Regulated output current source for cordless telephones
US4558177A · kind A · utility
8Cited by
8References
7Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Mar 7, 1985 |
| Grant date | Dec 10, 1985 |
| Priority date | — |
| Expiry date | Mar 7, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B2203/5441
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A circuit for providing a constant current to an output stage of a cordless telephone transmitter using AC power lines as a transmission medium to maintain the RF component on the AC lines to within regulated limits. The RF component is sensed to provide a control signal to a voltage-responsive capacitor in a tuned circuit connected to a tuned coupling transformer between a modulating circuit and the transmitter output amplifier. When the RF component exceeds the current limit of 90 mA, the coupling transformer is detuned to maintain the RF current in the power lines to within the regulated limits.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.