Data driver and organic light emitting diode display device thereof
A data driver for an OLED display device includes a shift register, a first data processing unit adapted to output a first voltage by employing upper bits of the digital data signal, and a second data processing unit adapted to output a second voltage employing lower bits of the digital data signal, where the analog data signal is generated to correspond to the first voltage and the second voltage.
1 . An organic light emitting diode display device, comprising:
a pixel unit adapted to display an image;
a data driver adapted to generate an analog data signal from a digital data signal, and to transmit the analog data signal to the pixel unit; and
a scan driver adapted to generate a scan signal and to transmit the scan signal to the pixel unit,
wherein the data driver includes:
a shift register;
a first data processing unit adapted to output a first voltage by employing upper bits of the digital data signal; and
a second data processing unit adapted to output a second voltage by employing lower bits of the digital data signal, wherein the analog data signal corresponds to the first voltage and the second voltage.
2 . The organic light emitting diode display device as claimed in claim 1 , wherein the first data processing unit comprises:
an upper bit sampling latch adapted to receive the upper bits of the digital data signal in series and to store the upper bits of the digital data signal by employing a control signal of the shift register;
an upper bit holding latch adapted to receive the upper bits of the digital data signal from the upper bit sampling latch, and to output the received upper bits of the digital data signal in parallel;
an upper bit level shifter adapted to output a signal corresponding to the upper bits of the digital data signal at an operation voltage; and
an upper bit D/A converter adapted to generate the first voltage by employing the signal output from the upper bit level shifter.
3 . The organic light emitting diode display device as claimed in claim 2 , wherein the upper bit D/A converter is adapted to generate a first reference voltage and a second reference voltage different from the first reference voltage.
4 . The organic light emitting diode display device as claimed in claim 1 , wherein the second data processing unit comprises:
a lower bit sampling latch adapted to receive the lower bits of the digital data signal in series and to store the lower bits of the digital data signal by employing a control signal of the shift register;
a lower bit holding latch adapted to receive the lower bits of the digital data signal from the lower bit sampling latch, and to output the received lower bits of the digital data signal in parallel;
a lower bit level shifter adapted to output a signal corresponding to the lower bits of the digital data signal at an operation voltage; and
a lower bit D/A converter adapted to generate the second voltage by employing the signal output from the lower bit level shifter.
5 . The organic light emitting diode display device as claimed in claim 4 , wherein the lower bit D/A converter is adapted to output a signal corresponding to the second voltage.
6 . The organic light emitting diode display device as claimed in claim 1 , wherein the first data processing unit and the second data processing unit are connected to a demux.
7 . The organic light emitting diode display device as claimed in claim 7 , wherein the demux is a 1:3 demux.
8 . A data driver adapted to receive a digital data signal and generate an analog data signal, comprising:
a shift register;
a first data processing unit adapted to output a first voltage by employing upper bits of the digital data signal; and
a second data processing unit adapted to output a second voltage by employing lower bits of the digital data signal,
wherein the analog data signal corresponds to the first voltage and the second voltage.
9 . The data driver as claimed in claim 8 , wherein the first data processing unit comprises:
an upper bit sampling latch adapted to receive the upper bits of the digital data signal in series and to store the upper bits of the digital data signal by employing a control signal of the shift register;
an upper bit holding latch adapted to receive the upper bits of the digital data signal from the upper bit sampling latch, and to output the received upper bits of the digital data signal in parallel;
an upper bit level shifter adapted to output a signal corresponding to the upper bits of the digital data signal at an operation voltage; and
an upper bit D/A converter adapted to generate the first voltage by employing the signal output from the upper bit level shifter.
10 . The data driver as claimed in claim 9 , wherein the upper bit D/A converter is adapted to generate a first reference voltage and a second reference voltage different from the first reference voltage.
11 . The data driver as claimed in claim 8 , wherein the second data processing unit comprises:
a lower bit sampling latch adapted to receive the lower bits of the digital data signal in series and to store the lower bits of the digital data signal by employing a control signal of the shift register;
a lower bit holding latch adapted to receive the lower bits of the digital data signal from the lower bit sampling latch, and to output the received lower bits of the digital data signal in parallel;
a lower bit level shifter adapted to output a signal corresponding to the lower bits of the digital data signal at an operation voltage; and
a lower bit D/A converter adapted to generate the second voltage employing the signal output from the lower bit level shifter.
12 . The data driver as claimed in claim 11 , wherein the lower bit D/A converter outputs a signal corresponding to the second voltage.
13 . The data driver as claimed in claim 8 , wherein the first data processing unit and an output terminal of the second data processing unit are connected to a demux.
14 . The data driver as claimed in claim 13 , wherein the demux is an 1:3 demux.
15 . A method for driving an organic light emitting diode display device, comprising:
dividing a data signal, input in series, into upper bits and lower bits;
receiving the upper bits and outputting the received upper bits from a first data processing unit in parallel;
receiving the lower bits and outputting the received lower bits from a second data processing unit in parallel; and
generating an analog data signal by selecting first and second reference voltages employing the upper bits output in parallel, and distributing the selected first and second reference voltages employing the lower bits output in parallel.
16 . The method for driving an organic light emitting diode display device as claimed in claim 15 , wherein the first data processing unit and an output terminal of the second data processing unit are connected to a demux.
17 . The method for driving an organic light emitting diode display device as claimed in claim 16 , wherein the demux is an 1:3 demux.
18 . The method for driving an organic light emitting diode display device as claimed in claim 15 , wherein the first data processing unit comprises:
an upper bit sampling latch adapted to receive the upper bits of the digital data signal in series and to store the upper bits of the digital data signal by employing a control signal of the shift register;
an upper bit holding latch adapted to receive the upper bits of the digital data signal from the upper bit sampling latch, and to output the received upper bits of the digital data signal in parallel;
an upper bit level shifter adapted to output a signal corresponding to the upper bits of the digital data signal at an operation voltage; and
an upper bit D/A converter adapted to generate a first voltage corresponding to the analog data signal by employing the signal output from the upper bit level shifter.
19 . The method for driving an organic light emitting diode display device as claimed in claim 15 , wherein the second data processing unit comprises:
a lower bit sampling latch adapted to receive lower bits of the digital data signal in series and to store the lower bits of the digital data signal by employing a control signal of the shift register;
a lower bit holding latch adapted to receive the lower bits of the digital data signal from the second sampling latch, and to output the received lower bits of the digital data signal in parallel;
a lower bit level shifter adapted to output a signal corresponding to the lower bits of the digital data signal at an operation voltage; and
a lower bit D/A converter adapted to generate a second voltage corresponding to the analog data signal by employing the signal output from the lower bit level shifter.
20 . The method for driving an organic light emitting diode display device as claimed in claim 15 , wherein the upper bit is a most significant bit, and the lower bit is a least significant bit.