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Digital ballast

  • US 7,199,530 B2
  • Filed: 02/25/2005
  • Issued: 04/03/2007
  • Est. Priority Date: 05/31/2003
  • Status: Expired due to Fees
First Claim
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1. A ceiling fan, comprising:

  • a ceiling-mountable fan housing containing a fan motor, the ceiling mountable fan housing configured to receive at least one fluorescent lamp ballast, the fan motor and at least one fluorescent lamp ballast configured to be driven by a single line voltage;

    a plurality of fan blades coupled to the fan motor to be turned by the fan motor;

    at least one fluorescent lamp ballast contained in the fan housing; and

    at least one fluorescent lamp driven by said ballast,wherein the fluorescent lamp ballast comprises;

    a switching section generating an AC drive current for driving the fluorescent lamp;

    a switching section controller for supplying switching signals to the switching section to control the switching frequency of the switching section wherein the switching section controller includes a voltage controlled oscillator (VCO) supplying said switching signals to the switching section, VCO control logic supplying a VCO control signal to the VCO to control the frequencies of the switching signals supplied by the VCO in response to a lamp current feedback signal and a lamp current control signal, and a signal conditioner generating said lamp current control signal such that the lamp current control signal has a voltage corresponding to the pulse width of the pulse width modulated signal provided by the microcontroller; and

    a microcontroller providing a pulse width modulated signal to the switching section controller, wherein the microcontroller controls the pulse width of the pulse width modulated signal to control the drive current supplied by the switching section.

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