×

Automated Dimming Methods and Systems For Lighting

  • US 20100176733A1
  • Filed: 05/01/2009
  • Published: 07/15/2010
  • Est. Priority Date: 01/14/2009
  • Status: Abandoned Application
First Claim
Patent Images

1. A system for automatically adjusting a light source in response to changes in ambient illumination level, comprisingat least one photosensor positioned to receive illumination from an area;

  • a controller coupled to receive an illumination level signal from the photosensor and configured to generate a control signal varying with the illumination level;

    a ballast circuit configured to be coupled to enable receipt of a time-varying DC voltage at a first node with respect to a second node, said DC voltage varying at twice a line frequency, and said DC voltage being rectified from an AC voltage power source alternating at said line frequency, wherein the ballast circuit is configured to present the DC voltage varying at twice the line frequency across said first terminal and said second terminal of a bypass capacitor, wherein the ballast circuit is further configured to allow said DC voltage to drop to 15% or less of a peak value of said DC voltage every half cycle of the line frequency, said ballast circuit comprising;

    a first switch coupled to the first node operable to selectively couple the first node to a resonant circuit, the resonant circuit having a resonant frequency less than a first frequency and configured to be coupled to a light source, wherein the resonant circuit stores energy during a first portion of a cycle of the first frequency, and a second switch operable to selectively couple the resonant circuit to the second node during a second portion of the cycle of the first frequency;

    said first and second switches configured to be coupled to provide an operating voltage to a light source positioned to provide illumination to the area; and

    a dimming circuit coupled to the controller and to the ballast circuit, the dimming circuit configured to receive and modify an AC line voltage based on the control signal to produce the time-varying DC voltage.

View all claims
  • 2 Assignments
Timeline View
Assignment View
    ×
    ×