EM65101
128COM/160SEG 16 Gray Scale Level LCD Driver
7.11 Voltage Regulator
The EM65101 has a built-in reference voltage regulator, which regulates the amplified
voltage from the internal temperature compensation output (VREF pin) to generate the
LCD drive voltage (V0). Even if the boost-up voltage level fluctuates, V0 remains
stable as long as VOUT is higher than V0. Stable power supply can be obtained by
using this constant voltage, even if the load fluctuates. The EM65101 uses the
generated LCD drive voltage (V0) level as the reference level for the electronic volume.
7.12 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 EM65101 is biased at 1/4, 1/5, 1/6, 1/7, 1/8, 1/9,
1/10, 1/11, 1/12, & 1/13. When using the internal power supply, connect a stabilizing
capacitor to each of Pins V0 to V4. The capacitor should be determined while selecting
the LCD panel to be used. When using the external power supply, apply external LCD
drive voltages to V0, V1, V2, V3, & V4. Disconnect Pins CAP1+, CAP1-, CAP2+,
CAP2-, CAP3+, CAP3-, CAP4+, CAP5+,V2X, VOUT, & VEE. When using only the
voltage conversion circuit, turn off the internal booster circuit, disconnect Pins CAP1+,
CAP1-, CAP2+, CAP2-, CAP3+, CAP3-, CAP4+, CAP5+ and VEE. Get the voltage
source to be supplied to the voltage converter from VOUT and V2X pins.
The following figure shows an application circuit on capacitor connections when using
the internal power circuit (with the voltage boosted several times as shown).
Boosted 6 times
Boosted 5 times
Boosted 4 times
VDD
VDD
VDD
VDD
VEE
VDD
VEE
VDD
VEE
VBA
VREF
VBA
VREF
VBA
VREF
CVREF
CVREF
CVREF
CAP5+
CAP5+
CAP3+
CAP5+
CAP3+
C1
CAP3+
CAP3-
CAP2-
CAP2+
CAP4+
C1
C1
C1
CAP3-
CAP2-
CAP2+
CAP4+
CAP3-
CAP2-
C1
C1
C1
C1
CAP2+
C1
CAP4+
CAP1+
CAP1-
V2X
CAP1+
C1
CAP1+
CAP1-
V2X
C1
C1
C1
C1
CAP1-
C1
V2X
C1
C1
C1
C1
VOUT
V0
VOUT
V0
VOUT
V0
vss
C1
vss
vss
C1
C1
C1
C1
C1
C1
C1
V1
V1
V1
V2
V2
V2
C1
C1
C1
C1
C1
C1
V3
V3
V3
V4
V4
V4
vss
vss
vss
Figure 7-12a Internal Power Capacitor Connections Application Circuits
(Voltage Boosted 6, 5 and 4 Times)
Product Specification (V0.4) 08.15.2005
• 25
(This specification is subject to change without further notice)
ELAN [ ELAN MICROELECTRONICS CORP ]
