SSD1801AV ETC [List of Unclassifed Manufacturers], SSD1801AV Datasheet - Page 20

• Manufacturer Part Number: SSD1801AV
• Description: LCD Segment / Common Driver with Controller for Character Display System
• Manufacturer: ETC [List of Unclassifed Manufacturers]

2. Voltage Regulator
resistor network. The reference voltage is selected by REF pin. When it is pulled low, internal voltage reference
V
required to be connected between AV
used to calculate the regulator output voltages.
When REF is low:
AND
When REF is high:
3. Contrast Control
Software control of the 32 contrast voltage levels at each voltage regulator feedback gain. The equation of calculating
the LCD driving voltage is given as:
When REF is low:
When REF is high:
where n is set in contrast control register.
4. Bias Divider
this bias divider saves most of the display current comparing to traditional design.
5. Bias Ratio Selection circuitry
19
V
V
V
SSD1801 Series
REF
out
out
out
The feedback gain control for LCD driving contrast can be adjusted by using reference voltage and external
Divide the regulator output to give the LCD driving voltages (V
=
=
=
is used. When it is pulled high, external voltage reference V
V
V
V
No.
31
32
V
V
L
L
L
1
2
3
4
.
.
.
6
6
6
out
REF
=
=
=
=









1
= V
1
1
V
+
X7
+
+
2 ±
L
-
-
-
-
-
-
-
-
R
R
6
R
R
R
R
2
1
Rev 1.1
01/2003
=
2
1
2
1







× 


× 

×
. 0
X6
1
V
-
-
-
-
-
-
-
-
06
+
V
V
EXT
REF
EXT
R
R
2
1
X5
-
-
-
-
-
-
-
-
×

× 

×






1
1
V
−
−
X4
Table 7- Contrast Control Register
REF
0
0
0
0
1
1
.
.
.
SS
150
150
n
n
and V






X3
0
0
0
0
1
1
.
.
.
F
(R1), and between V
X2
0
0
0
0
1
1
.
.
.
X1
0
0
1
1
1
1
.
.
.
X0
0
1
0
1
0
1
.
.
.
L5
-V
EXT
L2
F
0 (default)
). A low power consumption circuit design in
will be in use. The external resistors are
and V
30
31
n
1
2
3
.
.
.
L6
(R2). The following equations are
Maximum
Minimum
Vout
.
.
.
.
.
.
.
(“ - “: Don’t care)
Contrast
High
Low
.
.
.
.
.
.
.
SOLOMON