STE2002DIE1 STMicroelectronics, STE2002DIE1 Datasheet - Page 7

• Manufacturer Part Number: STE2002DIE1
• Description: 81 x 128 Single Chip LCD Controller/Driver
• Manufacturer: STMicroelectronics

The STE2002 provides three bits (BS0, BS1, BS2) for programming the desired Bias Ratio as shown below:
The following table Bias Level for m = 65 and m = 81 are provided:
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:
with the following values:
Note that the three PRS values produce three adjacent ranges for VLCD. If the V
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
than:
Symbol
BS2
Ao
A1
A2
To
B
0
0
0
0
1
1
1
1
Symbol
V1
V2
V3
V4
V5
V6
V
LCD
LCD
(T=To) = V
is:
0.0303
Value
10.71
BS1
2.95
6.83
27
V
0
0
1
1
0
0
1
1
L CD
V
o p
V
LCD
LCD(to)
=
=
m = 65 (1/9)
2/9*V V
----------------------------------- - V
o = (Ai+V
1/9 *V
---------------------------------------- -
8/9*V
7/9*V
2
6.85 V
V
V
1
= 6.85 · V
LCD
SS


+
1
LCD
LCD
LCD
0.03
LCD
–
m
-------- -
OP
th
1
m
–
· B)


th
A
i
BS0
Unit
°C
th
V
V
V
V
0
1
0
1
0
1
0
1
(i=0,1,2)
OP
register and PRS bits are
m = 81 (1/10)
9/10*V
8/10*V
2/10*V
1/10*V
V
V
LCD
PRS = [0;0]
PRS = [0;1]
PRS = [1;0]
SS
LCD
LCD
LCD
LCD
Note
n
7
6
5
4
3
2
1
0
STE2002
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