Protection for retrofit light emitting diode tube
US10009975B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 12, 2014 |
| Grant date | Jun 26, 2018 |
| Priority date | — |
| Expiry date | Nov 12, 2034 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/30
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Light sources (1) such as retrofit light emitting diode tubes comprise light circuits (11) with light emitting diodes (12) and feeding electrodes (13, 14), terminals (21-24) for exchanging signals with ballasts (2, 3) or supplies (4, 5), and filament circuits (31, 41) for coupling the terminals (21-24) and the feeding electrodes (13, 14). The filament circuits (31, 41) comprise switch circuits (32) and trigger circuits (33) for in response to presences of frequencies in the signals bringing the switch circuits (32) into conducting modes to introduce relatively low impedances in the filament circuits (31, 41). In non-conducting modes the switch circuits (32) introduce relatively large impedances. This way, in case the light source (1) is connected to a high-frequency ballast (2), the switch circuit (32) is triggered and the light source (1) is normally activated. In case the light source (1) is connected to mains (4) or an external direct-current driver (5) or an electro-magnetic ballast (3), the switch circuit (32) is not triggered, and the light source (1) is not activated and protected against damage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.