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(3) LCD drive bias/power supply
The LCD drive method can be selected from a 1/3 bias drive (V
(V
, V
= V
, V
SS
C1
C2
C3
For the LCD system power supply, either "internal" power (to generate internally) or "external" power
(to supply from outside of the IC) can be selected. When "external" power is selected, the specified
LCD drive voltage terminal (V
selected mask option.
• 1/3 bias
Internal
V
V
= V
C1
C1
3.0 V LCD
4.5 V LCD
When the voltage regurator in the LCD system voltage circuit is disabled by setting the mask option,
external elements can be minimized because one or two external capacitors for V
necessary. However when the LCD system voltage regurator is not used, the display quality of the
LCD panel, when the supply voltage fluctuates (drops), is inferior to when the LCD system voltage
regurator is used.
Figure 4.8.4.2 shows the external elements when the the LCD system voltage regurator is not used.
<4.5 V LCD panel>
1/4, 1/3, 1/2 duty, 1/3 bias
V
DD
V
C1
V
C2
V
C3
CA
CB
V
SS
Note: V
is shorted to V
C1
<3.0 V LCD panel>
1/4, 1/3, 1/2 duty, 1/3 bias
V
DD
V
C1
V
C2
V
C3
CA
CB
V
SS
Note: V
is shorted to V
C3
1/4, 1/3, 1/2 duty, 1/2 bias
V
DD
V
C1
V
C2
V
C3
CA
CB
V
SS
Fig. 4.8.4.2 External elements when LCD system voltage regurator is not used
S1C63358 TECHNICAL MANUAL
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (LCD Driver)
).
, V
or V
C1
C2
C3
External
V
= V
V
= V
DD
C2
DD
C3
DD
4.5 V LCD
3.0 V LCD
1.5 V
C
4
C
5
C
1
inside the IC.
DD
3.0 V
C
3
C
4
C
1
inside the IC.
DD
3.0 V
C
3
C
1
Note: V
, V
SS
) is connected to the V
• 1/2 bias
Internal
V
V
C1
×
3.0 V LCD
Combinations that are marked with an "×" cannot be selected.
1/4, 1/3, 1/2 duty, 1/3 bias
Note: V
C2
1/4, 1/3, 1/2 duty, 1/2 bias
Note: V
C1
is shorted to V
inside the IC.
C3
DD
EPSON
, V
, V
) or a 1/2 bias drive
C1
C2
C3
inside the IC according to the
DD
External
= V
V
= V
V
C1
DD
C2
DD
C3
×
3.0 V LCD
to V
C1
C3
V
DD
3.0 V
C
3
V
C1
V
C2
C
5
V
C3
CA
C
1
CB
V
SS
is shorted to V
inside the IC.
DD
V
DD
V
C1
1.5 V
V
C2
C
5
V
C3
CA
C
1
CB
V
SS
is shorted to V
inside the IC.
DD
= V
DD
are not
61
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