AAT3192/93
Low-Cost, 2-/3-Channel
Charge-Pump LED Drivers
20.00
15.00
10.00
5.00
EN Rising
Edges
D1-D3
Data
Current (mA)
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
20
17.3
14.7
12
9.3
6.7
4
0.00
1
2
3
4
5
6
7
8
S2Cwire Interface Data Code
1.3
Table 2: AAT3192/93-2 LED Current Settings
Figure 3: AAT3192/93-2 Current Control Profile
20.00
15.00
10.00
5.00
EN Rising
Edges
D1-D3
Data
Current (mA)
1
2
3
4
1
2
3
4
20
13.3
6.7
0.87
Table 3: AAT3192/93-3 LED Current Settings
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
100ꢀ (logic high) to 10ꢀ, 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.
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
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
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
