AAT3104 Datasheet, PDF (9/15 Pages) Advanced Analogic Technologies – Low Cost 1x/2x 4 Channel Charge Pump WLED Driver

ChargePump^TM
PRODUCT DATASHEET
AAT3104178
Low Cost 1x/2x 4 Channel Charge Pump WLED Driver
current reduces system noise and improves LED reliabil-
ity. The S²Cwire interface relies on the number of rising
edges to the EN/SET pin to set the register. A typical
write protocol is a burst of EN/SET rising edges, followed
by a pause with EN/SET held high for at least t_LAT (500μs).
The programmed current is then seen at the current
source outputs. When EN/SET is held low for an amount
of time longer than t_OFF (500μs), the AAT3104 enters into
shutdown mode and draws less than 1μA from the input
and the internal data register is reset to zero.
The AAT3104-1/2’s serial interface reduces the LED cur-
rent on each rising pulse of the enable input. If the
AAT3104 is in shutdown, the first rising edge of the EN/
SET input turns on the LED driver to the maximum cur-
rent. Successive rising edges decrease the LED current
as shown in Table 1 and Figure 2 for the AAT3104-1. For
the AAT3104-2, Table 2 and Figure 3 illustrate a 32-step
LED current control profile.
Data
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
EN Rising
Edges
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
D1-D4
Current (mA)
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0.5
Table 1: AAT3104-1 LED Current Settings.
Data
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
EN Rising Edges
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
D1-D4 Current (mA)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0.5
Table 2: AAT3104-2 LED Current Settings.
tHI
tLO
tOFF
OFF
1
2
3
OFF
Figure 1: EN/SET Timing Diagram.
3104.2008.09.1.0
www.analogictech.com
9