(19)
(11) EP 1 133 215 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
07.01.2004 Bulletin 2004/02

(43) Date of publication A2:
12.09.2001 Bulletin 2001/37

(21) Application number: 01660040.5

(22) Date of filing: 02.03.2001
(51) International Patent Classification (IPC)7H05B 41/04
(84) Designated Contracting States:
AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR
Designated Extension States:
AL LT LV MK RO SI

(30) Priority: 06.03.2000 FI 20000505

(71) Applicant: Helvar Oy Ab
00380 Helsinki (FI)

(72) Inventors:
  • Viljanen, Teijo
    02700 Kauniainen (FI)
  • Luomala, Jukka
    01260 Vantaa (FI)

(74) Representative: LEITZINGER OY 
Tammasaarenkatu 1
00180 Helsinki
00180 Helsinki (FI)

   


(54) Method and ignition circuit for switching a high pressure lamp on and off


(57) The invention relates to a method and an ignition circuit for switching a high pressure lamp on and off. A load circuit is capable of being short-circuited by means of a switch (3), which is connected in series with a primary winding (1) of a pulse transformer (1, 2) and whose on-off control is also used for generating ignition voltage pulses through a secondary winding (2) to a lamp (L). Upon a controlled closing of the switch (3) conductively for an extended period of time, a current ballast (Lk) will be subjected to a through-going short-circuit current for the load circuit and the lamp voltage falls to such a low level that the lamp is turned off. This lamp turn-off function can be used both for switching off a normally burning lamp and for terminating an abnormal status of gas discharge of a lamp not ignited between ignition attempts, in order to give the lamp a chance to cool down prior to another ignition attempt.







Search report