Patent ID: 8525765

Claim:
A display driver circuit, comprising: 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 grayscale voltage generator including 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, using the at least two gamma voltages, 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, 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.