LTC3216

1

3216fc

TYPICAL APPLICATION

FEATURES

APPLICATIONS

DESCRIPTION

1A Low Noise High Current

LED Charge Pump with

Independent Torch/Flash Current Control

DC/DC converter designed to power high current LEDs.

The part includes an accurate programmable current

source capable of driving loads up to 1A from a 2.9V to

4.4V input. Low external parts count (two flying capacitors,

two programming resistors and two bypass capacitors at

battery-powered applications.

Built-in soft-start circuitry prevents excessive inrush cur-

rent during start-up. High switching frequency enables

the use of small external capacitors. Independent high

and low current settings are programmed by two external

resistors. Shutdown mode and current output levels are

selected via two logic inputs.

An ultralow dropout current source maintains accurate

switching optimizes efficiency by monitoring the voltage

across the LED current source and switching modes only

in a small 3mm

× 4mm 12-Lead DFN package.

Modes with Automatic Mode Switching

Programming and Enable Pins

Profile)

× 4mm 12-Lead DFN Package

PDAs and Digital Cameras

L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.

All other trademarks are the property of their respective owners.

Protected by U.S. Patents including 6411531.

EN1

0

1

0

1

C1

2.2μF

C2

2.2μF

2.2μF

4.7μF

LED1

2.9V TO 4.4V

EN2

EN1

LTC3216

0 (SHUTDOWN)

200mA (TORCH)

600mA

800mA (FLASH)

EN2

0

0

1

1

3216 TA01a

LED1: LUMILEDS LXCL-PWF1 LUXEON FLASH

CPO

20k

1%

6.65k

1%

EN2 (FLASH)

EN1 (TORCH)

2.8

100

90

80

70

60

50

40

30

20

10

0

3.2

3.6

3.8

3216 TA01b

3.0

3.4

4.0

4.2

4.4

LUMILEDS LXCL-PWF1