AAT3192 Datasheet, PDF (11/17 Pages) Advanced Analogic Technologies – Low-Cost, 2-/3-Channel Charge-Pump LED Drivers

Data
1
2
3
4
5
6
7
8
EN Rising
Edges
1
2
3
4
5
6
7
8
D1-D3
Current (mA)
20
17.3
14.7
12
9.3
6.7
4
1.3
Table 2: AAT3192/93-2 LED Current Settings
AAT3192/93
Low-Cost, 2-/3-Channel
Charge-Pump LED Drivers
20.00
15.00
10.00
5.00
0.00
1
2
3
4
5
6
7
8
S²Cwire Interface Data Code
Figure 3: AAT3192/93-2 Current Control Profile
Data
EN Rising
Edges
D1-D3
Current (mA)
1
1
20
2
2
13.3
3
3
6.7
4
4
0.87
Table 3: AAT3192/93-3 LED Current Settings
PWM Control (AAT3192/93-4 only)
PWM (Pulse Width Modulation) is an industry stan-
dard technique of controlling LED brightness by
modulating the conduction duty cycle of the LED
current. LED brightness is determined by the aver-
age value of the PWM signal multiplied by the LED’s
intensity where intensity is proportional to the LED
drive current. A PWM control signal can be applied
into the EN/PWM pin of the AAT3192/93-4. By
20.00
15.00
10.00
5.00
0.00
1
2
3
4
S²Cwire Interface Data Code
Figure 4: AAT3192/93-3 Current Control Profile
changing the duty cycle of the PWM signal from
100% (logic high) to 10%, LEDs sink current can be
programmed from 20mA to 2.4mA. To save power
when not used, AAT3192/93-4 can be shutdown by
holding the EN/PWM pin low for 1ms.
Lastly, Table 4 and Figure 5 illustrate the
AAT3192/93-4’s LED current control profile as a
function of a PWM control signal.
3193.2007.05.1.0
11