Ballast circuit
US10015851B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jul 27, 2015 |
| Grant date | Jul 3, 2018 |
| Priority date | — |
| Expiry date | Jul 27, 2035 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/30
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A ballast circuit suitable for driving an LED or similar load, comprises a primary switch mode converter, means for measuring a modulation, such as a phase cut, as used for dimming light levels, on an input AC supply, a current regulator positioned in series with the load, and a feedback controller for controlling operation of the switch mode controller based upon measured modulation levels. The feedback controller is adapted to interrupt normal switching of the switch mode converter if modulation levels detected lead to the ballast working at a lower than desired efficiency (deep dimming), or if voltage levels across the current regulator are higher than desired. The feedback controller may have a further feedback means for controlling switch mode parameters during lower levels of modulation (shallow dimming). The circuit allows large dimming levels to be achieved without generating appreciable light flicker in the load.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.