Methods and apparatus to improve efficiency in cold cathode fluorescent light controllers
US7903105B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 24, 2008 |
| Grant date | Mar 8, 2011 |
| Priority date | — |
| Expiry date | Jan 30, 2029 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G3/3406
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Methods and apparatus to improve efficiency in cold cathode fluorescent light (CCFL) controllers using a full bridge resonant implementation. The secondary of a transformer drives the CCFL, with the primary of the transformer being driven through a capacitor from a full bridge. The bridge alternately and repetitively connects the capacitor and primary between power supply connections, across one of the power supply connections, between the power supply connections with an alternate polarity and again across one of the power supply connections. Instead of switching from across one of the power supply connections to between the power supply connections when the primary current is near zero, a delay is intentionally imposed before switching. This significantly improves the operating efficiency of a backlighting system. In preferred embodiments, the delay is made power supply voltage dependent.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.