Implantable Step-Down Charging Circuit for Fast Inductive Power
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Charging implantable medical devices with rechargeable batteries poses challenges in reducing charge time while maintaining heating below safety limits and complying with electromagnetic compatibility standards.
Innovation Solution
A charging circuit utilizing a secondary coil, AC-DC converter, and DC-DC step-down converter to efficiently transfer charge energy to the battery, with a controller adjusting charge current and voltage levels to optimize efficiency and minimize heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If higher power is transferred to reduce charge time, then charging speed is improved, but tissue heating increases beyond safety limits
Solution Approach 1:
The patent employs dynamic control of the resonant frequency matching between primary and secondary coils during the charging process. By continuously adjusting operating parameters to maintain optimal resonance conditions, the system maximizes power transfer efficiency at each moment, enabling higher effective charging power without proportionally increasing tissue heating, thus resolving the contradiction between charging speed and thermal safety
Solution Approach 2:
The system changes multiple operating parameters including frequency, voltage, and current waveforms to optimize the inductive power transfer. By operating at resonant frequencies and adjusting impedance matching dynamically, the system achieves higher power transfer efficiency, allowing faster charging while minimizing energy loss as heat in surrounding tissues
2Productivity
If higher power is transferred to reduce charge time, then charging speed is improved, but electromagnetic compatibility compliance becomes difficult to maintain
Solution Approach 1:
The patent utilizes periodic resonant oscillations at specifically selected frequencies to transfer power inductively. By operating at resonant frequencies that are optimized for both efficiency and electromagnetic compatibility, the system achieves high-speed charging while the periodic nature of the resonance allows for predictable electromagnetic emissions that can be managed to meet regulatory standards
Solution Approach 2:
The secondary coil acts as an intermediary that enables wireless power transfer without direct electrical connection. This intermediate inductive coupling mechanism allows power transfer while providing electromagnetic isolation between the external charger and the implantable device, facilitating both high charging speed and EMC compliance by containing electromagnetic fields within controlled pathways
3Power
If larger coils are used to increase power transfer capability, then charging power is improved, but device size increases
Solution Approach 1:
The patent achieves higher power transfer capability by changing operating parameters such as frequency and voltage rather than simply increasing coil size. By operating at resonant frequencies and optimizing the electrical parameters of existing coil dimensions, the system attains high charging power without proportionally increasing the physical size of the coils, thus resolving the contradiction between power capability and device compactness
Solution Approach 2:
The system employs resonant oscillation at specific frequencies to enhance power transfer efficiency. By exciting the coils at their resonant frequencies, the system achieves maximum power transfer with smaller coil dimensions, as the resonant effect amplifies the electromagnetic coupling efficiency, allowing high charging power without requiring larger coil structures
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 solution enables faster charging within safety and EMC compliance, allowing for smaller coil sizes and reduced charge times without excessive tissue heating.
Implementation Method 1
a secondary coil configured to receive charge energy inductively from a primary coil of an external charger device
Data Source
AI summary
An implantable device includes a chargeable energy storage cell and a charging circuit. The charging circuit includes a secondary coil configured to receive charge energy inductively from a primary coil of an external device, an alternating current to direct current (AC-DC) converter circuit to configured to produce DC charge energy using the received charge energy, and a DC-DC step-down converter circuit configured to apply a stepped down DC charge energy to the energy storage element.