VIN (V)

100

80

60

40

2.7

3.1

3.5

3.9

4.3

4.7

5.1

5.5

1 LED @ 1.2A

2 LEDs @ 600 mA

VIN (V)

100

90

80

70

60

50

40

2.7

3. 1

3.5

3.9

4.3

4. 7

5.1

5.5

Voltage Mode with IOUT = 500 mA

1 LED @ 1A with VLED = 3.7V

2 LEDs @ 500 mA with

VLED(total) = 6.725V

VIN (V)

2.20

1.85

1.50

1.15

0.80

90

80

70

60

50

3.0

3.5

4.0

4.5

5.0

5.5

IIN

äLED

VLED = 3.4V and ILED = 600 mA

2 LEDs in Series

VIN (V)

2.8

2.4

2.0

1.6

1.2

0.8

2.7

3.1

3.5

3.9

4.3

4.7

5.1

5.5

1 LED @ 1.2A

2 LEDs @ 600 mA

VIN (V)

2.80

2.20

1.60

1.00

90

80

70

60

50

3.0

3.5

4.0

4.5

5.0

5.5

IIN

äLED

VLED = 3.8V and ILED = 1.2A

VIN (V)

1.60

1.35

1.10

0.85

0.60

90

80

70

60

50

3.0

3.5

4.0

4.5

5.0

5.5

IIN

äLED

VLED = 3.35V and ILED = 500 mA

2 LEDs in Series

LM3553

www.ti.com

SNVS414B – FEBRUARY 2008 – REVISED MAY 2013

Typical Performance Characteristics (continued)

Unless otherwise specified: TA = 25°C; VIN = 3.6V; VM/F = VIN; RSET = 16.5kΩ; CIN= 10µF, COUT = 10µF;L = 2.2µH; VFB bit =

CL bit = '0'; OVP bit = '0' for 1 LED and VFB = '1' for two series LEDs;.

Input Current and LED Efficiency

Input Current and LED Efficiency

with 1.2A Flash Current

with 500mA Flash Current through 2 Series LEDs

Figure 9.

Figure 10.

Input Current

vs

Input Current and LED Efficiency

VIN

with 600mA Flash Current through 2 Series LEDs

1 LED @ 1.2A and 2 LEDs @ 600mA

Figure 11.

Figure 12.

LED Efficiency

vs

Converter Efficiency

VIN

vs

1 LED @ 1.2A and 2 LEDs @ 600mA

VIN

Figure 13.

Figure 14.

Copyright © 2008–2013, Texas Instruments Incorporated

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