Fluorescent lamp ballast with selectable power levels
US5592054A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 6, 1995 |
| Grant date | Jan 7, 1997 |
| Priority date | — |
| Expiry date | Sep 6, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B41/42
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Disclosed is a power-level selection circuit in combination with a lamp circuit including a fluorescent lamp having first and second cathodes with resistive-heating filaments each spaced at a respective end of a lamp tube; first and second power leads for respectively connecting the cathodes to an a.c. power source whose power can be selectively enabled and interrupted by a main power switch; and a ballast inductor in serial circuit with one of the power leads and including a plurality of filament-heating windings for supplying power to the cathodes. The power-level selection circuit is interposed between a first cathode and a filament-heating winding, and includes a power-receiving circuit coupled to the filament-heating winding to receive power therefrom. Further included is a filament-supply circuit for continuously supplying available power to the first cathode. A selectable-impedance circuit is serially coupled between the first power lead and the first cathode and is responsive to a predetermined duration of interruption of power from the a.c. source to the power leads for selecting a different impedance of the selectable-impedance circuit, thereby selecting a different power…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.