STE2004SDIE2 STMicroelectronics, STE2004SDIE2 Datasheet - Page 12

• Manufacturer Part Number: STE2004SDIE2
• Description: 102 x 65 single-chip LCD controller/driver
• Manufacturer: STMicroelectronics

Circuit description
3.6
12/79
Table 3. Bias level m=65 and m=49
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:
Table 4. LCD voltage generation
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
than:
Symbol
Ao
A1
A2
To
B
Symbol
V1
V2
V3
V4
V5
V6
V
LCD
(T=To) = V
0.0303
Value
V LCD
10.71
2.95
6.83
27
LCD
V op
V
LCD
LCD(to)
is:
=
=
m = 65 (1/9)
2/9*V V
o = (Ai+V
-------------------------------------- -
1/9 *V
8/9*V
7/9*V
(
--------------------------------------------
2
6.85
V
⋅
V
1
= 6.85 · V
LCD
SS
+
⎛
⎝
LCD
LCD
1
LCD
⋅
0.03
LCD
–
m
V th A i
-------- -
OP
1
m
–
⎞
⎠
· B)
th
⋅
Unit
°C
)
V
V
V
V
V th
(i=0,1,2)
m = 49 (1/8)
7/8*V
6/8*V
2/8*V
1/8*V
V
V
PRS = [0;0]
PRS = [0;1]
PRS = [1;0]
LCD
SS
LCD
LCD
LCD
LCD
Note
OP
STE2004S
register