HD66740 Datasheet, PDF (50/95 Pages) Hitachi Semiconductor – 112 x 80-dot Graphics LCD Controller/Driver

HD66740
Switching the Boosting Multiplying Factor
Instruction bits (BT1/0 bits) can optionally select the boosting multiplying factor of the internal booster.
According to the display status, power consumption can be reduced by changing the LCD drive duty and
the LCD drive bias, and by controlling the boosting multiplying factor for the minimum requirements.
For details, see the Partial-display-on Function section.
Due to the maximum boosting multiplying factor, the following external capacitor needs to be connected.
For example, when the maximum boosting is quadrupled, the capacitors between C4+ and C4– for five-
times boosting are not needed, so these pins must be open.
Table 18 VLOUT Output Status
BT1
BT0
VLOUT Output Status
0
0
Triple boosting output
0
1
Quadruple boosting output
1
0
Five-times boosting output
1
1
Setting inhibited
i) Maximum five-times boosting
ii) Maximum quadruple boosting
iii) Maximum triple boosting
Vci
0.47 µF ⁺
to 1 µF
0.47 µF ⁺
to 1 µF
0.47 µF ⁺
to 1 µF
0.47 µF ⁺
to 1 µF
1 µF ⁺
Vci
C1+
C1-
C2+
C2-
C3+
C3-
C4+
C4-
VLOUT
GND
Vci
0.47 µF ⁺
to 1 µF
0.47 µF ⁺
to 1 µF
0.47 µF ⁺
to 1 µF
1 µF ⁺
Vci
C1+
C1-
C2+
C2-
C3+
C3-
C4+
C4-
VLOUT
GND
Vci
Vci
0.47 µF ⁺
C1+
to 1 µF
C1-
0.47 µF ⁺
C2+
to 1 µF
C2-
C3+
C3-
C4+
1 µF ⁺
C4-
VLOUT
GND
Figure 25 Booster Output Multiplying Factor Switching
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