SC604A
POWER MANAGEMENT
Typical Characteristics
Startup with 4 LEDs at 20 mA
OVP Event with LED Open Circuit
Efficiency vs. Load at High Battery
Efficiency vs. Load at Low Battery
100
90
80
70
60
50
100
90
80
70
60
50
VIN = 3.4V
VIN = 3.6V
VIN = 3.8V
VIN = 4.0V
VIN = 4.2V
VIN = 2.8V
0
20
40
60
80
100
120
0
20
40
60
80
100
120
Total Load Current [mA]
Total Load Current [mA]
Mode Transition Voltage vs. LED Voltage
Quiescent Current Trend
5
3.9
1X to 1.5X Mode for 4 LEDs
3.8
3.7
3.6
3.5
3.4
3.3
3.2
4
3
2
1
0
Vf = 3.6V
Trend for 4 LEDs
Vf = 3.4V
Vf = 3.2V
0
5
10
15
20
25
30
35
0
20
40
60
80
100
120
LED Current [mA]
Total Output Current [mA]
2005 Semtech Corp.
www.semtech.com
12
SEMTECH [ SEMTECH CORPORATION ]
