Digital-to-analog converter and source driver using the same
A digital-to-analog converter including a resistor string configured to provide a plurality of gradation voltages formed by receiving a top voltage at one end thereof and a bottom voltage at the other end; a plurality of pass transistors including a pass transistor having one end which is electrically connected to the resistor string and outputting any one among the plurality of gradation voltages; and a decoder configured to control the plurality of pass transistors. The plurality of the pass transistors are included in any one among a plurality of groups according to values of the gradation voltages, and the pass transistors included in the any one group are divided into a first group and a second group according to output gradation voltages, and pass transistors included in the first group and pass transistors included in the second group are different types of pass transistors.
1. A source driver, comprising:
a digital-to-analog converter including a decoder which receives a digital signal, a resistor string which provides a plurality of gradation voltages, and a plurality of pass transistors which output a gradation voltage corresponding to the digital signal; and
a buffer amplifier configured to providing an amplified gradation voltage by amplifying the gradation voltage output from the digital-to-analog converter,
wherein the plurality of pass transistors are included in any one a plurality of groups according to output gradation voltages, and the number of pass transistors included in the groups are not expressed as a power of 2,
wherein pass transistors included in the same group are arranged in the same deep well, pass transistors arranged in the same deep well are arranged in an N well or a P well, and a gradation voltage provided from a pass transistor arranged in the N well or a gradation voltage provided from a pass transistor arranged in the P well is selected and output by a well selection transistor.
2. The source driver of claim 1 , wherein the digital-to-analog converter further comprises a plurality of group selection transistors configured to provide a gradation voltage provided from a pass transistor included in any one among the plurality of groups to the buffer amplifier.
3. The source driver of claim 2 , wherein the decoder decodes the digital signal and forms a signal which controls the plurality of pass transistors and a signal which controls the plurality of group selection transistors.
4. The source driver of claim 3 , wherein the signal which controls the group selection transistors is a signal which swings between a maximum voltage among the plurality of gradation voltages and a reference voltage.
5. The source driver of claim 1 , wherein the well selection transistor has a greater size than the pass transistor.
6. The source driver of claim 1 , wherein the decoder decodes the digital signal and forms a signal which controls the well selection transistor.
7. The source driver of claim 1 , wherein the groups are divided according to the gradation voltages provided from the pass transistors included in the groups, and the number of pass transistors included in a group providing a low gradation voltage is smaller than the number of pass transistors included in a group providing a high gradation voltage.
8. The source driver of claim 1 , wherein the groups are divided according to the gradation voltages provided from the pass transistors included in the groups, and the number of pass transistors included in a group providing a low gradation voltage is the same as the number of pass transistors included in a group providing a high gradation voltage.
9. The source driver of claim 1 , wherein the groups are divided according to the gradation voltages provided from the pass transistors included in the groups, and the number of pass transistors included in a group providing a low gradation voltage is greater than the number of pass transistors included in a group providing a high gradation voltage.
10. A source driver, comprising:
a digital-to-analog converter including a decoder which receives a digital signal, a resistor string which provides a plurality of gradation voltages, and a plurality of pass transistors which output a gradation voltage corresponding to the digital signal; and
a buffer amplifier configured to providing an amplified gradation voltage by amplifying the gradation voltage output from the digital-to-analog converter,
wherein the plurality of pass transistors are included in any one among a plurality of groups according to output gradation voltages, and the number of pass transistors included in each group are expressed as a power of 2,
wherein the plurality of groups comprises a first group and a second group,
wherein the first group comprises a plurality of PMOS pass transistors and the second group comprises a plurality of NMOS pass transistors, and
wherein gradation voltages output by the PMOS pass transistors are higher than gradation voltages output by the NMOS pass transistors.
11. The source driver of claim 10 , wherein the groups are divided according to the gradation voltages provided from the pass transistors included in the groups, and the number of pass transistors included in a group providing a low gradation voltage is smaller than the number of pass transistors included in a group providing a high gradation voltage.
12. The source driver of claim 10 , the digital-analog converter further comprises a plurality of group selection transistors configured to provide a gradation voltage provided from a pass transistor included in any one among the plurality of groups to the buffer amplifier.
13. The source driver of claim 10 , wherein the decoder decodes the digital signal and forms a signal which controls the plurality of pass transistors and a signal which controls the plurality of group selection transistors.
14. The source driver of claim 10 , wherein the first group and the second group are in same deep well.
15. The source driver of claim 10 , wherein a PMOS pass transistor included in the first group outputs highest gradation voltage and a NMOS pass transistor included in the second group outputs lowest gradation voltage.
16. A source driver, comprising:
a decoder configured to receive a digital signal and provide a control signal corresponding to the digital signal;
a plurality of pass transistor groups including a plurality of pass transistors, which are arranged in a plurality of wells to which different bias voltages are provided, are controlled by the control signal, and provide an output signal corresponding to the digital signal;
group selection transistors configured to select any one among the pass transistor groups; and
a plurality of precharge switches configured to precharge an output node of the group selection transistors to a potential corresponding to the output signal,
wherein the precharge switches precharge the output node of the group selection transistors to a well bias voltage provided to a well in which pass transistors outputting a next output signal are arranged.
17. The source driver of claim 16 , wherein the precharge switches are controlled by the decoder.
18. The source driver of claim 16 , wherein the precharge switches are controlled by a precharge decoder.