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C
P4
C
P3
C
P2
C
P1
V
C4
V
C3
V
C2
V
C1
When 1/3 bias is selected (LCD8PWR.BISEL bit = 0)
Figure 18.4.2.1 External Connection Example for External Voltage Application Mode 1 (resistor divider)
18.4.3 External Voltage Application Mode 2
In this mode, the LCD drive voltages V
generated. To put LCD8B into external voltage application mode 2, set the LCD8PWR.EXVCSEL bit to 1, set the
LCD8PWR.VCEN bit to 0 to turn the LCD voltage regulator off, and set the LCD8PWR.BSTEN bit to 1 to turn
the LCD voltage booster on. Figure 18.4.3.1 shows an external connection example for external voltage application
mode 2.
C
P4
C
P3
C
P2
C
P1
V
C4
V
C3
V
C2
V
C1
When 1/3 bias is selected (LCD8PWR.BISEL bit = 0)
Figure 18.4.3.1 External Connection Example for External Voltage Application Mode 2 (when V
18.4.4 LCD Voltage Regulator Settings
When using internal generation mode, select the reference voltage for boosting voltage generated by the LCD volt-
age regulator according to the power supply voltage V
"Electrical Characteristics" chapter and set the LCD8PWR.VCSEL bit. Current consumption can be reduced by
selecting reference voltage V
1, the LCD voltage regulator enters heavy load protection mode and ensures stable V
protection mode should be set when the display has inconsistencies in density. Current consumption increases in
heavy load protection mode, therefore do not set heavy load protection mode if unnecessary.
18.4.5 LCD Voltage Booster Setting
Set the booster clock frequency used in the LCD voltage booster using the LCD8TIM2.BSTC[1:0] bits. Set it to the
frequency that provides the best V
18.4.6 LCD Contrast Adjustment
The LCD panel contrast can be adjusted within 32 levels using the LCD8PWR.LC[4:0] bits. This function is real-
ized by controlling the voltage output from the LCD voltage regulator. Therefore, the LCD8PWR.LC[4:0] bits can-
not be used for contrast adjustment in external voltage application modes 1 and 2.
S1C17W18 TECHNICAL MANUAL
(Rev. 1.2)
Open
R
LCD3
R
LCD2
R
LCD1
or V
is applied from outside the IC and other voltages are internally
C1
C2
Open
C
LCD5
C
C
LCD2
LCD3
DD
as compared with reference voltage V
C2
–V
output stability after being evaluated using the actual circuit board.
C1
C4
Seiko Epson Corporation
C
P4
C
P3
C
P2
C
P1
V
C4
V
C3
V
C2
V
C1
When 1/4 bias is selected (LCD8PWR.BISEL bit = 1)
C
P4
C
LCD6
C
P3
C
P2
C
LCD5
C
P1
V
C4
V
C3
V
C2
V
C1
When 1/4 bias is selected (LCD8PWR.BISEL bit = 1)
. Refer to "LCD Driver (LCD8B) Characteristics" in the
. By setting the LCD8PWR.HVLD bit to
C1
18 LCD DRIVER (LCD8B)
Open
R
LCD4
R
LCD3
R
LCD2
R
LCD1
C
C
C
LCD2
LCD3
LCD4
is applied)
C1
to V
outputs. Heavy load
C1
C4
18-5
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