Korea Electrotechnology Research Institute

Ju Won Baek

Jong Hyun Kim

Dong Wook Yoo

Hyoung Woo Kim

Guen Hie Rim

Myung Hyo Ryu

Chu Hyun Cho

Kill Soo Seo

Evgueni P Pavlov

The present invention relates to an apparatus for controlling the operation of an LED and to a method for controlling the drive current thereof. More particularly, the present invention relates to an apparatus for controlling the operation of an LED, which is capable of driving a direct current-operated LED module or an alternating current-operated LED module using alternating current power, and to a method for controlling the drive current of the apparatus. According to the present invention, the drive current of an LED array can be output in the form of a sine wave by a constant-current regulation or constant-power regulation even when input voltage varies, thus suppressing harmonics, improving the power factor, minimizing flicker, and preventing a temperature increase in the LED array and in an LED operation control circuit.

Apparatus for controlling the operation of an LED, and method for controlling drive current thereof

The present invention is a device using a non-linear capacitor and voltage amplification effect, which can generate a pulse having a short pulse width at high voltage. The device comprises a rectification circuit for rectifying the AC input power supply, a semiconductor switch connected to one output terminal of said rectification circuit, a primary coil connected between an output of said semiconductor switch and the other output terminal of said rectification circuit, a diode in which the cathode thereof is connected to the output of said semiconductor switch, a capacitor connected between an anode of said diode and the other output terminal of said rectification circuit, a secondary coil in which one terminal thereof is connected to the anode of said diode, a non-linear capacitor connected between the other terminal of said secondary coil and the other output terminal of said rectification circuit, and a load connected in parallel across two terminals of said non-linear capacitor.

High voltage pulse generator using a non-linear capacitor

The present invention relates to a passive auxiliary circuit for driving power switches connected in series for much higher rating of a power system. The passive auxiliary circuit for an IGBT power switch connected in series with another, comprises two capacitors, which are connected in series across the IGBT; two resistors dividing a voltage applied across the IGBT, each resistor being connected in parallel with each capacitor; and a diode and a third resistor which are connected in series between a gate terminal of the IGBT and a node connecting the two capacitors, wherein the diode is placed such that its cathode is directed to the gate. This passive auxiliary circuit, whose structure is so simple, is able to distribute a supplied high voltage equally over series-connected IGBTs, to reduce additional power loss remarkably, and to relieve transient overvoltage like as a conventional active gate circuit.

Passive auxiliary circuit for series connection of a power switch

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Changwon-si, South Korea

Ju Won Baek