LTC3783EDHD-PBF 查看數據表（PDF） - Linear Technology

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LTC3783EDHD-PBF

PWM LED Driver and Boost, Flyback and SEPIC Controller

Linear Technology 

LTC3783

FEATURES

PWM LED Driver and Boost,

Flyback and SEPIC Controller

DESCRIPTION

n True Color PWMTM Delivers Constant Color with

3000:1 Dimming Ratio

n Fully Integrated Load FET Driver for PWM Dimming

Control of High Power LEDs

n 100:1 Dimming from Analog Inputs

n Wide FB Voltage Range: 0V to 1.23V

n Constant Current or Constant Voltage Regulation

n Low Shutdown Current: IQ = 20µA

n 1% 1.23V Internal Voltage Reference

n 2% RUN Pin Threshold with 100mV Hysteresis

n Programmable Operating Frequency

(20kHz to 1MHz) with One External Resistor

n Synchronizable to an External Clock Up to 1.3fOSC

n Internal 7V Low Dropout Voltage Regulator

n Programmable Output Overvoltage Protection

n Programmable Soft-Start

n Can be Used in a No RSENSETM Mode for VDS < 36V

n 16-Lead DFN and TSSOP Packages

APPLICATIONS

n High Voltage LED Arrays

n Telecom Power Supplies

n 42V Automotive Systems

n 24V Industrial Controls

n IP Phone Power Supplies

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

True Color PWM and No RSENSE are trademarks of Linear Technology Corporation.

All other trademarks are the property of their respective owners.

The LTC®3783 is a current mode LED driver and boost,

flyback and SEPIC controller that drives both an N-channel

power MOSFET and an N-channel load PWM switch. When

using an external load switch, the PWMIN input not only

drives PWMOUT, but also enables controller GATE switch-

ing and error amplifier operation, allowing the controller

to store load current information while PWMIN is low.

This feature (patent pending) provides extremely fast,

true PWM load switching with no transient overvoltage

or undervoltage issues; LED dimming ratios of 3000:1

can be achieved digitally, avoiding the color shift normally

associated with LED current dimming. The FBP pin allows

analog dimming of load current, further increasing the

effective dimming ratio by 100:1 over PWM alone.

In applications where output load current must be returned

to VIN, optional constant current/constant voltage regula-

tion controls either output (or input) current or output

voltage and provides a limit for the other. ILIM provides a

10:1 analog dimming ratio.

For low- to medium-power applications, No RSENSE mode

can utilize the power MOSFET’s on-resistance to eliminate

the current-sense resistor, thereby maximizing efficiency.

The IC’s operating frequency can be set with an external

resistor over a 20kHz to 1MHz range and can be synchro-

nized to an external clock using the SYNC pin.

The LTC3783 is available in the 16-lead DFN and TSSOP

packages.

TYPICAL APPLICATION

350mA PWM LED Boost Application

VIN

6V TO 16V

(< TOTAL VF OF LEDs)

1M

10µF

×2 2.2µH

ZETEX ZLLS1000

LTC3783

0.1µF

105k

RUN

VIN

PWMIN OV/FB

ITH PWMOUT

SS

ILIM

VREF GATE

FBP SENSE

237k

M1

LED*

STRING

M2

10µF

FBN INTVCC

FREQ GND

4.7µF

10k 6k

SYNC

0.05Ω 12.4k

0.3Ω

M1, M2: SILICONIX Si4470EY *LUMILEDS LHXL-BW02

VOUT

<25V

COUT

10µF

GND

3783 TA01a

VPWMIN

5V/DIV

VOUT

0.2V/DIV

AC COUPLED

IL

2.5A/DIV

ILED

0.5A/DIV

Typical Waveforms

1µs/DIV

3783 TA01b

3783fb

1

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