Multi-mode LED illumination system
First Claim
1. A lighting emitting diode (LED) illumination system that operates in a boost mode and a bypass mode, comprising:
- a plurality of LEDs that are coupled in series to form a LED string;
a plurality of bypass elements, each coupled in parallel with a respective group of one or more of the LEDs and configured to bypass selectively the respective group of LEDs in the bypass mode;
a boost converter, coupled to the plurality of LEDs, that is configured to generate a drive voltage to drive the plurality of LEDs, wherein the boost converter includes a boost controller that is configured to enable the boost mode in response to a boost enable signal; and
a first current sink and a second current sink, coupled to the plurality of LEDs, that are configured to provide two drive currents to drive the LEDs in the boost mode and the bypass mode, respectively;
wherein in the boost mode the boost controller is electrically coupled to control the boost converter to drive the LED string by a boosted drive voltage, and in the bypass mode the boost controller is deactivated to allow the boost converter to drive a subset of the plurality of LEDs by a regular drive voltage that is substantially lower than the boosted drive voltage.
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Accused Products
Abstract
This application discloses a lighting emitting diode (LED) illumination system that operates at least in a boost mode and a bypass mode. The LED illumination system includes a plurality of LEDs and bypass elements. Each bypass element is coupled in parallel with one or more LEDs, and configured to bypass them selectively in the bypass mode. A boost converter is configured to drive the LEDs. The boost converter includes a boost controller that is configured to enable the boost mode in response to a boost enable signal. In the boost mode, the boost controller is electrically coupled to control the boost converter to drive the LEDs by a boosted drive voltage, and in the bypass mode, the boost controller is deactivated to allow the boost converter to drive a subset of the LEDs by a regular drive voltage that is substantially lower than the boosted drive voltage.
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Citations
20 Claims
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1. A lighting emitting diode (LED) illumination system that operates in a boost mode and a bypass mode, comprising:
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a plurality of LEDs that are coupled in series to form a LED string; a plurality of bypass elements, each coupled in parallel with a respective group of one or more of the LEDs and configured to bypass selectively the respective group of LEDs in the bypass mode; a boost converter, coupled to the plurality of LEDs, that is configured to generate a drive voltage to drive the plurality of LEDs, wherein the boost converter includes a boost controller that is configured to enable the boost mode in response to a boost enable signal; and a first current sink and a second current sink, coupled to the plurality of LEDs, that are configured to provide two drive currents to drive the LEDs in the boost mode and the bypass mode, respectively; wherein in the boost mode the boost controller is electrically coupled to control the boost converter to drive the LED string by a boosted drive voltage, and in the bypass mode the boost controller is deactivated to allow the boost converter to drive a subset of the plurality of LEDs by a regular drive voltage that is substantially lower than the boosted drive voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A camera device that operates in two or more modes, comprising:
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a camera portion; and a LED illumination system that operates in a boost mode and a bypass mode associated respectively with a first mode and a second mode of the two or more modes of the camera device, including; a plurality of LEDs that are coupled in series to form a LED string; a plurality of bypass elements, each coupled in parallel with a respective group of one or more of the LEDs and configured to bypass selectively the respective group of LEDs in the bypass mode; a boost converter, coupled to the plurality of LEDs, that is configured to generate a drive voltage to drive the plurality of LEDs, wherein the boost converter includes a boost controller that is configured to enable the boost mode in response to a boost enable signal; and a first current sink and a second current sink, coupled to the plurality of LEDs, that are configured to provide two drive currents to drive the LEDs in the boost mode and the bypass mode, respectively; wherein in the boost mode the boost controller is electrically coupled to control the boost converter to drive the LED string by a boosted drive voltage, and in the bypass mode the boost controller is deactivated to allow the boost converter to drive a subset of the plurality of LEDs by a regular drive voltage that is substantially lower than the boosted drive voltage.
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18. A method of manufacturing a LED illumination system that operates in a boost mode and a bypass mode, comprising:
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providing a plurality of LEDs that are coupled in series to form a LED string; providing a plurality of bypass elements, including coupling each of the plurality of bypass elements in parallel with a respective group of one or more of the LEDs to bypass selectively the respective group of LEDs in the bypass mode; coupling a boost converter to the plurality of LEDs, the boost converter being configured to generate a drive voltage to drive the plurality of LEDs, wherein the boost converter includes a boost controller that is configured to enable the boost mode in response to a boost enable signal; and wherein in the boost mode the boost controller is electrically coupled to control the boost converter to drive the LED string by a boosted drive voltage, and in the bypass mode the boost controller is deactivated to allow the boost converter to drive a subset of the plurality of LEDs by a regular drive voltage that is substantially lower than the boosted drive voltage. - View Dependent Claims (19, 20)
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Specification