| 摘要 |
A circuit for operating a lamp includes supply input terminals for connection to a supply voltage source and a transformer provided with a primary winding L1 and a secondary winding L2. A first branch has terminals (N1,N2) for holding the lamp and connects a first end of the secondary winding L2 to a second end thereof. A second branch comprising a series circuit of a switching element (Q1) and the primary winding L1 interconnects the supply input terminals. A control circuit (SC1) is coupled to a control electrode of the switching element for generating a control signal for rendering the switching element conducting and non-conducting, and thus generating a first current in the primary winding L1 and a second current in the secondary winding L2. The second branch comprises a series arrangement of the primary winding, the switching element (Q1), and the terminals (N1,N2) for connection to the lamp. The total lamp current is controlled via the switching element which passes only a portion of the lamp current.
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