pcf8531 NXP Semiconductors, pcf8531 Datasheet - Page 14

• Manufacturer Part Number: pcf8531
• Description: 34 X 128 Pixel Matrix Driver
• Manufacturer: NXP Semiconductors

Philips Semiconductors
8.18.8
Table 3 Intermediate LCD bias voltages
8.18.9
The operating voltage V
The voltage at reference temperature [V
be calculated as: V
Table 4 Parameter values for the HV generator programming
2000 Feb 11
V1
V2
V3
V4
V5
V6
T
a
b
Programming range
cut
34
SYMBOL
LCD
S
128 pixel matrix driver
ET
V
BIAS VOLTAGE
SYMBOL
OP
VALUE
LCD
V
V
n
------------ -
n
n
------------ -
n
------------ -
n
------------ -
n
LCD
SS
+
+
+
+
2
+
1
+
VOLTAGES
(T
:
3
4
2
4
4
4
LCD
cut
BIAS
) = (a + V
V
V
V
V
can be set by software.
LCD
LCD
LCD
LCD
OP
V
6
5
2
1
V
LCD
EXAMPLE FOR
7
7
7
7
LCD
SS
b).
2.94 to 6.75
(T = T
1
V
V
V
V
PRS = 0
7
LCD
LCD
LCD
LCD
2.94
0.03
BIAS
27
cut
)] can
VALUE
14
The generated voltage is dependent on the temperature,
programmed Temperature Coefficient (TC) and the
programmed voltage at reference temperature (T
V
The parameter values are given in Table 4.
Two overlapping V
command ‘HV-gen control’ (see Table 4 and Fig.8).
The maximum voltage that can be generated depends on
the V
For Mux 1 : 34, the optimum operating voltage of the liquid
can be calculated as:
Where V
material used.
The practical value for V
V
typically when the LCD exhibits approximately
10% contrast.
As the programming range for the internally generated
V
user has to ensure, while setting the V
selecting the temperature compensation, that the V
limit of maximum 9 V will never be exceeded under all
conditions and including all tolerances.
V
6.75 to 10.56
LCD
off(rms)
LCD
LCD
PRS = 1
DD2
allows values above the maximum allowed V
= V
6.75
0.03
=
27
with a defined LCD threshold voltage (V
th
LCD
and V
-------------------------------------- -
2
is the threshold voltage of the liquid crystal
1
(T
+
DD3
cut
1
–
)
34
LCD
----------
voltages and the display load current.
1
34
[1 + TC
ranges can be selected via the
OP
V
is determined by equating
th
(T
=
5.30 V
UNIT
T
cut
Product specification
V
V
V
C
OP
)].
PCF8531
register and
th
th
cut
),
LCD
LCD
).
, the