LT3476EUHF(RevA) 查看數據表（PDF） - Linear Technology

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LT3476EUHF
(Rev.:RevA)

High Current Quad Output LED Driver

Linear Technology 

FEATURES

■ True Color PWMTM Dimming Delivers Up to 5000:1

Dimming Ratio (In Boost Configuration)

■ LED Current Regulation with High-Side Sense

■ VADJ Pin Accurately Sets LED Current Sense

Threshold Over Range 10mV to 120mV

■ Four Independent Driver Channels with 1.5A, 36V

Internal NPN Switches

■ Frequency Adjust Pin: 200kHz to 2MHz

■ High Efficiency Conversion = Up to 96%

■ Open LED Protection

■ Low Quiescent Current

22mA in Active Mode

<10μA in Shutdown Mode

■ Wide VIN Range: 2.8V to 16V

■ Thermally Enhanced, 38-Lead, 5mm × 7mm

QFN Package

U

APPLICATIO S

■ RGGB Lighting

■ Automotive and Avionic Lighting

■ TFT LCD Backlighting

■ Constant-Current Sources

LT3476

High Current

Quad Output LED Driver

DESCRIPTIO

The LT®3476 is a quad output DC/DC converter designed

to operate as a constant-current source for driving high

current LEDs. A fixed frequency, current mode architecture

results in stable operation over a wide range of supply and

output voltages. A frequency adjust pin allows the user to

program switching frequency between 200kHz and 2MHz

to optimize efficiency and external component size.

The LT3476 senses output current at the high side of

the LED. High side current sensing is the most flexible

scheme for driving LEDs, allowing buck, boost or buck-

boost configurations. Each current monitor threshold is

trimmed to within 2.5% at the full scale of 105mV. With

an external sense resistor, the user programs the output

current range of each channel. Each of the four regulators

is independently operated by that channel’s PWM signal.

This PWM feature allows precise adjustment of the color

mixing or dimming ratio of the LED source. Dimming

ratios up to 1000:1 can be achieved.

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

True Color PWM is a trademark of Linear Technology Corporation. All other trademarks are

the property of their respective owners.

TYPICAL APPLICATIO

100W Quad 1A × 8 LED Driver

PVIN

33V

CAP1

CAP2

CAP3

100mΩ

100mΩ

100mΩ

LED1

LED2

LED3

CAP4

100mΩ

LED4

UP TO

8 LEDS

1A

0.22μF

1A

0.22μF

1A

0.22μF

1A

0.22μF

2.2μF

×4

10μH

10μH

10μH

10μH

1000:1 PWM Dimming at 100Hz

PWM

5V/DIV

ILED

500mA/DIV

5μs/DIV

3476 TA02

VIN

2.8V TO 16V

PWM1-4

SHDN

2.2μF

SW1

CAP1-4

LED1-4

VIN

PWM1-4

SHDN

SW2

SW3

LT3476

GND

SW4

REF

VADJ1-4

VC1-4

RT

3476 TA01

1.05V

4.99k

100k

21k

1nF

3476fa

1

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