Discharge lamp ballast with feedback current control during an electrode heating operation
US8502475B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 24, 2010 |
| Grant date | Aug 6, 2013 |
| Priority date | — |
| Expiry date | Jun 9, 2031 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B70/10
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A discharge lamp ballast is provided with a feedback control operation to provide optimal lamp current flow during an electrode heating operation. A startup circuit coupled together with a discharge lamp between output terminals of a DC-AC power converter having a plurality of switches. The startup circuit generates a high voltage to ignite the lamp. A lamp current sensor detects an amplitude of an output current to the lamp. A control circuit controls the switches in accordance with each of a plurality of control operations including a startup operation to ignite the lamp using the high voltage generated by the startup circuit, an electrode heating operation wherein an operating frequency of the switches is controlled to set the amplitude of the detected output current to a predetermined target current amplitude, and a normal operation wherein the operating frequency is reduced to maintain stable lighting of the lamp.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.