High Current, High Efficiency Charge Pump
Typical Characteristics
V
IN
= 3.6V, C
IN
= 4.7µF, C
OUT
= 2.2µF, C
1
= C
2
= 1µF, T
A
= 25°C, unless otherwise noted.
Efficiency vs. Supply Voltage
100
90
80
AAT3174
Turn-On to 1X Mode
(V
IN
= 4.2V; I
LED
= 150mA)
Efficiency (%)
70
60
50
40
30
20
10
0
I
LED
= 150mA
EN
(2V/div)
I
LED
= 300mA
V
OUT
(2V/div)
V
SINK
(1V/div)
I
IN
(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 (200µs/div)
Turn-On to 1.5X Mode
(V
IN
= 3.2V; I
LED
= 150mA)
Turn-On to 1X Mode
(V
IN
= 4.2V; I
LED
= 600mA)
EN
(2V/div)
V
OUT
(2V/div)
V
SINK
(1V/div)
I
IN
(200mA/div)
EN
(2V/div)
V
OUT
(2V/div)
V
SINK
(1V/div)
I
IN
(500mA/div)
Time (200µs/div)
Time (200µs/div)
Turn-On to 2X Mode
(V
IN
= 3.2V; I
LED
= 600mA)
Turn-Off from 1.5X Mode
(V
IN
= 3.2V; I
LED
= 150mA)
EN
(2V/div)
V
OUT
(2V/div)
V
SINK
(1V/div)
I
IN
(500mA/div)
EN
(2V/div)
V
F
(1V/div)
I
IN
(200mA/div)
Time (200µs/div)
Time (200µs/div)
3174.2006.05.1.2
5
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
