PCF8811MU/2DA/1 PHILIPS [NXP Semiconductors], PCF8811MU/2DA/1 Datasheet - Page 37

• Manufacturer Part Number: PCF8811MU/2DA/1
• Description: 80 x 128 pixels matrix LCD driver
• Manufacturer: PHILIPS [NXP Semiconductors]

Philips Semiconductors
Table 19 Bias levels for MRA driving method
The row voltages (F) are not necessarily larger then the
column voltages. This depends on the number of rows
which are selected, the multiplexibility and the value of p.
However, the PCF8811 is designed in such a way that the
maximum column voltages are always equal to the row
voltages. In Table 20 the V
are given for the PCF8811. The V
Where F is defined in (1)
The bias system settings for different display modes are
given in Table 20. All bias levels can be calculated by
using the third column of Table 19 and the variables given
in Table 20. Programming of the bias levels is not
necessary in the PCF8811. The selection of the
appropriate bias level voltages for each display mode is
done automatically. Only the appropriate V
must be programmed according to equations (1) and (2)
for the display modes listed in Table 20.
The variables for calculating V
enabled, are given in Table 21. The icon row can only be
addressed in the extended command set.
The PCF8811 allows the value of p, for certain mux rates,
to be chosen manually.
2004 May 17
F = G
V
V3_H
V2_H
V1_H
V
V1_L
V2_L
V3_L
V
LCD
C
SS
80
max
128 pixels matrix LCD driver
SYMBOL
V
LCD
LCD
=
2 F
and the different bias levels
LCD
LCD
, when the icon row is
voltage is defined as:
F
0
–
–
–
p 2
p 4
p 6
F
LCD
p 6
p 4
p 2
–
–
–
–
–
–
voltage
--------------------------------- -
--------------------------------- -
--------------------------------- -
BIAS VOLTAGES
--------------------------------- -
--------------------------------- -
--------------------------------- -
m
m
m
m
m
m
–
–
–
–
–
–
(2)
F
F
F
F
F
F
m N
m N
m N
37
m N
m N
m N
–
–
–
–
–
–
This is only possible for the mux rates 1 : 64 and 1 : 80.
If other mux rates are chosen the PCF8811 determines
the optimum value of p. By setting the value of p manually
a compromise can be made between contrast and power
consumption with certain liquids for the high mux rates
1 : 64 and 1 : 80. However, care must be taken that the
liquid which is chosen ensures that the row voltages (F)
and the maximum column voltages are equal.
Table 20 Relationship between mux rates and bias
MUX RATE
1 : 16
1 : 24
1 : 32
1 : 40
1 : 48
1 : 56
1 : 64
1 : 72
1 : 80
setting variables without icon row
V
1
V
V
-------------
V
-------------
V
-------------
V
-------------
V
-------------
V
-------------
/
16
24
32
40
48
56
64
72
80
LCD
2
SS
N
LCD
LCD
LCD
LCD
LCD
LCD
2
2
2
2
2
2
V
DC SHIFTED BIAS VOLTAGES
LCD
1
1
1
1
1
1
+
+
+
–
–
–
--------------------------------- -
--------------------------------- -
--------------------------------- -
--------------------------------- -
--------------------------------- -
--------------------------------- -
m
m
m
m
m
m
25
49
81
49
64
81
64
81
81
m
–
–
–
–
–
–
p 6
p 4
p 2
p 2
p 4
p 6
Product specification
–
–
–
–
–
–
m N
m N
m N
m N
m N
m N
PCF8811
–
–
–
–
–
–
p
2
2
2
4
4
4
8
8
8