Controlled inverter-type fluorescent lamp ballast

  • US 6,121,733 A
  • Filed: 07/13/1994
  • Issued: 09/19/2000
  • Est. Priority Date: 06/10/1991
  • Status: Expired due to Fees
First Claim
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1. An arrangement comprising:

  • an AC source operative to provide an AC power line voltage at a pair of power line terminals;

    a gas discharge lamp having a pair of lamp terminals; and

    conditioner circuit connected between the power line terminals and the lamp terminals;

    the conditioner circuit being characterized by;

    (a) being operative to draw a low-frequency line current from the power line terminals;

    (b) including an inverter sub-circuit powered from a unidirectional voltage whose instantaneous absolute magnitude is equal to the larger of;

    (i) the absolute instantaneous magnitude of a substantially constant DC voltage; and

    (ii) the absolute instantaneous magnitude of a sinusoidal voltage whose peak absolute magnitude is higher than that of the substantially constant DC voltage;

    (c) being operative to draw current from the power line terminals even at times when the absolute instantaneous magnitude of the AC power line voltage is lower than that of the substantially constant DC voltage; and

    (d) supplying a high-frequency lamp current to the lamp terminals and thereby to the gas discharge lamp;

    the frequency of the high-frequency lamp current being substantially higher than that of the AC power line voltage;

    the crest factor of the high-frequency lamp current being equal to or lower than 1.7.

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