HD66724 Datasheet, PDF (70/117 Pages) Hitachi Semiconductor – (Graphics LCD Controller/Driver with Key Scan Function)

HD66724/HD66725
V LCD
GND
Vci
OPOFF=GND
VLCD
VR
V1OUT
R
V2OUT
R0
V3OUT
R
0.1 µF
to 0.5 µF
V4OUT
R
V5OUT
+++ ++
R
GND
HD66724/5
+
-
V1
+
-
V2
LCD
driver
+
-
V3
+
-
V4
+
-
V5
GND
Vci
C1+
0.47 µF ⁺
to 1 µF
C1-
Booster
C2+
0.47 µF +
to 1 µF
C2-
VLOUT
0.47 µF ⁺
to 1 µF
GND
SEG1 to SEG72 (96)
COM1 to COM24
COMS1 to COMS2
Notes: 1. The reference voltage input (Vci) must be adjusted so that the output voltage after boosting will not exceed
the absolute maximum rating for the liquid-crystal power supply voltage (7 V). Particularly, Vci must be
2.3 V or less for triple boosting.
2. Vci is both a reference voltage and power supply for the booster; connect it to Vcc directly or combine it with
a transistor so that sufficient current can be obtained.
3. Vci must be smaller than Vcc.
4. When using up to the double booster, no capacitors are required between C2+ and C2–.
5. Polarized capacitors must be connected correctly.
6. Circuits for temperature compensation should be based on the sample circuit below.
Figure 37 Internal Booster Circuit for LCD Drive Voltage Generation
HD66724/5
Vcc
Vcc
Thermistor
Tr ^Vci
GND
Figure 38 External Power Supply Circuit for LCD Drive Voltage Generation
70