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Chung Wook Roh

Chung Wook Roh, Seoul KR

Patent application numberDescriptionPublished
20080231404INTEGRATED TYPE TRANSFORMER - There is provided an integrated type transformer that reduces the volume by integrating a plurality of transformers transmitting power for driving a plurality of lamps in an inverter circuit for an LCD into one transformer structure. An integrated type transformer according to an aspect of the invention includes a bobbin unit including a bobbin body having a predetermined length and a through hole therein in a longitudinal direction of the bobbin unit, and a core unit including an inner core inserted into the through hole of the bobbin unit, and an outer core formed along one surface in the longitudinal direction among outer circumferential surfaces of the bobbin unit and electromagnetically coupled to the inner core to form one magnetic path.09-25-2008
20090243388MULTI-OUTPUT DC/DC CONVERTER - Disclosed is a multi-output DC/DC converter controlling power-conversion switching in synchronization with a frequency of one output voltage among multiple output voltages in an LLC resonant DC/DC converter. The multi-output DC/DC converter includes a power conversion circuit performing alternate switching on an input DC voltage to output multiple DC voltages including a first DC voltage and a second DC voltage each having a preset voltage level, and a control circuit controlling the alternate switching of the power conversion circuit in synchronization with a preset resonant frequency.10-01-2009
20090251120HIGH VOLTAGE POWER SUPPLY - There is provided a high voltage power supply capable of reducing voltage stress of a voltage multiplying device. The high voltage power supply includes: a power converter switching on/off and converting an input direct current power into a direct current power having a preset voltage level; and a voltage multiplier including a first multiplying cell multiplying the voltage level of the direct current power from the power converter, wherein the first multiplying cell includes: first and second capacitors charging the direct current power from the power converter, respectively; a first diode providing a path for transferring the direct current power when the power converter is switched off; and a second diode providing a path for transferring the direct current power when the power converter is switched on.10-08-2009
20090316447POWER SUPPLY HAVING MAXIMUM POWER POINT TRACKING FUNCTION - The present invention relates to power supplies, and more particularly, to a power supply having a maximum power point tracking function that can reduce manufacturing costs and circuit size by using a maximum power point tracking section with a simplified circuit in a solar photovoltaic power generator supplying power using sunlight instead of using a micro controller, the maximum power point tracking section that controls power switching according to a result of integration of a value obtained by dividing a power variation by a voltage variation to track a maximum power value. A power supply having a maximum power point tracking function according to an aspect of the invention may include: a converter section switching input power, and converting the switched input power into predetermined DC power; and a maximum power point tracking section detecting a voltage and a power value of the input power, dividing a variation of the detected power by a variation of the detected voltage, integrating a result of the division, and controlling the switching operation of the converter section according to a value of the integration.12-24-2009
20090316452POWER SUPPLY HAVING MAXIMUM POWER POINT TRACKING FUNCTION - The present invention relates to power supplies, and more particularly, to a power supply having a maximum power point tracking function that controls power switching so that a detected power value is within a reference range having a maximum power point in a predetermined current-voltage curve. A power supply having a maximum power point tracking function according to an aspect of the invention includes: a converter section switching input power and converting the switched input power into predetermined DC power; and a maximum power point tracking section detecting a power value determined according to a switching operation of the converter section among power values included in a predetermined power-voltage curve, and controlling the switching operation of the converter section so that the detected power value is located within a predetermined reference range having a maximum power value among the power values included in the power-voltage curve.12-24-2009
20100014321VARIABLE SWITCHING FREQUENCY TYPE POWER SUPPLY - There is provided a variable switching frequency type power supply that can achieve high efficiency by fixing a switching duty cycle to 50% and varying switching frequency. A variable switching frequency type power supply according to an aspect of the invention may include: a switching unit switching input power; a transformation unit converting a voltage level of the power switched by the switching unit into a predetermined voltage level; a rectification unit rectifying the power converted by the transformation unit; and a control unit fixing a switching duty cycle of the switching unit to a predetermined switching duty cycle, and varying switching frequency of the switching unit according to a voltage level of output power.01-21-2010
20100237799LED DRIVING CIRCUIT - The present invention provides an LED driving circuit including: an inverter unit for switching an input power source; a plurality of transformers including a plurality of primary windings connected to the inverter unit and connected to each other in series and a plurality of secondary windings each of which is coupled with each of the primary windings; a plurality of rectification units each of which is connected to each of the secondary windings; and a plurality of LEDs each of which is connected to each of the rectification units.09-23-2010

Patent applications by Chung Wook Roh, Seoul KR

Chung Wook Roh, Daegeon KR

Patent application numberDescriptionPublished
20090021179BACKLIGHT DRIVING SYSTEM FOR LIQUID CRYSTAL DISPLAY - There is provided a backlight driving system for a liquid crystal display that can reduce size and weight of a product because a DC-DC converter is not used when commercial AC power is converted into lamp driving power. A backlight driving system for a liquid crystal display according to an aspect of the invention includes a power supply unit converting commercial alternating current (AC) power into direct current (DC) power having a voltage level set beforehand, an inverter unit converting the DC power from the power supply unit into AC power at a one-to-one conversion ratio set beforehand, a boosting unit boosting the AC power from the inverter unit into lamp lighting power set beforehand; and a lamp group receiving the lamp lighting power from the boosting unit to emit light.01-22-2009