Fairchild Korea Semiconductor Ltd.

Ilyong Jung

Seunguk Yang

Jae-yong Lee

Chan Son

Moonho Choi

Young-Je Lee

Byung Kwon Choi

Jinkyum Kim

The present invention relates to an LED emitting device and a driving method thereof. The LED emitting device receives an input voltage and supplies a power supply voltage needed for operating an LED channel according to a switching operation of a power switch. The LED emitting device controls the power supply and also controls a load switch between the LED channel and an output voltage. The LED emitting device determines the LED channel to be short circuited when the output voltage is reduced to a predetermined threshold voltage during a predetermined short circuit sense period starting from the time when the output voltage reaches a regulated voltage before the LED channel is dimmed. During the short circuit sense period, the power supply is stopped and the load switch is turned on.

LED emitting device and driving method thereof

The present invention relates to a switch control circuit, a switch control method, and a converter using the same. An input voltage rectified from an AC input in a converter is transmitted to an inductor, and output power is generated from an inductor current by the input voltage. The converter includes a power switch connected to the inductor to control the inductor current and a sense resistor having a first end connected to a ground and a second end connected to the AC input. At a time point that a sense voltage generated in the sense voltage reaches the peak point and then decreased to an on-reference voltage, the power switch is turned on. The on-reference voltage is a sense voltage at a resonance start time point between a parasite capacitor of the power switch and the inductor.

Switch control circuit, converter using the same, and switch controlling method

An apparatus for driving an LED device having a plurality of LED channels is disclosed. Each LED channel has a plurality of LEDs connected in series. A power converter converts an input voltage into an output voltage and outputs the output voltage to an output terminal that is connected to first terminals of the plurality of LED channels. A plurality of current controllers are connected to second terminals of the plurality of LED channels, respectively. Each current controller controls a current of a corresponding LED channel. A detection controller determines a detection time based on voltages of the second terminals of the plurality of LED channels. A state detector detects the open-circuited states of the plurality of LED channels based on voltages of the second terminals of the plurality of LED channels at the detection time.

Apparatus and method for detecting open-circuited light emitting diode channels

A driving apparatus of an LED device is provided. The LED device includes a plurality of LED channels, and each LED channel includes a plurality of LEDs connected in series. A power converter has an output terminal connected to a first terminal of each LED channel, and converts an input voltage into an output voltage to output the output voltage to the output terminal. A plurality of current controllers correspond to the plurality of LED channels, respectively. Each current controller is connected to a second terminal of a corresponding LED channel, and controls a current of the corresponding LED channel. The voltage sensor outputs a sensed voltage corresponding to the output voltage of the output terminal. The fault controller determines whether to stop operation of the power converter by comparing the sensed voltage with a reference voltage.

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Bucheon, South Korea

Ilyong Jung