Solid-state lighting apparatus and methods using current diversion controlled by lighting device bias states
First Claim
1. A lighting apparatus comprising:
- a string of light emitting diode (LED) sets coupled in series, each set comprising at least one LED;
a resistor coupled in series with the string; and
a plurality of current diversion circuits, respective ones of which are coupled to respective nodes of the string and to a terminal of the resistor and configured to operate responsive to bias state transitions of respective ones of the LED sets, wherein a first one of current diversion circuits is configured to conduct current to a first one of the LED sets while bypassing a second one of the LED sets and to be turned off responsive to a voltage at the terminal of the resistor.
3 Assignments
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Accused Products
Abstract
A lighting apparatus includes a string of light emitting diode (LED) sets coupled in series, each set including at least one LED. The apparatus further includes a plurality of current diversion circuits, respective ones of which are coupled to respective nodes of the string and configured to operate responsive to bias state transitions of respective ones of the LED sets. In some embodiments, a first one of the current diversion circuits is configured to conduct current via a first one of the LED sets and is configured to be turned off responsive to current through a second one of the LED sets. The first one of the current diversion circuits may be configured to conduct current responsive to a forward biasing of the first one of the LED sets and the second one of the current diversion circuit may be configured to conduct current responsive to a forward biasing of a second one of the LED sets.
108 Citations
27 Claims
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1. A lighting apparatus comprising:
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a string of light emitting diode (LED) sets coupled in series, each set comprising at least one LED; a resistor coupled in series with the string; and a plurality of current diversion circuits, respective ones of which are coupled to respective nodes of the string and to a terminal of the resistor and configured to operate responsive to bias state transitions of respective ones of the LED sets, wherein a first one of current diversion circuits is configured to conduct current to a first one of the LED sets while bypassing a second one of the LED sets and to be turned off responsive to a voltage at the terminal of the resistor. - View Dependent Claims (2, 3, 4, 5)
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6. A lighting apparatus comprising:
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a string of light emitting diode (LED) sets coupled in series, each set comprising at least one LED; and a plurality of current diversion circuits, respective ones of which are coupled to respective nodes of the string and configured to operate responsive to bias state transitions of respective ones of the LED sets, wherein a first one of current diversion circuits is configured to conduct current to a first one of the LED sets while bypassing a second one of the LED sets and to be turned off responsive to a current through the second one of the LED sets, wherein each of the current diversion circuits comprises; a transistor providing a controllable current path between a node of the string and a terminal of a power supply; and a turn-off circuit coupled to a node of the string and to a control terminal of the transistor and configured to control the current path responsive to a control input. - View Dependent Claims (7, 8)
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9. A lighting apparatus comprising:
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a rectifier circuit configured to be coupled to an AC power source and to generate a rectified AC voltage; a resistor having a first terminal coupled to a first output node of the rectifier circuit; a string of serially-connected LED sets, the string having a first end coupled to a second terminal of the resistor and a second end coupled to a second output node of the rectifier circuit, each LED set comprising at least one LED; and a plurality of current diversion circuits, respective ones of which provide respective separate current paths from respective nodes of the string to the second terminal of the resistor and are configured to be selectively enabled and disabled responsive to bias state transitions of the LED sets as a magnitude of the rectified AC voltage varies. - View Dependent Claims (10, 11, 12, 13)
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14. A lighting apparatus comprising:
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a string of serially-connected LED sets, each LED set comprising at least one LED; a resistor coupled having a terminal coupled to an end of the string; and a plurality of transistors, respective ones of which are configured to provide respective separate controllable current paths between respective nodes of the string and the terminal of the resistor; and a control circuit configured to control the transistors responsive to a voltage at the terminal of the resistor. - View Dependent Claims (15, 16, 17, 18)
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19. An apparatus comprising:
a plurality of current diversion circuits, respective ones of which are configured to be coupled to respective nodes of a string of serially-connected LED sets and to a terminal of a resistor coupled in series with the string, the current diversion circuits further configured to operate responsive to bias state transitions of respective ones of the LED sets, wherein a first one of current diversion circuits is configured to conduct current to a first one of the LED sets while bypassing a second one of the LED sets and to be turned off responsive to a voltage at the terminal of the resistor. - View Dependent Claims (20, 21, 22, 23)
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24. An apparatus comprising:
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a plurality of current diversion circuits, respective ones of which are configured to be coupled to respective nodes of a string of serially-connected LED sets and to operate responsive to bias state transitions of respective ones of the LED sets, wherein a first one of current diversion circuits is configured to conduct current to a first one of the LED sets while bypassing a second one of the LED sets and to be turned off responsive to a current through the second one of the LED sets, wherein each of the current diversion circuits comprises; a transistor configured to provide a controllable current path between a node of the string and a terminal of a power supply; and a turn-off circuit coupled to a node of the string and to a control terminal of the transistor and configured to control the current path responsive to a control input. - View Dependent Claims (25)
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26. A method of operating a string of light emitting diode (LED) sets coupled in series, each set comprising at least one LED, the method comprising:
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conducting current from a first one of the LED sets while bypassing a second one of the LED sets using a first current diversion circuit coupled to a terminal of a resistor coupled in series with the string; conducting current from a second one of the LED sets using a second current diversion circuit coupled to the terminal of the resistor; and turning off the first current diversion responsive to a voltage at a terminal of the resistor. - View Dependent Claims (27)
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Specification