Analog Devices,inc.

Korea Institute of Science and Technology

Hyunick Shin

Jongho Lee

Hae-Weon Lee

Huesup Song

Joosun Kim

Sang-O Jeon

Jaegon Seo

Insoo Yoo

Chulmin Joo

A multi-string LED driving method and system requires generating pulse-width-modulated (PWM'd) driving signals to respective LED strings to control their brightness levels, and staggering the timing of the driving signals such that the number of LED strings driven on simultaneously varies over time by no more than one LED string. The PWM'd driving signals are generated to, for example, achieve local dimming for a display device which employs a multi-string LED backlight system; the present method enables local dimming to be achieved while maintaining a relatively constant load on the drive circuit. The staggering of the timing of the PWM'd driving signals is preferably implemented by arranging the ON times of the driving signals such that they occur serially, such that the loading imposed by the LED strings is spread throughout each switching cycle.

Multi-string LED driving method and system

A LED driving system and method suitable for driving one or more LEDs or strings of LEDs connected to a common output terminal which is driven with a boost converter. A LED ON signal indicates when the LEDs are to be turned on, with the boost converter nominally operated only when the LEDs are to be on. To enable a lower minimum LED duty cycle without risking boost voltage collapse, the LED ON signal may be delayed such that the LEDs are turned on after the boost converter. A second technique, which may be used in conjunction with the first, adaptively extends the operation time of the boost converter beyond the time at which LED ON turns off the LEDs.

LED driving system and method

Lighting system embodiments are provided to energize and calibrate strings of light-emitting diodes. These embodiments are particularly useful for calibration of strings of light-emitting diodes that are arranged to provide backlighting of liquid crystal displays. The systems are structured around the use of a single comparator that is multiplexed to facilitate calibration of a plurality of current sources. The systems can be adapted for use in displays in which different techniques (e.g., 'analog dimming' and 'pulse-width modulation') are used to vary the brightness of the display. The systems remove the need for special structures (e.g., fuse arrays, special test equipment, and interfaces).

Light-emitting diode backlighting systems

Disclosed is a method for manufacturing composite granules having a homogeneous particle distribution, comprising powders of multimodal particle size distribution and phenol resins, and a method for manufacturing green bodies having homogeneous microstructure without particle separation from the granules.

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Seoul, South Korea

Hyunick Shin