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ACX302AK

3. RGB Simultaneous Sampling

The horizontal driver samples R, G and B video signal simultaneously, which requires phase matching

between the R, G and B signals to prevent the horizontal resolution from deteriorating. Thus phase matching

by an external signal delay circuit is needed before applying the video signal to the LCD panel.

Two methods are applied for the delaying procedure: Sample-and-hold and Delay circuits. These two block

diagrams are as follows.

The ACX302AK has a right/left inversion function. The following phase relationship diagram indicates the

phase setting for right scan (RGT = high level). For left scan (RGT = low level), the phase setting should be

inverted for the B and G signals.

(1) Sample-and-hold (right scan)

20

21

AC Amp

AC Amp

AC Amp

S/H

S/H

S/H

S/H

S/H

CKB

CKG

CKG

CKG

CKR

B

R

G

BLUE

RED

GREEN

22

HCKn

CKB

CKR

CKG

AC Amp

AC Amp

AC Amp

Delay

Delay

Delay

B

R

G

BLUE

RED

GREEN

20

21

22

<Phase relationships of delaying sample-and-hold pulses> (right scan)

(2) Delay element (right scan)