Automatic Charger for Implantable Medical Devices

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Solution Overview

Problem

Existing external chargers for implantable medical devices require additional hardware and are inefficient in automatically determining implant vicinity and initiating charging, especially when the implant battery is depleted, leading to potential misalignment and increased power consumption.

Innovation Solution

An improved external charger system that automatically detects the presence of an implant using existing circuitry, such as control circuitry and Load Shift Keying (LSK) demodulator, and generates short-duration charging fields in a standby mode to assess proximity, allowing for automatic charging without an on/off switch, and uses LSK reply signals or user movement signatures to confirm implant presence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If additional telemetry hardware is added to automatically detect implant vicinity, then automation is improved, but device complexity increases

Engineering Contradiction:
Improveautomatic implant detectionVSAvoidhardware complexity
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The charging coil is designed to serve dual functions: both wireless power transmission and implant detection. By utilizing the existing charging coil for both charging and detecting implant vicinity, the system achieves automatic detection without adding separate telemetry hardware, thus improving automation while avoiding increased device complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The detection function is merged with the existing charging circuitry. The system combines the charging coil and control circuitry to perform both power transmission and implant detection functions through a single integrated system, eliminating the need for additional dedicated detection hardware

Inventive Principle:
Principle #5Merging (Combining)

2Productivity

If continuous charging field is generated to ensure charging, then productivity is improved, but power consumption increases

Engineering Contradiction:
Improvecharging efficiencyVSAvoidcharger power consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The system generates the charging field periodically rather than continuously. The control circuitry activates the charging field only during detected implant proximity and charging needs, creating periodic charging pulses that maintain charging effectiveness while significantly reducing overall power consumption compared to continuous field generation

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system uses the implant's own battery status signals and proximity detection to control charging activation. When the implant is detected and indicates charging need, the system automatically activates charging; when not detected or charging complete, it automatically stops, making the system self-regulating without continuous power consumption

Inventive Principle:
Principle #25Self-service

3Ease of operation

If charging field is generated without implant presence detection, then ease of operation is improved, but harmful factors increase

Engineering Contradiction:
Improveautomatic chargingVSAvoidoverheating and misalignment
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary detection of implant vicinity and proper alignment before activating the charging field. The control circuitry first detects the implant's presence and position using the charging coil, then only after confirming proper alignment does it generate the charging field, preventing overheating and misalignment issues before they occur

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors implant proximity and charging status through the charging coil and control circuitry. This feedback mechanism allows the system to adjust or stop charging field generation based on real-time conditions, preventing harmful overheating while maintaining ease of automatic operation

Inventive Principle:
Principle #23Feedback

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

Enables efficient and automatic charging of implantable medical devices without additional telemetry hardware, reducing power consumption and preventing overheating, even when the implant battery is depleted, by using existing circuitry to detect and respond to the implant's presence.

Implementation Method 1

Power transmission from the external charger 50 to the IPG 10 occurs wirelessly and transcutaneously through a patient's tissue 25 via inductive coupling

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The magnetic field 96 induces a current in the charging coil 38 within the IPG 10

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3042695B1Automatic on-off charger for an implantable medical device
Publication Date: 2018.05.16 BOSTON SCI NEUROMODULATION CORP
  • EP3042695B1 patent drawingFigure 1A~1C
  • EP3042695B1 patent drawingFigure 2
  • EP3042695B1 patent drawingFigure 3

AI summary

The present invention relates to an external charger for charging a battery in an implantable medical device, comprising a coil; and control circuitry configured to automatically energize the coil to generate a charging field without initiation by a user, wherein the control circuitry comprises circuitry to periodically energize the coil to generate a first field; evaluate a parameter of the coil to determine if the external charger is possibly proximate to the implantable medical device during the generation of the first field; and energize the coil to generate the charging field when it is determined that the external charger is possibly proximate to the implantable medical device.