Datasheet LT3756, LT3756-1, LT3756-2 (Analog Devices)

LT3756/LT3756-1/LT3756-2 100VIN, 100VOUT LED Controller
FEATURES DESCRIPTION
n
3000:1 True Color PWM™ Dimming
The LT®3756, LT3756-1 and LT3756-2 are DC/DC control- n
Wide Input Voltage Range: 6V to 100V
lers designed to operate as a constant-current source for n
Output Voltage Up to 100V
driving high current LEDs. They drive a low side external n
Constant-Current and Constant-Voltage Regulation
N-channel power MOSFET from an internal regulated 7.15V n 100mV High Side Current Sense supply. The fixed frequency, current-mode architecture n Drives LEDs in Boost, Buck Mode, Buck-Boost Mode, results in stable operation over a wide range of supply SEPIC or Flyback Topology and output voltages. A ground referenced voltage FB pin n Adjustable Frequency: 100kHz to 1MHz serves as the input for several LED protection features, n Open LED Protection and also makes it possible for the converter to operate n Programmable Undervoltage Lockout with Hysteresis as a constant-voltage source. A frequency adjust pin n Improved Open LED Status Pin (LT3756-2) allows the user to program the frequency from 100kHz n Frequency Synchronization (LT3756-1) to 1MHz to optimize efficiency, performance or external n PWM Disconnect Switch Driver component size. n CTRL Pin Provides Analog Dimming The LT3756/LT3756-1/LT3756-2 sense output current at n Low Shutdown Current: <1µA the high side of the LED string. High side current sensing n Programmable Soft-Start is the most flexible scheme for driving LEDs, allowing n Thermally Enhanced 16-Lead QFN (3mm × 3mm) boost, buck mode or buck-boost mode configuration. and MSOP Packages The PWM input provides LED dimming ratios of up to n AEC-Q100 Qualified for Automotive Applications 3000:1, and the CTRL input provides additional analog
APPLICATIONS
dimming capability. All registered trademarks and trademarks are the property of their respective owners. Protected n High Power LED Applications by U.S. patents, including 7199560 and 7321203. n Current Limited Constant Voltage Applications n Battery Charging
TYPICAL APPLICATION 94% Efficient 30W White LED Headlamp Driver Efficiency vs V
V
IN
IN 8V TO 60V 22µH (100V TRANSIENT) 100 4.7µF 1M V 1M 4.7µF IN 96 SHDN/UVLO FB 185k VREF ISP 14k 332k LT3756-2 0.27Ω 370mA 92 CTRL INTVCC ISN 40.2k GATE 88 100k SENSE EFFICIENCY (%) OPENLED 0.018Ω 30W PWM LED 84 SS STRING RT PWMOUT 0.01µF VC GND INTVCC 28.7k 80 375kHz 0 20 40 60 80 10k 1% INTVCC VIN (V) 0.001µF 4.7µF 375612 TA01b 375612 TA01a Rev. C Document Feedback For more information www.analog.com 1 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Package Description Revision History Typical Application Related Parts