µPD160040A
5. RELATIONSHIP BETWEEN INPUT DATA AND OUTPUT VOLTAGE VALUE
The µPD160040A incorporates a 8-bit D/A converter whose odd output pins and even output pins output
respectively gray scale voltages of differing polarity with respect to the LCD’s counter electrode voltage. The D/A
converter consists of ladder resistors and switches.
The ladder resistors (r0 to r253) are designed so that the ratio of LCD panel (γ -compensated voltages to V0’-V255’
and V0”-V255” is almost equivalent as shown in Figure 5−2. For the 2 sets of eight γ -compensated power supplies,
V0-V7 and V8-V15, respectively, input gray scale voltages of the same polarity with respect to the 0.5 VDD2.
Figure 5−1 shows the relationship between the driving voltages such as liquid-crystal driving voltages VDD2, VSS2 and
0.5 VDD2, and γ -corrected voltages V0-V15 and the input data. Be sure to maintain the voltage relationships below.
VDD2 –0.2 V ≥ V0 > V1 > V2 > V3 > V4 > V5 > V6 > V7 ≥ 0.5 VDD2 +0.5 V
0.5 VDD2 –0.5 V ≥ V8 > V9 > V10 > V11 > V12 > V13 > V14 > V15 ≥ 0.5 VSS2 +0.2 V
Also, V6-V7 and V8-V9 are left open in the IC. Be sure to input the gray scale level power supply at a constant level
to the all pins, as V0-V15.
Figures 5−2 shows γ-Corrected Voltages and Ladder Resistors Ratio and figure 5−3 shows the relation ship
between the input data and the output voltage (POL21, POL22 = L).
Figure 5−1. Relationship between Input Data and γ -corrected Power Supplies
0.2 V
VDD2
V0
V1
V2
V3
V4
V5
V6
V7
0.5 V
0.5 VDD2
0.5 V
V8
V9
V10
V11
V12
V13
V14
0.2 V
V15
V SS2
00 01
20
40
15
48
64
64
32
31
80
C0
Input data (HEX)
31
32
64
64
48
15
F0 FF
6
Data Sheet S15918EJ1V0DS