Display driver circuit and display device that outputs symmetrical grayscale voltages

A display device comprising:

• a panel including an array substrate including a plurality of pixel electrodes between a plurality of data lines and a plurality of gate lines, a counter substrate disposed to face the array substrate and including at least one common electrode, and a liquid crystal layer interposed between the array substrate and the counter substrate;
• a controller configured to output a source driver control signal, a gate driver control signal, and a polarity signal in response to image data and a command;
• a grayscale voltage generator configured to output a selection grayscale voltage in response to the polarity signal;
• a source driver configured to receive the selection grayscale voltage in response to the source driver control signal and apply a display data voltage to the plurality of data lines;
• and
• a gate driver configured to apply a gate-on voltage to the plurality of gate lines in response to the gate driver control signal,
• wherein the grayscale voltage generator includes:
• a reference voltage selection unit configured to receive and divide a first supply voltage and a second supply voltage, and select and output a maximum reference voltage and a minimum reference voltage;
• and
• a gamma voltage selector configured to receive the maximum and minimum reference voltages, generate at least two gamma voltages by dividing the maximum and minimum reference voltages, and generate at least two positive grayscale voltages that range from the minimum reference voltage to the maximum reference voltage or at least two negative grayscale voltages that range from the maximum reference voltage to the minimum reference voltage using the at least two gamma voltages,
• wherein an absolute value of a difference between a first positive grayscale voltage and a second positive grayscale voltage of the at least two positive grayscale voltages equals an absolute value of a difference between a first negative grayscale voltage and a second negative grayscale voltage of the at least two negative grayscale voltages;
• and
• wherein the grayscale voltage generator comprises at least two gamma selection buffers, each gamma selection buffer including:
• a first amplifier configured to receive a corresponding one of the at least two gamma voltages and a feedback voltage, sense and amplify a difference between the corresponding one of the at least two gamma voltages and the feedback voltage, and output the amplified difference;
• two second amplifiers configured to receive and buffer the output of the first amplifier, output a corresponding grayscale voltage to corresponding nodes of a positive resistor string and a negative resistor string of the gamma voltage selector, and apply the corresponding grayscale voltage to the first amplifier as the feedback voltage;
• and
• a switch configured to transfer the output of the first amplifier to one of the two second amplifiers in response to a polarity selection signal.