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

A lighting apparatus (100) includes one or more first LEDs (202) for generating a first spectrum of radiation (503), and one or more second LEDs (204) for generating a second different spectrum radiation (505). The first and second LEDs are electrically connected in series between a first node (516A) and a second node (516B), between which a series current (550) flows with the application of an operating voltage (516) across the nodes. A controllable current path (518) is connected in parallel with one or both of the first and second LEDs so as to at least partially divert the series current, such that a first current (552) through the first LED(s) and a second current (554) through the second LED(s) are different. Such current diversion techniques may be employed to compensate for shifts in color or color temperature of generated light during thermal transients, due to different temperature-dependent current-to-flux relationships for different types of LEDs.
Authors:
;
Publication Date:
OSTI Identifier:
1132607
Report Number(s):
8,736,197
12/681,631
DOE Contract Number:
FC26-06NT42932
Resource Type:
Patent
Resource Relation:
Patent File Date: 2008 Oct 08
Research Org:
Philips Color Kinetics Inc., Burlington, MA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING