Apparatus and method for regulating white LEDs
US7948455B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 20, 2005 |
| Grant date | May 24, 2011 |
| Priority date | — |
| Expiry date | Jul 22, 2028 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02M3/1582
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The present invention is an apparatus for driving white LEDs. The apparatus includes a switchable current sink, a DC-DC converter and a reference circuit. The DC-DC converter provides a driving voltage to a plurality of LEDs. The switchable current sink regulates currents through the plurality of LEDs, and the switchable current sink further provides a first reference voltage and outputs a plurality of voltage drops. The reference circuit receives the first reference voltage and the plurality of voltage drops to provide a second reference voltage to the DC-DC converter. The DC-DC converter adjusts the driving voltage provided to the plurality of LEDs according to the second reference voltage. In this way, the driving voltage is regulated to a minimum possible value and consequently the voltage drops across the switchable current sink is minimized. Hence, the LED driving system maintains higher efficiency.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.