Features and Benefits
- 3000:1 True Color PWM™ Dimming
- Wide Input Voltage Range: 6V to 100V
- Output Voltage Up to 100V
- Constant-Current and Constant-Voltage Regulation
- 100mV High Side Current Sense
- Drives LEDs in Boost, Buck Mode, Buck-Boost Mode, SEPIC or Flyback Topology
- Adjustable Frequency: 100kHz to 1MHz
- Open LED Protection
- Programmable Undervoltage Lockout with Hysteresis
- Improved Open LED Status Pin (LT3756-2)
- Frequency Synchronization (LT3756-1)
- PWM Disconnect Switch Driver
- CTRL Pin Provides Analog Dimming
- Low Shutdown Current: <1µA
- Programmable Soft-Start
- Thermally Enhanced 16-Lead QFN (3mm × 3mm) and MSOP Packages
- AEC-Q100 Qualified for Automotive Applications
The LT3756, LT3756-1 and LT3756-2 are DC/DC controllers designed to operate as a constant-current source for driving high current LEDs. They drive a low side external N-channel power MOSFET from an internal regulated 7.15V supply. The fixed frequency, current-mode architecture results in stable operation over a wide range of supply and output voltages. A ground referenced voltage FB pin serves as the input for several LED protection features, and also makes it possible for the converter to operate as a constant-voltage source. A frequency adjust pin allows the user to program the frequency from 100kHz to 1MHz to optimize efficiency, performance or external component size.
The LT3756/LT3756-1/LT3756-2 sense output current at the high side of the LED string. High side current sensing is the most flexible scheme for driving LEDs, allowing boost, buck mode or buck-boost mode configuration. The PWM input provides LED dimming ratios of up to 3000:1, and the CTRL input provides additional analog dimming capability.
- High Power LED Applications
- Current Limited Constant Voltage Applications
- Battery Charging
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (2)
Demonstration circuit 1319B-A/1319B-B is a high voltage and high current LED driver controller. The VIN pin input voltage is as high as 100V, and the LED output voltage is also as high as 100V. The demonstration circuit is assembled as a boost topology from 8V to 80V input and up to 80V LED output at 0.5A with an open-LED status pin (DC1319B-A) or a sync input pin (DC1319B-B). DC1319B features PWM dimming, analog dimming, shutdown, and open-LED overvoltage protection.
Demonstration circuit 1319B is a high voltage and high current LED driver controller feature the LT3756-1 (DC1319B-B) or the LT3756-2 (DC1319B-A). The device's VIN pin input voltage and LED output voltage can be as high as 100V; however, the demo board's open-LED overvoltage protection limits the input voltage to 80V and limits the output to approximately 92V if the LED string is opened.The demonstration circuit is assembled as a boost topology from 8V to 80V input and up to 80V LED output at 0.5A and features an open-LED status pin (DC1319B-A) or a sync input pin (DC1319B-B). DC1319B also features PWM dimming, analog dimming, shutdown, and open-LED overvoltage protection.
Documentation & Resources
R518 Reliability Data3/26/2018
DC1319B - Demo Manual11/13/2009
LT3756-2 Video Product Brief10/15/2018
Automotive LED Driver Power Conversion Topology Guide6/1/2022 Analog Dialogue
LED Driver with Integrated Spread Spectrum Reduces EMI without Adding Flicker10/1/2013 LT Journal
Accurate PWM LED Dimming without External Signal Generators, Clocks or µControllers10/1/2012 LT Journal
Don’t Want to Hear It? Avoid the Audio Band with PWM LED Dimming at Frequencies Above 20kHz3/1/2009 LT Journal
100V Controller in 3mm × 3mm QFN or MSE Drives High Power LED Strings from Just About Any Input1/1/2009 LT Journal
Tools & Simulations
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Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.