EP 0429716 B1 19930721 - ELECTRONIC BALLAST FOR FLUORESCENT LAMPS
Title (en)
ELECTRONIC BALLAST FOR FLUORESCENT LAMPS
Publication
Application
Priority
EP 89122189 A 19891201
Abstract (en)
[origin: US5049783A] In an electronic ballast for at least one fluorescent lamp equipped with heatable electrodes, the heatable electrodes must be adequately preheated before the actual ignition of the fluorescent lamp. Given a high-frequency preheating of the heating electrodes that is usually employed and given the utilization of a frequency shift of the high-frequency of the D.C.-A.C. converter, relatively long preheating times on the order of magnitude of >1.2 second result. In order to be able to significantly reduce the preheating tifme below 1 second, it is proposed that a D.C. path be provided wherein the heating electrtodes are connected in series with the secondary winding at the secondary side of a transformer and to connect this D.C. path to the operating D.C. voltage during the preheating phase via controlled switches.
IPC 1-7
IPC 8 full level
H05B 41/295 (2006.01)
CPC (source: EP US)
H05B 41/295 (2013.01 - EP US); Y10S 315/05 (2013.01 - EP US)
Designated contracting state (EPC)
BE DE FR GB IT
DOCDB simple family (publication)
EP 0429716 A1 19910605; EP 0429716 B1 19930721; DE 58904984 D1 19930826; US 5049783 A 19910917
DOCDB simple family (application)
EP 89122189 A 19891201; DE 58904984 T 19891201; US 60481190 A 19901029