Dual Output Boost Regulator Using Single Inductor

A8481

5

Allegro MicroSystems, Inc.

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

3 mA

10 mA

20 mA

40 mA

60 mA

80 mA

55

65

60

70

75

80

85

2468

10

80

mA = Full Brightness

Dimming Level

45

65

60

55

50

70

75

80

85

2468

10

12 mA

4 mA

20 mA (Full Brightness)

Dimming Level

(mA)

Efficiency with OUT1 off, OUT2 on, 5 WLEDs

Over range of dimming levels, LED voltage drop at 20 mA = 16.3 V

45

65

60

55

50

70

75

80

85

2468

10

12 mA

4 mA

20 mA (Full Brightness)

Dimming Level

(mA)

Efficiency with OUT1 on, OUT2 off

Efficiency with OUT2 on, OUT1 off, 3 WLEDs

Over range of dimming levels, LED voltage drop at 20 mA = 9 V

Performance Characteristics

Tests performed using application circuit shown in figure 1(a)