HD66766R Datasheet, PDF (69/97 Pages) Hitachi Semiconductor – 132 x 176-dot Graphics LCD Controller/Driver for 65K Colors

HD66766R
Rev. 1.0-1 / September 2002
n-raster-row Reversed AC Drive
The HD66766R supports not only the LCD reversed AC drive in a one-frame unit (B-pattern waveform)
but also the n-raster-row reversed AC drive which alternates in an n-raster-row unit from one to 64 raster-
rows (C-pattern waveform). When a problem affecting display quality occurs, such as cross-talk at
high-duty driving of more than 1/64 duty, the n-raster-row reversed AC drive (C-pattern waveform) can
improve the quality.
Determine the number of raster-rows n (NW bit set value + 1) for alternating after confirmation of the
display quality with the actual LCD panel. However, if the number of AC raster-rows is reduced, the
LCD alternating frequency becomes high. Because of this, the charge or discharge current is increased
in the LCD cells.
1 frame
1 frame
1 2 3 4 5 6 7 8 9 10 11 12 13
175176 1 2 3 4 5 6 7 8 9 10 11 12 13
175176 _{1 2 3}
B-pattern waveform drive
-1/176 duty
C-pattern
-wave form drive
- 1/176 duty
- 11 raster-row reversal
- Without EORs
C-pattern waveform drive
- 1/176 duty
- 11 raster-row reversal
- With EORs
Notice : Specify the number of AC drive raster-rows and the necessity of EOR so that the DC bias is not generated to the LCD.
Figure 53 Example of an AC Signal under n-raster-row Reversed AC Drive
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