Lamp bulb having integrated RFI suppression and method of restricting RFI to selected level
US5504395A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 4, 1994 |
| Grant date | Apr 2, 1996 |
| Priority date | — |
| Expiry date | Mar 4, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S323/908
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An incandescent lamp bulb which is driven by an electronic control module (ECM) and method of manufacture characterized in that an inductor comprising a magnetic element and a winding thereon is disposed within a screw shell base of the lamp bulb and surrounds the lamp exhaust tube therein. One end of the winding on the magnetic element is connected to a filament wire within the screw shell base and the other end of the inductive winding is connected to an output terminal of the ECM control module. In this manner, the inductor significantly reduces the di/dt rise time of voltage and current when a triac within the ECM module is driven to conduction on each one half cycle of the applied AC line voltage. This operation in turn produces a substantial reduction in radio frequency interference, both of radiation transmitted into space from the lamp bulb and by direct DC coupling back into the AC line voltage source. In a preferred embodiment, the di/dt rise time is calculated mathematically based on a Fourier series transformation of the current conducted through the filament by the triac.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.