摘要 |
The pre-heating circuit is used for the filaments (E1,E2) of at least one fluorescent lamp (FL) operated via an electronic bias circuit with a current regulator (3) inserted between a DC source (2) and earth. A switched voltage source (TR,DW1,DW2,HS) coupled to the output (HBO) of the current regulator is activated during the pre-heating phase, with a pair of outputs connected in parallel to the lamp filaments. Pref. the switched current source has a transformer (TR) coupled to the current regulator with a primary winding (P) connected in series with a controlled switch (4,HS) and a pair of secondary windings (S1,S2) coupled in parallel to respective lamp filaments. |