US 6,801,420 · Granted 2004-10-05
The Potting Patent That Makes Medical Devices Fail Safely
This patent describes a clever way to protect electronic circuits by coating some parts in protective material while leaving other parts exposed. If something goes wrong—like moisture sneaking in—the unprotected part breaks first, safely shutting down the whole device instead of letting the dangerous part fail.
The plain-English version
What it protects
The claim covers a selective potting method where a power driver circuit is encapsulated in protective potting material while a controller remains unencapsulated. What's protected here is the specific arrangement of leaving the controller exposed so that if a contaminant-induced electrical fault occurs, it happens in the controller first, disabling the system safely, rather than damaging the protected power driver circuit.
Why it matters
For medical devices like insulin pumps (the assignee Medtronic Minimed is a diabetes care company), controlled failure is critical—you need the device to stop working safely rather than malfunction dangerously. By engineering the failure point strategically, manufacturers can ensure that moisture or contaminants disable the device predictably and safely instead of causing unpredictable electrical hazards. This approach protects patients while maintaining reliability.
Real-world use
An insulin pump exposed to sweat or water during daily use would fail by shutting down the controller first, rather than having the power circuit malfunction and deliver an incorrect dose.
Original USPTO abstract
A selectively protected electrical system includes or operates with a power source, a load, a power driver circuit for controllably transferring power from the power source to the load, the power driver circuit being encapsulated in a potting material, and a controller for enabling and disabling the power driver circuit, the controller being un-encapsulated by the potting material. If a contaminant induced electrical fault occurs in the selectively protected electrical system, the electrical fault is more likely to occur in the un-encapsulated controller, such that the selectively protected electrical system is disabled. The contaminant is inhibited from contacting and inducing an electrical fault in the power driver circuit, thus providing for a controlled failure of the selectively protected electrical system.
Patent details
- Publication number
- US 6,801,420
- Filing date
- 2001-12-08
- Grant date
- 2004-10-05
- Assignee
- Medtronic Minimed, Inc.
- Inventor(s)
- TALBOT CARY D., MOBERG SHELDON B., CAUSEY, III JAMES D., YONEMOTO JAY A.
- CPC class
- H02M7/003
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