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High-frequency power circuit for gas discharge lamps

  • US 4,988,920 A
  • Filed: 02/07/1989
  • Issued: 01/29/1991
  • Est. Priority Date: 02/08/1988
  • Status: Expired due to Term
First Claim
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1. A high frequency power circuit for energizing at least one gas discharge lamp with two filaments, said circuit being adapted to be supplied with power from a DC voltage source, said circuit comprising semiconductor switching elements and control means for the semiconductor switching elements, as well as a high frequency transformer having at least one primary winding which, in operation, is supplied with an AC voltage signal by the semiconductor switching elements, and having at least one secondary main winding and secondary auxiliary windings, said secondary auxiliary windings, in operation, energizing the filaments of the at least one gas discharge lamp, characterized in that the control means are adapted to disconnect in a stand-by mode, by at least one controllable switching means, the connection between the at least one secondary main winding and the at least one gas discharge lamp, and, in the stand-by mode, to supply such an AC voltage signal to the at least one primary winding that the filaments of the gas discharge lamp(s) are preheated through the secondary auxiliary windings.

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