Battery-Optimized Compensation System for Medical Implants
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Solution Overview
Problem
Battery-powered systems used for transmitting power to medical implants face rapid battery depletion and potential disconnection due to variations in the resonance frequency of the transmitting coil, caused by changes in inductance and capacitance, leading to high current demands and efficiency drops.
Innovation Solution
A control circuitry system that sets a reference resonance frequency for the transmitting coil to maintain an efficiency of at least 70% and current delivery below 96% of the maximum, using a sensor to detect divergence and adjust the resonance frequency through electrical components to optimize power stage efficiency and reduce battery drain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the transmitting coil operates at maximum power transmission, then power delivery to the medical implant is maximized, but battery depletion occurs rapidly and overcurrent protection may trigger
Solution Approach 1:
The system dynamically adjusts the operating point of the transmitting coil by varying the capacitance in real-time based on feedback about the coil's resonance frequency and impedance characteristics. This allows the system to operate at optimal power transmission efficiency without exceeding battery current limits, thereby extending battery life while maintaining adequate power delivery to the implant.
Solution Approach 2:
The patent changes the electrical parameters (capacitance values) of the transmitting coil system to optimize the operating point. By adjusting the capacitance to match the varying inductance of the coil, the system maintains resonant operation at different power levels, enabling efficient power transmission across a range of battery states and preventing both overcurrent conditions and premature battery depletion.
2Adaptability or versatility
If the resonance frequency of the transmitting coil varies due to changes in inductance and capacitance, then the coil acts as a variable load causing efficiency drops, but maintaining fixed frequency operation limits adaptability to changing conditions
Solution Approach 1:
The system employs feedback mechanisms to monitor the resonance frequency and impedance of the transmitting coil in real-time. Based on this feedback, the control circuitry automatically adjusts the capacitance values to maintain optimal resonant operation. This closed-loop control ensures the system adapts to changing inductance conditions while minimizing energy losses and maintaining high power stage efficiency.
Solution Approach 2:
The system transitions from static to dynamic operation by continuously adjusting the capacitance values in response to changing coil characteristics. This dynamic adaptation allows the transmitting coil to maintain resonant operation despite variations in inductance caused by flexing, temperature changes, or proximity to metal objects, thereby preventing efficiency drops while maintaining adaptability.
3Power
If battery-powered control circuitry drives high current through the transmitting coil, then power transmission is sufficient, but the battery depletes rapidly and may disconnect due to overcurrent protection
Solution Approach 1:
The system applies partial action by operating the transmitting coil at an optimized power level that provides sufficient power transmission to the medical implant without exceeding the battery's safe current output limits. By carefully controlling the operating point to achieve just enough power transmission rather than maximum possible power, the system prevents overcurrent conditions that would trigger protection mechanisms while maintaining reliable battery connection and adequate implant power supply.
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 extends battery life by minimizing power input while maintaining sufficient power transmission to the medical implant, avoiding rapid battery depletion and overcurrent protection issues.
Implementation Method 1
A current flowing through a coil produces a magnetic field, which, in turn, will induce a current in a second coil. A coil inside a medical implant can therefore act as a receiving coil, while a coil outside a patient's body can act as a transmitting coil.
Implementation Method 2
A sensor coupled to the circuitry determines divergence of a resonance frequency of the transmitting coil when flexed from a nominal resonance frequency of the transmitting coil
Data Source
AI summary
A housing placeable against skin of a subject includes a transmitting coil. Battery-powered control circuitry including a power stage transmits power to an implant by activating the power stage to drive a current through the transmitting coil to induce an induced current in a receiving coil of the implant. A sensor indicates divergence of a real-time resonance frequency of the transmitting coil with respect to a reference resonance frequency of the transmitting coil at which (a) efficiency of the power stage is at least 70% of a maximum efficiency as a function of the resonance frequency, and (b) the current driven through the transmitting coil is less than 960 of a maximum current drivable through the transmitting coil as a function of the resonance frequency. The circuitry reduces the divergence by tuning the resonance frequency of the transmitting coil. Other applications are also described.