Shared Coil Tank Circuit for Dual-Frequency IMD Telemetry and Recharge
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Solution Overview
Problem
Implantable medical devices (IMDs) face challenges in miniaturization due to the need for separate coils for telemetry and recharge applications, which occupy significant space and restrict the ability to use a single coil for both functions.
Innovation Solution
The use of shared tank circuits with dedicated coils or coil portions that can be activated for either telemetry or recharge functions, allowing the same coil to be used for both applications by switching between frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate coils are used for telemetry and recharge applications, then both functions can be adequately established, but the space occupied by the coils increases, restricting miniaturization
Solution Approach 1:
The patent merges the telemetry coil and recharge coil into a single shared coil structure. The coil is configured with multiple windings that can operate at different frequencies, allowing both telemetry and recharge functions to be performed by the same physical component, thereby reducing the overall space required in the IMD.
Solution Approach 2:
The shared coil is designed to serve multiple functions: it can operate as a telemetry coil at telemetry frequency and as a recharge coil at recharge frequency. This multi-functionality is achieved through frequency-selective circuitry that routes signals appropriately based on the desired operation, eliminating the need for separate dedicated coils.
2Area of stationary object
If a single coil is used for both telemetry and recharge, then device size is reduced, but the circuit complexity increases due to shared tank circuits and switching requirements
Solution Approach 1:
The circuit incorporates dynamic switching mechanisms that allow the single coil to be selectively configured for different frequencies and functions. Switches and variable capacitors enable the circuit to adapt its resonant frequency and impedance characteristics based on whether telemetry or recharge operation is required, managing the complexity through controlled adaptability.
Solution Approach 2:
The patent utilizes parameter changes in the circuit components, particularly capacitance values, to tune the resonant frequency of the shared coil for different operations. By varying the capacitive elements in the tank circuit, the same coil can be optimized for either telemetry frequency or recharge frequency, reducing the need for separate fixed-frequency circuits.
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 the miniaturization of IMDs by reducing the space required for coils, allowing a single coil to be used for both telemetry and recharge operations, thereby enhancing the device's compactness and efficiency.
Implementation Method 1
The inductive downlink is obtained by a coil within the IMD that is tuned to a telemetry frequency, e.g., 175 kilohertz, being emitted by a coil within the external device.
Implementation Method 2
the recharge energy may be received via inductive coupling. The external device has a coil tuned to a recharge frequency, e.g., 5 kilohertz
Data Source
AI summary
Implantable devices and related systems utilize coils or coil portions of a coil for inductive telemetry at one frequency and recharge at another frequency. The coils or coil portions are included in one or more tank circuits that share at least one node between the coils or coil portions. The recharge application may be provided with variations for aspects including power management and rectification. The telemetry application may be provided with variations for aspects including receiver connectivity for the downlink and coil driving for the uplink.