UPD16640C NEC, UPD16640C Datasheet - Page 7

• Manufacturer Part Number: UPD16640C
• Description: 300/309-OUTPUT TFT-LCD SOURCE DRIVER 64 GRAY SCALE
• Manufacturer: NEC

4.1 -corrected Power Circuit
resistance ri between -corrected power pins differs depending on each pair of -corrected power pins. One pair of
as the sum of the seven or eight resistors. The resistance ratio between the -corrected power pins ( ri ratio) is
designed to be a value relatively close to the ratio of the -corrected voltages V
used in an actual LCD panel. Under ideal conditions where there is no difference between the two, therefore, there is
no voltage difference between the voltage of the -corrected power supplies and the gray-scale voltages in 8 steps of
the resistor ladder circuits of the PD16640C, and no current flows into the -corrected power pins V
result, a voltage-follower circuit is not necessary.
-corrected power pins consists of seven or eight series resistors, and resistance ri in the figure below is indicated
The reference power supply of the D/A converter consists of a ladder circuit with a total of 64 resistors, and
-corrected power pin
V
V
V
V
V
V
V
V
V
V
V
10
0
1
2
3
4
5
6
7
8
9
Figure 4-2.
Data Sheet S11269EJ1V1DS00
i
i
i
i
i
i
i
i
i
i
i
-corrected Power Circuit
0
1
2
3
4
5
6
7
8
9
10
-corrected resistor
R
R
R
R
R
R
R
R
R
R
0
1
2
3
4
5
6
7
8
9
= 2.39 k
=
=
=
=
=
=
=
=
i = 1
i = 1
i = 1
i = 1
i = 1
i = 1
i = 1
i = 1
= 2.55 k
7
8
8
8
8
8
8
7
r
r
r
r
r
r
r
r
i
i
i
i
i
i
i
i
= 4.45 k
= 6.19 k
= 3.58 k
= 2.15 k
= 2.03 k
= 1.61 k
= 2.03 k
= 3.39 k
1
to V
9
(gray-scale voltages in 8 steps)
PD16640C
Sum of eight
-corrected resistors
1
to V
PD16640C
9
. As a
7