PRODUCT DATASHEET
AAT1239-1
SwitchReg
TM
Typical Characteristics
Soft Start
(10 White LEDs; V
FB
= 0.6V)
Feedback Voltage (middle) (V)
Feedback Voltage (middle) (V)
EnableVoltage (top) (V)
Inductor Current (bottom) (A)
0.6
0.4
0.2
0
2
1
0
0V
3.3V
40V Step-Up Converter for 4 to 10 White LEDs
Soft Start
(10 White LEDs; V
FB
= 0.3V)
EnableVoltage (top) (V)
Inductor Current (bottom) (A)
3.3V
0V
0.4
0.2
0
2
1
0
0V
Time (200µs/div)
Time (200µs/div)
Shutdown
(10 White LEDs; V
FB
= 0.6V)
EnableVoltage (top) (V)
Feedback Voltage (middle) (V)
EnableVoltage (top) (V)
Feedback Voltage (middle) (V)
Inductor Current (bottom) (A)
3.3V
0V
0.6
0.4
0.2
0
0.5
0.0
3.3V
0V
0.4
0.2
0
Shutdown
(10 LEDs; V
FB
= 0.3V)
Inductor Current (bottom) (A)
0.5
0
Time (100µs/div)
Time (50µs/div)
Output Ripple
(10 White LEDs; V
IN
= 3.6V; C
OUT
= 2.2µF; I
LED
= 13mA)
V
OUT
(AC Coupled)
(20mV/div)
V
SW
(20V/div)
I
L
(500mA/div)
V
OUT
(AC Coupled)
(20mV/div)
V
SW
(20V/div)
I
L
(500mA/div)
Output Ripple
(10 White LEDs; V
IN
= 3.6V; C
OUT
= 2.2µF; I
LED
= 20mA)
Time (200ns/div)
Time (200ns/div)
6
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1239-1.2008.06.1.1
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