Ballast with filament heating control circuit
US7187132B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Mar 30, 2005 |
| Grant date | Mar 6, 2007 |
| Priority date | — |
| Expiry date | May 3, 2025 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S315/04
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A ballast (10) for powering at least one gas discharge lamp (20) having lamp filaments (22,24) comprises an inverter (200), an output circuit (300), a filament heating control circuit (400), and a dimming control circuit (500). Filament heating control circuit (400) is coupled to the dimming control circuit and at least one of the inverter and the output circuit. During operation, filament heating control circuit (400) controls the inverter and output circuit such that heating of the lamp filaments is provided during a preheat mode that occurs prior to ignition of the lamp, and during a dimming mode that optionally occurs after ignition of the lamp and that includes operating the lamp at a current level that is substantially less than a rated normal operating current of the lamp. No heating of the lamp filaments is provided during a full-light mode that occurs after ignition of the lamp and that includes operating the lamp at a current level that is substantially equal to the rated normal operating current of the lamp.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.