Electronic ballast for correcting asymmetrical current flow across a gas discharge lamp
US8330382B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jan 27, 2010 |
| Grant date | Dec 11, 2012 |
| Priority date | — |
| Expiry date | Oct 8, 2030 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/00
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An electronic ballast for powering a discharge lamp includes an asymmetry determination circuit functional to determine whether positive and negative polarities of an AC output current to the lamp are symmetrical. An inverter having a plurality of switching elements is coupled to a DC power source and converts the DC power to the AC output current. A control circuit is functional to control the plurality of switching elements dependent upon an operating mode and an output from the asymmetry determination circuit. The control circuit controls the switching elements in a normal mode upon receiving a determination of symmetrical current from the asymmetry determination circuit, and controls the switching elements in a restart mode for a predetermined period of time upon receiving a determination of asymmetrical current from the asymmetry determination circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.