SL20T0081 View Datasheet(PDF) - System Logic Semiconductor
Part Name
Description
MFG CO.
'SL20T0081' PDF : 56 Pages View PDF
SLS System Logic Semiconductor
SL20T0081
Voltage Regulator Circuits
The function of the internal voltage regulator circuits is to determine liquid crystal operating voltage, V0,by adjusting
resistors, Ra and Rb, within the range of [V0]< [VOUT]. Because VOUT is the operating voltage of operational
amplifier circuits showing Figure 10, it is necessary to be applied internally or externally.
For the Eq. 1, we determine V0 by Ra, Rb and VEV. The Ra are connected internally or externally by INTRS pin. And
VEV called the voltage of electronic volume is determined by Eq. 2,, where the parameter α is the value selected by
instruction, “Set Reference Voltage Register”, within the range 0 to 63. VREF voltage at Ta = 25oC is shown in
table 9.
Rb
V0 = ( 1 +
Ra
) x VEV
[V]
(Eq.1)
(63 -α )
VEV = ( 1 - 162 ) x VREF [V]
(Eq.2)
Table 9. VREF Voltage at Ta = 25oC
REF
H
Temp. coefficient
-0.05% / oC
L
External input
VREF [V]
2.1
VEXT
Table 10. Electronic Contrast Control Register (64 Steps)
VR5 VR4 VR3 VR2 VR1 VR0
Reference voltage
parameter
0
0
0
0
0
0
0
0
0
0
0
0
1
1
:
:
:
:
:
:
:
:
:
:
:
:
:
:
1
0
0
0
0
0
32(default)
:
:
:
:
:
:
:
:
:
:
:
:
:
:
1
1
1
1
1
0
62
1
1
1
1
1
1
63
V0
Contrast
Minimum
:
:
:
:
:
:
Maximum
Low
:
:
:
:
:
:
High
Share Link: 
