Magnetoelectric Stack for Bioimplant Energy Harvesting
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Solution Overview
Problem
Existing bioimplantable electronic devices face inefficiencies in energy transfer due to the quadratic scaling of energy with coil area, leading to poor recharging of small devices and orientation challenges in freely movable implants, limiting their application and longevity.
Innovation Solution
The use of a magnetoelectric conversion means with a three-dimensional geometry, comprising a stack of magnetoelastic and piezoelectric layers, applied to the casing of the device, allowing efficient energy harvesting from magnetic fields originating from multiple directions, thereby improving charging efficiency and design flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a flat rectangular or circular coil design is used for wireless charging, then the device structure is simple, but the energy transfer efficiency is poor especially for small footprint devices
Solution Approach 1:
The patent transitions from traditional flat 2D coil designs to a three-dimensional magnetoelectric stack structure. This stack comprises alternating layers of piezoelectric and magnetoelastic materials, creating a volumetric configuration that captures magnetic flux from multiple directions simultaneously, thereby dramatically improving energy transfer efficiency while maintaining manufacturing feasibility through layer-by-layer fabrication processes
Solution Approach 2:
The invention employs a composite magnetoelectric stack integrating piezoelectric layers (for electrical response) and magnetoelastic layers (for magnetic field interaction). This composite structure enables coupled magnetoelectric effects where magnetic field-induced strain in magnetoelastic layers transfers to piezoelectric layers, generating electrical energy more efficiently than conventional single-material coils
2Volume of moving object
If a small coil is used to reduce device size, then the device footprint is reduced, but the recharging capability is severely limited
Solution Approach 1:
By stacking multiple thin layers in the third dimension, the device achieves high energy transfer efficiency without increasing lateral footprint. The vertical stacking allows sufficient magnetoelectric material volume to be packed into a compact form factor, enabling effective wireless recharging in small implantable devices
Solution Approach 2:
The invention changes the geometric parameters from lateral expansion (2D coil area) to vertical stacking (3D layer thickness and number of layers). This parameter transformation allows the device to maintain small footprint while achieving adequate energy harvesting volume through increased layer count and optimized layer thickness
3Loss of energy
If the coil is oriented perpendicular to the applied magnetic field for maximum efficiency, then energy transfer is optimized, but this orientation is hard to achieve in freely moveable implantable devices
Solution Approach 1:
The magnetoelectric stack is designed with isotropic or multi-directional magnetic field sensitivity through careful selection of magnetoelastic material properties and layer orientation. This allows the structure to effectively convert magnetic flux regardless of the incident field direction, making the device equally efficient whether the magnetic field approaches from above, below, or at angles, thus accommodating freely moveable implantable applications
Solution Approach 2:
The patent employs spherical or rounded geometries in the magnetoelectric stack structure, which naturally distribute magnetic flux more uniformly from different directions compared to flat planar structures. This curved geometry enhances the device's ability to harvest energy regardless of orientation relative to the external magnetic field source
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enhances energy transfer efficiency, reduces the device size, and allows for reliable charging regardless of orientation, making it suitable for bioimplantation and other applications by converting magnetic fields into electrical energy effectively.
Implementation Method 1
magnetoelectric conversion means comprising at least one stack of at least one magnetoelastic layer and at least one piezoelectric layer
Implementation Method 2
the magnetoelastic layer and consequently the piezoelectric layer will be deformed resulting in the generation of an electrical current within the piezoelectric layer
Data Source
Figure 1~2
Figure 3
AI summary
The present application discloses an integrated circuit comprising a circuit portion (100) coupled between first and second power supply lines (110; 120); a first switch (115, 135) coupled between the first power supply line (110, 120) and the circuit portion (100) for disconnecting the circuit portion from the first power supply line during an inactive mode of the circuit portion; and an arrangement (315, 335, 410) for, during said inactive mode, providing the circuit portion (100) with a fraction of its active mode power supply at least when averaged over said inactive mode to prevent the circuit portion voltage to drop below a threshold value. The present application further discloses a method for controlling such an integrated circuit.