MC34270 Datasheet, PDF (7/12 Pages) Motorola, Inc – LIQUID CRYSTAL DISPLAY AND BACKLIGHT INTEGRATED CONTROLLER

MC34270 MC34271
Figure 11. Representative Block Diagram Electroluminescent Backlight Configuration
EL
Panel
169 k
Brightness
VB
DAC
SW1
32
DS1
1
EN1
ÎÎ ₂₆
VDD
8 Drv1
÷2
31 Sync
30 RT
Vref
27 ^{1.25 V}
Ref1
2
3 _FB1
4 Comp1
SS1
5
Ref2
23
22 FB2
Comp2
21 _SS2
20
DS2
24
Circuit #1 Bias Supply
En
S
Q
R
D1
7
S1 6
÷N
ELD
9
VDD
11
OSC
Mode
10
S
Q
R
En
ÎÎ^VDD_ÎÎ
VDD2
Circuit #2
Bias Supply
D2
18
S2 19
VB
17
V0
16
V1
15
25 EN2
VA
28
BIAS
Gnd
29
V2
14
VDD2
V3
13
VDD2
V4
12
“On/Off”
VDD
VB
6.0 V to 30 V
V0
V1
V2
V3
LCD
Display
V4
MOTOROLA ANALOG IC DEVICE DATA
7