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Researchers Submit Patent Application, "Single Stage Forward-Flyback Converter and Power Supply Apparatus for Light Emitting Diode", for Approval

July 23, 2014



By a News Reporter-Staff News Editor at Electronics Newsweekly -- From Washington, D.C., VerticalNews journalists report that a patent application by the inventors HAN, Sang Kyoo (Daejeon, KR); RYU, Byoung Woo (Suwon, KR); CHOI, Heung Gyoon (Suwon, KR); LEE, Keun Wook (Suwon, KR); PARK, Hong Sun (Suwon, KR), filed on June 27, 2013, was made available online on July 10, 2014.

The patent's assignee is Samsung Electro-mechanics Co., Ltd.

News editors obtained the following quote from the background information supplied by the inventors: "The present invention relates to a single stage forward-flyback converter and a power supply apparatus for a light emitting diode.

"In general, in order to drive an electronic device in a domestic, commercial or industrial setting, a power supply apparatus converting commercial power into driving power appropriate for the electronic device and supplying the converted driving power has been adopted in the interior or on an outer portion of the electronic device.

"The power supply apparatus may also be adopted in order to drive a light emitting diode.

"Recently, interest in and demand for light emitting diodes (LEDs) has increased.

"A device using the light emitting diode may be manufactured to be compact to thereby be used in a location in which it is difficult to install an existing electronic product. Further, in the case in which the light emitting diode is used as an illumination apparatus, it is easy to implement various colors of light and control illuminance, such that the light emitting diode may be used as a system illumination apparatus suitable in circumstances including watching a movie, reading books, and having a meeting.

"In addition, the light emitting diode consumes an amount of power equal to about of the power consumed by an incandescent lamp, has a lifespan of fifty thousand to a hundred thousand hours, 5 to 10 times longer than that of an incandescent lamp, and is environmentally-friendly as a mercury free light source and may be variously designed.

"Due to these characteristics, light emitting diode illumination projects have been promoted as government-backed national projects in a range of nations including America, Japan and Australia, as well as Korea.

"As described above, the light emitting diode, the use of which has increased, requires a driving apparatus for the driving thereof. However, as described in the following Related Art Document, in the case of a two-stage configuration including a power factor correction circuit stage performing power factor correction, and a direct current (DC) to DC converter circuit stage for a constant current control of an output load, power conversion efficiency is deteriorated, and in the case of driving an array including a plurality of light emitting diodes, when a required light emitting diode driving voltage rises, manufacturing costs may be increased due to the use of a high voltage element."

As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventors' summary information for this patent application: "An aspect of the present invention provides a single stage forward-flyback converter capable of improving a power factor and performing forward and flyback power conversion operations in a single power stage and performing forward and flyback power conversion operations regardless of an input power level, and a power supply apparatus for a light emitting diode.

"According to an aspect of the present invention, there is provided a single stage forward-flyback converter, including: a power converting unit switching input power to perform a forward power conversion operation while being switched on and perform a flyback power conversion operation while being switched off; a path providing unit clamping power formed by the forward power conversion operation of the power converting unit and power formed by the flyback power conversion operation thereof to provide power transfer paths; and a controlling unit controlling the power conversion operation of the power converting unit according to a voltage level of the input power.

"The controlling unit may detect the voltage level of the input power and control a switching on operation of the power converting unit when the detected voltage has a level of zero, to improve a power factor.

"The power converting unit may include: a power switch switching the input power; and a single transformer having a primary winding receiving the power switched by the power switch and a secondary winding electromagnetically coupled to the primary winding to receive power induced from the primary winding.

"The path providing unit may include: a balance capacitor maintaining balance in power levels between the power formed by the forward power conversion operation of the power converting unit and the power formed by the flyback power conversion operation thereof; a diode group providing the respective power transfer paths for the power formed by the forward power conversion operation of the power converting unit and the power formed by the flyback power conversion operation thereof; and a stabilization unit including first and second output inductors and an output capacitor to stabilize the power transferred via the power transfer path.

"The power switch may maintain a constant turn-on duty to improve a power factor of the input power.

"The input power may be rectified and transferred to the power converting unit.

"The diode group may include: a first diode having an anode connected to one terminal of the second output inductor of the stabilization unit and a cathode connected to one terminal of the first output inductor of the stabilization unit to provide the power transfer path; and a second diode having an anode connected to the other terminal of the second output inductor of the stabilization unit and a cathode connected to one terminal of the balance capacitor and the other terminal of the first output inductor to provide the power transfer path.

"An output of the power converting unit may be supplied to at least one light emitting diode.

"According to another aspect of the present invention, there is provided a power supply apparatus for alight emitting diode, including: a power converting unit switching input power to perform a forward power conversion operation while being switched on and perform a flyback power conversion operation while being switched off; a path providing unit clamping power formed by the forward power conversion operation of the power converting unit and power formed by the flyback power conversion operation thereof to provide power transfer paths and supplying the power to at least one light emitting diode; and a controlling unit controlling the power conversion operation of the power converting unit according to a voltage level of the input power, detecting the voltage level of the input power, and controlling a switching on operation of the power converting unit when the detected voltage has a level of zero, to improve a power factor.

BRIEF DESCRIPTION OF THE DRAWINGS

"The above and other aspects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

"FIG. 1 is a schematic circuit diagram of a single stage forward-flyback converter or a power supply apparatus for a light emitting diode according to an embodiment of the present invention;

"FIGS. 2 and 3 are schematic circuit diagrams respectively illustrating a current flow while the single stage forward-flyback converter is switched on and off, according to the embodiment of the present invention;

"FIG. 4 is a graph illustrating signal waveforms of main components while the single stage forward-flyback converter is switched on and off, according to the embodiment of the present invention; and

"FIGS. 5A and 5B are graphs illustrating electrical characteristics of the single stage forward-flyback converter according to the embodiment of the present invention."

For additional information on this patent application, see: HAN, Sang Kyoo; RYU, Byoung Woo; CHOI, Heung Gyoon; LEE, Keun Wook; PARK, Hong Sun. Single Stage Forward-Flyback Converter and Power Supply Apparatus for Light Emitting Diode. Filed June 27, 2013 and posted July 10, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=5829&p=117&f=G&l=50&d=PG01&S1=20140703.PD.&OS=PD/20140703&RS=PD/20140703

Keywords for this news article include: Electronics, Light-emitting Diode, Samsung Electro-mechanics Co. Ltd.

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Source: Electronics Newsweekly


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