100VIN, 100VOUT LED Controller



Features
■ 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: <1(jA
■ Programmable Soft-Start
■ Thermally Enhanced 16-Lead QFN (3mm x 3mm) and MSOP Packages

Applications
■ High Power LED Applications
■ Current Limited Constant Voltage Applications
■ Battery Charging

Description
The LT®3756, 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 MOSFETfrom 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.