DC Power supply circuit for line interface circuits
US4562525A · kind A · utility
3Cited by
3References
8Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jul 9, 1984 |
| Grant date | Dec 31, 1985 |
| Priority date | — |
| Expiry date | Jul 9, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M19/005
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A circuit for supplying direct current to a line (a, b) from a battery via two supply resistors (RA, RB). Part of the current supplied by the battery flows in a secondary path including a resistor (R4) and a transistor (16), and is maintained at a constant value. A symmetrical and differential resistance bridge connected between the supply resistors and the line detects the transverse alternating current flowing into the battery, and means (15) are provided to cause the transistor to generate a negative-feedback alternating current whose value is adjusted to cancel said transverse alternating current.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.