Osram Sylvania Inc.

Robert Martin

Nitin Kumar

Shashank Bakre

Daniel Marian

Arunava Dutta

Valery A Godyak

Markus Ziegler

Benjamin Alexandrovich

Jean F Rouleau

Aline Tétreault

A ballast for energizing a lamp at a lighting level selected from a plurality of lamp lighting levels. The ballast includes a buck converter circuit configured to receive a DC voltage signal having a substantially constant magnitude. The buck converter circuit has a duty cycle for generating a lamp voltage output signal from the DC voltage signal. The lamp voltage output signal has a magnitude that is varied by the duty cycle to energize the lamp at the plurality of lamp lighting levels. A controller is configured to receive a dim input signal indicative of the selected lamp lighting level and to provide a control signal to the buck converter circuit as a function of the dim input signal. The control signal indicates a particular duty cycle corresponding to a lamp voltage output signal having a magnitude for energizing the lamp at the selected lamp lighting level.

Dim mode start for electrodeless lamp ballast

A electrodeless lamp including a fluorescent discharge vessel, a tip, an amalgam, a lamp core, and a heater. The vessel contains a gas having a partial vapor pressure and a fluorescent material. The tip has an inner end engaging the vessel, and an opening in communication with the gas. The amalgam is positioned within the opening, in heat transfer relation with the tip. When the temperature of the amalgam decreases, mercury vapor in the gas condensates onto the amalgam, causing a decrease in the partial vapor pressure of the gas. The opposite occurs when the amalgam temperature increases. The lamp core generates a magnetic flux, causing an electrical discharge in the gas. The heater includes a positive temperature coefficient connected to a winding of the lamp core. The heater is in heat transfer relation with the tip and heats the tip when the electrodeless lamp is in a dimming mode.

Amalgam tip temperature control for an electrodeless lamp

A lamp assembly adapted to operate as one of a total number of lamp assemblies that are connected together in series and connected to a ballast. The lamp assembly comprises an electrodeless, closed-loop, tubular lamp envelope enclosing mercury vapor and a buffer gas, and a transformer core disposed around a portion of the lamp envelope. An input winding is disposed on the transformer core so that it has a particular number of turns, N. An auxiliary winding is disposed on the transformer core so that it has a particular number of turns, N. The auxiliary winding is adapted to connect to the ballast and to couple with the input winding. The ratio of the particular number of turns Nto the particular number of turns Nis substantially proportional to the total number of lamp assemblies that are adapted to operate in series together.

Power splitter circuit for electrodeless lamp

An electrodeless lamp (), wherein the lamp comprises a closed-loop, tubular lamp envelope () with parallel cylindrical glass tubes () containing an arc generating and sustaining medium, means () in the form of magnetic toroids for energizing the medium; and a reflector coating () associated with the envelope () and affixed thereto. In a preferred embodiment of the invention the reflector coating () is on the internal surface () of the envelope and comprises a layer of a reflective m, such as alumina. Alternatively, the reflective coating () can be applied to the external surface of the envelope.

Electrodeless lamp with incorporated reflector

A mounting assembly () for an electrodeless 1 amp (). The mounting assembly () comprises a fixture housing () having an inner surface () and an outer surface (). The fixture housing is preferably made from aluminum. Spaced-apart heat sinks () are affixed to the inner surface () of the fixture housing (). A reflector (), which is preferably concave, as is the fixture housing, is positioned within the fixture housing (). The reflector () contains two apertures () that are aligned with the heat sinks (). Thermal insulators () are positioned in the apertures and surround the heat sinks, thus thermally isolating the reflector from the heat sinks. The lamp () is mounted in the fixture housing by attaching brackets (), which surround the ferrite transformer cores of the lamp, directly to the top surfaces of the heat sinks (). Mounting is preferably accomplished by having threaded holes formed in the heat sinks and fixing the brackets in place via screws through the legs () and screw receiving slots ().

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Nicholasville, KY, United States of America

Robert Martin