AAT3169
High Efficiency 1X/1.5X/2X Charge
Pump for White LED Applications
The maximum current level is determined by the
value set in Register 3, the Max Current register.
Three scales are available for high operating cur-
rents with maximum current levels of 30mA, 20mA,
or 15mA. Each scale maintains approximately
1.8dB steps between settings. A separate mode is
available for ultra-low LED current operation.
When the Max Current register (Register 3) is set
to the Low Current setting, the Low Current regis-
ter (Register 4) must be programmed. The two
most significant bits of the Low Current register
control whether or not a given bank of current sinks
is enabled. The least two significant bits of the Low
Current register sets the current level for both
banks. For low current settings, the charge pump
may be enabled if required by the battery voltage
and LED forward voltage conditions, and 1X mode
quiescent current is approximately 130µA for multi-
ple channels or 65µA for Channel 6 operation only.
Both banks of current sinks must be in the same
high or low current mode of operation.
Low Current Register (Address 4)
Main Low
Sub Low
Data
Current On Current On Current
1
2
No
No
No
No
3
No
No
4
No
No
5
No
Yes
Yes
Yes
Yes
No
115µA
175µA
280µA
400µA
115µA
175µA
280µA
400µA
115µA
175µA
280µA
400µA
6
No
7
No
8
No
9
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
10
11
12
13
14
15
16
No
No
No
Yes
Yes
Yes
Yes
When EN/SET is held low for an amount of time
greater than TOFF, the AAT3169 enters shutdown
mode and draws less than 1µA from the input.
Data and Address registers are reset to 0 during
shutdown.
Auto-Disable Feature
AAT3169 is equipped with an auto-disable feature
for each LED channel. After the IC is enabled and
started up, a test current of 120µA (typical) is
forced through each sink channel. The channel will
be disabled if the voltage of that particular SINK pin
does not drop to a certain threshold. This feature is
very convenient for disabling an unused channel or
during an LED fail-short event.
AS2Cwire Serial Interface Addressing
EN/SET
Address Rising Edges
Data Register
AAT3169
0
1
2
3
4
17
18
19
20
21
1&2: D1~D6 Current
1: D1~D5 Current
2: D6 Current
Thermal Protection
The AAT3169 has a built-in thermal protection cir-
cuit that will shut down the charge pump if the die
temperature rises above the thermal limit, as would
be the case during a short circuit of the OUTCP pin.
3: Max Current
4: Low Current
Data
Max Current
1
2
3
4
20mA
30mA
15mA
Low Current
(see Low Current Register for values)
10
3169.2006.08.1.2
AAT [ ADVANCED ANALOG TECHNOLOGY, INC. ]
