Driving circuit and organic light emitting diode display device including the same

1. A circuit, comprising:

a first decoder adapted to output a plurality of first decoding signals employing first bits of a digital data signal;

a first selection unit adapted to generate a plurality of first selection signals and a plurality of first inverse selection signals in correspondence with the first decoding signals;

a switch unit adapted to select a first reference voltage and second reference voltage from a plurality of reference voltages employing the first selection signals and the first inverse selection signals, the second reference voltage being lower than the first reference voltage;

a second decoder adapted to output a plurality of second decoding signals employing second bits of the digital data signal;

a second selection unit adapted to generate a plurality of second selection signals and a plurality of second inverse selection signals in correspondence with the second decoding signals; and

a plurality of voltage distribution units adapted to receive and distribute the selected first reference voltage and the selected second reference voltage, wherein a voltage distribution unit includes a data voltage generation unit adapted to receive the second selection signals and the second inverse selection signals to generate a data voltage, wherein the switch unit includes:

a first transistor adapted to receive a first selection signal and switch the first reference voltage;

a second transistor adapted to receive a first inverse selection signal and switch the first reference voltage;

a third transistor adapted to receive the first selection signal and switch the second reference voltage; and

a fourth transistor adapted to receive the first inverse selection signal and switch the second reference voltage.

2. The circuit as claimed in claim 1 , wherein the first selection unit is adapted to operate in correspondence with one bit of the digital data signal.

3. The circuit as claimed in claim 1 , wherein the second selection unit is adapted to operate in correspondence with one bit of the digital data signal.

4. The circuit as claimed in claim 1 , wherein the first decoder is adapted to select two reference voltages.

5. The circuit as claimed in claim 1 , wherein the data voltage generation unit includes a voltage distribution unit adapted to receive the first reference voltage and the second reference voltage to generate four grey level voltages by employing a resistance ratio.

6. The circuit as claimed in claim 1 , wherein the data voltage generation unit comprises:

a fifth transistor adapted to switch the first reference voltage in correspondence with the second selection signal;

a sixth transistor adapted to switch the first reference voltage in correspondence with the second inverse selection signal;

a resistor array in which first, second, and third resistors are connected in series;

a seventh transistor connected between the first and second resistors and adapted to output a grey level voltage of the data signal in correspondence with the second selection signal; and

an eighth transistor connected between the second and third resistor and adapted to output a grey level voltage of the data signal in correspondence with the second inverse selection signal.

7. The circuit as claimed in claim 1 , wherein the switch unit is adapted to select two reference voltage lines from nine reference voltage lines to select the first reference voltage and the second reference voltage.

8. A data driver, comprising:

a shift register unit adapted to output control signals;

a latch unit adapted to receive digital data signals in series and output digital data signals in parallel in correspondence with the control signal; and

a D/A converter unit adapted to convert a digital data signal to a data voltage,

wherein the D/A converter unit includes:

a first decoder adapted to output a plurality of first decoding signals employing first bits of a digital data signal;

a first selection unit adapted to generate a plurality of first selection signals and a plurality of first inverse selection signals in correspondence with the first decoding signals;

a switch unit adapted to select a first reference voltage and second reference voltage from a plurality of reference voltages employing the first selection signals and the first inverse selection signals, the second reference voltage being lower than the first reference voltage;

a second decoder adapted to output a plurality of second decoding signals employing second bits of the digital data signal;

a second selection unit adapted to generate a plurality of second selection signals and a plurality of second inverse selection signals in correspondence with the second decoding signals; and

a plurality of voltage distribution units adapted to receive and distribute the selected first reference voltage and the selected second reference voltage,

wherein a voltage distribution unit includes a data voltage generation unit adapted to receive the second selection signals and the second inverse selection signals to generate a data voltage, and

wherein the switch unit includes:

a first transistor adapted to receive a first selection signal and switch the first reference voltage;

a second transistor adapted to receive a first inverse selection signal and switch the first reference voltage;

a third transistor adapted to receive the first selection signal and switch the second reference voltage; and

a fourth transistor adapted to receive the first inverse selection signal and switch the second reference voltage.

9. The data driver as claimed in claim 8 , wherein the first selection unit is adapted to operate in correspondence with one bit of the digital data signal, the second selection unit is adapted to operate in correspondence with one bit of the digital data signal, and the first decoder is adapted to select two reference voltages.

10. The data driver as claimed in claim 8 , wherein the data voltage generation unit includes a voltage distribution unit adapted to receive the first reference voltage and the second reference voltage to generate four grey level voltages by employing a resistance ratio.

11. The data driver as claimed in claim 8 , wherein the data voltage generation unit comprises:

a fifth transistor adapted to switch the first reference voltage in correspondence with the second selection signal;

a sixth transistor adapted to switch the first reference voltage in correspondence with the second inverse selection signal;

a resistor array in which first, second, and third resistors are connected in series;

a seventh transistor connected between the first and second resistors and adapted to output a grey level voltage of the data signal in correspondence with the second selection signal; and

an eighth transistor connected between the second and third resistor and adapted to output a grey level voltage of the data signal in correspondence with the second inverse selection signal.

12. The data driver as claimed in claim 8 , wherein the switch unit is adapted to select two reference voltage lines from nine reference voltage lines to select the first reference voltage and the second reference voltage.

13. An organic light emitting diode display device, comprising:

a pixel unit adapted to receive a data voltage and a scan signal to display an image;

a data driver adapted to generate the data voltage; and

a scan driver adapted to generate the scan signal,

wherein the data driver includes:

a shift register unit adapted to output control signals;

a latch unit adapted to receive digital data signals in series and output digital data signals in parallel in correspondence with the control signal; and

a D/A converter unit adapted to convert a digital data signal to data voltage,

wherein the D/A converter unit includes:

a first decoder adapted to output a plurality of first decoding signals employing first bits of a digital data signal;

a first selection unit adapted to generate a plurality of first selection signals and a plurality of first inverse selection signals in correspondence with a plurality of the first decoding signals;

a switch unit adapted to select a first reference voltage and second reference voltage from a plurality of reference voltages employing the first selection signals and the first inverse selection signals, the second reference voltage being lower than the first reference voltage;

a second decoder adapted to output a plurality of second decoding signals employing second bits of the digital data signal;

a second selection unit adapted to generate a plurality of second selection signals and a plurality of second inverse selection signals in correspondence with the second decoding signals; and

a plurality of voltage distribution units adapted to receive and distributing the selected first reference voltage and the selected second reference voltage, wherein a voltage distribution unit includes a data voltage generation unit adapted to receive the second selection signals and the second inverse selection signals to generate a data voltage, wherein the switch unit includes:

a first transistor adapted to receive a first selection signal and switch the first reference voltage;

a second transistor adapted to receive a first inverse selection signal and switch the first reference voltage;

a third transistor adapted to receive the first selection signal and switch the second reference voltage; and

a fourth transistor adapted to receive the first inverse selection signal and switch the second reference voltage.

14. The organic light emitting diode display device as claimed in claim 13 , wherein the first selection unit is adapted to operate in correspondence with one bit of the digital data signal, the second selection unit is adapted to operate in correspondence with one bit of the digital data signal, and the first decoder selects two reference voltages.

15. The organic light emitting diode display device as claimed in claim 13 , wherein the data voltage generation unit includes a voltage distribution unit adapted to receive the first reference voltage and the second reference voltage to generate four grey level voltages by employing a resistance ratio.

16. The organic light emitting diode display device as claimed in claim 13 , wherein the data voltage generation unit comprises:

a fifth transistor adapted to switch the first reference voltage in correspondence with the second selection signal;

a sixth transistor adapted to switch the first reference voltage in correspondence with the second inverse selection signal;

a resistor array in which first, second, and third resistors are connected in series;

a seventh transistor connected between the first and second resistors and adapted to output a grey level voltage of the data signal in correspondence with the second selection signal; and

an eighth transistor connected between the second and third resistor and outputting a grey level voltage of the data signal in correspondence with the second inverse selection signal.

17. The organic light emitting diode display device as claimed in claim 13 , wherein the switch unit is adapted to select two reference voltage lines from nine reference voltage lines to select the first reference voltage and the second reference voltage.