Specifications

8–18 EPSON
SED1240 Series
• Voltage regulating circuit using the electronic volume
function
When the electronic volume function is used, the
liquid crystal drive voltage V
5 can be controlled by the
command to adjust the density of liquid crystal display.
Regarding this method, set 5-bit data in the electronic
volume register, and the liquid crystal drive voltage
V
5 can take one of 32 states of voltage value.
When the electronic volume function is used, the
voltage regulating circuit must be turned on by the
power control command.
+
−
0
• •
α
V 5
R b
R a
V
R
V 0
V DD
V EV
V REG
n a
[Constant setup example when using the electronic volume function]
Table 6
V
5
= (1 +
R
b
) × V
EV
Ra
However: VEV = VREG – α
α = V
REG / 150
No. Electronic volume register α V5
0 (0, 0, 0, 0, 0) 0 Large
1 (0, 0, 0, 0, 1) 1α •
2 (0, 0, 0, 1, 0) 2α •
3 (0, 0, 0, 1, 1) 3α •
•• ••
•• ••
30 (1, 1, 1, 1, 0) n-1α •
31 (1, 1, 1, 1, 1) nα Small
When the electronic volume function is not used, set the electronic volume register to (0,0,0,0,0).