Controlling circuit for a light emitting device
US8120274B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 26, 2009 |
| Grant date | Feb 21, 2012 |
| Priority date | — |
| Expiry date | May 25, 2030 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B45/50
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A controlling circuit and a controlling method are disclosed. The controlling circuit includes a plurality of switches and a comparator. The first terminals of the switches are respectively coupled to one of a plurality of LED channels. The switches are conducted according to a plurality of switching signals respectively, wherein the switching signals are asserted alternately. The first input terminal of the comparator is coupled to the second terminals of the switches and the second input terminal of the comparator receives a reference voltage for the comparator to compare the voltage of the first input terminal with the voltage of the second input terminal so as to output a comparison result. In this way, whether the LED channels work abnormally or not may be detected. In addition, the hardware cost may also be reduced by employing fewer comparators through a sharing mode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.