Electronic battery feed circuit for telephone systems
US4612417A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 27, 1984 |
| Grant date | Sep 16, 1986 |
| Priority date | — |
| Expiry date | Jul 27, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M19/005
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Resistive circuits are provided at the input of an electronic battery feed circuit feedback path for lowering the voltage level of feedback signals to a metallic signal feedback portion and a common mode signal feedback portion so a common mode amplifier can be implemented in a much lower voltage technology than line amplifiers of the battery feed circuit. Additional resistive circuits at the feedback output apply metallic signals to complementary inputs of the tip and ring line amplifiers without requiring a phase splitting amplifier. In addition, signals derived from the feedback circuit are used to vary the supply voltage for the line feed circuit elements as a function of feedback signal level and to provide a common mode reference signal which causes the tip and ring amplifiers to be biased symmetrically with respect to ground and the variable negative supply.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.