hd66740 Renesas Electronics Corporation., hd66740 Datasheet - Page 51

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

Example of Power-supply Voltage Generator for More Than Five-times Boosting Output
The HD66740 incorporates the booster for up to five-times boosting. However, the LCD drive voltage
(VLCD) will not be enough for five-times boosting from Vcc when the power-supply voltage of Vcc is
low or when the LCD drive voltage is high for the high-contrast LCD display. In this case, the reference
voltage (Vci) for boosting can be set higher than the power-supply voltage of Vcc.
Set the Vci input voltage for the booster to 3.6 V or less within the range of Vcc + 1.0 V.
Vci voltage so that the boosting output voltage (VLOUT) should be less than the absolute maximum
ratings (17 V).
Battery
3.6 V
VLCD (= 15 V)
Vcc (= 3 V)
Vcc (= 2.5 V)
GND (= 0 V)
Figure 26
GND
Usage Example of Booster at Vci > Vcc
Regula
Regula
-tor
-tor
(1)
(2)
3.0 x 5 = 15 V
1 F
GND
2.5 V
3.0 V
51
+
Vcc
Vci
VLOUT
VLCD
HD66740
Logic circuit
Booster
LCD driver
GND
GND
C1+
C2+
C3+
C4+
C1-
C2-
C3-
C4-
+
+
+
+
SEG1 to SEG112
COM1 to COM80
1 F
1 F
1 F
1 F
HD66740
Control the