EP 0201624 A3 19870325 - BALLAST CIRCUIT FOR A FLUORESCENT LAMP
Title (en)
BALLAST CIRCUIT FOR A FLUORESCENT LAMP
Publication
Application
Priority
- DE 3517297 A 19850514
- DE 3524681 A 19850711
Abstract (en)
[origin: EP0201624A2] The fluorescent lamp (14) is connected in a bridge circuit of electronic switches T1 to T4. This bridge circuit is supplied via a series circuit consisting of an electronic switching element (TS), a current sensor (I) and an inductor (L). The signals from the current sensor (I) are compared with threshold values in a comparator (16). The switching element (TS) is alternately opened and closed so that the lamp current (iL) remains constant within a predetermined band width. The reversing of the polarity of the lamp (14) is carried out by the control mechanism (15) at relatively large time intervals of e.g. one hour. The time integral of this current is formed during one half period of the lamp current. The current of opposite polarity is maintained until its integral has reached the same value. In this way, electrophoresis on the lamp 14 is avoided. The balanced circuit can be operated equally well at different supply voltages and with lamps of different power, without having to carry out any changeovers. <IMAGE>
IPC 1-7
IPC 8 full level
H05B 41/298 (2006.01); H05B 41/392 (2006.01)
CPC (source: EP)
H05B 41/2988 (2013.01); H05B 41/392 (2013.01)
Citation (search report)
- [A] US 3999100 A 19761221 - DENDY KING HUBERT, et al
- [A] US 4260932 A 19810407 - JOHNSON VANCE
Designated contracting state (EPC)
AT BE CH DE FR GB IT LI LU NL SE
DOCDB simple family (publication)
DOCDB simple family (application)
EP 85111393 A 19850910