Passive Energy Harvesting for Implantable Device Data Retrieval
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Solution Overview
Problem
Implantable medical devices with depleted power sources cannot be interrogated for information retrieval, limiting the ability to understand failure modes and performance issues, especially for devices that cannot be explanted.
Innovation Solution
A passively energized circuit with an energy harvesting component allows for remote powering of the implantable medical device, enabling memory-to-memory transfer of information to a non-volatile memory, even after the internal power source is depleted, using an external device for communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the implantable medical device uses a non-rechargeable internal battery to function continuously over a long period, then the operational lifetime of the device is extended, but the device cannot be interrogated for information retrieval after the battery is depleted
Solution Approach 1:
The device performs preliminary actions by continuously updating and storing device status information in non-volatile memory during its operational lifetime. This ensures that all critical information is captured and preserved before battery depletion occurs, making it accessible later through the passive energy harvesting mechanism.
Solution Approach 2:
The patent introduces an intermediary mechanism consisting of a passive circuit with energy harvesting capability that acts as a bridge between the depleted device and the external programmer. This intermediary allows information retrieval without requiring active power from the implanted device, resolving the contradiction between long battery life and post-depletion accessibility.
2Adaptability or versatility
If the implantable medical device is intended to be physically inaccessible and not explanted, then the device can remain implanted indefinitely, but it becomes impossible to retrieve any desired information after power source depletion
Solution Approach 1:
The device provides self-service functionality by incorporating a passive energy harvesting circuit that can be activated by an external programmer. This allows the device to retrieve and transmit its own stored information without requiring surgical explantation or physical access, enabling permanent implantation while maintaining information accessibility.
Solution Approach 2:
The patent replaces the mechanical/surgical approach (explantation for information retrieval) with an electromagnetic field-based approach. The external programmer uses electromagnetic fields to wirelessly transfer energy to the passive circuit and retrieve information, eliminating the need for physical device removal.
3Reliability
If conventional processes rely on returned implantable medical devices to understand failure modes, then information can be accessed, but the device must be explanted and returned, which is not feasible for future devices
Solution Approach 1:
The passive energy harvesting circuit serves as an intermediary that enables failure mode analysis without requiring device return. The circuit allows the external programmer to interrogate the device in situ, transferring energy wirelessly to power the communication circuitry temporarily for information retrieval, thus maintaining reliability analysis capability while eliminating the complex return process.
4Loss of energy
If the device cannot be interrogated via telemetry after battery depletion, then power consumption is minimized, but the ability to monitor device performance and identify issues is lost
Solution Approach 1:
The device employs periodic action by using brief, intermittent activation of the passive circuit through external electromagnetic field pulses. The external programmer provides short bursts of energy to power the communication circuitry only when information transfer is needed, minimizing overall power consumption while enabling periodic performance monitoring and information retrieval throughout the device's life and after depletion.
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
Enables the retrieval of device status and failure modes prior to battery depletion, ensuring that critical information is accessible indefinitely, facilitating monitoring and maintenance of implantable medical devices without the need for physical access.
Implementation Method 1
An energy harvesting circuit is provided for sourcing energy from an external device to power the passively energized circuit
Data Source
AI summary
Techniques for retrieving information from an implantable medical device (IMD) having a depleted internal energy source such as a non-rechargeable battery are disclosed. The IMD is powered by and communicates with an external interrogation device to access a memory location of the IMD and for transfer of the information in the memory location to the external interrogation device subsequent to depletion of the internal energy source. In an embodiment, the memory location is included in a non-volatile memory component of the IMD to maintain the information stored in the memory component.