Samsung Electronics Co., Ltd.

Do-youn Kim

Jae-Hong Ko

Seung-jung Lee

Jae-Suk Yu

Kee-Moon Chun

Jae-Wook Kwon

Chang-Hwe Choi

Sung-Pil Choi

Byoung-kwon An

Ho-hak Rho

Provided are a method of driving a liquid crystal panel which prevents unintended digital image data from being displayed on a liquid crystal panel when power is provided or interrupted, and a source driver and a liquid crystal display apparatus. The source driver includes output buffers; output pads; and a switching unit which is disposed between the output buffers and the output pads and controls an electrical connection state of the output pads. If a level up or a level down of a power voltage occurs, the switching unit prevents output signals of the output buffers from being transmitted to the liquid crystal panel via corresponding output pads and performs at least one of a charge sharing operation for connecting the output pads to each other and a discharging operation for providing a discharge path from the output pads to a ground terminal, in a preset period.

Liquid crystal panel driving method, and source driver and liquid crystal display apparatus using the method

In a liquid crystal display (LCD) panel driver with a self-masking function using a power-on reset signal, and in a method of driving the same, the LCD panel driver includes a power-on reset signal generation unit that generates a power-on reset signal in response to a supply voltage applied to a LCD panel; a latch unit that receives a start pulse signal instructing that source lines of the LCD panel be driven and generates first and second set signals for setting an initial value of an output signal of a flip-flop to be in a predetermined default logic level, in response to the power-on reset signal; and a counter unit that generates a start pulse masking signal by masking at least one pulse of the start pulse signal in response to the first and second set signals and the start pulse signal.

LCD panel driver with self masking function using power on reset signal and driving method thereof

An output buffer with an improved slew rate and method thereof. The output buffer may include a differential amplifier, a controller and an output unit. The output buffer may generate a pull signal and a control signal based on received input and output signals. The controller may transition an output node to a control voltage in response to the control signal and a bias voltage. The output unit may maintain the first output signal between a given voltage and the control voltage based on the pull signal and the bias voltage.

Output buffer with improved slew rate and method thereof

An operational amplifier includes: a differential amplifier for differentially amplifying first and second differential input signals to generate first and second output signals through first and second nodes; a driver for driving an output node in response to the second output signal; and a drive current adjuster for adjusting a driving current of the driver in response to the first output signal. The drive current adjuster includes: a first transistor including a drain connected to the output node, a gate, and a source connected to a ground voltage; a second transistor including a gate connected to the first node, a drain, and a source connected to a source voltage; a third transistor including a drain connected to the drain of the second transistor, a source, and a gate connected to a first bias voltage; and a fourth transistor including a drain connected to the source of the third transistor, a source connected to the ground voltage, and a gate connected to a second bias voltage, wherein the gate of the first transistor is commonly connected to the drains of the second and third transistors.

Operational amplifier for output buffer and signal processing circuit using the same

A position coordinates signal detecting circuit of a sensor panel is provided. The position coordinates signal detecting circuit of the sensor panel according to the present invention includes first through fourth resistors each of which has one end connected to one of the left upper-most edge, the left lower-most edge, the right upper-most edge, and the right lower-most edge of the sensor panel. First through fourth driving signal generators are respectively connected to the other side of the first through fourth resistors for generating a driving signal so as to drive the sensor panel. Analog switches receive first through fourth pairs of voltages respectively generated at both ends of the first through fourth resistors. The first through fourth pairs of voltage are multiplexed in response to first through fourth selecting signals to provide a multiplexed signal, and a differential amplifier for amplifies the multiplexed signal. The position coordinates detecting circuit of the sensor panel according to the present invention makes it possible to amplify the voltage difference between both end of the variable resistors. Thus, the characteristics mismatching between different amplifiers is reduced, and the position coordinates are detected accurately.

Growing community of inventors

Hwaseong-si, South Korea

Do-youn Kim