Electronic ballast having current waveform control within the half wave
US8076866B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 6, 2009 |
| Grant date | Dec 13, 2011 |
| Priority date | — |
| Expiry date | Aug 19, 2030 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/00
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Aspects of the invention include an electronic ballast and method for controlling current through a lamp to produce various current waveforms through the lamp. In one embodiment, the ballast samples and adjusts the current through the lamp on a micro-second time scale within each half-cycle of the current waveform (i.e., at least twice within a period of a reference waveform). The ballast can accommodate different lamp types, provide arbitrary current waveforms, operate a lamp at multiple power levels, and provide power to the lamp as a function of an operational state of a lamp. For example, in one embodiment, the ballast increases power to the lamp and adjusts the current waveform provided to the lamp as the lamp ages to minimize luminous flux loss caused by darkening of lamp walls and changes in lamp chemistry.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.