High intensity discharge lamp ballast and lighting system

  • US 6,075,326 A
  • Filed: 04/20/1998
  • Issued: 06/13/2000
  • Est. Priority Date: 04/20/1998
  • Status: Expired due to Term
First Claim
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1. A ballast for a direct current high intensity arc discharge lamp comprising:

  • (a) starting circuits having an output producing high frequency alternating current starting voltage of at least ten times the nominal voltage of said lamp;

    (b) operating circuits including a source of direct current lamp energizing power interconnected with said lamp for providing operating power for energizing said lamp, said starting circuits and said source of direct current lamp energizing power being effectively connected in series;

    (c) control circuits interconnected with said starting and operating circuits;

    (d) means including said starting circuits for establishing an operating arc within said lamp;

    (e) means for monitoring levels of voltage and current through said arc; and

    (f) control means responsive to said voltage and current through said arc for maintaining the product of said voltage and said current substantially constant at predetermined selectable wattage levels.

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