pcf2113duf4 NXP Semiconductors, pcf2113duf4 Datasheet - Page 7

• Manufacturer Part Number: pcf2113duf4
• Description: Lcd Controllers/drivers
• Manufacturer: NXP Semiconductors

Philips Semiconductors
7
7.1
The LCD supply voltage may be generated on-chip. The
voltage generator is controlled by two internal 6-bit
registers: V
at room temperature is given by the relationship:
7.2
Programmed value: 1 to 63. Voltage: 1.90 to 6.86 V.
T
Values producing more than 6.5 V at operating
temperature are not allowed. Operation above this
voltage may damage the device. When programming the
operating voltage the V
be taken into account.
Values below 2.2 V are below the specified operating
range of the chip and are therefore not allowed.
Value 0 for V
(i.e. V
Usually register V
character mode and register V
mode.
When V
decoupled to V
V
compensated.
Table 2 Bias levels as a function of multiplex rate
Note
1. The values in the above table are given relative to V
2003 Jan 30
V
MULTIPLEX
ref
LCD
OP(nom)
LCD controllers/drivers
= 27 C.
FUNCTIONAL DESCRIPTION
RATE
1 : 18
1 : 9
1 : 2
is independent of V
A
LCD supply voltage generator
Programming ranges
= 0 in character mode, V
LCD
=
A
is generated on-chip the V
A
and V
integer value of register 0.08
and V
SS
OF LEVELS
NUMBER
A
with a suitable capacitor. The generated
B
is programmed with the voltage for
. The nominal LCD operating voltage
B
5
5
4
switches the generator off
LCD
DD
temperature coefficient must
and is temperature
B
with the voltage for icon
B
= 0 in icon mode).
V
V
V
V
op
op
op
1
LCD
pads should be
+
1.82
3/4
3/4
2/3
V
2
(1)
op
7
V
When the generator and the direct mode are switched off
an external voltage may be supplied at connected pads
V
During direct mode (program DM register bit) the internal
voltage generator is turned off and the V
is directly connected to V
consumption during icon mode and Mux 1 : 9 (depending
on the V
The LCD supply voltage generator ensures that, as long as
V
voltage V
7.3
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
depends on the multiplex rate, the LCD threshold voltage
(V
scheme for 1 : 18 maximum rate allows V
most LCD liquids. The intermediate bias levels for the
different multiplex rates are shown in Table 2. These bias
levels are automatically set to the given values when
switching to the corresponding multiplex rate.
ss
LCD1
DD
th
, e.g. 3/4 means 3/4
) and the number of bias levels. Using a 5-level bias
1/2
1/2
2/3
V
is in the valid range (2.2 to 4 V), the required peak
. V
3
LCD bias voltage generator
DD2
LCD1
OP
value and the LCD liquid properties).
= 6.5 V can be generated at any time.
may be higher or lower than V
1/2
1/2
1/3
V
4
(V
DD2
op
. This reduces the current
V
ss
1/4
1/4
1/3
V
).
5
Product specification
PCF2119X
LCD
LCD
output voltage
DD
< 5 V for
.
V
V
V
V
ss
ss
ss
6
LCD