External Charging Device for Implantable Medical Devices
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Solution Overview
Problem
Implantable medical devices face challenges in efficiently recharging their power sources without causing excessive heat transfer to patient tissue, leading to potential discomfort and reduced charging efficiency due to conservative charging methods that do not accurately account for resistive heat losses and electromagnetic energy absorption.
Innovation Solution
An external charging device estimates the energy transfer to patient tissue by calculating resistive heat losses and electromagnetic absorption, allowing for dynamic adjustment of charging power levels to ensure safe and efficient recharging of implantable medical devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If transcutaneous charging is performed via inductive coupling with high power levels, then charging speed and efficiency are improved, but excessive heat is transferred to patient tissue causing discomfort and safety concerns
Solution Approach 1:
The system continuously monitors the actual energy transferred to tissue during charging and uses this feedback to dynamically adjust the charging power level. The external charging device calculates estimated energy transfer based on measured parameters and modifies subsequent charging cycles to maintain safety while maximizing charging efficiency, resolving the contradiction between fast charging and heat management.
Solution Approach 2:
The charging system transitions from static, conservative power levels to dynamic, adaptive power control. The charging device adjusts power levels in real-time based on measured energy transfer characteristics, allowing the system to operate at optimal power levels that balance charging speed with tissue safety, rather than using fixed conservative limits.
2Object-affected harmful factors
If conservative charging methods are used to limit tissue heating, then patient safety is improved, but charging efficiency and speed are reduced
Solution Approach 1:
The system uses real-time feedback from energy transfer measurements to optimize charging parameters. By monitoring actual energy deposition in tissue and adjusting charging power accordingly, the system achieves both safe heat management and high charging efficiency, eliminating the need for conservative power limits that reduced productivity.
Solution Approach 2:
The system dynamically changes charging parameters (power level, pulse duration, frequency) based on measured tissue energy absorption characteristics. This allows optimization of the charging process to achieve maximum efficiency while maintaining safety, rather than using fixed conservative parameters that limited performance.
3Measurement precision
If the external charging device accurately calculates and monitors energy transfer to tissue, then charging safety and efficiency are improved, but device complexity increases
Solution Approach 1:
The system uses the existing charging device components and standard measurements to calculate energy transfer, rather than requiring separate complex measurement systems. The charging device leverages its own operational parameters and standard electrical measurements to derive energy transfer information, maintaining simplicity while achieving accurate monitoring.
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 approach enables faster and more complete recharging of implantable medical devices while minimizing tissue heating, reducing discomfort and extending device operational life.
Implementation Method 1
transcutaneous charging may be performed via inductive coupling between a primary coil in the charging device and a secondary coil in the implantable medical device. When a current is applied to the primary coil and the primary coil is aligned to the secondary coil, electrical current is induced in the secondary coil within the patient.
Implementation Method 2
determining, by a processor, an estimated power stored in the rechargeable power source during charging of the rechargeable power source, the estimated power stored being separate from a resistive heat loss of the rechargeable power source during charging of the rechargeable power source
Data Source
AI summary
Devices, systems, and techniques for estimating energy transfer to tissue of a patient during battery charging for an implantable medical device are disclosed. Implantable medical devices may include a rechargeable power source that can be transcutaneously charged. An external charging device may calculate an estimated energy transfer to tissue of the patient that may include a resistive heat loss from the rechargeable power source and/or electromagnetic energy transfer directly to tissue. Based on the estimated energy transfer, the external charging device may select a power level for charging of the rechargeable power source. In one example, the charging device may select a high power level when the estimated energy transfer has not exceeded an energy transfer threshold and select a low power level when the estimated energy transfer has exceeded the energy transfer threshold.