AAT3194
High Efficiency 1.5X Fractional Charge
Pump For White LED Applications
Test Current/Channel Disable
Thermal Protection
Each channel of the output is equipped with a test
current function. The AAT3194 uses a small (~2µA)
current source injected into each output pin to
detect the presence of an LED. Unused channels
that are tied to ground or LED load fail short will be
automatically diasbled instead of wasting the pro-
grammed output current.
The AAT3194 has a thermal protection circuit that
will shut down the charge pump and current out-
puts if the die temperature rises above the thermal
limit.
Application Circuits
Typical AAT3194 Application Circuit:
IN
C1+
C1
1μF
C1-
C2+
OUT
CIN
COUT
C2
1μF
VBATTERY
AAT3194
1μF
1μF
C2-
D1
D2
D3
D4
EN/SET
EN/SET
GND
D4
D3
D2
D1
THI > 50ns
300ns < TLO < 75μs
50ns minimum to enable
OFF
n
ON/1
2
3
4
5
6
(n < =32)
Enable / Disable / LED Brightness Level Set Data Input
12
3194.2006.09.1.0
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
