Display panel driving apparatus, display and method for correcting positive and negative polarity grayscale voltage

A display apparatus comprising:

• a display panel which displays an image and comprising a gate line and a data line;
• and
• a display apparatus comprising a grayscale voltage outputting part which generates a first positive polarity grayscale voltage and a first negative polarity grayscale voltage, compares the first positive polarity with a first reference voltage to output a first comparison voltage, compares the first negative polarity grayscale voltage with a second reference voltage to output a second comparison voltage, compares the first comparison voltage with the second comparison voltage to output a voltage deviation value, and outputs a second positive polarity grayscale voltage and a second negative polarity grayscale voltage based on the voltage deviation value, a data driving part which outputs a data signal based on image data to the data line of the display panel, using the second positive polarity grayscale voltage and the second negative polarity grayscale voltage, and a gate driving part which outputs a gate signal to the gate line of the display panel.