LTC3453 データシートの表示（PDF） - Linear Technology

部品番号

コンポーネント説明

一致するリスト

LTC3453

Synchronous Buck-Boost High Power White LED Driver

Linear Technology 

LTC3453

Synchronous Buck-Boost

High Power White LED Driver

FEATURES

■ High Efficiency: 90% Typical Over Entire

Li-Ion Battery Range

■ Wide VIN Range: 2.7V to 5.5V

■ Up to 500mA Continuous Output Current

■ Internal Soft-Start

■ Open/Shorted LED Protection

■ LED Current Matching Typically <2%

■ Constant Frequency 1MHz Operation

■ Low Shutdown Current: 6µA

■ Overtemperature Protection

■ Small Thermally Enhanced 16-Lead (4mm x 4mm)

QFN Package

U

APPLICATIO S

■ Cell Phones

■ Digital Cameras

■ PDAs

■ Portable Devices

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

All other trademarks are the property of their respective owners.

DESCRIPTIO

The LTC®3453 is a synchronous buck-boost DC/DC con-

verter optimized for driving up to 4 white LEDs at a

combined current of up to 500mA from a single Li-Ion

battery input. The regulator operates in either synchro-

nous buck, synchronous boost, or buck-boost mode,

depending on input voltage and LED maximum forward

voltage. Optimum efficiency is achieved using a propri-

etary architecture that determines which LED requires the

largest forward voltage drop at its programmed current,

and regulates the common output rail for lowest dropout.

Efficiency of 90% can be achieved over the entire usable

range of a Li-Ion battery (2.7V to 4.2V).

LED current is programmable to one of four levels (includ-

ing shutdown) with dual current setting resistors and dual

enable pins. In shutdown, the supply current is only 6µA.

A high constant operating frequency of 1MHz allows the

use of a small external inductor. The LTC3453 is offered

in a low profile (0.75mm) thermally enhanced 16-lead

(4mm x 4mm) QFN package.

TYPICAL APPLICATIO

High Efficiency Torch/Flash LED Driver

VIN

1-CELL

Li-Ion

2.7V to 4.2V

2.2µF

L1

4.7µH

VIN PVIN SW1

SW2 VOUT 150mA/500mA

4.7µF

0.1µF

VC

EN1 (TORCH)

EN2 (FLASH)

8.25k

1%

3.48k

1%

EN1

EN2

ISET1

ISET2

1MHz

BUCK-BOOST

GND

GND

D1

LED1

LED2

LED3

LED4

LTC3453

PGND 3453 TA01a

D1: LUMILEDS LXCL-PWF1

L1: VISHAY DALE IDCS-2512

EN1 EN2 ILED

0 0 0 (SHUTDOWN)

1 0 150mA

0 1 350mA

1 1 500mA

Torch Mode Efficiency vs VIN

100

180

90

160

EFFICIENCY

80

140

70

60

ILED = 150mA

50 TA = 25°C

2.7 3.1 3.5

IIN

3.9 4.3 4.7

VIN (V)

120

100

80

5.1 5.5

3453 TA01b

3453fa

1

Share Link: