static power consumption and power consumption when performing stimulation output. The static power consumption is much smaller than the power consumption when performing stimulation output. When the electrical stimulation module is converted from static power consumption to stimulation output, the energy consumed by the electrical stimulation module increases. If the DC voltage output by the rectifier circuit is not enough, the external transmitting end increases the output power of the power amplifier.

[0119] The resonant receiving coil 610 receives energy sent by the transmitting coil of the transmitting end and outputs an AC voltage. As the transmitting end increases the output power of the power amplifier, the DC voltage output by the rectifier circuit 620 increases.

[0120] The voltage divider circuit 630 divides the DC voltage output by the rectifier circuit 620 to generate a target DC voltage. The ADC acquisition circuit 640 samples and performs analog-to-digital conversion on the target DC voltage to generate a digital signal corresponding to the target DC voltage. The MCU 650 receives the digital signal corresponding to the target DC voltage, and adjusts the frequency and duty cycle of the PWM wave by monitoring the change of the DC voltage output by the rectifier circuit 620. Specifically, when the DC voltage output by the rectifier circuit 620 is greater than the preset voltage threshold, the frequency and duty cycle of the PWM wave are increased, and vice versa, the frequency and duty cycle of the PWM wave are reduced.

[0121] A load 680 is connected between the drain of the NMOS tube in the NMOS switch circuit 690 and the DC output end of the rectifier circuit 620. The gate of the NMOS tube receives the PWM wave generated by the MCU 650. When the PWM wave is at a high level, the NMOS tube is turned on, so that the circuit for discharging the DC voltage after the rectifier circuit 620 through the load 680 is turned on. At this time, current flows through the load 680, thereby consuming the rectified electric energy and reducing the DC voltage after the rectifier circuit 620. When the PWM wave is at a low level, the NMOS tube is cut off, so that the circuit for discharging the DC voltage after the rectifier circuit 620 through the load 680 is disconnected. At this time, no current flows through the load 680 and the rectified electric energy is not consumed.

[0122] Since the MCU650 will increase the frequency and duty cycle of the PWM wave when the DC voltage output by the rectifier circuit 620 is greater than the preset voltage threshold, the NMOS tube's conduction frequency and conduction time will increase, and the conduction frequency and conduction time of the circuit in which the DC voltage after the rectifier circuit 620 is discharged through the load 680 will increase, and the load 680 will consume more electric energy after rectification, thereby effectively reducing the DC voltage after the rectifier circuit 620. When the DC voltage after the rectifier circuit 620 drops to a preset voltage threshold, the frequency and duty cycle of the PWM wave decrease, the NMOS tube is in a cut-off state for a long time, and the circuit for discharging the DC voltage after the rectifier circuit 620 through the load 680 is disconnected. The load 680 almost no longer consumes the rectified electric energy, so that the DC voltage output by the rectifier circuit 620 is stable within a preset range, thereby improving the stability of the rectified DC voltage. Due to the improved stability of the rectified DC voltage, the AC voltage output by the resonant receiving coil 610 before the rectifier circuit 620 will tend to be stable, thereby avoiding erroneous demodulation data output by the signal demodulation circuit 670, thereby improving the effectiveness and accuracy of wireless communication of implantable medical devices based on coil-pair coupling communication.

[0123] It should be noted that, in this article, relational terms such as target and target are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0124] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. An implantable medical device, characterized in that: include: The receiving coil is used to receive the energy sent by the sending coil at the sending end and output an AC voltage; A rectifier circuit, used for converting the AC voltage into a DC voltage; The electrical stimulation module has static power consumption and power consumption when performing stimulation output, wherein the static power consumption is less than the power consumption when performing stimulation output; A load balancing circuit, used to generate a pulse width modulation (PWM) wave according to the DC voltage and a preset voltage threshold, wherein the PWM wave is used to control the DC voltage output by the rectifier circuit provided to the load; Wherein, the load balancing circuit includes: A switch circuit, wherein a control end of the switch circuit receives the PWM wave and is turned on when the PWM wave is at a high level, so as to provide the DC voltage output by the rectifier circuit to the load, and discharge through the load to consume the rectified electric energy; and the switch circuit is turned off when the PWM wave is at a low level, so as not to provide the DC voltage output by the rectifier circuit to the load, so that the load stops discharging and does not consume the rectified electric energy, thereby stabilizing the DC voltage output by the rectifier circuit within a preset range.

2. The implantable medical device according to claim 1, characterized in that: The load balancing circuit comprises: A voltage dividing circuit, used for dividing the DC voltage to generate a target DC voltage; An analog-to-digital converter (ADC) acquisition circuit is used to sample and perform analog-to-digital conversion on the target DC voltage to generate a digital signal corresponding to the target DC voltage; The microcontroller unit MCU is used to receive the digital signal corresponding to the target DC voltage and generate a PWM wave according to the DC voltage and the preset voltage threshold.

3. The implantable medical device according to claim 1, characterized in that: The switch circuit includes an NMOS tube, the load is connected between the drain of the NMOS tube and the DC output end of the rectifier circuit, and the NMOS tube is specifically used for: The gate of the NMOS tube receives the PWM wave, and the NMOS tube is turned on when the PWM wave is at a high level to provide the DC voltage to the load.

4. The implantable medical device according to claim 1, characterized in that: The load balancing circuit is specifically used for: The frequency and duty cycle of the PWM wave are determined according to a comparison result between the DC voltage and the preset voltage threshold.

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