External Charger Alignment and Centering for Implantable Medical Devices
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Solution Overview
Problem
Existing wireless external chargers for implantable medical devices face inefficiencies in power transmission due to poor alignment between the charging coil and the implantable medical device, leading to reduced coupling and longer charging times, which can result in increased power consumption and potential patient safety risks.
Innovation Solution
An external charger equipped with concentric sense coils and control circuitry that determine the position of the charging coil relative to the implantable medical device, providing alerts and adjusting the magnetic field to ensure optimal alignment and centering, thereby improving coupling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If wireless power transmission is used to charge the implantable medical device, then convenience and patient safety are improved, but power transmission efficiency deteriorates due to poor alignment between charging coil and device
Solution Approach 1:
The patent implements feedback mechanisms including alignment detection circuitry that monitors the positional relationship between the external charger and implantable device, providing real-time feedback signals to guide proper alignment. This feedback system enables the charging process to maintain optimal efficiency by detecting and correcting misalignment conditions.
Solution Approach 2:
The patent employs preliminary alignment actions before power transmission begins. The system performs initial positioning verification and alignment adjustments prior to initiating wireless charging, ensuring that the charging coil and device are properly aligned to maximize power transfer efficiency from the outset.
2Loss of energy
If alignment detection and adjustment mechanisms are added to the external charger, then power transmission efficiency is improved, but device complexity increases
Solution Approach 1:
The patent integrates multiple functions into unified components. The external charger combines power transmission, alignment detection, positional monitoring, and adjustment capabilities within a single integrated system, reducing overall complexity despite the added functionality. Components serve multiple purposes, such as using detection circuitry that also provides charging control.
Solution Approach 2:
The patent merges alignment detection and power transmission functions into a coordinated system. The detection circuitry, control logic, and power delivery mechanisms are combined and synchronized to operate as a unified charging system, eliminating the need for separate independent subsystems and reducing overall device complexity.
3Loss of energy
If proper alignment and centering are ensured during charging, then power transmission efficiency is improved, but charging time increases due to alignment adjustment procedures
Solution Approach 1:
The patent performs alignment verification and adjustment as preliminary actions before the main charging process begins. By completing positioning optimization upfront, the system ensures efficient power transmission throughout the charging duration, preventing energy loss that would occur with mid-charging realignment interruptions.
Solution Approach 2:
The patent maintains continuous power transmission during the charging process by establishing proper alignment before charging begins and maintaining that alignment throughout. This continuous operation avoids interruptions and time losses associated with stopping and resuming charging during alignment adjustments.
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
Enhances charging efficiency by ensuring proper alignment and centering, reducing power consumption and minimizing the risk of overheating or injury to the patient, while maintaining effective battery charging and data transmission.
Implementation Method 1
Power transmission from the external charger 50 to the IMD 10 occurs wirelessly and transcutaneously through a patient's tissue 25, via inductive coupling. Primary charging coil 52 in the external charger 50 is energized via charging circuit 64 with an AC current, Icharge, to create an AC magnetic charging field 66.
Implementation Method 2
at least one sense coil, wherein each at least one sense coil is concentric with the charging coil and comprises one or more turns, each turn having a constant radius, wherein each at least one sense coil is configured to be induced by the magnetic field with an induced signal affected by a position of the charging coil with respect to the IMD
Data Source
Figure 1A~1C
Figure 2~3
Figure 4A~4C
AI summary
A charging system for an Implantable Medical Device (IMD) is disclosed having a charging coil and one or more sense coils. The charging coil and one or more sense coils are preferably housed in a charging coil assembly coupled to an electronics module by a cable. The charging coil is preferably a wire winding, while the one or more sense coils are concentric with the charging coil and preferably formed in one or more traces of a circuit board. One or more voltages induced on the one or more sense coils can be used to determine whether the charging coil is (i) centered, (ii) not centered but not misaligned, or (iii) misaligned, with respect to the IMD being charged, which three conditions sequentially comprise lower coupling between the charging coil and the IMD. A charging algorithm is also disclosed that control charging dependent on these conditions.