PCF2119AU/2DA/2 NXP [NXP Semiconductors], PCF2119AU/2DA/2 Datasheet - Page 10

• Manufacturer Part Number: PCF2119AU/2DA/2
• Description: LCD controllers/drivers
• Manufacturer: NXP [NXP Semiconductors]

NXP Semiconductors
Table 6.
PCF2119X_5
Product data sheet
Multiplex
rate
1:18
1:9
1:2
Bias levels as a function of multiplex rate
Number of
bias levels
5
5
4
8.5 LCD bias voltage generator
8.6 LCD row and column drivers
see
(it is set by
consumption increases (see
When the V
be supplied at connected pins V
lower than V
In direct mode (see Icon_ctl instruction,
turned off and the V
current consumption depending on V
The V
required peak voltage V
The intermediate bias voltages for the LCD display are also generated on-chip. This
removes the need for an external resistive bias chain and significantly reduces the system
current consumption. The optimum value of V
threshold voltage (V
1:18 multiplex rate allows V
The intermediate bias levels for the different multiplex rates are shown in
bias levels are automatically set to the given values when switching to the corresponding
multiplex rate.
The PCF2119x contains 18 row and 80 column drivers, which drive the appropriate LCD
bias voltages in sequence to the display in accordance with the data to be displayed. R17
and R18 drive the icon rows. Unused outputs should be left open.
The bias voltages and the timing are selected automatically when the number of lines in
the display is selected.
Section
Bias voltages
V
V
V
V
LCD
1
LCD
LCD
LCD
generator ensures that, as long as V
Equation
LCD
10.2.3.4). If still a higher multiplication factor is chosen, V
DD2
V
3
-- - V
4
3
-- - V
4
2
-- - V
3
2
generator and the direct mode are switched off, an external voltage may
.
LCD
LCD
LCD
LCDOUT
th
–
–
–
2) but the current that can be delivered will be higher. Also current
) and the number of bias levels. Using a 5-level bias scheme for the
V
V
V
Rev. 05 — 13 August 2009
SS
SS
SS
Figure 3
LCD
LCD
output voltage is directly connected to V
= 6.5 V can be generated at any time.
Section
V
1
-- - V
2
1
-- - V
2
2
-- - V
3
< 5 V for most LCD liquids.
LCDIN
3
to
LCD
LCD
LCD
Figure 5
16.6).
DD2
and V
–
–
–
V
V
V
Section
value and LCD liquid properties.
SS
SS
SS
LCDOUT
show typical waveforms.
LCD
DD
10.2.3.3) the internal V
V
1
-- - V
2
1
-- - V
2
1
-- - V
3
is in the valid range (2.2 V to 4 V), the
depends on the multiplex rate, the LCD
4
. V
LCD
LCD
LCD
LCDIN
–
–
–
V
V
V
and V
SS
SS
SS
LCD controllers/drivers
LCDOUT
V
1
-- - V
4
1
-- - V
4
1
-- - V
3
DD2
5
PCF2119x
LCD
LCD
LCD
LCD
© NXP B.V. 2009. All rights reserved.
. This reduces the
LCD
may be higher or
will not increase
Table
–
–
–
generator is
V
V
V
SS
SS
SS
6. These
10 of 79
V
V
V
V
6
SS
SS
SS