Wireless Charger Alignment via Reflected Impedance Tactile Feedback
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Solution Overview
Problem
Current wireless chargers for implantable pulse generators (IPGs) in spinal cord stimulation systems face inefficiencies, improper alignment issues, and lack of proper charging termination, making them inconvenient for patients.
Innovation Solution
A wireless charger system that includes a charging coil, a reflected impedance sensor, and an alignment circuit with a vibrator to provide tactile feedback for optimal alignment and detect when charging is complete.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a percutaneous trial stimulator is implanted through the skin, then the insertion is easier and less invasive, but the stimulator tends to move from its original location and is considered temporary
Solution Approach 1:
The system transitions from a static percutaneous trial stimulator to a dynamic permanent implant system where the stimulator is moved to a stable subcutaneous pocket and secured with fixation mechanisms, allowing the system to adapt from temporary to permanent stable positioning
2Stability of the object's composition
If the IPG is implanted in the lower abdominal area, then the placement is more stable and effective, but the wireless charging alignment becomes more difficult for patients
Solution Approach 1:
The wireless charging system incorporates feedback mechanisms including audible tones and visual LED indicators that guide the patient in aligning the external charger with the implanted IPG, making the charging process intuitive and easy to perform despite the IPG's deep abdominal placement
Solution Approach 2:
The system replaces manual mechanical alignment methods with electromagnetic field-based wireless charging that uses automated alignment assistance through sensors and feedback signals, eliminating the need for precise manual positioning
3Use of energy by moving object
If current wireless chargers are used for the IPG, then charging can be performed, but the charging is inefficient and lacks proper termination detection
Solution Approach 1:
The wireless charging system uses reflected impedance sensing to continuously monitor the charging status and provide feedback to the external charger, enabling efficient power transfer and automatic termination when the battery is fully charged, preventing energy waste from overcharging
Solution Approach 2:
The system dynamically adjusts charging parameters such as power transfer rate and frequency based on real-time impedance measurements and battery charge level, optimizing charging efficiency at different stages of the charging process
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
The system ensures efficient and accurate charging by aligning the charger with the IPG through tactile feedback and detects the end of charging, enhancing user experience and preventing battery damage from overcharging.
Implementation Method 1
The charging coil is wirelessly coupled to a receiving coil of the IPG to charge the rechargeable battery
Implementation Method 2
The reflected impedance sensor is coupled to the charging coil to detect a reflected impedance of the charging coil
Data Source
AI summary
A wireless charger for inductively charging a rechargeable battery of an implantable pulse generator (IPG) is provided. The charging coil in the charger is wirelessly coupled to a receiving coil of the IPG to charge the rechargeable battery. The alignment circuit continuously detects a reflected impedance of the charging coil through a reflected impedance sensor, and controls a vibrator to output a tactile signal which is indicative of the alignment of the charging coil to the receiving coil based on the detected reflected impedance. Advantageously, the tactile feedback to the patient provides an optimal way to indicate the extent of the charger's alignment with the IPG.