Neurostimulator Output Switching Circuitry Self-Test Mode
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Implantable medical devices (IMDs) lack effective self-test mode functionality that allows for the testing of output switching circuitry integrity and performance without being connected to an external load, such as a patient's tissue, which is essential for ensuring device reliability and safety.
Innovation Solution
The implementation of selectively connectable output switching circuitry with dual mode switches and stimulation engine selection switches within a hermetically sealed package, enabling a self-test mode through wireless communication links to establish internal circuit paths for measurement and testing, allowing for the assessment of switch elements and pulse current programmability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the IMO is hermetically sealed for reliability, then device protection is improved, but self-test capability deteriorates
Solution Approach 1:
The output switching circuitry is segmented into multiple independently controllable switch elements (first switch, second switch, third switch) that can be selectively activated. This segmentation allows the system to perform self-tests by activating specific switch combinations to create internal circuit paths without requiring external load connections, thus maintaining hermetic sealing while enabling comprehensive self-test functionality.
Solution Approach 2:
The system implements self-service through self-test mode functionality that allows the IMO to test its own output switching circuitry integrity and performance. The measurement circuit, in conjunction with the controllable switch elements, enables the device to autonomously verify its operational status without requiring external testing equipment or load connections, maintaining both hermetic sealing and self-diagnostic capability.
2Measurement precision
If external load connections are required for testing, then measurement accuracy is improved, but device complexity and ease of operation deteriorate
Solution Approach 1:
The system uses internal measurement circuits combined with selectively activatable switch elements to perform self-tests without external load connections. The switch elements can be controlled to create appropriate circuit paths that allow the measurement circuit to assess output switching circuitry integrity and performance internally, eliminating the need for external testing equipment and simplifying operation while maintaining measurement capability.
Solution Approach 2:
The output switching circuitry is designed with multi-functionality, serving both its primary function of driving electrodes during normal operation and its secondary function of enabling self-tests through internal circuit paths. The same switch elements (first, second, third switches) that control electrode connections also facilitate self-test mode by creating internal measurement paths, eliminating the need for separate testing hardware and improving ease of operation.
Data Source
AI summary
An implantable medical device (IMO) includes one or more stimulation engines (SEs) and selectively connectable output switching circuitry for driving a plurality of output nodes associated with a respective plurality of electrodes of the IMO's lead system when implanted in a patient. The output switching circuitry may be configured to facilitate self-test mode (STM) functionality in the IMO (e.g., when it is in a hermetically sealed package) by using a dual mode switch in series with a stimulation engine selection switch with respect to each output node in the output switching circuitry under mode selection control.