Reforming wet-tantalum capacitors in implantable medical devices
US7131988B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 16, 2004 |
| Grant date | Nov 7, 2006 |
| Priority date | — |
| Expiry date | Apr 28, 2025 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61N1/3956
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Miniature defibrillators and cardioverters detect abnormal heart rhythms and automatically apply electrical therapy to restore normal heart function. Critical to this function, aluminum-electrolytic capacitors store and deliver life-saving bursts of electric charge to the heart. This type of capacitor requires regular “reform” to preserve its charging efficiency over time. Because reform expends valuable battery energy, manufacturers developed wet-tantalum capacitors, which are generally understood not to require reform. Yet, the present inventors discovered through extensive study that wet-tantalum capacitors exhibit progressively worse charging efficiency over time. Accordingly, to address this problem, the inventors devised unique reform techniques for wet-tantalum capacitors. One exemplary technique entails charging wet-tantalum capacitors to a voltage equal to about 90% of their rated voltage and allowing the charge to dissipate through system leakage for a period of time, before discharging through a non-therapeutic load.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.