Data driver, display apparatus including the same and method of driving display panel using the same

A data driver comprising:

• a digital to analog converter configured to receive a data signal having a digital type and to convert the data signal into a data voltage having an analog type;
• a buffer configured to buffer the data voltage and to output the data voltage;
• and
• a buffer controller configured to determine a parameter of the buffer based on previous line data of the data signal and present line data of the data signal, wherein the buffer comprises:
• a differential input part configured to receive an input voltage;
• a power supplier configured to provide a bias current to the differential input part;
• an amplifier configured to amplify the input voltage;
• and
• an output part configured to output the amplified input voltage as an output voltage, wherein the differential input part comprises:
• a first p-type transistor connected to a first input terminal;
• a first n-type transistor connected to the first input terminal;
• a second p-type transistor connected to a second input terminal and connected to the first p-type transistor;
• and
• a second n-type transistor connected to the second input terminal and connected to the first n-type transistor, wherein the power supplier comprises:
• a first current source connected to a first power voltage terminal and a first node and configured to have a first bias current;
• a second current source connected to the first power voltage terminal and the first node and configured to have a second bias current different from the first bias current;
• a first switch connected between the second current source and the first node;
• a 1-2 current source connected between a second node and a second power voltage terminal and configured to have the first bias current;
• a 2-2 current source connected between the second node and the second power voltage terminal and configured to have the second bias current;
• and
• a 1-2 switch connected between the second node and the 2-2 current source,
• wherein the first p-type transistor and the second p-type transistor are connected at the first node, and
• wherein the first n-type transistor and the second n-type transistor are connected at the second node.

A display apparatus comprising:

• a display panel configured to display an image based on input image data;
• a driving controller configured to generate a data signal having a digital type based on the input image data;
• a data driver comprising a digital to analog converter configured to receive the data signal and to convert the data signal into a data voltage having an analog type and a buffer configured to buffer the data voltage and to output the data voltage to the display panel, wherein the buffer comprises:
• a first current source connected to a first power voltage terminal and a first node and configured to have a first bias current;
• a second current source connected to the first power voltage terminal and the first node and configured to have a second bias current different from the first bias current;
• and
• a first switch connected between the second current source and the first node;
• and
• a buffer controller configured to determine a parameter of the buffer based on previous line data of the data signal and present line data of the data signal.

A method of driving a display panel, the method comprising:

• generating a data signal having a digital type based on input image data;
• determining a bias current of a buffer based on previous line data of the input image data and present line data of the input image data, wherein the buffer comprises:
• a first current source connected to a first power voltage terminal and a first node and having a first bias current;
• a second current source connected to the first power voltage terminal and the first node and having a second bias current different from the first bias current;
• and
• a first switch connected between the second current source and the first node;
• converting the data signal into a data voltage having an analog type;
• and
• buffering the data voltage with the buffer by the bias current and outputting the data voltage to the display panel.