Samsung Electronics Co., Ltd.

Byung-Hun Han

Jae-hyuck Woo

Jae-Goo Lee

Chul Jun Choi

In-Suk Kim

In-suk Kim

Byung-kwon An

A gradation voltage generator for applying a gradation voltage according to gamma characteristics of a display panel includes a reference gamma selector that receives a maximum reference voltage, a minimum reference voltage, and a first reference voltage, and selects and outputs a maximum gamma voltage and a minimum gamma voltage from among voltages between the maximum reference voltage and the minimum reference voltage, wherein when the maximum reference voltage changes, the minimum gamma voltage is compensated by a difference the changed maximum reference voltage and the first reference voltage and a gamma curve controller that receives the maximum gamma voltage and the minimum gamma voltage, and generates and outputs a plurality of gradation voltages.

Gradation voltage generator and display driving apparatus

Provided are a level shifter circuit and a corresponding method for controlling voltage levels of a clock signal and an inverted clock signal for driving gate lines of a ASG thin film transistor liquid crystal display panel, where the level shifter circuit includes first and second level shifters, the first level shifter controls the voltage level of the clock signal to swing between a negative external voltage level and a positive external voltage level in response to a clock activating signal, and increases the voltage level of the clock signal from the negative external voltage level to a power supply voltage level or decreases it from the positive external voltage level to a ground voltage level while a pre-charge clock activating signal is activated, the second level shifter controls the voltage level of the inverted clock signal to swing between the negative external voltage level and the positive external voltage level in response to an inverted clock activating signal, and increases the voltage level of the inverted clock signal from the negative external voltage level to the power supply voltage level or decreases it from the positive external voltage level to the ground voltage level while an inverted pre-charge clock activating signal is activated, and the level shifter circuit increases or decreases the voltage levels of the clock signal and inverted clock signal using a battery voltage or a ground voltage, thereby reducing current consumption caused by the increase or decrease in the voltage level.

Level shifter circuit and method for controlling voltage levels of clock signal and inverted clock signal for driving gate lines of amorphous silicon gate-thin film transistor liquid crystal display

A differential delay circuit type ring oscillator allows for an increase in operation enabling frequency and dynamic range. At each stage of the ring, delay circuit output signals arc linearly varied above and below the circuit switching level. The ring oscillator includes a plurality of differential delay circuits coupled in series in a ring configuration, a differential amplifier, and a comparator. Each of the differential delay circuits receives first and second differential input signals, and delays the received signals by a predetermined time in response to a predetermined control signal to generate first and second differential output signals. The differential amplifier receives the first and the second differential output signals of one of the differential delay circuits and amplifies the received signals to generate first and second differential amplified signals. The comparator receives first and the second differential amplified signals, and compares them to generate an oscillating signal in accordance with the comparison results.

Growing community of inventors

Eunpyeong-gu, South Korea

Byung-Hun Han