1. Meeting report
Zhoutianyu

2. 1. the delay of DAC and buffer
2. gamma with linear DAC
3. two-stage R-DAC

3. 1. the delay of DAC and buffer

4. 2. gamma with linear DAC
Usually, gamma correction is realized by using non-linear DAC architecture
Since the non-linear DAC architecture uses piece wise method to fit the gamma curve, precision problem is a considerable disadvantage in this architecture.
Adjustable Gamma Correction Circuit for TFT LCD

5. the upper left is an ‘Applied voltage to LCD transparency’ curve, while the upper right is the gray level curve that we are going to present, and the lower left is the gamma curve of the input to output transformation.
The actual value of γ may range from about 2.2 to 2.6
Adjustable Gamma Correction Circuit for TFT LCD

6. Adjustable Gamma Correction Circuit for TFT LCD

7. Adjustable Gamma Correction Circuit for TFT LCD

8. Simulation Result
Adjustable Gamma Correction Circuit for TFT LCD

9. Advantage of this method
Simplify the efforts of the resistor issue
A better match of gamma curve
3) Less external reference voltage source required
4) Flexibility to support multiple gamme values

10. 3.two-stage R-DAC
Adjustable Gamma Correction Circuit for TFT LCD

11. Adjustable Gamma Correction Circuit for TFT LCD

12. thanks