High Efficiency 1X/1.5X/2X Charge Pump
For White LED Applications
Typical Characteristics
C
IN
= C
OUT
= C
1
= C
2
= 1.0µF; T
A
= 25°C, V
IN
= 3.6V, unless otherwise noted.
AAT3155
Efficiency vs. Supply Voltage
100
90
5mA/ch
V
F
= 3V
20mA/ch
V
F
= 3.4V
Turn-On to 1X Mode
(V
IN
= 4.2V; 20mA Load)
Efficiency (%)
80
70
60
50
40
30
2.7
2.9
3.1
3.3
3.5
3.7
3.9
4.1
4.3
4.5
500µA/ch
V
F
= 2.7V
EN
(2V/div)
V
OUT
(2V/div)
V
SINK
(1V/div)
I
IN
(100mA/div)
μ
Time (200μs/div)
Supply Voltage (V)
Turn-On to 1.5X Mode
(V
IN
= 3.5V; 20mA Load)
Turn-On to 2X Mode
(V
IN
= 2.8V; 20mA Load)
EN
(2V/div)
V
OUT
(2V/div)
V
SINK
(1V/div)
I
IN
(200mA/div)
μ
Time (200μs/div)
EN
(2V/div)
V
OUT
(2V/div)
V
SINK
(500mV/div)
I
IN
(200mA/div)
μ
Time (200μs/div)
Turn-Off from 1.5X Mode
(V
IN
= 3.5V; 20mA Load)
22.0
21.5
21.0
20.5
20.0
19.5
19.0
18.5
18.0
-40
Diode Current vs. Temperature
(20mA/channel)
EN
(2V/div)
V
F
(1V/div)
Diode Current (mA)
I
D1
I
D2
I
D3
I
IN
(100mA/div)
I
D4
-25
-10
5
20
35
50
65
80
95
μ
Time (200μs/div)
°
Temperature (°C)
3155.2006.05.1.1
5
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
