Restart circuit for multiple lamp electronic ballast
US8008873B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 28, 2009 |
| Grant date | Aug 30, 2011 |
| Priority date | — |
| Expiry date | Apr 27, 2030 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/00
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A restart circuit for causing an electronic ballast to perform a restart in response to reconnecting any lamp of a multiple lamp configuration of the electronic ballast to the electronic ballast is disclosed. The electronic ballast includes a filament health check circuit for providing a first current through a monitored filament of the lamps to a controller of the ballast. The controller restarts the electronic ballast when a determined ratio of the first current to a reference current indicates that the monitored filament has been disconnected or broken (i.e., the first current substantially decreases) and is subsequently replaced or reconnected to the ballast (i.e., the first current returns to a predetermined level). The ballast further comprises a dv/dt circuit for reducing the first current for a transient time period in response to reconnecting a filament other than the monitored filament to the ballast, causing the controller to restart the ballast.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.