Light emitting diode control device
US7049752B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Jan 21, 2004 |
| Grant date | May 23, 2006 |
| Priority date | — |
| Expiry date | Apr 16, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B45/10
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A control device of LEDs includes a lighting-up circuit and a lighting-out circuit, both of which generate pulse signals being pulse-width modulated by varying cycles and corresponding duty ratios based on an input signal during a start-up period and a falling period, respectively. The control device then provides LEDs with the electric current relative to the pulse signals. Both of the lighting-up circuit and lighting-out circuit vary the cycles and corresponding duty ratios of the pulse signals, so that a luminance variation characteristic of the LEDs becomes nonlinear, leading to being approximated to a luminance variation characteristic of an electric bulb.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.