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

• Main Authors: LYS IHOR A, DATTA MIKE
• Format: Patent
• Language: Chinese; English
• Published: 13.10.2010
• Subjects: BLASTING; ELECTRIC HEATING; ELECTRIC LIGHTING NOT OTHERWISE PROVIDED FOR; ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; HEATING; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATINGELEMENTS; LIGHTING; MECHANICAL ENGINEERING; NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; WEAPONS

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.