Dimming ballast for compact fluorescent lamps
US6603274B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 2, 2002 |
| Grant date | Aug 5, 2003 |
| Priority date | — |
| Expiry date | Apr 2, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B45/355
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A fluorescent lamp ballast circuit including a phase cut dimmer connectable to a source of AC power, the selectable phase cut dimmer and an electronic switch having a trigger voltage and a conduction period, when the electronic switch triggers to the end of the half cycle, a rectifying and charging circuit coupled to the output of the phase cut dimmer for providing a DC voltage across a DC bus, a filter circuit receiving the output of said phase cut dimmer and converting the output to a control signal related to the firing angle of the electronic switch; an output stage coupled to the lamp, the output stage having at least one electronic switching device; the ballast control circuit including a control input for changing a frequency of said pulsed power signal, the control input being coupled to said control signal, the control signal varying in accordance with the firing angle of he electronic switch, thereby varying the brightness level of said fluorescent lamp.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.