Active implantable medical device and method for transmitting energy and data

Abstract

The present invention relates to an active implantable medical device comprising, once implanted, a module external to the patient and a module internal to the patient, the external module and the internal module being intended to transfer energy and data from one to the other.

Description

Technical Field

[0001] This invention relates to medical devices, and more particularly to active implantable medical devices (AIMDs). Background Technology

[0002] In a conventional and well-known manner, an active implantable medical device (AIMD) is defined as a device whose operation depends on an energy source rather than one generated by the human body, and which acts on the supplied energy by altering or converting density. AIMDs may be designed for partial or complete insertion into the human body to restore vital functions, compensate for deficiencies, and / or measure physiological parameters. Typically, an AIMD therefore contains at least one active element, designed for partial insertion into the human body via clinical intervention, and to remain in situ for at least 30 days post-operatively. Broadly speaking, AIMDs are considered to allow the transmission of energy and information across the skin of the implanted patient. As is known from the prior art, the best current approach for managing the transmission of energy and / or information from an implant is wireless power transfer (WPT) based on electromagnetic field transmission. Therefore, most implantable devices include two coils, the first located outside the implanted subject and the second inside the implanted subject. This transmission is thus performed through the skin and in the near field via a (inductive) wireless link, more specifically via NFC technology (13.56 MHz HF, according to standards ISO 14443 or ISO 15693). NFC technology allows for a reduction in coil size. The abbreviation "NFC" stands for "Near Field Communication," and its French equivalent is "CCP," also for "Near Field Communication." It consists of short-range, high-frequency wireless communication technology. This well-known technology enables information exchange between peripheral devices (typically an NFC chip and an NFC reader) over distances of approximately 10 cm. This technology is an extension of the standard ISO / CE I14443, which standardizes proximity cards using Radio Identification (RFID), combining smart cards and readers into a single peripheral device. In a manner known in the prior art, an NFC chip typically consists of an antenna and integrated circuits, and has an input stage containing protection circuitry designed to protect the NFC chip (specifically including at least one Zener diode), resulting in: limiting the voltage generated in the antenna. As is known from the prior art, this inherent characteristic of NFC chips limits the energy that can be recovered by other functional elements of the implant. In fact, the inherent limitation of this technology is that (in this case, passive) the NFC chip returns relatively little energy it receives, resulting in very low efficiency (500mW transmitted, approximately 15mW recovered).

[0003] These observations can be applied to any type of chip, including those with antennas designed to receive energy and / or information.

[0004] Furthermore, in certain cases of implantable devices, the transmission of energy and / or information is severely attenuated by the tissue of the person equipped with the device. This attenuation leads to several constraints. On the one hand, the transmitted signal must be of sufficient strength to be properly received by the receiver. On the other hand, energy transmission must be limited according to specific absorption rate (SAR) regulatory restrictions to avoid damaging the tissue. This trade-off is rarely considered in existing technologies.

[0005] The purpose of this invention is to optimize the recovery of energy while controlling the extent of the implant, so as to transmit energy and data from an external device to the implant via a sensing link.

[0006] The present invention achieves the above-mentioned objective by proposing the addition of an electronic component, which includes an antenna associated with an internal circuit, which may be an NFC chip, to allow voltages exceeding the limits imposed by the internal circuitry to be generated by the receiver antenna. Summary of the Invention

[0007] Therefore, the present invention relates to an active implantable medical device capable of being partially implanted in a subject, wherein, once implanted, the device includes an external module outside the subject and an internal module inside the subject, the external module and the internal module being designed to transmit data from one to the other and to transmit energy from the external module to the internal module.

[0008] - The external module includes an external antenna.

[0009] -Internal modules include:

[0010] ■ Internal antenna with two terminals;

[0011] ■ The connection between the terminals is a series connection between an internal integrated circuit and a capacitor associated with an internal antenna. The internal integrated circuit has an equivalent input impedance, which has a capacitive portion C4, and the capacitor has a capacitance C3, with a ratio... Greater than or equal to 0.1, and

[0012] ■ The energy recovery electronic component connected to the terminal is located outside the internal integrated circuit.

[0013] Therefore, this solution allows for the achievement of the aforementioned objectives. Specifically, this invention allows for the transfer of energy and data to an implanted device via a percutaneous link using a technology including an antenna associated with an integrated circuit (e.g., NFC technology). This invention allows for matching the impedance of the integrated circuit (and the impedance of the associated antenna) to optimize the recovered energy. Therefore, this impedance matching is based on adding electronic components to the integrated circuit (e.g., the integrated circuit of an NFC chip) so that the associated antenna can reach voltages exceeding the limits imposed by the integrated circuit, and optimizing the energy transfer efficiency between the external and internal modules of the device.

[0014] The device according to the invention may include one or more of the following features, which may be considered independently or in combination with each other:

[0015] -ratio Greater than or equal to 0.25, preferably 0.3 to 0.6,

[0016] - The external module includes a single external antenna, and the internal module includes a single internal antenna.

[0017] Each antenna is connected to an impedance matching circuit, and each antenna and its associated impedance matching circuit resonate at a frequency of 12MHz to 14MHz, more specifically at a frequency of 13.56MHz.

[0018] - The external and internal modules are designed to simultaneously transfer energy and data from one to the other.

[0019] - External and internal modules are designed to transfer data from one to the other in a bidirectional manner.

[0020] - External and internal modules are designed to transfer energy and data from one to the other on a single frequency band.

[0021] The present invention also relates to a method for transmitting energy and data, the method being implemented by a device according to any of the features described above, wherein the voltage supplied to the internal integrated circuit is 100mV to 5V and the voltage supplied to the energy recovery electronic components is 100mV to 50V.

[0022] The method according to the invention may include one or more of the following features, which may be considered independently or in combination with each other:

[0023] The transmission rate between the external module and the internal module is from 6 kbit / s to 900 kbit / s, preferably from 106 kbit / s to 847 kbit / s or from 6.62 kbit / s to 26.48 kbit / s.

[0024] - The energy transfer efficiency between external and internal modules is 10% to 70%.

[0025] The transmission rate between the external module and the internal module is 6 kbit / s to 900 kbit / s, preferably 106 kbit / s to 847 kbit / s or 6.62 kbit / s to 26.48 kbit / s, and the energy transfer efficiency between the external module and the internal module is 10% to 70%. Detailed Implementation

[0026] Therefore, the present invention relates to an active implantable medical device (AIMD) 10, and more particularly to a sensing link for the AIMD 10, such as... Figure 1 As schematically shown, it can be partially implanted in a subject. More specifically, the device 10 includes two complementary communication and power transmission modules 12, 14 (external module 12 and internal module 14) and a stimulator 15. Instead of the stimulator, some embodiments may have, for example, devices for measuring physiological or physical signals within the human body, including EMG (electromyography), EEG (electroencephalography), ECG (electrocardiography), or ENG (electroneurography) or temperature measurement.

[0027] When device 10 is applied to a subject, the external module 12 is located outside the subject, for example, attached to the subject's skin, while the internal module 14 is implanted inside the subject, for example, under the subject's skin. The stimulator 15 is connected to the internal module 14, and therefore, after implantation, the stimulator 15 is also located inside the subject. In embodiments including the stimulator 15, the stimulator 15 may be designed to stimulate, for example, tissues, nerves, or muscles, in order to control the movement of organs or limbs of the body.

[0028] The external module 12 and the internal module 14 are designed to transfer energy and data from one to the other. The energy is then transferred to the stimulator 15. More specifically, the energy transfer is unidirectional (from the external module 12 to the internal module 14), while the data transfer can be bidirectional (from the external module 12 to the internal module 14 and vice versa).

[0029] according to Figure 1 In the embodiment shown, the external module 12 is an NFC reader 16, which includes:

[0030] - Generator 18, which is in Figure 1 It consists of a 13.56MHz sine wave generator G and an associated resistor R. G Modeling,

[0031] - External antenna 20 connected to generator 18 (and associated resistor R) 20 ),

[0032] - An external impedance matching network 22 is located between the generator 18 of the NFC reader 16 and the external antenna 20. The external impedance matching network 22 includes a first capacitor with capacitance C1 and a second capacitor with capacitance C2, which are connected to form a capacitive voltage divider bridge.

[0033] like Figure 2 As shown, generator 18, external antenna 20, and external impedance matching network 22 form the analog section 16b of NFC reader 16. Furthermore, NFC reader 16 may include a digital section 16a linked to the analog section 16b via a digital-to-analog converter.

[0034] The use of NFC readers enables data exchange in both directions. The exchanged data includes:

[0035] -Stimulation commands and parameters from external module 12 to internal module 14,

[0036] - Responses, error notifications, and measurement data returned from internal module 14 to external module 12.

[0037] Impedance matching is a technique used to optimize power transmission between a transmitter and an electrical receiver in order to optimize the exchange of data and / or energy between the receiver and the transmitter, including the exchange of communication signals.

[0038] Internal module 14 includes:

[0039] - The internal antenna 24 (and associated resistor R) defines two terminals (241, 242). 24 ),

[0040] - Chip 26, designed to work with NFC reader 16 of external module 12, is connected to internal antenna 24, and also includes a series connection between terminals 241 and 242 of internal antenna 24:

[0041] ○ A third capacitor with capacitance C3, and

[0042] ○ The internal integrated circuit 28 has an equivalent input impedance Z, the capacitance portion of which is modeled by a fourth capacitor with capacitance C4, and the ratio If the value is greater than or equal to 0.1, C3 and C4 form a capacitor voltage divider bridge.

[0043] - An energy recovery electronic component (not shown), connected to the internal antenna 24 and designed to provide power to the stimulator 15, the recovery electronic circuitry being external to the internal integrated circuit 28 of the chip 26.

[0044] - An energy recovery electronic circuit includes a rectifier circuit 30 located upstream of the energy storage electronic circuit and the voltage regulation circuit (not shown). The rectifier circuit 30 includes a plurality of diodes D1, D2, D3, and D4 designed to generate a DC voltage source intended to power the energy recovery electronic components.

[0045] - Impedance matching internal network 32, located between internal antenna 24 and rectifier circuit 30, includes a fifth capacitor and a sixth capacitor with capacitances C5 and C6 respectively, which are connected to form an L-shaped network to allow impedance matching.

[0046] Preferably, the internal integrated circuit 28 is an NFC-type circuit.

[0047] In addition, such as Figure 2 As shown, the micro storage module 31a and the voltage regulation module 31b can be disposed between the rectifier circuit 30 and the stimulator 15.

[0048] exist Figure 1 In the illustrated embodiment, resistor RG has a value of 50Ω, and resistors R20 and R24 have a value of 5Ω. Furthermore, the first capacitor C1 has a value of 38pF, the second capacitor C2 has a value of 62pF, and the capacitor C3 has a value of 36pF. The fourth capacitor C4 has a value of 35pF, the fifth capacitor C5 has a value of 6.8pF, and the sixth capacitor C6 has a value of 8.2pF. In other embodiments, the values ​​of the different capacitors may vary slightly, but will still remain on the same order of magnitude. In this embodiment, the ratio... The value is approximately 0.5, which results in a good distribution of the signal received by the internal antenna 24 between the chip 26 on one side and the energy recovery electronics on the other side.

[0049] In this invention, the external module 12 includes a single external antenna 20, and the internal module 14 includes a single internal antenna 24. Each antenna 20, 24 is both a receiver antenna and a transmitter antenna. More specifically, the external antenna 20 is an energy and data transmitter antenna and may be a data receiver antenna, while the internal antenna 24 is a data and energy receiver antenna and may be a data transmitter antenna. Taking into account the equivalent input impedance Z of the internal integrated circuit 28 of the chip 26, the external antenna 20 and the internal antenna 24 are designed to obtain inductance values ​​that allow resonance at frequencies from 12 MHz to 14 MHz (more specifically at a frequency of 13.56 MHz (the so-called ISM frequency)).

[0050] Because of these two antennas 20 and 24, the external module 12 and the internal module 14 simultaneously transmit power and data from one to the other on a single frequency band. Furthermore, as previously described, the external module 12 and the internal module 14 are capable of transmitting data bidirectionally from one to the other.

[0051] As described in the introduction, the internal integrated circuit 28 of chip 26 has an input stage that includes protection circuitry (particularly including at least one Zener diode), thereby limiting the voltage generated at the terminals of the internal antenna 24. In an alternative embodiment, protection can be achieved by means of a cascade of conventional diodes. This limits the energy that can be recovered by the energy recovery components designed to power stimulator 15. The addition of a series-connected capacitor C3 allows for limiting the voltage supplied to the internal integrated circuit 28 of chip 26 while maintaining a high voltage at the input terminals of the energy recovery electronics, thereby allowing for a good energy supply to stimulator 15.

[0052] ratio This represents the energy distribution between the energy recovery electronics of chip 26 and the internal integrated circuit 28 of chip 26. Without capacitor C3, the ratio is zero and energy transfer is very limited. It has been observed that for ratios greater than 0.1... Energy transfer is significantly improved. Preferably, the ratio is... Greater than 0.25, or even greater than 0.3. Preferably, the ratio... The ratio is less than 0.9, or even less than 0.7. If the ratio approaches 0 (smaller compared to C4), as if there were no longer a capacitor voltage divider bridge, the Zener diode of the internal integrated circuit 28 of chip 26 begins to limit the input voltage of the energy recovery circuit. Conversely, for a ratio approaching 1 (higher compared to C4), the internal integrated circuit 28 of chip 26 no longer receives a signal, and all of it is transmitted to the energy recovery circuit according to the following formula:

[0053]

[0054] Inductive chargers typically seek to deliver maximum energy, but this is not advisable in the case of implantable devices, where the energy that can be delivered is limited by tissue sensitivity and the strength of the signal (transmitted along with the energy) must be sufficient to be properly received.

[0055] In one embodiment, the ratio It ranges from 0.3 to 0.6.

[0056] In this configuration, from the perspective of the energy recovery electronics, the internal integrated circuit 28 of chip 26 is regarded as a capacitor in parallel with a variable resistor whose value depends on the input voltage, in order to model the Zener effect of a real NFC circuit, thereby forming, for example, the portion of the impedance matching network between the internal antenna 24 and the energy recovery electronics.

[0057] Therefore, in this invention, the assembly formed by the internal integrated circuit 28 of chip 26, the third capacitor C3, and the internal impedance matching network 32 ensures the following two points:

[0058] - Impedance matching to optimize the coupling between the internal antenna 24 and the energy recovery electronics.

[0059] - Partial diversion of the received energy is used to ensure a stable and sufficient energy supply for the energy recovery electronic components without affecting the operation of chip 26.

[0060] Therefore, the special feature of the percutaneous link of the present invention is that it transmits energy and data simultaneously through a single and identical near-field link via a single and identical antenna on each side of the subject's skin (data is further transmitted in a bidirectional manner), while recovering optimized energy at the internal module 14.

[0061] Compared with the prior art, the advantages of the present invention are as follows:

[0062] -In the absence of mutual constraints, energy transfer and communication occur simultaneously.

[0063] Device 10 includes only a single set of antennas 20, 24 (i.e., a single antenna on each side of the subject's skin), thus avoiding the use of multiple antennas and significantly reducing spatial steric hindrance.

[0064] Energy and data are transmitted on a single, identical frequency band.

[0065] Device 10 is compatible with standard NFC reading systems.

[0066] - A reduced data transmission range helps limit the risk of eavesdropping and intrusion, thus ensuring better transmission security.

[0067] In particular, the use of only one set of antennas 20, 24 allows for coordinated exchange of information and energy, representing a change from existing technologies: in practice, devices typically comprise two separate systems (one for information and the other for energy), while the method of this invention allows for their merging, thereby effectively reducing size. This result is achieved without complicating the device, as only a few passive components are added.

[0068] Existing implants often include only one antenna; however, this antenna does not operate in the specified frequency band and does not perform NFC (13.56 MHz HF, according to standard ISO 14443 or ISO 15693) with energy recovery.

[0069] The device 10 according to the invention allows for the implementation of a method for transdermal transfer of energy and data, wherein the voltage supplied to the internal integrated circuit 28 is 100mV to 5V, and the voltage supplied to the energy recovery electronics is 100mV to 50V. Therefore, the energy transfer efficiency between the external module 12 and the internal module 14 is 10% to 70%. Furthermore, the transfer rate between the external module 12 and the internal module 14 is 6kbit / s to 900kbit / s, preferably 106kbit / s to 847kbit / s or 6.62kbit / s to 26.48kbit / s, so as to also cover the standard ISO / IEC 15693.

[0070] Therefore, the key point of the present invention is to improve the efficiency of transcutaneous energy transfer by associating an integrated circuit (e.g., a standard NFC chip) with an external energy recovery electronic component, so as to obtain a device 10 that combines good energy transfer efficiency with a reliable wireless communication link. Attached Figure Description

[0071] Figure 1 This is an electronic circuit diagram of the device according to the present invention.

[0072] Figure 2 This is a block diagram of the device according to the present invention.

Claims

1. An active implantable medical device (10) capable of being partially implanted in a subject, once implanted, comprising an external module (12) outside the subject and an internal module (14) inside the subject, the external module (12) and the internal module (14) being intended to simultaneously transmit data from one to the other and to transmit energy from the external module (12) to the internal module (14), - the external module (12) comprising an external antenna (20), - the internal module (14) comprising: • an internal antenna (24) defining two terminals (241, 242); • an association between the terminals (241, 242) and an internal integrated circuit (28) associated with the internal antenna (24) and a capacitor in series, the internal integrated circuit having an equivalent input impedance having a capacitive part C4, the capacitor having a capacitance C3, the ratio greater than or equal to 0.1 and less than 0.7, the internal integrated circuit (28) being of the NFC type, configured to receive stimulation commands intended for the stimulator (15), and • an electrical energy recovery electronic assembly connected to the terminals (241, 242), the electrical energy recovery electronic assembly being external to the internal integrated circuit (28).

2. Active implantable medical device (10) according to the preceding claim, characterized in that The ratio greater than or equal to 0.

25.

3. The active implantable medical device (10) according to claim 1, characterized in that The ratio is 0.3 to 0.

6.

4. The active implantable medical device (10) according to claim 1, characterized in that The external module (12) comprises a unique external antenna (20) and the internal module (14) comprises a unique internal antenna (24).

5. The active implantable medical device (10) according to claim 1, characterized in that Each antenna (20, 24) is connected to an impedance matching circuit (22, 32) and each antenna (20, 24) and its associated impedance matching circuit (22, 32) resonate at a frequency of 12 MHz to 14 MHz.

6. The active implantable medical device (10) according to claim 1, characterized in that The external module (12) and the internal module (14) are intended to transmit data from one to the other in a bidirectional manner.

7. The active implantable medical device (10) according to claim 1, characterized in that The external module (12) and the internal module (14) are intended to transmit energy and data from one to the other on a unique frequency band.

8. A method for transmitting energy and data, the method being implemented by the active implantable medical device (10) according to claim 1, the voltage supplied to the internal integrated circuit (28) being 100 mV to 5 V and the voltage supplied to the electrical energy recovery electronic assembly being 100 mV to 50 V.

9. The method for transmitting energy and data of claim 8, wherein, The transmission rate between the external module (12) and the internal module (14) is 6 kbit / s to 900 kbit / s.

10. The method for transmitting energy and data of claim 8, wherein, The transmission rate between the external module (12) and the internal module (14) is 106 kbit / s to 847 kbit / s or 6.62 kbit / s to 26.48 kbit / s.

11. The method for transmitting energy and data of claim 8, wherein, The energy transmission efficiency between the external module (12) and the internal module (14) is 10% to 70%.

12. The method for transmitting energy and data of claim 8, wherein, The transmission rate between the external module and the internal module is 6 kbit / s to 900 kbit / s and the energy transmission efficiency between the external module and the internal module is 10% to 70%.

13. The method for transmitting energy and data of claim 8, wherein, The transmission rate between the external module and the internal module is 106 kbit / s to 847 kbit / s or 6.62 kbit / s to 26.48 kbit / s.

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