AAT3175
High Efficiency 1X/1.5X/2X Charge Pump
For White LED Flash Applications
Typical Characteristics
C
IN
= C
OUT
= C
1
= C
2
= 1µF, T
A
= 25°C, V
IN
= 3.5V, unless otherwise noted.
Efficiency vs. Supply Voltage
100
90
300mA LED Pulse
(V
IN
= 3.8V)
Efficiency (%)
80
70
60
50
40
30
60mA
V
F
= 3.0V
150mA
V
F
= 3.2V
V
OUT
(2V/div)
I
OUT
(200mA/div)
2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4.0 4.1 4.2
Supply Voltage (V)
Time (100ms/div)
Turn-On to 1X Mode
(V
IN
= 4.2V; 300mA Load)
Turn-On to 1.5X Mode
(V
IN
= 4.0V; 300mA Load)
EN
(2V/div)
V
OUT
(2V/div)
V
SINK
(1V/div)
I
IN
(400mA/div)
Time (200µs/div)
µ
EN
(2V/div)
V
OUT
(2V/div)
V
SINK
(1V/div)
I
IN
(400mA/div)
Time (200µs/div)
µ
Turn-On to 2X Mode
(V
IN
= 3.8V; 300mA Load)
EN
(2V/div)
V
F
(1V/div)
Turn-Off from 1.5X Mode
(V
IN
= 4.0V; 300mA Load)
EN
(2V/div)
V
OUT
(2V/div)
V
SINK
(1V/div)
I
IN
(400mA/div)
Time (200µs/div)
µ
I
IN
(200mA/div)
Time (200µs/div)
µ
3175.2006.01.1.2
5
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
