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Methods and apparatus for controlling respective load currents of multiple series-connected loads

  • US 8,736,197 B2
  • Filed: 10/08/2008
  • Issued: 05/27/2014
  • Est. Priority Date: 10/09/2007
  • Status: Expired due to Fees
First Claim
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1. A lighting apparatus, comprising:

  • at least one first LED for generating first radiation having a first spectrum;

    at least one second LED for generating second radiation having a second spectrum different from the first spectrum, wherein the at least one first LED and the at least one second LED are electrically connected in series between a first node and a second node, and a series current flows between the first node and the second node when an operating voltage is applied across the first node and the second node;

    a controllable current path connected in parallel with the at least one second LED, the controllable current path including an energy storage device and a switch; and

    a switching power supply for providing power factor correction and the operating voltage, the switching power supply controlling the switch of the controllable current path to selectively divert at least a portion of the series current around the at least one second LED to the energy storage device, such that a first current through the at least one first LED and a second current through the at least one second LED are different,wherein the energy storage device subsequently provides the diverted portion of the series current to the at least one first LED.

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