Buffer circuit and organic light emitting display with data integrated circuit using the same

A data integrated circuit, comprising:

• a shift register part;
• a latch part for storing data corresponding to signals supplied in sequence from the shift register part;
• a D/A converter for generating gradation voltage corresponding to a gradation level of the data;
• and
• a plurality of buffers for supplying the gradation voltage to a data line;
• wherein each buffer comprises:
• a first capacitor for receiving external gradation voltage through a first terminal;
• a first inverter having an input terminal connected to a second terminal of the first capacitor;
• a second capacitor having a first terminal connected to an output terminal of the first inverter;
• a second inverter having an input terminal connected to a second terminal of the second capacitor;
• a third capacitor having a first terminal connected to an output terminal of the second inverter;
• and
• a first transistor connected to a second terminal of the third capacitor, and controlling current flowing from a first power source to a data line so as to supply the gradation voltage to the data line in correspondence to the voltage supplied by the third capacitor.

An organic light emitting display, comprising:

• a plurality of scan lines and data lines;
• a scan driver for supplying a scan signal to the scan line;
• and
• a data driver comprising a plurality of buffers connected to the respective data lines, and supplying a data signal to the data line;
• wherein each buffer comprises:
• a first capacitor receiving external gradation voltage through a first terminal;
• a first inverter having an input terminal connected to a second terminal of the first capacitor;
• a second capacitor having a first terminal connected to an output terminal of the first inverter;
• a second inverter having an input terminal connected to a second terminal of the second capacitor;
• a third capacitor having a first terminal connected to an output terminal of the second inverter;
• and
• a first transistor connected to a second terminal of the third capacitor, and controlling current flowing from a first power source to a data line so as to supply the gradation voltage to the data line in correspondence to the voltage supplied by the third capacitor.