Precautions - Epson S1C88655 Technical Manual

VCON: 00FF09H•D4
Controls the V voltage generator.
C1–4
When "1" is written: ON
When "0" is written: OFF
Reading:
When "1" is written to VCON, the V
generator goes ON and outputs the LCD drive
voltages V –V . However, the V
C1 C4
be supplied from the V
these voltages can be generated. When "0" is
written to VCON, the V
OFF.
At initial reset, VCON is set to "0" (OFF).
Note: While the LCD panel is turned OFF, the LCD
drive power supply circuit should be turned
OFF to reduce current consumption using
LBON, VC5ON, and VCON.
LBIAS: 00FF09H•D5
Selects the bias ratio for LCD drive.
When "1" is written: 1/9 bias
When "0" is written: 1/7 bias
Reading:
When "1" is written to LBIAS, 1/9 bias is selected
and when "0" is written, 1/7 bias is selected. This
setting controls the V
C1–4
outputs.
At initial reset LBIAS is set to "1" (1/9 bias).
LRSEL0–LRSEL2: 00FF0AH•D0–D2
Selects a resistance ratio to adjust the output
voltage of the V voltage generator.
C5
Table 4.3.2 Adjusting resistance ratio
in V voltage generator
C5
LRSEL2 LRSEL1
1 1
1 1
1 0
1 0
0 1
0 1
0 0
0 0
At initial reset, LRSEL is set to "0".
LEV0–LEV5: 00FF0BH•D0–D5
Adjusts the reference voltage for the V
generator in 64 levels (0 to 63). The contrast of the
LCD panel can be adjusted with both this register
and the LRSEL0–LRSEL2 register. See Chapter 19,
"Electrical Characteristics", for relationship between
the setting values and the V
At initial reset, LEV is set to "0".
S1C88655 TECHNICAL MANUAL
Valid
voltage
C1–4
voltage must
C5
voltage generator before
C5
voltage generator goes
C1–4
Valid
voltage generator
LRSEL0 (Ra+Rb)/Ra
1 Not allowed
0 8.69
1 8.13
0 7.20
1 6.46
0 5.60
1 4.84
0 4.06
voltage
C5
voltage values.
C5

4.4 Precautions

(1) Be sure not to use the voltages output from the
V and V terminals for driving external
D1 D2
circuits.
The V –V terminal outputs can only be used
C1 C5
to drive a recommended LCD driver.
(2) The supply voltage booster circuit must be
configured so that the V
higher than the desired V
sure that the V
absolute maximum rating (see Chapter 19,
"Electrical Characteristics") when setting the
boosting ratio.
EPSON
4 POWER SUPPLY
voltage level is
D2
. However, make
C5
voltage does not exceed the
D2
31