High efficiency driver for color light emitting diodes (LED)
AssigneeThe University of Hong Kong
InventorsMan Hay Pong, Franki Ngai Kit Poon, Joe Chui Pong Liu
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Abstract
An efficient power driver for color light emitting diodes (LED) is disclosed for driving multiple LEDs for producing different desired colors. Such LED combinations comprising LEDs with different primary colors are suitable for implementing pixels in displaying a digitized image. This disclosed invention provides switching power conversion embodiments such that a single apparatus drives different color LEDs. Furthermore, the disclosed invention provides configurations with and without input to output isolation while enabling control of the current through each LED, for instance by an inductor or operating condition.
Claims10
An apparatus to provide power to a plurality of light emitting diodes for producing a desired color and brightness, the apparatus comprising:
- an inductor coupled in series with a first light emitting diode;
- a second light emitting diode coupled in parallel to the inductor and the first light emitting diode such that the second light emitting diode is reverse biased when a power source drives a current through the inductor and the first light emitting diode;
- and
- a switch controlling the connection of the inductor and the first light emitting diode to the power source.
An apparatus to provide power to drive a plurality of light emitting diodes comprising:
- an inductor coupled in series with a first light emitting diode, a switch controlling a connection of the inductor and the first light emitting diode to a power source;
- and a first terminal and a second terminal of the power source connected in series to the inductor via the switch and at least one second light emitting diode, the at least one second light emitting diode having a forward voltage higher than input voltage across the first and second terminals, wherein furthermore, the second light emitting diode is connected in parallel to the switch and the first light emitting diode, wherein furthermore, the second light emitting diode is coupled in series with the inductor and the power source.
An apparatus to provide power to drive a plurality of light emitting diodes comprising:
- a switching forward power converter with a transformer;
- a secondary winding coupled to the transformer having at least two terminals;
- a first light emitting diode having a first end and a second end, the first end of the first light emitting diode coupled to a first terminal of the secondary winding and the second end of the first light emitting diode coupled to a first end of an inductor and a first end of a second light emitting diode, wherein furthermore, a second end of the second light emitting diode being coupled to a second terminal of the secondary winding;
- and a third light emitting diode coupled in parallel with the series combination of the second light emitting diode and the inductor.
An apparatus to provide power to drive a plurality of light emitting diodes comprising:
- a switching flyback power converter with a transformer;
- a plurality of secondary windings coupled to the transformer;
- and at least one light emitting diode coupled to each of two of the plurality of secondary windings.
An apparatus to provide power to drive a plurality of light emitting diodes comprising:
- a switching bridge power converter with a transformer;
- a plurality of secondary windings including at least a first secondary winding and a second secondary winding coupled to the transformer such that a first terminal of the first secondary winding has the opposite polarity to that of a first terminal of the second secondary winding;
- a first and a second light emitting diode coupled together at their cathodes, wherein furthermore, an anode of the first light emitting diode being connected to the first terminal of the first secondary winding and an anode of the second light emitting diode being connected to the first terminal of the second secondary winding;
- and
- an inductor coupled to the cathodes of the first and the second light emitting diodes, the inductor further coupled to a second terminal of the first secondary winding and a second terminal of the second secondary winding via a third light emitting diode.
Dependencies are inferred from the claim text.