Light Emitting Diode Driving Device
First Claim
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1. A light emitting diode (LED) driving device comprising:
- an LED unit having an input side adapted to receive an external AC input voltage, and an output side, said LED unit outputting at said output side a driving current corresponding to the input voltage; and
a current limiting unit coupled to said output side of said LED unit, and receiving the driving current from said output side of said LED unit, said current limiting unit including a parallel connection of a bypass switch and a current limiting circuit coupled across said output side of said LED unit, said bypass switch being operable between an ON-state and OFF-state;
wherein said current limiting unit is operable so as to permit flow of the driving current through one of said bypass switch and said current limiting circuit such that said current limiting unit has a first conduction impedance when said bypass switch is in the ON-state, and a second conduction impedance larger than the first conduction impedance when said bypass switch is in the OFF-state.
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Abstract
An LED driving device includes: an LED unit outputting a driving current corresponding to an external AC input voltage; and a current limiting unit receiving the driving current from the LED unit, including a parallel connection of a bypass switch and a current limiting circuit, and operable so as to permit flow of the driving current through one of the bypass switch and the current limiting circuit such that the current limiting unit has a first conduction impedance when the bypass switch is in an ON-state, and a second conduction impedance larger than the first conduction impedance when the bypass switch is in an OFF-state.
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Citations
37 Claims
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1. A light emitting diode (LED) driving device comprising:
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an LED unit having an input side adapted to receive an external AC input voltage, and an output side, said LED unit outputting at said output side a driving current corresponding to the input voltage; and a current limiting unit coupled to said output side of said LED unit, and receiving the driving current from said output side of said LED unit, said current limiting unit including a parallel connection of a bypass switch and a current limiting circuit coupled across said output side of said LED unit, said bypass switch being operable between an ON-state and OFF-state; wherein said current limiting unit is operable so as to permit flow of the driving current through one of said bypass switch and said current limiting circuit such that said current limiting unit has a first conduction impedance when said bypass switch is in the ON-state, and a second conduction impedance larger than the first conduction impedance when said bypass switch is in the OFF-state. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A light emitting diode (LED) driving device comprising:
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a LED unit having an input side adapted to receive an external AC input voltage, and an output side, said LED unit outputting at said output side a driving current corresponding to the input voltage; and an variable impedance unit coupled across said output side of said LED unit, permitting flow of the driving current therethrough, and having a conduction impedance that is variable based on an adjusting signal. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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37. A light emitting diode (LED) driving device comprising:
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a bridge rectifier having an input side adapted to receive an external AC input voltage from an AC power source, and an output side; an LED unit coupled across said output side of said bridge rectifier; and a current limiting unit adapted to be coupled between the AC power source and said input side of said bridge rectifier, and including two NMOSFETs coupled inversely in parallel, said current limiting unit being operable so as to permit flow of a driving current that is not greater than a predetermined threshold current through said bridge rectifier to said LED unit.
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Specification