Osram Sylvania Inc.

Kerry J Denvir

Ming Chu Li

Steven C Allen

Philip E Moskowitz

Fred L Palmer

Embodiments are disclosed for driving a multi-color solid state light source luminaire so as to maintain a color point as temperature varies within a given range. An array of solid state light sources includes two or more strings and is driven by a single constant current source. The array is topologically arranged to allow for control of the division of current between the strings of solid state light sources. In one such current-sharing scenario, the duty cycle of a switching control signal corresponds directly to the proportion of current that flows in one of two distinct strings of solid state light sources. Thermal feedback is used to control the duty cycle. In this way, the amount of current that flows in both strings may be adjusted as temperature changes.

Driving a multi-color luminaire

A driver circuit for a light source including one or more solid state light sources, a luminaire including the same, and a method of so driving the solid state light sources are provided. The driver circuit includes a rectifier circuit that receives an alternating current (AC) input voltage and provides a rectified AC voltage. The driver circuit also includes a switching converter circuit coupled to the light source. The switching converter circuit provides a direct current (DC) output to the light source in response to the rectified AC voltage. The driver circuit also includes a mixing circuit, coupled to the light source, to switch current through at least one solid state light source of the light source in response to each of a plurality of consecutive half-waves of the rectified AC voltage.

Driver circuit for solid state light sources

A light emitting diode (LED) controller for controlling a plurality of LED channels includes channel select circuitry, detection circuitry, and error processor circuitry. The channel select circuitry is configured to drive N&#x2212;1 LED channels of a plurality of (N) LED channels at a nominal modulation frequency and to selectively drive a selected one of the N LED channels at a probe modulation frequency. The detection circuitry is configured to receive a composite brightness signal corresponding to brightness signals from the N LED channels. The detection circuitry is further configured to filter the composite bright signal and generate a selected brightness signal corresponding to a brightness of the selected LED channel at the probe modulation frequency. The error processor circuitry is configured to compare the selected brightness signal to user defined and/or preset photometric quantities and generate a control signal for adjusting the brightness of the selected LED channel.

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Cambridge, MA, United States of America

Kerry J Denvir