Implantable bioelectronic devices based on magnetoelectric materials

Abstract

Some disclosed embodiments relate to a system (and / or use or manufacture) including a magnetoelectric (ME) component, the ME component comprising: one or more first layers, each of which comprises a piezoelectric material; and one or more second layers, each of which comprises a magnetostrictive material, and having a thickness ratio defined as the cumulative thickness of the one or more first layers to the cumulative thickness of the one or more second layers being 0.2 to 0.5. The system may also include an energy collection circuit, which includes a rectifier circuit, and is coupled to the ME component.

Description

[Technical Field]

[0001] Cross-reference of related applications This application claims the benefit and priority of U.S. Provisional Patent Application No. 63 / 579,638, filed on 30 August 2023, which is incorporated herein by reference in its entirety for all purposes.

[0002] Statement on federal government funding This invention was made possible with government support under grant number U18EB029353 from the National Institutes of Health, grant number FA8650-21-2-7119 from the Defense Advanced Research Projects Agency, and grant number 2236422 from the National Science Foundation. The government has certain rights in this invention. [Background technology]

[0003] Often known as implantable medical devices, implantable bioelectronic devices can be instrumental tools in diagnostic and therapeutic medical procedures. Implantable bioelectronic devices may be used to provide stimulation therapies that are more tailored and / or more effective in treating a given disorder and / or a given target (compared to, for example, conventional pharmaceutical treatments). For instance, an implantable medical device may be positioned and used to provide a therapy that is targeted and delivered to stimulate a specific biological location of interest (e.g., a specific axon bundle, brain region, organ, etc.). Thus, when an implantable bioelectronic device is used against a device positioned on (or even externally) the surface of a person's skin, signal noise may be reduced. Similarly, stimulation may have an effect that is more focused and more effective compared to pharmaceutical compositions.

[0004] Several implantable devices (e.g., cardiac pacemakers and deep brain systems) have been used as stimulation and / or recording devices. However, a given stimulation protocol is likely to elicit different physiological responses among individuals. Additionally, given characteristic properties of recorded biological activity may indicate different physiological basis and / or different therapeutic responses among individuals. Therefore, it would be advantageous to control stimulation parameters in a manner customized for specific individuals.

[0005] Typically, implanting an implantable device requires surgery involving deep incisions and cranial measurements. However, recent advances have also enabled the introduction of implantable devices into target areas using less invasive techniques, and these devices may be, and / or need to be, much smaller than those used in recent years. For example, devices may be implanted via endoscopic surgery or intravenous administration. Some minimally invasive devices are available to subjects in a manner that does not require incisions.

[0006] Furthermore, implanted devices are becoming more sophisticated in that a given device may include multiple electrodes for providing electrical stimulation and / or multiple electrodes for collecting recordings (where some or all of the stimulating electrodes may also collect at least some recordings, or conversely, recording electrodes may also provide stimulation). Consequently, the amount of data transmitted and / or received over a given period of time has increased substantially. Moreover, more implanted devices are configured to receive frequent signals that can control stimulation signals and / or recording parameters.

[0007] Therefore, implanted devices may require a considerable amount of power to support their operation. Furthermore, implanted devices may be positioned so as not to have connections for providing wireless power, much less connections for providing sufficient wireless power in real time. As use cases expand, in terms of having implanted devices in various body locations and using more sophisticated technologies for processing real-time data and sending real-time commands, power requirements are also expanding and becoming more complex.

[0008] More efficient power delivery would enable implanted bioelectronics to support more power-intensive functions, multi-channel or multimodal operation, and smaller devices. For example, multi-channel neural recording devices typically require up to 2mW per recording channel, and neural stimulation devices typically require up to 21mW. Increasing the received power can facilitate the addition of more recording or stimulation channels. Similarly, bioelectronic devices have been developed to perform multiple functions simultaneously, enabling the monitoring and control of biological processes in multimodal closed-loop systems. Each additional sensing and recording capability requires additional power. Furthermore, improved wireless power transfer (WPT) would allow implanted bioelectronics to support their existing functions with smaller shape factors, enabling less invasive surgical implantation and access to hard-to-reach targets.

[0009] Approaches developed for wirelessly powering implantable bioelectronic devices face trade-offs regarding penetration depth, power density, and alignment tolerances. For example, tissue scattering and absorption of both radiofrequency electromagnetic waves and light typically limit these approaches to shallow implants. In the case of near-field inductive coupling (NIC), power density decreases significantly as the device is miniaturized, making NIC unsuitable for small implants. NIC and ultrasound are highly sensitive to alignment errors and are therefore difficult to implement in applications requiring continuous power. Electrostatic coupling and ultrasound require the transmitter to be in contact with the body, which is problematic for applications requiring free movement or continuous operation of the implant.

[0010] Magnetoelectric (ME) devices may be a promising solution for powering implanted bioelectronic devices compared to other wireless power transfer techniques. Magnetoelectric devices have the potential to deliver higher power to smaller devices, with better alignment tolerances and minimal signal attenuation through air or tissue. However, because magnetoelectric devices rely on a magnetic field source (which may be outside the object in which they are implanted), they can be particularly sensitive to environmental fluctuations, interference, and / or activity within the object.

[0011] Therefore, there is a need for techniques, methods, and systems to improve power supply to implantable devices that can effectively stimulate and / or record physiologically. Such improvements could facilitate the effective reduction of the size of implantable bioelectronic devices and improve their performance. [Overview of the project]

[0012] In some embodiments, a system is provided comprising a magnetoelectric (ME) component, the ME component comprising one or more first layers, each of which may contain a piezoelectric material, and one or more second layers, each of which may contain a magnetostrictive material, and having a thickness ratio defined as the cumulative thickness of the one or more first layers to the cumulative thickness of the one or more second layers being 0.2 to 0.5.

[0013] Magnetostrictive materials may include metoglas.

[0014] Piezoelectric materials may contain lead zirconate titanate (PZT).

[0015] The system may include an energy acquisition circuit (in addition to one or more other parts of the system disclosed herein) which includes a rectifier circuit and is coupled to the ME component. In some cases, the rectifier circuit may include a full-bridge rectifier, and the energy acquisition circuit may include a power point tracking circuit. The power point tracking circuit may include a maximum power point tracking circuit, and the energy acquisition circuit is configured to present an optimal impedance for the magnetostrictive material over a range of workloads. In some cases, the rectifier circuit may include an active full-bridge rectifier, and the energy acquisition circuit may include a power point tracking circuit. The power point tracking circuit may include a maximum power point tracking circuit, and the energy acquisition circuit is configured to operate at the maximum power point of the magnetostrictive material regardless of the system workload by tracking the half-open circuit voltages of the ME and DC-DC impedance tuning. The energy collection circuit may include one or more power point tracking circuits, each configured to adjust the output voltage for different voltage domains, store excess collected energy in a storage element, and / or to trigger the use of at least a portion of the stored excess collected energy when it detects that the power collected by the energy collection circuit has fallen below a threshold.

[0016] Storage elements disclosed herein and / or used to store energy (e.g., excess energy) may include (e.g.) capacitors and / or batteries (e.g., miniature / micro solid-state batteries such as Ilika® Micro Solid-State Batteries). In some cases, batteries include or are solid-state rechargeable batteries. Batteries such as solid-state rechargeable batteries can power lower-energy processes (e.g., sensing biological / neural activity) for hours or days, in addition to providing additional energy in a delayed manner or in response to surge demands when the film itself cannot supply sufficient energy, which can support a more continuous data stream even during periods of use of external power.

[0017] A storage element may be configured to store a significant portion (e.g., at least 25%, at least 50%, or at least 75%) of the energy received by the storage element in a given time, at least until the next stimulus and / or recording session. A storage element may be configured to store a significant portion (e.g., at least 25%, at least 50%, or at least 75%) of the energy received by the storage element in a given time, at least for a period of at least (e.g.) 1 minute, 10 minutes, 30 minutes, 1 hour, 3 hours, 6 hours, 12 hours, 1 day, 3 days, 1 week, 3 weeks, 1 month, 3 months, 6 months, or 1 year.

[0018] The storage element may be part of the system, external to the system, physically connected to the system, and / or electrically connected to the system. The energy collection circuit may include a bidirectional DC-DC converter and / or a unidirectional DC-DC converter. The system may be configured to store energy in the storage element when the maximum detected power of the system is greater than the load in the rectifier of the energy collection system.

[0019] The system may include an open-circuit voltage sampler (in addition to, for example, one or more other parts of the system disclosed herein). The open-circuit voltage sampler may be configured to sample magnetoelectricity at the start of the power transfer phase to the system.

[0020] The system may be or may include an implantable bioelectronic device.

[0021] The system may or may include a battery-free implant.

[0022] The total thickness of implantable bioelectronic devices may be less than 1 mm.

[0023] The system may comprise one or more electrodes configured to record electrical signals (in addition to, for example, one or more other parts of the systems disclosed herein).

[0024] The system may comprise (for example, in addition to one or more other parts of the systems disclosed herein) a capacitor and a switching circuit, the switching circuit being configured to dynamically change its connection to the capacitor.

[0025] The system may comprise a battery (e.g., a miniature / micro solid-state battery such as an Ilika® micro solid-state battery) and a switching circuit (in addition to one or more other parts of the system disclosed herein) and the switching circuit being configured to dynamically change the connection to the battery. The battery, such as a solid-state rechargeable battery, may power lower-energy processes (e.g., sensing biological / neural activity) for hours or even days, in addition to providing additional energy in a delayed manner or in response to surge demands when the film itself cannot supply sufficient energy, which may support a more continuous data stream even during periods of use of external power.

[0026] The system may include a low-noise amplifier (for example, in addition to one or more other parts of the system disclosed herein).

[0027] The mechanical bond between one or more first layers and one or more second layers may be configured to have an interfacial bonding coefficient of 0.42 to 0.70. The mechanical quality coefficient of the system may be 43.2 to 75.9. The thickness of one or more second layers may be 20 μm to 30 μm. The thickness of one or more first layers may be 100 μm to 150 μm. The thickness ratio of the cumulative thickness of one or more first layers to the sum of the one or more first layers and one or more second layers may be 0.70 to 0.95.

[0028] The system may include a power source or energy source configured to supply power or energy (e.g., potentially dynamically) to another part of the system (e.g., in addition to one or more other parts of the system herein). For example, the power source or energy source may be configured to be located outside the subject, while magnetoelectric components, energy collection circuits, and / or power point tracking circuits may be part of an implantable device configured to be implanted in the subject's body (e.g., brain, heart, lungs, other organs, blood vessels, etc.).

[0029] In some embodiments, methods for supplying or energizing a device or system disclosed herein are provided. Such a device or system may include one or more configuration characteristics disclosed herein, one or more components disclosed herein, one or more operating capabilities or characteristics disclosed herein, one or more specifications disclosed herein, and so on.

[0030] In some embodiments, some or all of the systems disclosed herein may provide stimulation to organs, blood vessels, etc., and / or to record one or more types of biological signals. The power or energy delivered to the magnetoelectric components of the system may depend on various factors that can be detected or inferred by the system or another system, such as preceding, recent, or instantaneous noise, signal intensity, location of the system's implanted device, stimulation protocol, movement of the subject, intensity / presence of the subject's symptoms, etc.

[0031] The terms and expressions used are for illustrative purposes only, not limiting purposes, and in using such terms and expressions, there is no intention to exclude any equivalents of the exhibited and described features or parts thereof, but it is recognized that various modifications are possible within the scope of the claimed invention. Accordingly, although the claimed invention has been specifically disclosed by embodiments and optional features, it should be understood that optional features, modifications, and variations of the concepts disclosed herein can be made by those skilled in the art, and such modifications and variations are considered to be within the scope of the invention as defined by the appended claims.

[0032] This disclosure will be explained in conjunction with the attached drawings. [Brief explanation of the drawing]

[0033] [Figure 1] Figure 1 shows an exemplary system associated with a mechanism and equivalent circuit model that implements the use of magnetoelectric (ME) radio power transfer (WPT). [Figure 2] Figure 2 shows an exemplary arrangement of one or more layers within a magnetoelectric device according to several embodiments of the present invention. [Figure 3]Figure 3 illustrates adaptive magnetoelectric receiver circuits and relationships according to several embodiments of the present invention: (a) circuit diagram, (b) electrical impedance (Zelec) as a function of the ratio of the rectifier output voltage (Vrec) to the open-circuit voltage (VOC) of the magnetoelectric receiver, and (c) output power as a function of the rectifier output voltage at different frequencies. [Figure 4] Figure 4 illustrates exemplary implementations of magnetoelectric power collection circuits according to several embodiments of the present invention. [Figure 5] Figure 5 illustrates the relationship between the output power from a thin magnetoelectric transducer and the output power from a thick magnetoelectric transducer, with and without an MPPT magnetoelectric wireless power transfer interface. [Figure 6] Figures 6A to 6H illustrate the relationship between the ME voltage coefficient (αME) and various variables based on the theoretical model disclosed herein. Panels (a to d) show αME as a function of frequency for varying (a)k, (b)QM, (c)ttotal, and (d)η, which are ME material properties that can be controlled during manufacturing and clamping. Panels (e to h) illustrate the relationship between the maximum ME voltage coefficient (αME,max) and k, Qmttotal, and η, respectively. [Figure 7] Figures 7A to 7H illustrate the relationship between the ME power coefficient (pME) and various variables, based on the inventors' theoretical model disclosed herein. Panels (a to d) show pME as a function of load resistance for varying (a)k, (b)QM, (c)ttotal, and (d)η. Panels (e to h) show the maximum ME power coefficient (pME,max), which can be calculated from Equation 6, as a function of (e)k, (f)QM, (g)ttotal, and (h)η. [Figure 8]Figures 8A to 8D illustrate the experimental verification of the equivalent circuit model of the ME WPT for both two-layer and three-layer configurations, as well as for different mechanical characteristics of the ME receiver. The experimental measurements (circles) for αME (red) and pME (blue) show close agreement with the theoretical values ​​(solid lines) calculated from the models for (a) a two-layer (Metglass-PZT) ME receiver and (b) a three-layer (Metglass-PZT-Metglass) ME receiver. (c) The 2D contour plot shows the theoretical values ​​of pME,max for fluctuating QM and k. The red circles represent data collected in this study using a two-layer ME receiver, and the black diamonds represent data from previous studies by our group.28 (d) The percentage error of the theoretical pME,max (|theory-experiment| / experiment × 100%) is less than 9% for all samples. [Figure 9] Figures 9A–9D show plots illustrating the optimization of interfacial bonding, clamping, and thickness of each layer for increased power. (a) Performance of the ME receiver against seven different epoxies (each, n≧90). M-Bond epoxy yields a higher voltage amplitude compared to all other epoxies (***p<0.001 for all pairs via Wilcoxon rank-sum test). (b) Comparison of power and QM using two different clamping methods: adhesive clamping and mechanical clamping. (c) Measured power from four different ME receiver configurations (configurations 1–4, each n=3) as a function of magnetic field strength. (d) An enlarged version of (c) from 0–1mT. Different shades indicate different configurations. [Figure 10]Figures 10A–10B illustrate data for a configured ME receiver demonstrated through exvivota tissue and compared with other WPT technologies. (a) Measured power density in two different sized ME receivers as a function of distance through tissue (n=3 for each size). (b) Comparison of the configured ME receiver with previously reported mm-sized bioelectronics wirelessly powered by ME[A], near-field inductive coupling (NIC)[BD], light[E], ultrasound[F,G], radio frequency electromagnetic waves (RF)[H], and mid-range inductive coupling (MDF)[I]. Compared to a 16mm²NIC-driven device (C), it achieved more than four times the power density and more than five times the power. [Modes for carrying out the invention]

[0034] While magnetoelectric (ME) materials have been studied for compact antennas, they have recently been used for power transfer terminals (WPTs) in bioelectronics, demonstrating power delivery of up to 2 mW. The most commonly used ME receivers for powering bioelectronics are multilayer laminates that convert magnetic energy into electrical energy through mechanical coupling between magnetostrictive and piezoelectric layers. This conversion is most efficient when the magnetic field frequency matches the acoustic resonance frequency of the ME receiver, thereby generating maximum voltage and power.

[0035] Since ME performance depends on several material properties, and this WPT approach is relatively new in bioelectronics, the techniques of the present invention relate to systems and methods for increasing the power density of an ME receiver based on its material properties. It will be understood that some approaches aim to improve ME performance by optimizing ME material properties. Such approaches may focus primarily on increasing the voltage generated by a cm-scale ME receiver in a sub-mT-scale magnetic field, and these findings are not very applicable to WPT in implantable bioelectronics. Some embodiments disclosed herein relate to configuring ME material properties to improve power transfer to a mm-scale ME receiver in an mT-scale magnetic field.

[0036] In some embodiments, a system is provided that includes one or more magnetoelectric materials for wirelessly powering an implantable bioelectronic device, thereby delivering higher power with alignment tolerances and low signal attenuation. The magnetostrictive layer of the system can generate an alternating magnetic field, which is converted into elastic excitations through a magnetostrictive response. The elastic excitations can be converted into an electric field through a piezoelectric response influenced by a piezoelectric layer. As a result, the electric field generated during this process can be used to wirelessly power an implantable bioelectronic device. Thus, a system utilizing one or more magnetoelectric materials can act as an energy collection source for high-power delivery to one or more other devices (such as implantable bioelectronic devices).

[0037] An implantable bioelectronic device may include one or more layers of magnetoelectric (ME) material coupled to an energy harvesting circuit. The one or more layers of magnetoelectric material may be configured to generate an alternating magnetic field. The generated magnetic field may facilitate elastic excitation based on a magnetostrictive response. The magnetostrictive response may include a change in shape or dimensions of the one or more layers of the magnetoelectric material during the magnetization process. The elastic excitation may additionally or alternatively be converted into an electric field based on a piezoelectric response by a piezoelectric layer. The resulting electric field may be used to support one or more power support functions, which may include multi-channel or multi-modal operation.

[0038] FIG. 1 illustrates an example system associated with mechanisms and equivalent circuit models implementing use of magnetoelectric (ME) wireless power transfer (WPT). In the representation shown in FIG. 1, the voltage coefficient (α ME ), defined as the ratio of the change in the receiver's open circuit voltage (OCV) to the change in the applied magnetic field, is used as an intermediate term to calculate power. (Equation 1 - wherein V is the OCV from the ME receiver, and H ac is the applied alternating magnetic field.)

Math

[0039] Based on the equivalent circuit model, α ME can be defined in terms of magnetoelastic and electroelastic coupling coefficients (φ m and φ p ), equivalent mechanical impedance (Z M ), and load impedance (Z L ), respectively. (Equation 2)

Math

[0040] The magnetoelastic coupling coefficient (φ m ) relates the transmission of an applied magnetic field to elastic excitation of a magnetostrictive layer (FIG. 1, green), and relates to a width (W), a magnetostrictive layer thickness (t m ), a tensor element s33,m The magnetorheological compliance represented by and the tensor element d 33,m It depends on the piezoelectric magnetic modulus expressed by [formula].

[0041] As shown in the highlighted green area of ​​Figure 1, the transmitter coil generates an alternating magnetic field that is converted into elastic excitations through the magnetostrictive response in the magnetostrictive layer of the magnetoelectric device. The magnetoelectric device may correspond to a multilayer structure including a two-layer laminated structure having at least one magnetostrictive layer and at least one piezoelectric layer, or a three-layer laminated structure having one or more magnetostrictive layers and at least one piezoelectric layer between one or more magnetostrictive layers. Additionally and / or alternatively, the magnetoelectric device may include one or more layers of magnetoelectric material having mechanical properties that vary across at least two layers and / or across one, more, or all adjacent layers. The two- or three-layer laminated structures of the magnetoelectric device may correspond to and / or include materials such as: terphenol-lead zirconate titanate (PZT) / magnesium lead niobate-lead titanate (PMN-PT), metoglass-lead zirconate titanate (PZT) / magnesium lead niobate-lead titanate (PMN-PT), metoglass-lithium niobate, etc.

[0042] Furthermore, as shown in the purple-highlighted portion of Figure 1, the piezoelectric response generated by the piezoelectric device can facilitate the conversion of elastic excitations into an electric field. The piezoelectric device may comprise one or more layers of piezoelectric material. The piezoelectric device may comprise one or more layers of piezoelectric material, including lead zirconate titanate (PZT), magnesium lead niobate-lead titanate (PMN-PT), lithium niobate, and the like. In some embodiments, at least one piezoelectric layer may correspond to the piezoelectric device.

[0043] In the equivalent circuit model shown in Figure 1 (as described above), H ac φ is the output of the current source, which represents the amplitude of the applied alternating magnetic field. m and φ p These are the magnetoelastic and electroelastic coupling coefficients, respectively. Therefore, the electroelastic coupling coefficient (φp ) relates the transmission of mechanical stress to electrical excitation within the piezoelectric layer. Furthermore, φ p is the width (W) and the tensor element s. 11,p The electroelastic compliance represented by and the tensor element d 31,p It depends on the piezoelectric modulus expressed by Z. M Q is the equivalent mechanical impedance, the interlayer coupling (k) of a laminate, and the mechanical quality coefficient (Q), which is a measure of strain amplification in an ME receiver. M ), total thickness (t total It depends on factors such as the load impedance (Z), and the thickness ratio (η), which is the ratio of PZT thickness to total thickness. L ) depends on the resistive load receiving the power and capacitance of the piezoelectric layer, C0 is the capacitance of the piezoelectric material, V is the voltage difference across the magnetoelectric device, and R L This is the load resistance.

[0044] As shown in the highlighted blue portion of Figure 1, the mechanical impedance can be controlled to represent the loss of elastic excitation. The mechanical impedance is related to the interfacial adhesion and / or interfacial coupling coefficient (k), clamp, and total thickness (t) of the magnetoelectric device. total Elastic excitation can be controlled based on one or more parameters, such as (t), and the thickness ratio (η) of the magnetoelectric device. m The thickness of the magnetostrictive layer can be expressed as (t), and the conversion between elastic excitation and electric field is in a manner such as that illustrated by the equation in Figure 2. p This can be associated with the thickness of the piezoelectric material, which can be expressed as ).

[0045] Figure 2 shows an exemplary arrangement of one or more layers in a magnetoelectric device according to one embodiment of the present invention. The magnetoelectric device and / or receiver may correspond to a multilayer structure comprising at least one piezoelectric layer (e.g., for a lead zirconate titanate (PZT) layer) between one or more magnetostrictive layers (e.g., for one or more layers of metoglass).

[0046] One or more properties may be controlled and optimized in sequence based on (and / or to improve) the expected induced voltage and / or power within the magnetoelectric device. These properties may include (e.g.) the thickness ratio and / or composition ratio (η) of the magnetoelectric device, the interfacial coupling coefficient (k), and the mechanical quality coefficient (Q). M ), thickness of the magnetostrictive layer (t m ), thickness of piezoelectric material (t p ), and / or the total thickness (t) of the magnetoelectric device total ) may include.

[0047] For example, the composition ratio and / or thickness ratio (η) of a magnetoelectric device is the thickness (t) of the piezoelectric layer. p ) the total thickness (t) of the magnetoelectric device total It can be expressed as the value obtained by dividing by (t). The total thickness of a magnetoelectric device is the thickness of the piezoelectric layer (t p ) and the thickness of one or more magnetoelectric layers (t m This may relate to the total thickness including the magnetoelectric device (t). total The total thickness (t) of the magnetoelectric device can range from at least (for example) 140 μm or 0.140 mm, 145 μm or 0.145 mm, 148 μm or 0.148 mm, 149 μm or 0.149 mm, 150 μm or 0.15 mm to at least 319 μm or 0.319 mm, 318 μm or 0.318 mm, or 317 μm or 0.317 mm. total The total thickness (t) of the magnetoelectric device can range from (for example) less than 1000 μm or 1 mm, 500 μm or 0.5 mm, 450 μm or 0.450 mm, to at least 400 μm or 0.400 mm, 350 μm or 0.350 mm, or 325 μm or 0.325 mm. In some embodiments, the total thickness (t) of the magnetoelectric device is also used. totalThe thickness can range from 150 μm or 0.15 mm to 317 μm or 0.317 mm. The composition ratio and / or thickness ratio of the multilayer laminated structure can be less than (e.g.) 0.2, 0.25, 0.3, 0.4, 0.5, and / or greater than (e.g.) 0.30, 0.25, 0.20, 0.15, 0.10, 0.08, etc. In some embodiments, the composition ratio and / or thickness ratio of the multilayer laminated structure can be between 0.2 and 0.5.

[0048] Thickness of piezoelectric material (t p The thickness (t) of the piezoelectric material can be at least (for example) 121 μm or 0.121 mm, 122 μm or 0.122 mm, 124 μm or 0.124 mm, 127 μm or 0.127 mm, and / or less than (for example) 261 μm or 0.261 mm, 262 μm or 0.262 mm, 264 μm or 0.264 mm, 267 μm or 0.267 mm, etc. In some embodiments, the thickness (t) of the piezoelectric material can be at least 121 μm or 0.121 mm, 122 μm or 0.122 mm, 124 μm or 0.124 mm, 127 μm or 0.127 mm, and / or less than 261 μm or 0.261 mm, 262 μm or 0.262 mm, 264 μm or 0.264 mm, 267 μm or 0.267 mm, etc. p The thickness of the magnetostrictive material (t) can be (for example) 127 μm or 0.127 mm to 267 μm or 0.267 mm. m ) can be greater than (for example) 20 μm or 0.20 mm, 25 μm or 0.25 mm, 30 μm or 0.30 mm, etc.

[0049] Thickness of magnetoelectric material (t m ) can be at least (e.g.) 25 μm or 0.25 mm, and can be less than (e.g.) 200 μm or 0.200 mm, 150 μm or 0.150 mm, 100 μm or 0.100 mm, 50 μm or 0.50 mm, 45 μm or 0.45 mm, 30 μm or 0.30 mm, and / or can be less than (e.g.) 100 μm or 0.10 mm, 75 μm or 0.075 mm, 50 μm or 0.050 mm, 300 μm or 0.030 mm, etc.

[0050] It should be understood that, as referred to herein, the “thickness” of a piezoelectric or magnetoelectric material may refer to the cumulative value, maximum value, median value, mean value, or mode across all layers in a system having the corresponding material across any layer or all layers.

[0051] In some embodiments, the thickness (t) of the magnetoelectric material m The thickness of the magnetostrictive material (t) can be (for example) 127 μm or 0.127 mm to 267 μm or 0.267 mm. m ) can be greater than (for example) 20 μm or 0.20 mm, 25 μm or 0.25 mm, 30 μm or 0.30 mm, etc.

[0052] Mechanical quality factor (Q M The mechanical quality factor (Q) can be greater than (for example) 35, 38, 40, 41, 42, 43, 44, 44.4, 45, 47, 50, etc., and / or less than (for example) 85, 80, 79, 78, 77.1, 77, 76, 75.9, 75, 74.7, 70, 65, etc. The mechanical quality factor may be influenced by and / or based on (for example) one or more interfacial bonding techniques and / or clamping mechanisms. Therefore, the mechanical quality factor (Q) M This can be associated with the strain amplification coefficient of a magnetoelectric device.

[0053] The interfacial coupling coefficient (k) can be at least (e.g.) 0.25, 0.3, 0.35, 0.37, 0.38, 0.40, 0.42, 0.44, 0.46, 0.48, 0.50, and / or less (e.g.) 0.8, 0.78, 0.76, 0.74, 0.72, 0.70, 0.68, 0.66, 0.64, 0.6, etc. In some cases, the interfacial coupling coefficient is 0.38–0.74, 0.42–0.70, or 0.46–0.66. The interfacial coupling coefficient may be influenced by and / or based on the interfacial bonding technique and / or clamping mechanism. Thus, the interfacial coupling coefficient (k) may relate to the coupling between one or more magnetostrictive layers and at least one piezoelectric layer. The overall packaging, including interfacial bonding and clamping mechanisms between one or more layers, has such interfacial bonding coefficient (k) and mechanical quality coefficient (Q). M Factors such as ) can be affected. In some embodiments, the clamping mechanism can affect the mechanical quality factor (Q). M This can affect the following: During the manufacture of magnetoelectric devices, one or more characteristics may be controlled and optimized within a range to improve the induced voltage and power in small magnetoelectric devices.

[0054] Therefore, one or more properties and associated thresholds and / or ranges may be related to one or more common attributes. For example, interfacial bonding and clamping mechanisms have a bonding coefficient (k) and a mechanical quality coefficient (Q). M This can affect one or both of the piezoelectric material's thickness (t). Another example is the thickness of the piezoelectric material (t). p ) can affect the total thickness and / or composition ratio of a magnetoelectric device (for example).

[0055] Adaptive magnetoelectric radio power receiving electronic circuit To extract a large amount (e.g., the maximum amount) of power from a given magnetoelectric transducer, the electrical impedance (Z) presented by the energy collection circuit is used. elec The electrical impedance Z can be dynamically set to attempt to match the impedance of the magnetic-electrical receiver. elecThis can be adjusted by changing the output voltage of the rectifier. Figure 3(a) shows an exemplary circuit for performing adaptive impedance matching.

[0056] The simulation results show that for a magnetoelectric receiver operating at a given frequency, the rectifier output voltage is approximately half (V) of the open-circuit voltage, regardless of the operating frequency. OC This indicates that the output power peaks when the rectifier output voltage is V / 2. (Figure 3(c).) Therefore, Maximum Power Point Tracking (MPPT) employs a DC-DC converter and the rectifier output voltage is V OC This can be achieved by adjusting it to be / 2. A DC-DC converter can isolate the variable load from the magnetoelectric receiver, thus enabling load-independent power at the rectifier output.

[0057] Figure 4 shows one implementation of a magnetoelectric power acquisition circuit with adaptive magnetoelectric wireless power transfer capability. The magnetoelectric power acquisition circuit comprises an active rectifier, a DC-DC converter, and various control circuits. To facilitate MPPT control, the output voltage of the rectifier (V) rec ) uses a DC-DC converter to achieve the maximum power point voltage (V MPP Voltage window (V) centered around ) ref,l ~V ref,h It is adjusted within ). rec ga V ref,h When it exceeds a certain value, DC-DC is enabled in the forward direction. R Power is extracted from and thereby V rec Reduce V rec ga V MPP When it falls below C R Charge accumulates in V rec This increases. In this way, the output power is maintained at the peak point, and the excess energy is stored in the storage capacitor C. S It is stored in (and / or another type of storage element such as a battery). SThe energy in these devices can often be used to supply various applications, such as nerve stimulation, which require high voltage and sufficient instantaneous power. Batteries may include miniature / micro solid-state batteries, such as (e.g.) Ilika® micro solid-state batteries. Batteries such as solid-state rechargeable batteries can power lower-energy processes (e.g., sensing biological / neural activity) for hours or even days, in addition to providing additional energy in a delayed manner or in response to surge demands when the film itself cannot supply sufficient energy, which can support a more continuous data stream even during periods of external power use.

[0058] As an example, the systems disclosed herein may include a battery and configuration such that external power can be used to deliver bioelectrotherapy, and excess energy is collected to charge the battery (e.g., if the battery is in an implantable device of the system delivering bioelectrotherapy, and / or if the battery is a solid-state battery). After the external power has been removed, the system may use the battery to perform periodic sensing of bioactivity (e.g., neuronal activity). Periodic sensing may be evaluated within or outside the system to predict the current or future response of a subject to bioelectrotherapy (or the response of a part of the subject's body, such as the response of a given organ or a part of a given organ). For example, periodic sensing may be evaluated to predict neuronal responses in a specific area of ​​the subject's brain over the next few hours or days.

[0059] Furthermore, some disclosed embodiments support bidirectional energy transfer, enabling the system to supply power to the load from a storage capacitor (and / or other type of storage element) in the event of substantial load surges. rec ga V ref,l If it falls below that, the DC-DC switches to the reverse direction, C R Refill and V rec V MPP Maintain in the vicinity. The system will set the maximum magnetoelectric power (P MPPWhen the load at the rectifier output (within the low-voltage domain) is greater than the load, the excess energy is stored in a capacitor (C) S It can be stored in (and / or another type of storage element). Conversely, the system can store P MPP It allows energy to be drawn from storage when instantaneous load power exceeding P occurs. MPP If a more consistently lower voltage is expected, a bidirectional DC-DC converter can be replaced with a unidirectional DC-DC converter. Open-circuit voltage (V) OC The sampler transmits magnetoelectric V at the start of the power transfer phase. OC Sampling is used for V for DCDC control. MPP , V ref,l , and V ref,h This makes it possible to acquire it.

[0060] As shown in Figure 5, the simulation results demonstrate that adaptive MPPT power receivers enable both thin and thick magnetoelectric receivers to consistently maintain high power levels across a wide range of loads. Due to the limited DC-DC power conversion efficiency, there is a slight deviation in MPPT power from the ideal peak power of the magnetoelectric receiver. Nevertheless, the technology demonstrates significant power enhancement in a full system with fluctuating light load conditions.

[0061] The system may further include a transmitter and potentially a receiver (which may be a single transceiver). The transmitter may be configured to communicate data to a computing device which is part of the system. Depending on the subject, the computing device may be a device operated by a healthcare provider associated with the subject's treatment, or an entity that facilitates the medical monitoring or treatment of the subject. Such communication may be made using any of a variety of commercially available protocols, such as wireless networks including short-range connections (e.g., Bluetooth®, BTLE, or ultra-wideband connections), or through a Wi-Fi network such as the Internet. The receiver may be configured to receive commands or requests from the computing device, such as a command to start recording a signal or a request to send data to the computing device.

[0062] The system may further include processing components that can perform initial processing using signals. One or more initial processing actions may be performed, either by default or additionally, on a computing device to which the signal is sent. The computing device may include mobile devices (e.g., smartphones), tablets, laptops, desktop computers, computer servers, and the like.

[0063] Power generated based on an electric field can be used to power implantable bioelectronic devices. The power generated based on the electric field can be transmitted to one or more energy collection circuits. The power generated based on the electric field can be transmitted to one or more circuits corresponding to a full-bridge rectifier and optimal load resistance, a full-bridge rectifier with a maximum power point tracking circuit, a DC-DC converter, and a full-bridge rectifier with a wide range of load resistances and a maximum power point tracking circuit, a bidirectional DC-DC converter, a wide range of load resistances, and instantaneous load power greater than the maximum power of the magnetoelectric device.

[0064] The system may include a magnetoelectric (ME) transducer and / or one or more electrodes. One or more electrodes may be coupled through the ME transducer to one or more circuits disclosed herein. A circuit (for example) may utilize power from the ME transducer and be configured to transmit and / or receive data collected via a second pair of electrodes.

[0065] In some cases, one electrode of the first pair of electrodes is mounted on the outer surface of the magnetostrictive material, and the other electrode of the first pair of electrodes is mounted on the outer surface of the piezoelectric material. The system may also, or alternatively, include a low-noise amplifier (LNA) (e.g., having a fixed gain) configured to amplify a weak electrical signal from the ME transducer and produce a consistent response for measuring the signal strength. To modulate the ME transducer during uplink communication, a switching circuit may be configured that can electrically connect and disconnect storage elements based on sensing data collected via the sensing electrodes.

[0066] Implantable bioelectronic devices can be associated with the treatment of neurological disorders. Power can be supplied to the implantable bioelectronic device using electricity generated based on an electric field. For example, a patient may be diagnosed with one or more neurological disorders, including cognitive impairment, attention deficit, motor impairment, and sensory impairment. The patient may exhibit one or more neurological symptoms, such as cognitive decline, decreased attention, or motor impairment.

[0067] Implantable bioelectronic devices can be introduced into a subject's body through minimally invasive medical procedures. Power generated by magnetoelectric devices and / or supplied by one or more energy acquisition circuits can facilitate computing functions such as capturing physiological data, stimulating one or more channels, monitoring physiological and biological processes, and monitoring tissue health. Implantable bioelectronic devices can facilitate additional sensing and recording functions based on wireless power transfer. Implantable bioelectronic devices can support existing functions within a smaller shape factor, which would enable less invasive surgical implantation and access to hard-to-reach targets in the subject.

[0068] In some embodiments, the system may further include a symptom monitoring system that can communicate with an implantable bioelectronic device to monitor biological, physiological, and / or behavioral information related to the subject. For example, an intelligent symptom monitoring system may include a user device (e.g., a mobile phone), or a wearable user device (e.g., a smartwatch), or an application installed on a (wearable) user device. The (wearable) user device may include one or more sensors that can be configured to detect signals corresponding to the subject's motor activity, physiological metrics, biometric information, etc. For example, the user device may include an accelerometer and / or gyroscope that can be used to collect signals that can be processed to estimate one or more types of motion.

[0069] In some embodiments, the implantable bioelectronic device can be configured to stimulate a general area or axonal bundle track. Stimulation may be located in areas such as the subthalamic nucleus, medial forebrain bundle, central thalamic nucleus, internal capsule, dentate gyrus, or prefrontal cortex. Based on communication between a computing system and a symptom monitoring system, the implantable bioelectronic device may perform desired actions to improve the subject's condition. [Examples]

[0070] The following embodiments are included to illustrate preferred embodiments. Those skilled in the art will understand that the techniques disclosed in the following embodiments represent techniques that the inventors have found to work well in the practice of the embodiments and can therefore be considered to constitute a preferred mode of that practice. However, those skilled in the art will understand that, in view of this disclosure, many modifications can be made to the specific embodiments disclosed without departing from the spirit and scope of this disclosure, and similar or comparable results can still be obtained.

[0071] approach A multi-stage approach was taken to improve the performance of the ME receiver. As will be described in more detail below, a model based on the analytical formula and equivalent circuit model of the ME receiver was used to determine which factors could be optimized to increase power density (the amount of power transferred divided by the receiver footprint (length × width)). The model was then experimentally validated using an ME receiver consisting of mechanically coupled metoglass and lead zirconate titanate (PZT). Based on these studies, key factors that can be experimentally controlled and optimized to increase power density were identified. Based on these findings, an ME receiver was manufactured to test whether the inventors' modifications actually experimentally improve power density. Finally, to demonstrate that the ME receiver can achieve high power density through tissue under human safety limits, the power received through 1–5 cm of pig tissue was measured.

[0072] result Equivalent circuit model research. How to α ME To understand how to maximize the maximum ME voltage coefficient,

number

Math

Math

Math

Math

Math

[0073] Fig. 6 includes a plot showing how the ME voltage coefficient (α ME ) depends on the four variables described above based on the theoretical model disclosed herein. Panels (a-d) show (a) k, (b) Q M , (c) t total, and (d) α as a function of frequency for varying η ME , which are ME material properties that can be controlled during manufacturing and clamping. When k is increased from 0.2 to 1.0 and η is increased from 0.1 to 0.9, the resonance frequency decreases. Q M from 10 to 90, and t total from 0.1 mm to 0.3 mm does not affect the resonance frequency. Panels (e to h) show the maximum ME voltage coefficient (α M ), (g) t total and (h) η, which can be calculated from Equation 3, as a function of (e) k, (f) Q ME,max ). As shown in FIGS. 6(e to h), α ME,max is linearly related to Q M and t total and nonlinearly related to k and η, α ME,max increases with increasing Q M , t total and k, and α ME,max is maximized at an optimal η. It should be understood that the α ME,max curves shown in FIGS. 6(e to h) are generated by detecting the maximum α ME values in the individual curves shown in FIGS. 6(a to d).

[0074] ME power transfer was also quantified in terms of predetermined ME material properties. Herein, the concept of the ME power coefficient (p ME ) is introduced. Similar to the ME voltage coefficient, p ME is the square of the amplitude of the magnetic field

Mathematical Expression

Mathematical Expression

[0075] ME power coefficient (p ME) was optimized to receive high power from the ME receiver. Equation 4 can be expressed in terms of other predefined variables.

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[0076]

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[0077] As shown in Figures 7(a) and 7(b), p ME is the load resistance (R L ) depends on the optimal load resistance

number

number

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[0078] Verification of the equivalent circuit model. The equivalent circuit model was verified for both two-layer and three-layer configurations, as well as for different mechanical characteristics of the ME receiver. Therefore, the expected voltage and power from our ME receiver can be accurately calculated using the equivalent circuit model. To collect experimental data to verify our model, a 9×3mm 2 ME receivers were fabricated using 267 μm thick PZT and 25 μm thick Metglass, and OCV and power were measured for each ME receiver under a magnetic field of 0.3 mT. M And k was determined experimentally.

[0079] Figure 8 shows experimental verification of the equivalent circuit model of the ME WPT for both two-layer and three-layer configurations, as well as for different mechanical characteristics of the ME receiver. ME (Red) and p METhe experimental measurements (circles) for (blue) show close agreement with the theoretical values ​​(solid lines) calculated from the equivalent circuit models of (a) a two-layer (mettuglass-PZT) ME receiver and (b) a three-layer (mettuglass-PZT-mettuglass) ME receiver. Figure 8(c) shows the fluctuating Q M and p for k ME,max This includes a 2D contour plot showing the theoretical values. Red circles represent data collected in this study using a dual-layer ME receiver, and black diamonds represent data from previous studies by our group of inventors. 28 Figure 8(d) shows the theoretical p ME,max Percentage error

number

[0080] Improvements in interfacial adhesion, clamping, and material thickness lead to increased power. Equivalent circuit model analysis identified three key factors that can be optimized to increase the power density of our ME receiver: interfacial adhesion, clamping, and material thickness. Based on these findings, the ME receiver was manufactured and tested using various methods to experimentally confirm that these factors indeed improve the performance of the ME receiver as predicted.

[0081] As shown in Figure 1 and Table 1, the model parameters k and Q M t m t p t total, and η are p ME,max These are ME material properties that can be optimized during manufacturing and clamping to increase the interfacial bonding coefficient (k), which is influenced by the adhesion between the Metglass layer and the PZT layer. The mechanical quality coefficient (Q) is also a factor of mechanical quality. M ) is affected by interfacial adhesion and clamping. Metoglass (t m ) and PZT(t p The thickness of both layers is the total thickness (t total This affects both the interfacial adhesion and the thickness ratio (η). Based on these dependencies, it was hypothesized that power density could be improved by experimentally improving the interfacial adhesion, clamping, and material thickness selection. [Table 1]

[0082] Interfacial bonding was optimized by fabricating ME receivers using new adhesives, resulting in higher output voltages. Based on previous research, seven epoxys were selected for testing: Hardman Double Bubble Red, M-Bond 43-B, Devcon 5 Minute, West System 105A, Epo-Tek H20E, 3M ScotchWeld DP460, and Masterbond EP30LV. Each epoxy was used to fabricate at least 90 5×2mm electrodes. 2 We manufactured ME receivers and measured the output voltage amplitude of each receiver at 1.5 mT.

[0083] Figure 9 shows data for optimizing the interfacial adhesion, clamping, and thickness of each layer for increased power. Figure 9(a) shows the ME receiver performance for seven different epoxies (n≧90 each). M-Bond epoxy yielded a higher voltage amplitude compared to all other epoxies (***p<0.001 for all pairs via Wilcoxon rank-sum test). Hardman epoxy yielded the lowest voltage amplitude. M-Bond epoxy also showed a lower standard deviation of voltage amplitude compared to the other epoxies, which is a consideration for manufacturing yield. Based on its high voltage amplitude and low standard deviation, M-Bond 43-B was selected for further study.

[0084] A new mechanical clamp package has been designed for ME receivers, and it has a mechanical quality factor (Q M This improved the Q ratio and subsequently increased the received power. In previous studies, an adhesive clamping method was used to connect the ME receiver to the device. This method involves coating the surface of the ME receiver with conductive silver epoxy, which dampens the mechanical vibrations of the receiver and thus lowers the Q ratio. M This brings about Q by minimizing attenuation. M To increase performance, this embodiment designed a mechanical clamping method utilizing conductive spring-loaded pins. This clamping method was applied to 9 × 3 mm of 267 μm thick PZT and 25 μm thick Metglass under a magnetic field of 0.3 mT. 2 A two-layer ME receiver was used for comparison with the previous method. In Figures 8(c) and 8(d), the mechanical clamping method was used for samples #1 to #3, and the adhesive clamping method was used for samples #4 to #7. Figure 9(b) shows the measured power and Q of the two clamping methods. M This shows that Q is achieved through a mechanical clamping method. M [Something] increased by 57%, and power increased by 67% (by an independent t-test, ***p<0.001).

[0085] Figure 9(c) shows the measured power from four different ME receiver configurations (configurations 1-4, each with n=3) as a function of magnetic field strength. Figure 9(d) shows an enlarged version of Figure 9(c) from 0-1mT.

[0086] By utilizing different thicknesses for the Metglass and PZT layers in the ME receiver of the present invention, the received power was also increased. To test various thickness parameters, four versions of the ME receiver (two two-layer configurations and two three-layer configurations) were manufactured. The maximum power received by each ME receiver (n=3) was measured with respect to magnetic field strength (Figures 9(c) and 9(d)). The three-layer receiver using 127 μm thick PZT received a maximum power of 9.78 mW at 0.6 mT, which is more than 250% greater than that of the two-layer ME receiver using 267 μm thick PZT (Figure 9(c)). This result is consistent with the predictions obtained from the equivalent circuit model analysis herein. It was also observed that the ME receiver began to saturate above 0.6 mT (Figure 9(d)). The equivalent circuit model accurately predicted the experimental results in the pre-saturation regime. Figures 9(c) and 9(d) compare the power at the optimal load resistance for each configuration.

[0087] High power density experimentally demonstrated through porcine tissue. The above results demonstrate that an optimized ME receiver can achieve high power density through tissue within human safety limits. Specifically, using an 8.0 mT magnetic field on the tissue surface, compliant with IEEE standard C95.1-2019, electric field safety limits for humans in unrestricted environments, a 5 × 2 mm sample was passed through exvivobuta tissue. 2 and 9×3mm 2 Power was transmitted wirelessly to the ME receiver.

[0088] Figure 10 shows results demonstrating the improved performance of the ME receiver following the build disclosed in this embodiment compared to other WPT techniques. To represent a range of implantation depths, the tissue thickness was varied from 1 cm to 5 cm between the transmitter and ME receiver (Tx-Rx distance) (Figure 10(a), (inset)). At each TX-RX distance, the maximum power with respect to the load resistance was measured and the corresponding power density was calculated. In Figure 10(a), the red and black lines represent 5 × 2 mm, respectively. 2 ME and 9×3mm 2This diagram represents an ME receiver. The dots represent the average power density for each size, and the error bars indicate the standard deviation. The diagram shows a 5×2mm sample across a 1cm tissue. 2 and 9×3mm 2 The power density from the ME receivers was 3.1 mW / mm². 2 and 2.1 mW / mm 2 These resulted in power transfers of 31mW and 56mW, respectively.

[0089] Figure 10(b) shows a comparison between an ME receiver configured according to this embodiment and previously reported mm-sized bioelectronics wirelessly powered by ME, near-near-field inductive coupling (NIC), light, ultrasound, radio frequency (RF), and intermediate magnetic inductive coupling (MDF). The comparison focused on devices suitable for clinical use in that the transmitter power levels are within safety limits. While there are many examples of wireless power for freely moving animals, these demonstrations often use transmitter power levels that exceed IEEE safety standards for human use and / or transmitters that are too large to be comfortably worn. To directly compare the performance of different WPT modalities, the evaluated output power and power density were tens of milliseconds. 2 For devices having a receiver area in the range of , this has been demonstrated in in vivo animal models or ex vivo tissue experiments with a Tx-Rx distance of at least 1 cm. Notably, among the devices previously reported by the inventors, it has the highest power at 16 mm 2 Compared to other NIC driving devices, more than five times the power was achieved.

[0090] analysis This embodiment suggests that ME enables the maximum power density reported for mm-sized battery-free bioelectronics. This disclosure defines power density as the output power delivered to the load resistor divided by the footprint (length × width) of the ME receiver, as done in prior studies. In most applications, the footprint is several orders of magnitude larger than the cross-sectional area (thickness × width). Consequently, the footprint is a key factor when calculating power density, as this metric determines the amount of space required for the power-receiving element. To achieve higher power in smaller devices, this power density is a primary factor that would be sought to optimize. In this embodiment, an experimentally validated model for ME WPT is demonstrated and used to determine three key factors that can be optimized to achieve high power density: interfacial bonding, clamping, and material thickness selection. By optimizing these factors, each of the following can be achieved: 2 and 10mm 2 Using the ME receiver, power outputs of 56 mW and 31 mW were achieved through 1 cm of porcine tissue. This represents more than four times the power density and more than five times the power previously reported for bioelectronic devices of similar size at similar tissue depths. (Figure 10(b))

[0091] The disclosures described herein have many practical applications. For example, this study can be used as a guideline for the manufacture and packaging of ME receivers for applications that benefit from improvements or optimizations in power, size, and safety requirements. The equivalent circuit model used is accurate for ME receivers with lower magnetic field strengths (pre-saturation regime) (Figure 10(d)), but improvements in the pre-saturation regime also led to improvements in the saturation regime over other ranges. Additionally, the total power transmitted depends on the load resistance, which can be calculated from our model. As shown in Figure 7(d), the load resistance at which maximum power is achieved depends on η. At low η, power drops sharply at suboptimal load resistances, while at high η, power remains relatively constant at suboptimal load resistances. These findings convey a circuit design that prioritizes matching η and impedance. Furthermore, although we did not attempt to optimize the length and width of the material in this embodiment, these factors can also be studied using the disclosed model.

[0092] This example demonstrates that ME WPT is highly dependent on the material properties of the receiver, and therefore, advances and innovations in ME materials engineering can further improve the power density and total power transfer of ME receivers. Here, an order of magnitude improvement was observed compared to previously reported ME receivers.

[0093] Some embodiments of this disclosure include a system comprising one or more data processors and a non-temporary computer-readable storage medium that, when executed on one or more data processors, includes instructions causing one or more data processors to perform some or all of the methods disclosed herein.

[0094] In some embodiments, the system includes a non-temporary computer-readable storage medium that, when executed on one or more data processors, includes instructions causing one or more data processors to perform some or all of one or more of the methods disclosed herein and / or some or all of one or more processes. Some embodiments of the present disclosure include a computer program product tangibly embodied in the form of a non-temporary machine-readable storage medium that includes instructions configured to cause one or more data processors to perform some or all of one or more of the methods disclosed herein and / or some or all of one or more processes.

[0095] The terms and expressions used are for illustrative purposes only, not limiting purposes, and in using such terms and expressions there is no intention to exclude any equivalent of the exhibited and described features or any part thereof, but it is recognized that various modifications are possible within the scope of the claimed invention. Accordingly, although the claimed invention has been specifically disclosed by embodiments and optional features, it should be understood that optional features, modifications, and variations of the concepts disclosed herein can be made by those skilled in the art, and such modifications and variations are considered to be within the scope of the invention as defined by the appended claims.

[0096] This description provides only preferred exemplary embodiments and is not intended to limit the scope, applicability, or configuration of the disclosure. Rather, this description of preferred exemplary embodiments will provide a useful explanation for implementing various embodiments for those skilled in the art. It will be understood that various modifications can be made to the function and arrangement of the elements without departing from the spirit and scope set forth in the appended claims.

[0097] Specific details are provided in this description to allow for a full understanding of the embodiments. However, it will also be understood that embodiments may be practiced without these specific details. For example, circuits, systems, networks, processes, and other components may be shown as components of block figures so as not to obscure the embodiments with unnecessary details. In other examples, well-known circuits, processes, algorithms, structures, and techniques may be shown without unnecessary details to avoid obscuring the embodiments.

Claims

1. It is a system, It comprises a magnetoelectric (ME) component, and the ME component is One or more first layers, each of which contains a piezoelectric material, A system comprising one or more second layers, each of which contains a magnetostrictive material, and having a thickness ratio defined as the cumulative thickness of the one or more first layers to the cumulative thickness of the one or more second layers being 0.2 to 0.

5.

2. The system according to claim 1, wherein the magnetostrictive material includes metoglas.

3. The system according to claim 1, wherein the piezoelectric material comprises lead zirconate titanate (PZT).

4. The system according to claim 1, further comprising an energy collection circuit including a rectifier circuit, which is coupled to the ME component.

5. The system according to claim 4, wherein the rectifier circuit includes a full-bridge rectifier, and the energy acquisition circuit includes a power point tracking circuit.

6. The system according to claim 5, wherein the power point tracking circuit includes a maximum power point tracking circuit, and the energy acquisition circuit is configured to provide an optimal impedance for the magnetostrictive material over a range of workloads.

7. The system according to claim 4, wherein the rectifier circuit includes an active full-bridge rectifier, and the energy acquisition circuit includes a power point tracking circuit.

8. The system according to claim 7, wherein the power point tracking circuit includes a maximum power point tracking circuit, and the energy acquisition circuit is configured to operate at the maximum power point of the magnetostrictive material regardless of the workload of the system by tracking the half-open circuit voltages of the ME and DC-DC impedance tuning.

9. The energy collection circuit includes one or more PowerPoint tracking circuits, and the one or more PowerPoint tracking circuits, Adjust the output voltage for different voltage domains. Excess collected energy is stored in a storage element, and / or, The system according to claim 4, wherein when it detects that the power collected by the energy collection circuit falls below a threshold, it is configured to trigger the use of at least a portion of the stored excess collected energy.

10. The system according to claim 9, wherein the storage element includes a capacitor.

11. The system according to claim 9, wherein the storage element includes a battery.

12. The system according to claim 4, wherein the energy collection circuit includes a bidirectional DC-DC converter.

13. The system according to claim 4, wherein the energy collection circuit includes a unidirectional DC-DC converter.

14. The system according to claim 4, further comprising a storage element connected to the rectifier circuit.

15. The system according to claim 14, wherein the system is configured to store energy in the storage element when the maximum power detected by the system is greater than the load in the rectifier of the energy collection system.

16. The system according to claim 4, further comprising an open-circuit voltage sampler.

17. The system according to claim 16, wherein the open-circuit voltage sampler is configured to sample magnetoelectricity at the start of the power transfer phase to the system.

18. The system according to claim 1, wherein the system is an implantable bioelectronic device.

19. The system according to claim 18, wherein the system is a battery-free implant.

20. The system according to claim 18, wherein the total thickness of the implantable bioelectronic device is less than 1 mm.

21. The system according to claim 1, further comprising one or more electrodes configured to record electrical signals.

22. Capacitors and, Equipped with a switching circuit and further, The system according to claim 1, wherein the switching circuit is configured to dynamically change its connection with the capacitor.

23. The system according to claim 1, further comprising a low-noise amplifier.

24. The system according to claim 1, wherein the mechanical bond between the first layer of the one or more first layers and the second layer of the one or more second layers is configured to have an interfacial bonding coefficient of 0.42 to 0.

70.

25. The system according to claim 1, wherein the mechanical quality factor of the system is 43.2 to 75.

9.

26. The system according to claim 1, wherein the thickness of one or more second layers is 20 μm to 30 μm.

27. The system according to claim 1, wherein the thickness of one or more first layers is 100 μm to 150 μm.

28. The system according to claim 1, wherein the thickness ratio of the cumulative thickness of the one or more first layers to the sum of the one or more first layers and the one or more second layers is 0.70 to 0.95.

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