Specifications

EPSON 8–17
SED1240 Series
SED1240
Series
[When using the V5 voltage regulating built-in resistor (Use of V5 voltage regulating built-in resistor is set by command.)]
When the V5 voltage regulating built-in resistor and the electronic volume function are used, the liquid crystal supply
voltage V
5 can be controlled and the density of liquid crystal display can be controlled by commands only without adding
any external resistor.
The V
5 voltage can be obtained by the following expression 2 by adjusting resistors Ra and Rb within the range of
| V
5 | < | VOUT |.
V
5
= (1 +
R
b
) • V
EV
..............................
2
R
a
In this case, VEV is determined by the constant-voltage source within the IC and by setting the electronic volume. When
the electronic volume value is (00000), V
REG
·
=
·
2.0 V, being constant.
The voltage range of the V5 output can be adjusted by
changing the built-in resistor ratio (1 + Rb/Ra) by
command. Reference values are shown in Table 5 and
Fig. 2.
Table 5 V
5 voltage regulating built-in resistor ratio
set values (reference values)
Built-in R a Built-in R b
V 0
V DD
+
V
5
V EV (constant-voltage source
+ electronic volume)
-
Ra
Rb
Command
(1 + Rb/Ra)
IR1 IR0
0 0 2.81
0 1 3.27
1 0 3.72
1 1 4.21
Fig. 2
(00)
(10)
(01)
(11)
0
–10
–9
–8
–7
–6
–5
–4
–3
–2
–1
0
8 162432
V5[V]
V5 voltage by V5 voltage regulating built-in resistor
ratio set value and electronic volume resistor value
(reference value)
[Fig. 2]
V5 voitage regulating built-in
resistor ratio set value (IRI. IRO)
Electronic volume resistor value(decimal)