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.
Feature
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
Applications
Catalogue
FPGA / CPLD
Memory
MOS 
MCU 
DSP
OCEP
Secondary 
Other 
