Variable inductive power supply arrangement for cold cathode fluorescent lamps
US7723929B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Nov 27, 2007 |
| Grant date | May 25, 2010 |
| Priority date | — |
| Expiry date | Nov 27, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B41/2827
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A plurality of cold cathode fluorescent lamps (CCFLs) for a backlight of a display device are connected, each in series with a respective variable inductance, in parallel to an AC supply from a power converter. Each variable inductor comprises a first inductor in series with the CCFL, a second inductor inductively coupled to the first inductor, and an AC switch for selectively shorting the second inductor. A capacitor in parallel with the first inductor forms a resonant circuit tuned to the AC supply frequency when the switch is open. Each switch is opened and closed with a controlled duty cycle to provide individual control of an average current of each CCFL.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.