LIGHT EMITTING DEVICE WITH LOW VOLTAGE-ENDURANCE COMPONENTS
First Claim
1. A light emitting device with one or more low voltage-endurance components, the light emitting device comprising:
- a light emitting diode string comprising M pieces of first light emitting diode connected in series, and one end of the light emitting diode string coupled to a node of an input voltage;
M pieces of first control circuit, each of which comprises a first switch that is connected to corresponding one of the M pieces of first light emitting diode in parallel and configured to selectively enable a bypass current path;
a detection circuit configured to detect a current, flowing through one or more of the M pieces of first light emitting diode, to produce a current detection signal when the input voltage is applied to the light emitting diode string;
a current control circuit coupled to the M-th piece of the first control circuits and the detection circuit and configured to in response to the current detection signal control the M-th piece of the first control circuits to provide a preset voltage to the first switch in the M-th piece of the first control circuits, so as to electively enable the bypass current path;
wherein when the first switch in the M-th piece of the first control circuits does not enable the bypass current path, in response to a potential of the input voltage the M-th piece of the first control circuits further selectively controls the (M−
1)th piece of the first control circuits to provide the preset voltage to the first switch in the (M−
1)th piece of the first control circuits, and M is a positive integer larger than 1.
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Accused Products
Abstract
A light emitting device with low voltage-endurance components includes a light emitting diode string, M pieces of first control circuit, a detection unit and a current control circuit. The light emitting diode string includes M pieces of first light emitting diode connected in series. Each first control circuit includes a first switch. One end of the light emitting string is coupled to a node of an input voltage. The first switch is connected to its related first light emitting diode in parallel and can enable a bypass current path. The detection unit detects the potential of the input voltage to produce a current detection signal. The current control circuit is coupled to the M-th piece of the first control circuits and the detection unit and controls the M-th piece of the first control circuits to selectively enable the bypass current path according to the current detection signal.
24 Citations
22 Claims
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1. A light emitting device with one or more low voltage-endurance components, the light emitting device comprising:
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a light emitting diode string comprising M pieces of first light emitting diode connected in series, and one end of the light emitting diode string coupled to a node of an input voltage; M pieces of first control circuit, each of which comprises a first switch that is connected to corresponding one of the M pieces of first light emitting diode in parallel and configured to selectively enable a bypass current path; a detection circuit configured to detect a current, flowing through one or more of the M pieces of first light emitting diode, to produce a current detection signal when the input voltage is applied to the light emitting diode string; a current control circuit coupled to the M-th piece of the first control circuits and the detection circuit and configured to in response to the current detection signal control the M-th piece of the first control circuits to provide a preset voltage to the first switch in the M-th piece of the first control circuits, so as to electively enable the bypass current path; wherein when the first switch in the M-th piece of the first control circuits does not enable the bypass current path, in response to a potential of the input voltage the M-th piece of the first control circuits further selectively controls the (M−
1)th piece of the first control circuits to provide the preset voltage to the first switch in the (M−
1)th piece of the first control circuits, and M is a positive integer larger than 1. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A light emitting device with one or more low voltage-endurance components, the light emitting device comprising:
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a light emitting diode string comprising M pieces of first light emitting diode connected in series; a second light emitting diode directly connected to the M-th piece of the first light emitting diodes; a third light emitting diode having two ends that are directly connected to the first piece of the first light emitting diodes and a node of an input voltage, respectively; and M pieces of first control circuit, each of which comprises a first switch connected to corresponding one of the M pieces of first light emitting diode and configured to selectively enable a bypass current path in response to a command of the first control circuit; Wherein when the input voltage is larger than a first threshold, the second light emitting diode and the third light emitting diode simultaneously emit light; when the input voltage is larger than a second threshold larger than the first threshold, the M pieces of first control circuit respectively disable the bypass current paths sequentially so that the M pieces of first light emitting diode sequentially emit light; and M is a positive integer larger than 1. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A light emitting device with one or more low voltage-endurance components, the light emitting device comprising:
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a light emitting diode string comprising N pieces of first light emitting diode connected in series, wherein the N-th piece of the first light emitting diodes in the light emitting diode string is coupled to a node of an input voltage, and the first piece of the first light emitting diodes in the light emitting diode string is farthest from the node of the input voltage; and (N−
2) pieces of first control circuit which respectively correspond to and are connected in parallel to the second to (N−
1)th first light emitting diodes in the light emitting diode string;Wherein when the input voltage successively becomes larger, the N-th piece of the first light emitting diodes and the first piece of the first light emitting diodes emit limit before the rest of the first light emitting diodes emit light in turn.
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Specification