EM65565A ELAN Microelectronics Corp, EM65565A Datasheet - Page 25

• Manufacturer Part Number: EM65565A
• Description: 65 Com/ 132 Seg Stn Lcd Driver
• Manufacturer: ELAN Microelectronics Corp

Product Specification (V1.0) 06.06.2005
(This specification is subject to change without further notice)
6.1.15 Step-up Voltage Circuit
Using the step-up voltage circuit built-in within the EM65565A IC, it is possible to
produce a five times step-up, a four times step-up, a three times, and a two times
step-up of the V
6.1.16 Voltage Regulator Circuit
The step-up voltage generated at V
voltage regulator circuit.
Since the EM65565A IC has an internal high-accuracy fixed voltage power supply with
a 64-level electronic volume function and internal resistors for the V
systems can be constructed without having to include high-accuracy voltage regulator
circuit components.
(a) Using the V
Through the use of the V
function, the liquid crystal power supply voltage V
alone (without adding any external resistors), making it possible to adjust the LCD
brightness. The V
V

V
V
0
OUT
0
<V
V
VDD
CAP4+
CAP3+
CAP1+
CAP2+
CAP1-
CAP2-
VOUT
=2xV
EV
VSS
OUT
VCI
1 (
CI

.
VCI
1 (
Rb
Ra

C
+
C
-
+
-
162
)
V
D
0
CI
EV
voltage regulator internal resistors
voltage levels. The step-up voltage relationship is shown in Figure 8.
)
0
V
V
OUT
voltage can be calculated using equation A over the range where
REG
1 (
VDD
CAP4+
CAP3+
CAP1+
CAP2+
CAP1-
CAP2-
VOUT
=3xV
VSS

VCI
0
Fig. 8 Step-up Voltage Circuits
CI
Rb
Ra
voltage regulator internal resistors and the electronic volume
VCI
)(
C
C
+
+
C
-
-
-
+
1

162
D
OUT
V
OUT
)
, outputs the LCD driver voltage V
V
VDD
CAP4+
CAP3+
CAP1+
CAP2+
CAP1-
CAP2-
VOUT
=4xV
REG
VSS
VCI
CI
-------------------------------------------------- (A)
VCI
C
C
C
+
+
+
C
+
-
-
-
-
0
65 COM/132SEG STN LCD Driver
can be controlled by commands
V
OUT
VDD
CAP4+
CAP3+
CAP1+
CAP2+
CAP1-
CAP2-
=5xV
VOUT
VSS
VCI
CI
VCI
+
C
C
+
+
C
C
+
-
-
-
-
0
voltage regulator,
+
C
-
EM65565A
0
through the
x 19