Global Patent Index - EP 1087644 A1

EP 1087644 A1 20010328 - Improvements in driving of discharge lamps in particular for vehicle headlamps

Title (en)

Improvements in driving of discharge lamps in particular for vehicle headlamps

Title (de)

Verbesserungen in der Steuerung von Entladungslampen, insbesondere in Fahrzeugscheinwerfern

Title (fr)

Perfectionnements à la commande de l'alimentation de lampes à décharge notamment de projecteurs de véhicule automobile

Publication

EP 1087644 A1 20010328 (FR)

Application

EP 00402459 A 20000906

Priority

FR 9912114 A 19990927

Abstract (en)

The incoming supply is received by a DC/DC converter (1), the input being derived through a switching transistor (Q1) which controls the primary of a transformer (T). The converter output forms the input to a DC/AC converter, supplying the lamp. This converter's bridge rectifier employs transistors switched at frequencies in the range 200-1000 Hz and gives rise to significant electromagnetic interference. The switching of the DC/DC converter transistor is controlled by a regulator (4). By suitably programming the latter, the power delivered to the lamp is modulated in a pseudo-random sequence by a fractional amount, e.g. plus or minus 500 mW on a mean power of 35 W, the resulting frequency spectrum spread substantially reducing the interference, typically by up to 8 dB. Opt., modulation is achieved by the analogue addition of a separately generated power increment/decrement at the output of the DC/DC converter.

Abstract (fr)

Selon le procédé pour la commande d'un dispositif d'alimentation d'une lampe à décharge notamment de projecteur de véhicule automobile, ledit dispositif d'alimentation comportant un convertisseur continu/alternatif, on module dans le temps la puissance d'alimentation fournie audit convertisseur continu/alternatif. La puissance d'alimentation fournie au convertisseur continu/alternatif est modulée selon une séquence pseudo-aléatoire. L'invention concerne également un dispositif d'alimentation qui met en oeuvre ce procédé. <IMAGE>

IPC 1-7

H05B 41/292

IPC 8 full level

H05B 41/24 (2006.01); H02M 7/537 (2006.01); H05B 41/16 (2006.01); H05B 41/292 (2006.01)

CPC (source: EP)

H05B 41/2928 (2013.01)

Citation (search report)

  • [XY] EP 0744883 A1 19961127 - PRAEZISA IND ELEKTRONIK [DE]
  • [X] EP 0785702 A2 19970723 - OSRAM SYLVANIA INC [US]
  • [Y] EP 0291223 A1 19881117 - EMI PLC THORN [GB]
  • [Y] EP 0944294 A2 19990922 - MATSUSHITA ELECTRIC IND CO LTD [JP]
  • [X] STORMBERG H -P ET AL: "EXCITATION OF ACOUSTIC INSTABILITIES IN DISCHARGE LAMPS WITH PULSEDSUPPLY VOLTAGE", LIGHTING RESEARCH AND TECHNOLOGY,GB,ILLUMINATING ENGINEERING SOCIETY, LONDON, vol. 15, no. 3, 1 March 1983 (1983-03-01), pages 127 - 132, XP002052920, ISSN: 0024-3426

Designated contracting state (EPC)

DE ES GB IT

DOCDB simple family (publication)

EP 1087644 A1 20010328; EP 1087644 B1 20061102; DE 60031620 D1 20061214; DE 60031620 T2 20070906; ES 2275478 T3 20070616; FR 2799062 A1 20010330; FR 2799062 B1 20011221; JP 2001157463 A 20010608; JP 4542251 B2 20100908; US 6556463 B1 20030429

DOCDB simple family (application)

EP 00402459 A 20000906; DE 60031620 T 20000906; ES 00402459 T 20000906; FR 9912114 A 19990927; JP 2000292475 A 20000926; US 67071100 A 20000927