Method and driving unit for driving a gas-discharge lamp
US8217593B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 8, 2008 |
| Grant date | Jul 10, 2012 |
| Priority date | — |
| Expiry date | Oct 3, 2028 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/00
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
In this method an arc-length control value, indicating the current length of a discharge arc of the gas-discharge lamp (1), is monitored and the lamp (1) is driven in a first operation mode (OMP) with a first current wave-shape when the arc-length control value indicates that the arc-length is higher than a switching threshold, which first current wave-shape is selected to result in a tip (31) growing on an electrode (30) of the lamp (1), and the lamp (1) is driven in a second operation mode (OMn) with a second current wave-shape when the arc-length control value indicates that the arc-length is lower than a switching threshold, which second current wave-shape is selected such that the tip (31) on the electrode (30) is at least partly melted back. In this method an operating frequency of the lamp is switched from a first frequency value (fi) to a second frequency value (f2), which second frequency • (f 2) value is higher than the first frequency value (fi)′, if a first time criterion pertaining to a duration of driving of the lamp (1) in the second operation mode (OMn) is fulfilled and the operating frequency is switched from the second frequency value (f2) to the first frequency v…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.