a-Si TFT LCD Single Chip Driver
240RGBx320 Resolution and 262K color
ILI9325
Ladder resistors and 8-to-1 selector Block configuration
The reference voltage generating block consists of two ladder resistor units including variable resistors and
8-to-1 selectors. Each 8-to-1 selector selects one of the 8 voltage levels generated from the ladder resistor
unit to output as a grayscale reference voltage. Both variable resistors and 8-to-1 selectors are controlled
according to the γ-correction registers. This unit has pins to connect a volume resistor externally to
compensate differences in various characteristics of panels.
Variable resistors
ILI9325 uses variable resistors of the following three purposes: gradient adjustment (VRCP(N)0/VRCP(N)1);
amplitude adjustment (1) (VROP(N)0); and the amplitude adjustment (2) (VROP(N)1). The resistance values
of these variable resistors are set by gradient adjustment registers and amplitude adjustment registers as
follows.
Gradient adjustment
Amplitude adjustment (1)
VRP(N)0[3:0] VROP(N)0
Amplitude adjustment (2)
VRP(N)1[4:0] VROP(N)1
PRP(N)0/1[2:0] VRCP(N)0
Register
000
Resistance
0R
Register
0000
0001
0010
:
Resistance
Register
00000
00001
00010
:
Resistance
0R
2R
4R
:
0R
1R
2R
:
001
4R
010
8R
011
12R
100
16R
:
:
:
:
101
20R
1101
1111
1111
26R
28R
30R
11101
11110
11111
29R
30R
31R
110
24R
111
28R
8-to-1 selectors
The 8-to-1 selector selects one of eight voltage levels generated from the ladder resistor unit according to the
fine adjustment register and output the selected voltage level as a reference grayscale voltage (VgP(N)1~6).
The table below shows the setting in the fine adjustment register and the selected voltage levels for
respective reference grayscale voltages.
Fine adjustment registers and selected voltage
Register
Selected Voltage
KP(N)[2:0] VgP(N)1 VgP(N)8 VgP(N)20 VgP(N)43 VgP(N)55 VgP(N)62
000
001
010
011
100
101
110
111
VP(N)1
VP(N)2
VP(N)3
VP(N)4
VP(N)5
VP(N)6
VP(N)7
VP(N)8
VP(N)9
VP(N)10
VP(N)11
VP(N)12
VP(N)13
VP(N)14
VP(N)15
VP(N)16
VP(N)17
VP(N)18
VP(N)19
VP(N)20
VP(N)21
VP(N)22
VP(N)23
VP(N)24
VP(N)25
VP(N)26
VP(N)27
VP(N)28
VP(N)29
VP(N)30
VP(N)31
VP(N)32
VP(N)33
VP(N)34
VP(N)35
VP(N)36
VP(N)37
VP(N)38
VP(N)39
VP(N)40
VP(N)41
VP(N)42
VP(N)43
VP(N)44
VP(N)45
VP(N)46
VP(N)47
VP(N)48
The information contained herein is the exclusive property of ILI Technology Corp. and shall not be distributed,
reproduced, or disclosed in whole or in part without prior written permission of ILI Technology Corp.
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Version: 0.35