Koninklijke Philips Corporation N.V.

Alb IP Holding LLC

Alejandro Lopez

Towfiq M Chowdhury

Yuhong Fang

Feng Chen

Bruce Robeson Rhodes

George Grouev

Michael Z Gielniewski

Arun Ganesh

Sanjaya Kumar Pradhan

Sree Venkit

Techniques are described to allow a low-cost light fixture to produce light with a relatively high color rendering index (CRI) across a range of color temperatures. A rectified AC voltage may be provided to multiple groups of light-emitting diodes (LEDs) having characteristics related to a range of color temperatures and a target CRI level. The multiple groups of LEDs may be controlled based on a received control signal, such that the combined groups of LEDs produce combined light having a produced color temperature within the range of color temperatures, and having a produced CRI level that is approximately the target CRI level. In some implementations, the received control signal is modified by a modification circuit, and the multiple groups of LEDs may be controlled based on the modified control signal.

Color mixing for solid state lighting using direct AC drives

An electronic ballast and startup method including an electronic ballast operably connected to a lamp having a lamp filament, the electronic ballast having a timer () generating an inverter control signal () and a preheat control signal (); a converter () receiving AC power and generating DC power (); a self-oscillating inverter () receiving DC power () and being operable to provide lamp power () to the lamp, the self-oscillating inverter () being responsive to the inverter control signal (); and a filament preheater () receiving DC power () and being operable to provide filament power () to the lamp filament, the filament preheater () being responsive to the preheat control signal (). When AC power is initially applied, preheat control signal () directs the filament preheater () to provide filament power (), and inverter control signal () directs the self-oscillating inverter () not to provide lamp power ().

Electronic ballast and startup method

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Lake Zurich, IL, United States of America

Alejandro Lopez