White LED light emitting device driven directly by constant alternating current
US9386639B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 25, 2012 |
| Grant date | Jul 5, 2016 |
| Priority date | — |
| Expiry date | Mar 18, 2033 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B45/59
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The present invention discloses a white LED light emitting device driven directly by constant current in manner of being supplied with alternating current. N parallel branches, consisting of LED modules and constant current units which are in series connection with the LED modules, are connected to an output terminal of a rectification circuit, and by setting the current value, the turning-off voltage, and the turning-on voltage of the constant current unit of each branch, the periodic flickers generated due to changes in the voltage of the alternating current can be avoided. Because the current of each branch is constant, the changes in junction temperatures do not result in the current changing in LED, and the reliability is improved. Along with the increase of the number of the branches, the driving current waveform approximates a sine wave, and the power factor and the efficiency of the light emitting device are improved.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.