Patent ID: 8049692

Claim:
A common voltage generation circuit comprising: a common voltage adjusting circuit that adjusts a level of a common voltage in response to a compensation signal and that provides the adjusted common voltage to a liquid crystal panel; and a common voltage compensating circuit that includes: an amplifier that amplifies and outputs the adjusted common voltage, a resistor that produces potential differences between the adjusted common voltage and each of positive and negative polarity data voltages output from a data driver, wherein the resistor is connected between an output terminal of the amplifier and an output terminal of the data driver, a first voltage detector that detects across the resistor a potential difference between the adjusted common voltage and the negative polarity data voltage, a second voltage detector that detects across the resistor a potential difference between the adjusted common voltage and the positive polarity data voltage, and a voltage comparator that compares output signals of the first and second voltage detectors and that feeds the compensation signal back to the common voltage adjusting circuit, wherein output signals of the first and second voltage detectors are compared with each other to determine whether the output signal of the first voltage detector is greater than the output signal of the second voltage detector and the compensation signal is output as a result of a comparison of the output signals of the first and second voltage detectors.