hd66740 Renesas Electronics Corporation., hd66740 Datasheet - Page 50

• Manufacturer Part Number: hd66740
• Description: 112 X 80-dot Graphics Lcd Controller/driver - Hitachi Semiconductor
• Manufacturer: Renesas Electronics Corporation.

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
BT1
0
0
1
1
i) Maximum five-times boosting
0.47 F
to 1 F
0.47 F
to 1 F
0.47 F
to 1 F
0.47 F
to 1 F
Vci
1 F
GND
+
+
+
+
+
VLOUT Output Status
Vci
C1+
C1-
C2+
C2-
C3+
C3-
C4+
C4-
VLOUT
BT0
0
1
0
1
Figure 25
Booster Output Multiplying Factor Switching
ii) Maximum quadruple boosting
0.47 F
to 1 F
0.47 F
to 1 F
0.47 F
to 1 F
Vci
VLOUT Output Status
Triple boosting output
Quadruple boosting output
Five-times boosting output
Setting inhibited
1 F
+
+
+
GND
+
50
Vci
C1+
C1-
C2+
C2-
C3+
C3-
C4+
C4-
VLOUT
iii) Maximum triple boosting
0.47 F
to 1 F
0.47 F
to 1 F
Vci
1 F
GND
+
+
+
Vci
C1+
C1-
C2+
C2-
C3+
C3-
C4+
C4-
VLOUT