Electronic ballast with lamp flicker suppression during start-to-steady state transition
US8299723B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 27, 2009 |
| Grant date | Oct 30, 2012 |
| Priority date | — |
| Expiry date | Aug 6, 2030 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B41/388
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An electronic ballast is provided for powering a discharge lamp and suppressing lamp flicker during startup transition. A power converter receives DC input power and converts it into an AC power output. A resonant circuit is coupled with the lamp and also between output terminals of the power converter. A controller controls the power converter with respect to particular modes of operation. The controller in a starting operation sets the output frequency of the power converter to a predetermined start frequency upon lamp startup to make the lamp begin discharging. The controller shifts from the starting operation to steady-state operation by setting the output frequency of the power converter at a predetermined steady-state frequency lower than the start frequency. The predetermined start frequency is set to a frequency identical or close to 1/(an odd whole number) of the resonant frequency of the resonant circuit with the lamp unlit, and also to a frequency identical or close to the resonant frequency of the resonant circuit with the discharge lamp lit. The start frequency is sufficient to make the discharge lamp start discharging, and to raise a temperature of each electrode of t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.