Specifications
8–20 EPSON
SED1240 Series
2 Using only the voltage regulating circuit and the voltage follower.
CAP1+
CAP1–
V
OUT
V
5
V
DD
, V
0
C
2
C
2
C
2
C
2
C
2
V
1
V
2
V
3
V
4
V
5
V
S1
V
R
V
SS
V
SS2
SED124XD
XX
CAP2–
CAP2+
[When using a V
5
voltage regulating built-in resistor]
(Example of V
SS2
= V
SS
)
External
power
supply
CAP1+
CAP1–
V
OUT
V
5
R
3
R
2
R
1
V
DD
, V
0
C
2
C
2
C
2
C
2
C
2
V
1
V
2
V
3
V
4
V
5
V
S1
V
R
V
SS
V
SS2
SED124XD
XX
CAP2–
CAP2+
[When using no V
5
voltage regulating built-in resistor]
(Example of V
SS2
= V
SS
)
External
power
supply
CAP1+
CAP1–
V
OUT
V
5
V
DD
, V
0
C
2
C
2
C
2
C
2
C
2
V
1
V
2
V
3
V
4
V
5
V
S1
V
R
V
SS
V
SS2
SED124XD
XX
CAP2–
CAP2+
(Example of V
SS2
= V
SS
)
External
power
supply
CAP1+
CAP1–
V
OUT
V
DD
, V
0
V
1
V
2
V
3
V
4
V
5
V
S1
V
R
V
SS
V
SS2
SED124XD
XX
CAP2–
CAP2+
(Example of V
SS2
= V
SS
)
External
power
supply
Reference set values: C1: 0.47 to 4.7 µF It is recommended to set optimum values suitable for the panel size in
C2: 0.1 to 4.7 µF capacitors C1 and C2 while watching the liquid crystal display and drive
waveforms.
*1 Because the input impedance of the V
R pin is high, use a short wire and a shielding wire.
*2 Determine C1 and C2 values depending on the size of the LCD panel to be driven. Set proper values that permit
stabilizing the liquid crystal drive voltages.
[Setting example] • Turn on the voltage regulating circuit and the voltage follower and give a voltage to V
OUT from
the outside.
• Display a LCD heavy load pattern like horizontal stripes and determine a C
2 value so that the
liquid crystal drive voltages (V
1 to V5) may be stabilized. However, it is necessary to set the
same capacity value in C2 in every case.
• Next, turn on the built-in power supply and determine a C
1 value.