S1D1 Epson Electronics America, Inc., S1D1 Datasheet - Page 356

• Manufacturer Part Number: S1D1
• Description: LCD Controller-driver With Built-in Character ROM
• Manufacturer: Epson Electronics America, Inc.

S1D15700 Series
9. LCD DRIVER POWER SUPPLY
Generating LCD Drive Voltages
To obtain individual voltage levels for LCD driver,
register-split the potential between V
the LCD with the voltage follower using the operation
amplifier. When using an operation amplifier, V
V
However, if the potential of V
potential or V
difference increases, the LCD driver capability decreases.
To avoid this, set V
to 2.5 V. If an operation amplifier is not used, connect V
and V
If there are direct resistors on the V
voltage falls in V
caused by I
result, the relationship (V
for intermediate potential of LCD can not be maintained
and the LSI may be damaged.
To insert a protective resistor, the voltage must be stabi-
lized according to the capacity.
9–14
DD,
V
DD,
5
and V
V
DD
5
and V
DOFF
EE
5
(I
EE
is higher than V
EE
are separated.
) at the time of signal change. As a
DD
EE
(V
.
DD
and V
V
V
V
V
V
DD
DD
DD
SS
EE
SS
) at the LSI power pins. This is
V
0
V
or V
0
0
EE
5
EE
V
is lower than V
and V
EE
2
(V
and the potential
– V
DD
V
3
EE
t1
DD
) power line,
within 0 V
V
and drive
5
0
V
and
EE
DD
t3
0
EPSON
)
System Power-up
This LSI has high LCD drive voltage. As a result, if the
logic power is being floated or if the V
above –2.5Vdc and high voltage is applied in the LCD
driver, the LSI may be damaged because of the excess
current.
Until the LCD drive voltage is stabilized, use the display
off function (DOFF) to set the potential of the LCD drive
output to V0 level.
Follow the sequence given below when turning the
power on/off.
To turn on the power – Turn on the logic power
To turn off the power – Turn off the LCD driver
To avoid excess current, insert the high-speed fuse in
series with the LCD power. Select the appropriate value
for a protective resistor according to the capacity of a
LCD cell.
t2
Turn the LCD driver on.
(On turn them on simultaneously.)
Turn off the logic power.
(Or turn them off simultaneously.)
t1, t2, t3
SS
voltage is kept
0s
Rev. 3.0