STE2002_06 ST Microelectronics, Inc., STE2002_06 Datasheet - Page 10

• Manufacturer Part Number: STE2002_06
• Description: 81 x 128 Single-chip LCD Controller/driver
• Manufacturer: ST Microelectronics, Inc.

Circuit description
2.5
10/61
LCD voltage generation
The LCD Voltage at reference temperature (To = 27°C) can be set using the VOP register
content according to the following formula:
V
with the following values:
Table 4.
Note that the three PRS values produce three adjacent ranges for VLCD. If the V
and PRS bits are set to zero the internal voltage generator is switched off.
The proper value for the VLCD is a function of the Liquid Crystal Threshold Voltage (Vth)
and of the Multiplexing Rate. A general expression for this is:
For MUX Rate m = 65 the ideal V
V
then:
LCD
LCD(to)
(T=To) = V
Symbol
= 6.85 · V
Ao
A1
A2
To
B
LCD voltage values
LCD
th
o = (Ai+V
OP
V LCD
0.0303
Value
10.71
· B)
2.95
6.83
27
V op
LCD
=
is:
=
-------------------------------------- -
(i=0,1,2)
(
--------------------------------------------
2
6.85
⋅
1
+
⎛
⎝
1
⋅
0.03
–
m
V th A i
-------- -
1
m
–
⎞
⎠
Unit
⋅
°C
V
V
V
V
)
V th
PRS = [0;0]
PRS = [0;1]
PRS = [1;0]
Note
OP
STE2002
register