EM65570
68COM/ 98SEG 65K Color STN LCD Driver
7.19 Voltage Generation Circuit
The voltage converter contains the voltage generation circuit. The LCD drive voltages
other than V0 (that is, V1, V2, V3 and V4) are obtained by dividing V0 through a resistor
network. The LCD drive voltage from the EM65570 is biased at 1/4, 1/5, 1/6, 1/7, 1/8 ,
1/9. When using the internal power supply, connect a stabilizing capacitor C2 to each
of pins V0 to V4. The capacitance of C2 should be determined while selecting the LCD
panel to be used.
Boosted 2 times
Boosted 3 times
Boosted 4 times
VDD
VDD
VDD
VDD
VEE
VDD
VEE
VDD
VEE
CAP5+
CAP3+
CAP1+
CAP1-
CAP5+
CAP3+
CAP1+
CAP1-
CAP5+
CAP3+
CAP1+
CAP1-
C1
C1
C1
C1
CAP2-
CAP2+
CAP4+
CAP2-
CAP2+
CAP4+
CAP2-
CAP2+
CAP4+
C1
C1
C1
C1
C1
VOUT
VOUT
VOUT
vss
vss
vss
vss
vss
vss
V0
V1
V2
V3
V4
V0
V1
V2
V3
V4
V0
V1
V2
V3
V4
C1
C1
C1
C1
C1
C1
C1
C1
C1
C1
C1
C1
C1
C1
C1
Figure 7-17a Internal Power Capacitor Connections Application Circuits
(Voltage Boosted 2, 3, and 4 Times)
Recommended value:
C1
1.0 to 1.5 uF
NOTE
The X5R type external capacitor must be used.
38 •
Product Specification (V1.0) 09.05.2005
(This specification is subject to change without further notice)
ELAN [ ELAN MICROELECTRONICS CORP ]
