Electronic ballast with lamp type determination
US7521876B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 9, 2004 |
| Grant date | Apr 21, 2009 |
| Priority date | — |
| Expiry date | May 27, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B41/2985
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An electronic ballast includes open circuit voltage regulation comprises an filament current sensing circuit 224 operably connected to an output of the electronic ballast and generating a sensed output voltage signal, and a regulating pulse width modulator U3 receiving the sensed output voltage signal and operably connected to control voltage at the output of the electronic ballast, the regulating pulse width modulator U3 having an output voltage threshold limit. The regulating pulse width modulator U3 limits the voltage at the output of the electronic ballast when the sensed output voltage signal exceeds the output voltage threshold limit. The regulating pulse width modulator U3 can limit the output voltage by limiting the pulse width to the high voltage driver and the resonant half bridge. The filament current sensing circuit 224 can sense the output voltage indirectly, such as by sensing tank current, or can sense the output voltage directly.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.