PCA85133 NXP [NXP Semiconductors], PCA85133 Datasheet - Page 7

• Manufacturer Part Number: PCA85133
• Description: Universal LCD driver for low multiplex rates
• Manufacturer: NXP [NXP Semiconductors]

NXP Semiconductors
PCA85133_1
Product data sheet
Bias is calculated by
The RMS on-state voltage (V
V
where the values for n are
The RMS off-state voltage (V
Discrimination is the ratio of V
Using
1
1
The advantage of these LCD drive modes is a reduction of the LCD full scale voltage V
as follows:
These compare with
It should be noted that V
V
D
2
2
•
•
on RMS
off RMS
a = 1 for
a = 2 for
n = 1 for static mode
n = 2 for 1:2 multiplex
n = 3 for 1:3 multiplex
n = 4 for 1:4 multiplex
bias is
bias is
=
1:3 multiplex (
1:4 multiplex (
----------------------- -
V
V
Equation
off RMS
on RMS
=
----------
=
1
1
3
3
21
V
2
3
V
LCD
bias
bias
=
LCD
=
=
3, the discrimination for an LCD drive mode of 1:3 multiplex with
1.732
----------------------------- -
n
a
1.528
----------------------------- -
n
1
1
a
2
2
2
2
------------------------------------------- -
+
a
a 1
bias):
bias):
–
V
------------ -
1
1
2a
Rev. 1 — 23 October 2009
1
+
–
2a
and the discrimination for an LCD drive mode of 1:4 multiplex with
LCD
1
+
+
.
+
LCD
1
a
+
a
+
a
, where the values for a are
2
2
n
V
V
2
n
=
+
+
2
is sometimes referred as the LCD operating voltage.
on(RMS)
off(RMS)
LCD
LCD
on(RMS)
3V
n 1
n 1
–
–
off RMS
=
=
) for the LCD is calculated with
) for the LCD is calculated with
to V
--------------------- -
6 V
4
3
off(RMS)
Universal LCD driver for low multiplex rates
when
off RMS
3
=
1
and is determined from
3
2.309V
bias is used.
=
2.449V
off RMS
off RMS
Equation 1
Equation
PCA85133
© NXP B.V. 2009. All rights reserved.
Equation
2:
3:
7 of 44
LCD
(1)
(2)
(3)