LIGHTING APPARATUS AND CIRCUITS FOR LIGHTING APPARATUS
First Claim
1. A lighting apparatus comprising:
- a plurality of parallel circuits, each parallel circuit comprising a switching element and one or more light emitting diodes coupled in series between a common node and one of a power rail and a ground rail; and
a common circuit comprising one or more light emitting diodes coupled in series between the common node and the other one of the power rail and the ground rail.
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Accused Products
Abstract
The present invention discloses a lighting apparatus that includes a plurality of parallel circuits and a common circuit. The parallel circuits each comprise a switching transistor and a set of LEDs, the sets of LEDs having different characteristics such as different light output wavelengths. In operation, one of the parallel circuits is selected by activating the corresponding switching transistor, thus selecting the respective LEDs to be activated. The common circuit also comprises a set of LEDs, these LEDs being activated no matter which parallel circuit is selected. In various implementations, the lighting apparatus can generate a wide spectrum of light outputs by selectively activating the plurality of parallel circuits within time slots of a duty cycle. In some cases, balancing of loads across the parallel circuits is desired to maintain the appropriate current flowing through the LEDs.
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Citations
20 Claims
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1. A lighting apparatus comprising:
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a plurality of parallel circuits, each parallel circuit comprising a switching element and one or more light emitting diodes coupled in series between a common node and one of a power rail and a ground rail; and a common circuit comprising one or more light emitting diodes coupled in series between the common node and the other one of the power rail and the ground rail. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A lighting apparatus comprising:
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a first circuit comprising a first transistor and one or more first light emitting diodes, a source of the first transistor being coupled to one of a power rail and a ground rail and a gate of the first transistor operable to receive a first control signal to activate the first transistor;
the one or more first light emitting diodes being coupled in series between a drain of the first transistor and a common node;a second circuit comprising a second transistor and one or more second light emitting diodes, a source of the second transistor being coupled to the one of the power rail and the ground rail and a gate of the second transistor operable to receive a second control signal to activate the second transistor;
the one or more second light emitting diodes being coupled in series between a drain of the second transistor and the common node; anda third circuit comprising one or more third light emitting diodes coupled in series between the common node and the other one of the power rail and the ground rail.
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Specification