Fluorescent lamp ballast dimming control cicuit
US5539284A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 29, 1994 |
| Grant date | Jul 23, 1996 |
| Priority date | — |
| Expiry date | Sep 29, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S315/04
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A dimming control circuit for connection to a nondimming ballast in a fluorescent lighting system is disclosed herein. The control circuit is switchably connected to a source of AC voltage within the lighting system, while the ballast includes terminals for connecting to a fluorescent lamp. A power control module within the control circuit is operative to conduct a controllable portion of the voltage waveform provided by the source of AC voltage to the ballast in accordance with a brightness control signal received by a phase control circuit. A turn-on module, operatively coupled to the power control module, operates to shunt current from the phase control circuit during a turn-on interval commencing upon connection of the dimming control circuit to the source of AC voltage in order that substantially the entire voltage waveform is provided to the ballast during the turn-on interval.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.