STE2002 Datasheet, PDF (8/51 Pages) STMicroelectronics – 81 X 128 SINGLE CHIP LCD CONTROLLER / DRIVER

STE2002
Temperature Coefficient
As the viscosity, and therefore the contrast, of the LCD are subject to change with temperature, there's the need
to vary the LCD Voltage with temperature. The STE2002 provides the possibility to change the VLCD in a linear
fashion against temperature with eight different Temperature Coefficient selectable through the T2, T1 and T0
bits. Only four of them are available with basic instruction set (TC1 & TC0 Bits).
NAME
TC1
TC0
0
TC2
0
TC3
1
TC6
1
TC0
Value
Unit
0
-0.0· 10^-3
1/ °C
1
-0.7 · 10^-3
1/°C
0
-1.05· 10^-3
1/°C
1
-2.1 · 10^-3
1/°C
NAME
TC2
TC1
TC0
Value
Unit
TC0
0
0
0
-0.0· 10^-3
1/ °C
TC1
0
1
1
-0.35 · 10^-3
1/°C
TC2
1
0
0
-0.7 · 10^-3
1/°C
TC3
1
1
1
-1.05· 10^-3
1/°C
TC4
1
1
1
-1.4 · 10^-3
1/°C
TC5
1
1
1
-1.75· 10^-3
1/°C
TC6
1
1
1
-2.1 · 10^-3
1/°C
TC7
1
1
1
-2.3· 10^-3
1/°C
Figure 5.
VLCD
B
A2
A0 + B
A1
A0
00h 01h 02h 03h 04h 05h …. 7Ch 7Dh 7Eh 7Fh 00h 01h 02h 03h 04h 05h …. 7Ch 7Dh 7Eh 7Fh 00h 01h 02h 03h 04h 05h …. 7Ch 7Dh 7Eh 7Fh
PRS = [0;0]
PRS = [0;1]
PRS = [1;0]
VO
Finally, the V_LCD voltage at a given (T) temperature can be calculated as:
V_LCD(T) = V_LCDo · [1 + (T-To) · TC]
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