LED failure detection
US9341664B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 31, 2013 |
| Grant date | May 17, 2016 |
| Priority date | — |
| Expiry date | Feb 22, 2034 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B45/54
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A fault detecting circuit in a string of LEDs D1-Dc containing comparing operational amplifiers IC1/IC2 connected to a current source is divided into sections, D1-Da, D2-Db, and D3-Dc, wherein the common between the Da cathode and the D2 anode is connected to the noninverting-input of IC1, while the common between the Db cathode and the D3 anode is connected to the noninverting-input of IC2, and to the string D1-Db is connected in parallel to a divider comprising R1/R2, while the string comprising D2-Dc is connected in parallel to a divider comprising R3/R4, and the common of R1/R2 is connected to the inverting-input of IC1 and the common of R3/R4 is connected to the inverting-input of IC2, while the outputs of IC1/IC2 are connected to the bases of corresponding transistors T1/T2, whose emitters are connected to ground and collectors are connected to the voltage source and also to the output terminal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.