Data Driver and Display Apparatus Including the Same

• US 20190051264A1
• Filed: 12/06/2017
• Published: 02/14/2019
• Est. Priority Date: 08/10/2017
• Status: Active Grant

• Current Assignee: DB HiTek Co., Ltd.
• Original Assignee: DB HiTek Co., Ltd.
• Inventors: Kim, Bo Sung, Chung, Hae Lyong, Yoon, Sun Young, Hong, Yu Min
• Granted Patent: US 10,446,107 B2
• Time in Patent Office: Days
• CPC Class Codes: G09G 2310/0286 Details of a shift registers arranged for use in a driving circuit
• CPC Class Codes: G09G 2310/0289 Details of voltage level shifters arranged for use in a driving circuit
• CPC Class Codes: G09G 2310/0291 Details of output amplifiers or buffers arranged for use in a driving circuit
• CPC Class Codes: G09G 2310/0294 Details of sampling or holding circuits arranged for use in a driver for data electrodes
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 2330/023 using energy recovery or conservation
• CPC Class Codes: G09G 3/3677 suitable for active matrices only
• CPC Class Codes: G09G 3/3688 suitable for active matrices only
• CPC Class Codes: G09G 3/3696 Generation of voltages supplied to electrode drivers
• CPC Class Codes: H03K 5/22 Circuits having more than one input and one output for comparing pulses or pulse trains with each other according to input signal characteristics, e.g. slope, integral indicating phase difference of two cyclic pulse trains G01R25/00

Abstract

A data driver includes a latch unit configured to store sequential first data and second data, a comparator configured to receive the first data and the second data from the latch unit and to output a comparison signal by comparing the received first data with the received second data, a digital-analog converter configured to output an analog signal corresponding to the first data from the latch unit, an output unit configured to provide a drive current having a current value, the drive current configured to drive a display panel based on a bias signal and the analog signal, and a bias unit configured to adjust, set or maintain the bias signal based on the comparison signal. The current value is based on the bias signal.

Claims

1. A data driver comprising:

a latch unit configured to store first data and second data;

a comparator configured to receive the first data and the second data from the latch unit and to output a comparison signal by comparing the received first data with the received second data;

a digital-analog converter configured to output an analog signal corresponding to the first data from the latch unit;

an output unit configured to provide a drive current having a current value, the drive current configured to drive a display panel based on a bias signal and the analog signal; and

a bias unit configured to adjust, set or maintain the bias signal based on the comparison signal,

wherein the current value is based on the bias signal.

2. The data driver according to claim 1, wherein the comparator outputs a comparison signal having (i) a first logical value if the first data is equal to the second data, and (ii) a second logical value different from the first logical value if the first data is not equal to the second data.

3. The data driver according to claim 1, wherein the comparator generates the comparison signal by performing a logic operation on the first data and the second data.

4. The data driver according to claim 1, wherein the latch unit includes:

a first latch unit configured to store the first data; and

a second latch unit configured to receive the first data from the first latch unit

wherein the second latch unit stores the first data when the first latch unit receives the second data.

5. The data driver according to claim 4, wherein the comparator receives the first data from the second latch unit and the second data from the first latch unit.

6. The data driver according to claim 1, wherein the first data includes a number of bits that is equal to a number of bits of the second data.

7. The data driver according to claim 6, wherein the comparator includes:

a first logical operation unit configured to output first logical values from a first logic operation on each of the bits of the first data and each of the corresponding bits of the second data; and

a second logical operation unit configured to generate a second logical value from a second logic operation on the first logical values and to output the comparison signal.

8. The data driver according to claim 7,

wherein the first logical operation unit includes a plurality of AND gates, and

each of the plurality of AND gates performs an AND operation on one of the bits of the first data and the corresponding one of the bits of the second data.

9. The data driver according to claim 1, wherein the bias unit adjusts, sets or maintains a voltage level of the bias signal based on a value of the comparison signal.

10. The data driver according to claim 9, wherein:

the output unit includes a differential amplifier,

a tail current of the differential amplifier is adjusted or maintained based on the voltage level of the bias signal, and

the current value is adjusted or maintained based on the tail current.

11. The data driver according to claim 1, wherein the first data is data configured to drive pixels of an i-th (i being a natural number equal to or greater than 1) row of the display panel, and the second data is data configured to drive pixels of an adjacent row of the display panel.

12. A display device comprising:

the data driver of claim 1;

a display panel including gate lines, data lines and pixels connected to the gate lines and the data lines, the pixels being in a matrix including rows and columns;

a data driver configured to drive the data lines; and

a gate driver configured to drive the gate lines.

13. A method of driving a display panel including gate lines, data lines and pixels connected to the gate lines and the data lines, the pixels being in a matrix including rows and columns, the method comprising:

first data configured to drive pixels of an i-th (i being a natural number equal to or greater than

     1) row of the display panel;

storing second data configured to drive pixels of an (i+1)-th row of the display panel;

determining whether the stored first data is equal to the stored second data; and

adjusting, setting or maintaining a current value of a drive current configured to drive pixels of the (i+1)-th row to or at a first current value or a second current value depending on whether the stored first data is equal to the stored data.

14. The method according to claim 13, wherein when the first data is not equal to the second data, the current value of the drive current is adjusted or set to or maintained at the first current value.

15. The method according to claim 14, wherein when the first data is equal to the second data, the current value of the drive current is adjusted or set to or maintained at the second current value, and the second current value is less than the first current value.

16. The method according to claim 13, wherein the first data has a number of bits that is equal to that of the second data.

17. The method according to claim 13, wherein determining whether the stored first data is equal to the stored second data comprises performing a logic operation on the first data and the second data.