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Fluorescent lamp controllers

  • US 4,952,849 A
  • Filed: 07/15/1988
  • Issued: 08/28/1990
  • Est. Priority Date: 07/15/1988
  • Status: Expired due to Term
First Claim
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1. A controller for a fluorescent lamp load, comprising:

  • DC-AC converter means having an input and an output, DC supply means coupled to said input, output circuit means coupled to said output and arranged for coupling to said fluorescent lamp load, and control means for controlling operation of said DC-AC converter and said DC supply means, said output circuit means including inductance means and resonant capacitor means forming a circuit which is resonant at no-load and load-condition resonant frequencies with loads equivalent to those respectively obtained prior to and after lamp ignition, said control means being arranged to operate in a lamp ignition phase to operate said converter at a frequency within a range offset from said no-load resonant frequency, and said control means being arranged to operate in an operating phase after lamp ignition to operate said converter in a frequency range offset in the same direction from said load-condition resonant frequency.

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