LT3745 Просмотр технического описания (PDF) - Linear Technology

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LT3745

16-Channel 50mA LED Driver with Buck Controller

Linear Technology 

LT3745

16-Channel 50mA LED

Driver with Buck Controller

Features

n 6V to 55V Power Input Voltage Range

n 16 Independent LED Outputs Up to 75mA/36V

n ±3% LED Current Matching at 50mA (Typ ±1%)

n 6-Bit Dot Correction Current Adjustment

n 12-Bit Grayscale PWM Dimming

n 0.5µs Minimum LED On-Time

n Adaptive LED Bus Voltage for High Efficiency

n Cascadable 30MHz Serial Data Interface

n Full Diagnostic and Protection: Individual Open/Short

LED and Overtemperature Fault

n 40-Lead 6mm × 6mm QFN Package

Applications

n Large Screen Display LED Backlighting

n Mono-, Multi-, Full-Color LED Displays

n LED Billboards and Signboards

L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and

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

property of their respective owners.

Description

The LT®3745 integrates a 16-channel LED driver with a 55V

buck controller. The LED driver lights up to 75mA/36V of

LEDs in series per channel, and the buck controller gener-

ates an adaptive bus voltage supplying the parallel LED

strings. Each channel has individual 6-bit dot correction

current adjustment and 12-bit grayscale PWM dimming.

Both dot correction and grayscale are accessible via a

serial data interface in TTL/CMOS logic. A ±3% LED cur-

rent matching and a 0.5µs minimum LED on-time can be

achieved at 50mA per channel.

The LT3745 performs full diagnostic and protection

against open/short LED and overtemperature fault. The

fault status is sent back through the serial data interface.

The 30MHz fully-buffered, skew-balanced, cascadable

serial data interface makes the chip extremely suitable

for large screen LCD dynamic backlighting and mono-,

multi-, full-color LED displays.

Typical Application

16-Channel LED Driver, 1MHz Buck, 10 LEDs, 25mA to 75mA per Channel, 500Hz 12-Bit Dimming

VIN

42V TO 55V

0.47µF

EN

VCC

3V TO 5.5V

10µF

VIN CAP

EN/UVLO

GATE

100k

VCC

SYNC

GND

46.4k

RT

SS

10nF

ISP

LT3745

ISN

FB

60.4k

ISET

TSET

32.4k

2.048MHz CLOCK

PWMCK

LED00

LED01

LED...02

LED13

LED14

LED15

SCKI

SCKO

TTL/CMOS

SDI

SDO

3745 TA01

LDI

LDO

4.7µF

47µH 25mΩ

267k

C1

2 × 47µF

10k

.....

.....

.....

TTL/CMOS

..... ..... .....

3745f

1

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