LT3744

PRODUCTION

High Current Synchronous Step-Down LED Driver

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Overview

  • Ideal for Driving Up to 40A LEDs
  • Up to 3000:1 PWM Dimming
  • 20:1 Analog Dimming
  • ±3% Current Regulation Accuracy
  • ±3% Voltage Regulation Accuracy
  • Unique Inverting Buck-Boost Topology Allows Grounded Heat Sink to Be Used for RGB LEDs
  • 3.3V to 36V Input Voltage Range
  • Peak Current Mode with DC LED Current Sensing
  • Open and Shorted LED Protection and Fault Reporting
  • Floating LED Driver Allows Single Power Solution to Drive Multicolor LEDs or Single LED with Three Different Regulated Currents
  • Thermally Enhanced 5mm × 6mm QFN 36-Lead Package

The LT3744 is a fixed frequency synchronous step-down DC/DC controller designed to drive a LED load at up to 20A continuous or 40A pulsed. The peak current mode controller will maintain ±3% LED current regulation over a wide output voltage range, from VEE to VIN. By allowing VEE to float to negative voltages, several LEDs in series can be driven from a single Li-Ion battery with a simple, single step-down output stage. PWM dimming is achieved with the PWM pins. The regulated LED current is set with analog voltages at the CTRL pins. Regulated voltage and overvoltage protection are set with a voltage divider from the output to the FB pin. The switching frequency is programmable from 100kHz to 1MHz through an external resistor on the RT pin.

Additional features include an accurate external reference voltage, a control input for thermally derating regulation current, an accurate EN/UVLO pin, an open-drain output fault flag, OVLO, frequency synchronization, and thermal shutdown.

Applications

  • LED Driver for DLP Projectors
  • Heads-Up Displays
  • High Power LED
LT3744
High Current Synchronous Step-Down LED Driver
LED Driver for DLP Projectors LED Current Waveforms (2000:1) 0A to 6.7A to 13.3A to 20A Product Package 1
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Documentation

Data Sheet 1

Reliability Data 1

User Guide 2

Technical Articles 3

Data Sheet

This is the most up-to-date revision of the Data Sheet.

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Software Resources

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Hardware Ecosystem

Parts Product Life Cycle Description
Protection Switches & Controllers 1
LT4363
RECOMMENDED FOR NEW DESIGNS High Voltage Surge Stopper with Current Limit
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Tools & Simulations

LTspice 1

Models for the following parts are available in LTspice:

  • LT3744
LTspice

LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.

Evaluation Kits

eval board
schematic 1
DC1930A

LT3744 Demo Board | Inverting Buck-Boost LED Driver, 3.3V ≤ VIN ≤ 30V, Drives 3 LEDs @ up to 12A

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Product Details

Demonstration circuit 1930A is a high current synchronous inverting buck-boost LED driver featuring the LT3744. The unique drive stage used on the LT3744 allows the anodes of three LEDs to be connected together for better heat sinking in both the inverting buck-boost configuration (LED anodes at ground) and the step-down configuration (shown in a separate demonstration circuit DC2339A). The pros and cons of each configuration can be found in the data sheet.

The DC1930A targets high power LEDs and laser diodes (not included). The 3 LEDs are driven from the same output, but each LED is individually controlled. The input voltage range is 3.3V to 30V; however to maintain 12A current regulation, a minimum of 7V must be applied.

eval board
schematic 2
schematic 3
schematic 4
schematic 5
schematic 6
DC2339A

LT3744 Demo Board | Sync Buck LED Driver, 5.5V ≤ VIN ≤ 24V, Drives 3 LEDs @ up to 20A Each

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Product Details

Demonstration circuit 2339A is a high current synchronous step-down LED driver featuring the LT3744. The unique drive stage used on the LT3744 allows the anodes of three LEDs to be connected together for better heat sinking in both the step-down configuration and the inverting buck-boost configuration (shown in a separate demonstration circuit DC1930A). The pros and cons of each configuration can be found in the data sheet. 


The DC2339A targets high power LEDs and laser diodes (not included). The 3 LEDs are driven from the same output, but each LED is individually controlled. The input voltage range is 5.5V to 30V.
DC1930A
LT3744 Demo Board | Inverting Buck-Boost LED Driver, 3.3V ≤ VIN ≤ 30V, Drives 3 LEDs @ up to 12A
DC1930A - Schematic
DC2339A
LT3744 Demo Board | Sync Buck LED Driver, 5.5V ≤ VIN ≤ 24V, Drives 3 LEDs @ up to 20A Each
DC2339A Demo Board DC2339A Demo Board DC2339A Demo Board DC2339A Demo Board DC2339A - Schematic

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