AAT3169 Datasheet, PDF (10/14 Pages) Advanced Analogic Technologies – High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications

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.
When EN/SET is held low for an amount of time
greater than T_OFF, the AAT3169 enters shutdown
mode and draws less than 1µA from V_IN. Data and
Address registers are reset to 0 during shutdown.
AS²Cwire Serial Interface Addressing
Address
0
1
2
3
4
EN/SET
Rising Edges
17
18
19
20
21
Data Register
AAT3169
1&2: D1~D6 Current
1: D1~D5 Current
2: D6 Current
3: Max Current
4: Low Current
Data
1
2
3
4
Max Current
20mA
30mA
15mA
Low Current
(see Low Current Register for values)
Low Current Register (Address 4)
Data
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Main Low
Current On
No
No
No
No
No
No
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Sub Low
Current On
No
No
No
No
Yes
Yes
Yes
Yes
No
No
No
No
Yes
Yes
Yes
Yes
Current
115µA
175µA
280µA
400µA
115µA
175µA
280µA
400µA
115µA
175µA
280µA
400µA
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 certain threshold. This feature is
very convenient for disabling an unused channel or
during an LED fail-short event.
Thermal Protection
The AAT3169 has built-in thermal protection circuit
that will shut down the charge pump if the die tem-
perature rises above the thermal limit, as is the
case during a short circuit of the V_OUT pin.
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3169.2006.04.1.0