Samsung Electro-mechanics Co., Ltd.

Samsung Electronics Co., Ltd.

Lg Electronics Inc.

Samsung Led Co., Ltd.

Jeong In Cheon

Byoung Own Min

Yu Jin Jang

Chang Woo Ha

Seung Kon Kong

Jung Chul Gong

Sang Cheol Shin

Young Jin Lee

Jae Shin Lee

Deuk Hee Park

Bo Hyun Hwang

Dae Hoon Han

Jang Hwan Cho

Bon Ahm Goo

Se Joon You

Yun Jin Jang

Do Hyung Lee

A light emitting diode (LED) illumination device having a power compensation function is provided. The illumination device includes a light emitting unit including a plurality of LEDs connected in series, a rectifier for rectifying input AC power to provide a rectified voltage to the light emitting device, and a power compensator for detecting a change in the rectified voltage provided to the light emitting device and compensating a current provided to the light emitting device according to the detected change in the rectified voltage.

Power compensation device and light emitting diode illumination apparatus having the same

In an FSC mode LCD, a controller operates in response to an external adjustment, and a DC/DC converter converts a battery voltage into a driving voltage under control of the controller. A color LED backlight includes first, second and third color LED arrays connected in parallel, which are operated by the driving voltage. An FSC generator generates first, second and third color PWM signals according to an internal sawtooth voltage and a dimming voltage. A 3-channel current source generates first, second and third driving currents under control of the controller, and on/off switches paths of the first, second and third driving currents flowing through the first, second and third color LED arrays according to the first, second and third color PWM signals generated from the FSC generator, thereby adjusting luminance of the first, second and third color LED arrays of the color LED backlight.

Field sequential color mode liquid crystal display

The present invention relates to a light emitting diode driver that integrates a light emitting diode control function and a power switching control function at a secondary side insulated from a primary side in a power supply circuit, without using a photo coupler to control power switching at the primary side.

Light emitting diode driver

There are provided a reference signal generator and a PWM control circuit for LCD backlight. The reference signal generator and the PWM control circuit for LCD backlight may be configured to respectively include: a current control unit that controls generation of a variable current sequentially changing; a current generating unit that generates a variable current changing sequentially; and a reference signal generating unit that controls charging until a charged voltage charged by the variable current generated by the current generating unit reaches a first reference voltage level, starts discharging when the charged voltage reaches the first reference voltage level, controls discharging until the charged voltage reaches a second reference voltage level, and generates a triangular wave reference signal that has a frequency buffering interval in which a frequency sequentially changes when the initial driving completion signal or the protection signal is input.

Reference signal generator and PWM control circuit for LCD backlight

The present invention relates to a light emitting diode driver having a protection function that activates hiccup mode for a predetermined period of time when a light emitting diode performs an abnormal operation to thereby protect the light emitting diode. A light emitting diode driver having a protection function according to an aspect of the invention may include: a light emitting unit emitting light; a reference signal generating unit generating a reference signal having pulses with a predetermined period when the light emitting unit performs an abnormal operation; a control unit controlling operating time in hiccup mode according to the reference signal from the reference signal generating unit, the hiccup mode where output is switched on and off at a predetermined period; and a driving unit driving the light emitting unit in the hiccup mode for the operating time determined by the control unit.

Light emitting diode having protection function

A driver for display provides a driving signal having a frequency synchronized with that of an image signal when the image signal is normal and provides a driving signal having a predetermined frequency when the image signal is abnormal, thereby performing a stable operation. The driver includes a frequency detection unit detecting a frequency difference between a frequency of an inputted image signal and a frequency of a frequency-divided driving signal, a driving signal generation unit generating the driving signal having a frequency synchronized with the frequency of the image signal according to a detection result of the frequency detection unit, and a control unit stopping a frequency detection operation of the frequency detection unit when the detection result of the frequency detection unit shows an abnormal operation.

Driver for a display having a frequency detection unit

Disclosed is a liquid crystal display (LCD) backlight inverter. The LCD backlight inverter includes a lamp open detection unit outputting a first open detection voltage for a preset time period when it is determined that a predetermined lamp is open, based on a current voltage corresponding to the current of the predetermined lamp of a plurality of lamps, a first open determination unit outputting an open detection signal when the first open detection voltage is input, a second open determination unit outputting a protection signal when it is determined that all of the plurality of lamps are open based on detection voltages of the plurality of lamps, a temporary protection determination unit outputting a frequency change signal when both the open detection signal and the protection signal are input, and an operating frequency control unit changing an operating frequency to a preset protective frequency according to the frequency change.

LCD backlight inverter

A dimming buck type light emitting diode (LED) driving apparatus includes a main switch controlling a driving current flowing into an LED; a current detector detecting a driving current flowing into the LED; a power level determination unit determining a level of the driving power; a dimming capacitor for dimming control; a dimming control unit controlling charging and discharging of the dimming capacitor according to a power level determination signal and an enable signal; a reset circuit unit generating a reset signal according to a detection voltage from the current detector and a voltage of the dimming capacitor; a pulse generation unit generating a pulse signal; and a latch set by the pulse signal of the pulse generation unit and reset by the reset signal of the reset circuit unit to generate a switching signal, and turning on and off the main switch using the switching signal.

Dimming buck type LED driving apparatus

An inverter driver integrated circuit (IC) includes a control signal generator generating a first control signal and a second control signal by use of a pulse width modulation oscillator signal, a comparator comparing a half-wave rectified signal of a lamp feedback signal fed back from a lamp with a preset reference signal to output a lamp state signal, a first sensor receiving the lamp state signal and the second control signal to output a first sensing signal, and a second sensor receiving the first sensing signal and the first control signal to output a second sensing signal.

Inverter driver integrated circuit

There is a provided a dual mode clock generator that is applicable to a direct current-direct current converter of a power supply. The dual mode clock generator includes a frequency controller for controlling generation of charge and discharge; a current source unit for generating a charge, and generating a charge; a capacitor for charging a voltage according to the charge current generated by the current source unit; an oscillation controller for controlling switch-on or switch-off to charge and discharge the capacitor; a switch for controlling the charging and discharging of the capacitor through the ON or OFF control of the oscillation controller; and a current sink unit for generating a discharge current according to the second current in the first operation mode and generating a discharge current according to the third current and the fourth current in the second operation mode.

Dual mode clock generator

A control circuit of a DC-DC converter is provided. A mode selection section selects an Active Clamp Forward (ACF) or a Logic Link Control (LLC) mode. A soft start section generates a soft start signal in the ACF and LLC modes. A PWM comparison section compares a current detection signal with a feedback signal, a feedback reference signal and the soft start signal in the ACF mode, and generates a PWM signal based on a comparison result. A selection section selects the PWM signal of the PWM comparison section in the ACF mode. A clock generation section generates a clock signal having a fixed frequency in the ACF mode, and generates a clock signal having a frequency based on an operating current and the soft start signal in the LLC mode. A latch section maintains the PWM signal in response to the clock signal in the ACF mode and maintains the clock signal in the LLC mode.

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Seoul, South Korea

Jeong In Cheon