Seoul Semiconductor Co., Ltd.

Young Do Jong

Kang Nyung Lee

Sang Wook Han

Hye Man Jung

Hyun Gu Kang

Sung Ho Jin

Kwang Bea Lim

Kwan Hyun Lee

June Sik Kwak

Motonobu Takeya

Jae Gil Lee

Ho Young Cha

Bong Ryeol Park

A driving circuit for a light emitting diode connected to a TRIAC dimmer configured to modulate an input AC voltage depending on a selected dimming level including a rectifier configured to full-wave rectify the modulated AC voltage output from the TRIAC dimmer to generate and output a driving voltage, a driving module configured to receive the driving voltage of the rectifier to detect the selected dimming level and drive a plurality of light emitting diode groups depending on the detected dimming level, and a bleeder circuit configured to provide a bleeder current to the TRIAC dimmer, in which the bleeder circuit is configured to provide the bleeder current only for a preset on-duty time.

Driving circuit and lighting apparatus for light emitting diode

A lighting apparatus including a light emitting diode connected to a dimmer configured to modulate an input AC voltage depending on a selected dimming level, a rectifier configured to full-wave rectify the modulated AC voltage output from the dimmer to generate and output a driving voltage, a driving module configured to receive the driving voltage of the rectifier to detect the selected dimming level, and select one of three driving modes of a stop mode, a resistance driving mode, and a sequential driving mode depending on the detected dimming level, and a plurality of light emitting diode groups configured to emit light depending on a control of the driving module.

Disclosed herein are a driving circuit and a lighting apparatus for a light emitting diode capable of improving a flicker, light efficiency, and electrical characteristics. The disclosed driving circuit for a light emitting diode includes: a dimmer modulating an AC voltage input depending on a selected dimming level; a rectifier full-wave rectifying the modulated AC voltage output from the dimmer to generate and output a driving voltage; and a driving module receiving the driving voltage of the rectifier to detect the selected dimming level and controlling a driving mode of a plurality of light emitting diode groups depending on the detected dimming level, in which the driving module selects one of a resistance driving mode driving all the plurality of light emitting diode groups and a sequential driving mode sequentially driving the plurality of light emitting diode groups to improve light efficiency and electrical characteristics.

A light-emitting diode (LED) driving circuit configured to drive LED units includes a rectification circuit unit to receive an alternating current (AC) power voltage and rectify the AC power voltage to output a unidirectional ripple voltage, a pulse-width modulation (PWM) signal generation unit to generate PWM decision signals. The PWM signal generation unit is configured to sequentially drive the LEDs according to the PWM decision signals.

LED luminescence apparatus and method of driving the same

An LED driving circuit package includes a rectification unit to receive an AC power voltage and rectify the AC power voltage to generate a ripple voltage, an LED driving switching unit including a plurality of switch units and a plurality of current control units. The LED driving circuit package further includes a low voltage control unit including a circuit power supply unit to generate low voltage power, a voltage detection unit to detect a magnitude of the ripple voltage, a reference frequency generation unit to generate a reference frequency, and a reference pulse generation unit to generate a reference pulse for controlling the operation of the LED driving switch unit according to the reference frequency and a magnitude of the voltage detected by the voltage detection unit.

LED driving circuit package

A vertical gallium nitride transistor according to an exemplary embodiment of the present invention includes a semiconductor structure including a first semiconductor layer of a first conductivity-type having a first surface and sidewalls, a second semiconductor layer of the first conductivity-type surrounding the first surface and the sidewalls of the first semiconductor layer, and a third semiconductor layer of a second conductivity-type disposed between the first semiconductor layer and the second semiconductor layer, the third semiconductor layer separating the first and second semiconductor layers from each other.

Vertical gallium nitride transistors and methods of fabricating the same

Exemplary embodiments of the present invention disclose a unidirectional heterojunction transistor including a channel layer made of a first nitride-based semiconductor having a first energy bandgap, a barrier layer made of a second nitride-based semiconductor having a second energy bandgap different from the first energy bandgap, the barrier layer including a recess, a drain electrode disposed on a first region of the barrier layer, and a recessed-drain Schottky electrode disposed in the recess of the barrier layer, the recessed-drain Schottky electrode contacting the drain electrode.

Nitride semiconductor device and method of manufacturing the same

An LED luminescence apparatus includes a plurality of LED units connected in series which are configured to receive a unidirectional ripple voltage, a plurality of switch units, one end of each being connected to the cathode of one of the plurality of LED units, a plurality of constant current control circuit units, one end of each being connected to an another end of a respective switch unit to receive a current from the respective switch unit, each of the constant current control circuit units being configured to output a current control signal to the respective switch unit to control a magnitude of the received current to have a specific value, and a current comparison unit to receive currents flowing from the plurality of switching units, and generate a plurality of switching control signals for the respective switch units to sequentially drive the plurality of constant current control circuit units.

Growing community of inventors

Ansan-si, South Korea

Young Do Jong