Load control device for use with lighting circuits having three-way switches
US7847440B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 9, 2007 |
| Grant date | Dec 7, 2010 |
| Priority date | — |
| Expiry date | Apr 9, 2029 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02B20/40
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A smart dimmer for control of a lighting load from an AC power source can replace any switch in a three-way or four-way lighting control system. The smart dimmer can be connected on the line-side or the load-side of a three-way system with a standard three-way switch in the other location. According to one embodiment of the present invention, the dimmer includes two triacs to control the intensity of the connected lighting load. The dimmer preferably includes two gate drive circuits coupled to the gates of the triacs for rendering the triacs conductive each half-cycle of the AC power source. The gate drive circuits include sensing circuits for detect whether the gates currents are flowing after the triacs are rendered conductive. A controller is operable to determine the state of the lighting load in response to whether the gate current is flowing or not flowing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.