pcf8814 NXP Semiconductors, pcf8814 Datasheet - Page 34

• Manufacturer Part Number: pcf8814
• Description: Pcf8814 65 X 96 Pixels Matrix Lcd Driver
• Manufacturer: NXP Semiconductors

Philips Semiconductors
11.8
The bias voltage levels (see Fig.33) are a function of the
row voltage F and ‘a’ where:
Depending on the value of p, the bias levels are set
according to the following ratios:
When p = 2, the bias level is: R
When p = 4, the bias level is: R
The value of
2003 Mar 13
F
F G
F
--- -
G
F
handbook, full pagewidth
65
=
=
=
V
-------------
G a
------------- -
a
-- -
p
LCD
Bias levels
2
p
96 pixels matrix LCD driver
is in the range from 0.15 to 1.35.
R
R
R
R
R
R
p = 4
R
2R
R
V LCD = F
V COL(max) = G
V1H
VC
V1L
V COL(min) = G
V SS = F
2R
R
R
R
Fig.33 Bias system.
R
34
The value of F is determined by (2 + 4)
of G is determined by 4R.
Also from:
or:
the relationship between a and
given by:
This leads to the bias settings given in Table 19. The bias
can be selected in software and also programmed by OTP.
a
--- -
G
F
=
=
=
a
-- -
p
R
R
R
R
R
R
-- -
--- - 1
G
2
F
p = 2
=
+
–
1
--------------------------------
2
V LCD = F
V COL(max) = G
VC
V COL(min) = G
V SS = F
p
+
2
4R
4
R
MCE009
=
=
--------------------- -
2
a
-- - 1
p
–
4
+
4
for a given value of p is
Objective specification
2
=
1
+
PCF8814
R, and the value
-- -
2