CIRCUIT AND METHOD FOR INDEPENDENT CONTROL OF SERIES CONNECTED LIGHT EMITTING DIODES

Described herein is a circuit and method for independent control of series connected light emitting diodes (LEDs). The circuit includes a first light emitting diode (LED) connected in series with a second LED. A current source is connected in series with the first LED and the second LED and a shunt...

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Bibliographische Detailangaben
Hauptverfasser:	TOFILESCU, Pompilian, ERMILOV, Alexander
Format:	Patent
Sprache:	eng ; fre ; ger
Schlagworte:	BASIC ELECTRONIC CIRCUITRY ELECTRIC HEATING ELECTRIC LIGHTING NOT OTHERWISE PROVIDED FOR ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR ELECTRICITY PULSE TECHNIQUE
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Beschreibung
Zusammenfassung:	Described herein is a circuit and method for independent control of series connected light emitting diodes (LEDs). The circuit includes a first light emitting diode (LED) connected in series with a second LED. A current source is connected in series with the first LED and the second LED and a shunt circuit is connected in parallel with the first LED and the second LED. The shunt circuit includes a pair of serially connected resistors. The shunt circuit prevents inadvertent excitement of the LEDs due to leakage currents but minimally affect illumination characteristics of the LEDs. A pair of transistors is connected to the first LED and the second LED, respectively, and is biased using a set of bias resistors. A tri-state control signal switches on and off the pair of transistors and enables excitation of the first LED, the second LED or both via the current source.