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Discharge lamp control circuit with feedback loop to lower harmonic distortion

  • US 5,757,143 A
  • Filed: 11/12/1996
  • Issued: 05/26/1998
  • Est. Priority Date: 11/21/1995
  • Status: Expired due to Fees
First Claim
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1. A circuit arrangement for operating a discharge lamp with a high frequency current, comprising:

  • input terminals for connection to a source of low frequency supply voltage,rectifier means coupled to said input terminals for rectifying said low frequency supply voltage,a first circuit comprising a series arrangement of first unidirectional means, second unidirectional means and first capacitive means coupled to a first output terminal of said rectifier means and to a second output terminal of said rectifier means,inverter means shunting said first capacitive means for generating the high frequency current,a load circuit comprising a series arrangement of inductive means, second capacitive means and means for applying a voltage to the discharge lamp, said load circuit connecting a terminal of said inverter means to a first terminal between the first unidirectional means and the second unidirectional means, and a second circuit comprising third capacitive means for connecting the first terminal to the second output terminal, andwherein the first output terminal of the rectifier means is connected to a second terminal between the second unidirectional means and the first capacitive means by means of a third circuit comprising a series arrangement of third unidirectional means and fourth unidirectional means, and a third terminal between said third unidirectional means and said fourth unidirectional means is connected to a terminal that is part of the load circuit by means of a fourth circuit, and in that neither the first circuit nor the third circuit comprises inductive means.

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