AAT2846
High Current Charge Pump with Dual LDO
for Backlight and Flash Applications
Address
Data
THI
TLAT
TLO
TLAT
EN/SET
Address
1
2
17
0
18
1
2 . . .
n ≤ 16
1
0
0
n
Data Reg 1
Data Reg 2
2
Figure 1: AS Cwire Serial Interface Timing.
The AAT2846 incorporates additional circuitry that
optimizes performance for exceptionally low back-
light current settings. A separate address is used to
activate this circuitry. To program the low current
settings with improved performance and efficiency,
write to Address 3. Unlike Addresses 0-3, which
have current level settings according to Table 2 and
Figure 2, Address 3 possesses a separate set of
current levels described by the Low Current
Backlight settings found in Table 3.
Data
1
2
3
4
5
6
7
8
30mA Max (mA) 20mA Max (mA)
30.0
27.9
26.1
24.2
21.0
19.2
17.3
15.0
12.7
10.9
8.1
20.0
19.0
17.8
16.5
14.3
13.0
11.8
10.2
8.5
9
Main
Sub
Current
(µA)
10
11
12
13
14
15
16
7.3
5.4
Data
Current On Current On
1
2
No
No
No
No
0
0
6.2
4.1
4.4
2.9
3
No
No
0
3.5
2.2
4
No
No
0
2.6
1.6
5
6
7
8
No
No
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
No
No
No
Yes
Yes
Yes
Yes
95
0
0
500
950
1900
95
500
950
1900
95
Table 2: Data Code for Backlight Current Level
,
Address 0-2.
9
35.0
30.0
25.0
20.0
10
11
12
13
14
15
16
500
950
1900
30mA (Full Scale)
15.0
10.0
5.0
20mA (Full Scale)
0.0
Table 3: Data Code for Low-Level Backlight
Current, Address 3, FS = 20mA range.
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16
Data Code
Figure 2: Data Code for Address 0-2 vs.
Backlight Current Level
.
2846.2007.08.1.0
13
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
