Display device and method of driving the same

A display device comprising:

• a pixel column comprising first to n-th pixels connected to a data line and respectively connected to gate lines;
• a data driving chip which outputs a test data voltage in a test mode and outputs image data voltages in a normal mode;
• a sensing circuit electrically which is connected to the data line and the data driving chip in the test mode, senses a current output to the first pixel by the test data voltage during a first period, and senses a current output to an i-th pixel by the test data voltage during a second period shorter than the first period;
• and
• a signal controller which compares a reference charge amount calculated based on the current sensed during the first period to a first charge amount calculated based on the current sensed during the second period and compensates for a level of an image data voltage applied to the i-th pixel among the image data voltages based on a compared result.