Isolation Circuits for IMD Crosstalk Reduction
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Solution Overview
Problem
Implantable medical devices (IMDs) face issues with crosstalk between therapy and sensing modules due to shared components, leading to common-mode interference and shunt current, which can result in incorrect detection of physiological conditions and undesirable therapy delivery.
Innovation Solution
The implementation of isolation circuits that break or reduce the electrical path between therapy and sensing modules, using components like capacitors and switches to isolate the power source and create a high impedance path, thereby reducing common-mode interference and shunt current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If therapy and sensing modules share common power source and ground, then device complexity is reduced, but common-mode interference and shunt current increase causing incorrect sensing and undesirable therapy delivery
Solution Approach 1:
The patent divides the power distribution system into separate isolated paths for therapy and sensing modules. Each module receives power through its own isolation circuit, breaking the shared electrical path that causes crosstalk. This segmentation eliminates the common-mode interference while maintaining separate functional integrity of each module.
Solution Approach 2:
Isolation circuits serve as intermediary components between the power source and the therapy/sensing modules. These circuits include high-impedance paths and isolation barriers that prevent direct electrical coupling, thereby blocking the transmission of common-mode interference and shunt current while still allowing power transfer.
2Reliability
If isolation circuits are implemented between therapy and sensing modules, then common-mode interference and shunt current are reduced, but device complexity increases
Solution Approach 1:
The isolation circuits are designed to serve multiple functions simultaneously: they provide electrical isolation to block common-mode interference, enable power transfer between modules, and maintain ground reference stability. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity.
Solution Approach 2:
The patent employs high-impedance isolation paths and adjustable isolation parameters to optimize the balance between interference rejection and power efficiency. By carefully selecting isolation circuit parameters, the system achieves effective crosstalk reduction while minimizing the complexity overhead of the isolation infrastructure.
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 solution effectively minimizes crosstalk, allowing accurate sensing and therapy delivery by isolating the power source and reducing the impact of common-mode interference and shunt current, ensuring proper operation of IMDs.
Implementation Method 1
The at least one isolation circuit is configured to electrically isolate the power source from the neurostimulation module to reduce common-mode interference on the neurostimulation module. The common-mode interference is caused by the cardiac module delivering electrical stimulation therapy to the patient.
Implementation Method 2
The at least one isolation circuit is configured to electrically isolate the power source from the second module to reduce at least one of common-mode interference and shunt current on the second module. The at least one of common-mode interference and shunt current is caused by the first module delivering electrical stimulation therapy to the patient.
Data Source
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AI summary
The disclosure describes techniques of reducing or eliminating a commonality between two modules within the same implantable medical device. Each module within the implantable medical device provides therapy to a patient. The commonality between the two modules exists due to at least one common component shared by the two modules. The commonality between the two modules may create common-mode interference and a shunt current. In accordance with this disclosure, various isolation circuits located at various locations are disclosed to reduce or eliminate the commonality between the two modules. The reduction or elimination of the commonality between the two modules may reduce or eliminate common-mode interference and the shunt current.