Surge protection data access arrangement (DAA)
US6061445A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 15, 1997 |
| Grant date | May 9, 2000 |
| Priority date | — |
| Expiry date | Sep 15, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M3/18
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
An improved surge protection circuit for withstanding surges is provided. A first node is provided for coupling to a tip lead, and second node is provided for coupling to a ring lead. The surge protection circuit has a first current path for turning on a first transistor, and a second current path for redirecting current from the remaining excess surge energy from one lead to the other lead. The first current path further includes a first sub-path to direct the initial voltage surge to the base electrode of the first transistor to cause the first transistor to turn on hard. The second sub-path redirects current from the initial excess surge energy from the voltage surge to a capacitor prior to the time before the first transistor is fully turned on, so as to protect the base-emitter junction of a second transistor from being reverse biased. The second current path according to the present invention includes the first transistor and a resistor having a first terminal coupled to the emitter electrode of the first transistor and a second terminal coupled to the second node. When the first transistor is fully turned on, the remaining excess voltage is redirected from the tip ring to th…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.