AAT3167_07 Datasheet, PDF (10/14 Pages) Advanced Analogic Technologies – High Efficiency 1X/1.5X/2X Charge Pump for White LED Applications

AAT3167
High Efficiency 1X/1.5X/2X Charge
Pump for White LED Applications
the Max Current register (Register 3) is set to the
Low Current setting, the Low Current register
(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 set 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 100µA for multi-
ple channels or 50µA for Channel 5 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 AAT3167 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
AAT3167
1&2: D1~D5 Current
1: D1~D4 Current
2: D5 Current
3: Max Current
4: Low Current
Data
1
2
3
4
Max Current
18mA
27mA
14mA
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
The AAT3167 is equipped with an auto-disable fea-
ture 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.
Thermal Protection
The AAT3167 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.
10
3167.2007.03.1.4