Implantable PCB Testing via Extender Tabs
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Solution Overview
Problem
The challenge in constructing and testing printed circuit boards (PCBs) for implantable pulse generators (IPGs) lies in their small size, making electrical testing difficult before integration with other components, and the risk of component damage during handling, as well as the potential for short circuits due to severed traces exposed after singulation.
Innovation Solution
The PCB is formed as part of a larger test PCB with an extender portion and edge connector, allowing for pre-assembly testing and subsequent singulation with PCB tabs or recesses to prevent shorting with conductive structures, ensuring an offset distance and reducing the risk of mechanical shock and thermal expansion-induced shorts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the PCB is made small to fit the IPG, then the device size is reduced, but electrical testing becomes difficult before integration
Solution Approach 1:
The PCB is segmented into two parts: the final small IPG PCB and an extender portion. The extender portion provides additional space for edge connectors and testing access points, allowing comprehensive electrical testing while the final IPG PCB maintains its compact size for implantation.
Solution Approach 2:
The extender portion acts as an intermediary between the small IPG PCB and the testing equipment. It provides edge connectors that interface with test fixtures, enabling electrical testing of the compact PCB without requiring direct access to its limited surface mounting points.
2Reliability
If the PCB is handled separately before assembly, then testing is enabled, but component damage risk increases
Solution Approach 1:
The IPG PCB is merged with the extender portion to form a single test PCB assembly during manufacturing. This allows the compact PCB to be handled as part of a larger, more robust structure that includes the extender, reducing the risk of damage to delicate components during handling and testing operations.
3Ease of manufacture
If the PCB is singulated from the test PCB, then the final product is achieved, but exposed traces create short circuit risk
Solution Approach 1:
PCB tabs are formed at the severed edge before the PCB is fully assembled into the IPG. This preliminary action ensures that the tabs are already in place to protect exposed traces from shorting to conductive structures like feedthroughs, addressing the short circuit risk before assembly occurs.
Solution Approach 2:
The PCB is singulated (cut apart) from the extender portion after testing, separating the final IPG PCB from the temporary testing infrastructure. This extraction completes the manufacturing process while the previously formed tabs continue to protect the exposed traces from short circuits.
Data Source
AI summary
Designs and methods of construction for a printed circuit board (PCB) in an implantable pulse generator (IPG) are disclosed which facilitate IPG PCB testing while also providing for protection of IPG circuitry in a simple and cost effective manner. The IPG PCB is formed as part of a larger test PCB, which includes an extender portion with traces routing nodes of interest in the IPG PCB to an edge connector. IPG electronics are mounted or soldered to the IPG PCB, and then such electronics are tested via the edge connector. The IPG PCB is then singulated from the extender portion in a manner leaving one or more PCB tabs at the severed edge of the PCB. The PCB tab(s) extend from the severed edge, and create an offset distance preventing traces severed and now exposed at the severed edge from contacting and potentially shorting to conductive structures in the IPG.