Datasheet LT3797 (Analog Devices)

LT3797 Triple Output LED Driver Controller
FEATURES DESCRIPTION
n
Three Independent LED Driver Channels
The LT®3797 is a triple output DC/DC controller designed n
Wide Input Voltage Range: 2.5V to 40V
to drive three strings of LEDs. The fixed frequency, current n
VIN Transient Ride-Through Up to 60V
mode architecture results in stable operation over a wide n
Rail-to-Rail LED Current Sense: 0V to 100V
range of supply and output voltages. The LT3797 includes n
3000:1 PWM Dimming
an integrated DC/DC converter to produce a regulated 7.5V n
TG Drivers for PMOS LED Disconnection
supply for the N-channel MOSFET gate drivers of the three n Operates in Boost, Buck Mode, Buck-Boost Mode, channels. This high efficiency converter enables the part to SEPIC or Flyback Topology operate from a wide input voltage range from 2.5V to 40V. n Open-LED Protection The LT3797 is designed so that each converter can use n Short-Circuit Protected Boost Capable the most suitable configuration to drive its LED load, n Fault Flags for Independent Channels whether step-up, step-down or a combination. Two key n Programmable VIN Undervoltage and Overvoltage features enable this flexibility: first the LT3797 can sense Lockout output current at the high side of the LED string; and n Adjustable Switching Frequency: 100kHz to 1MHz second, the voltage feedback pin, FBH, is referred to the n Synchronizeable to an External Clock ISP current sensing input. The CTRL inputs provide out- n CTRL Pins Provide Analog Dimming put current analog dimming capability. The TG drivers n Programmable Soft-Start level shift the PWM signals to drive the gates of external n Low Profile 52-Lead 7mm x 8mm QFN and 48-Lead LED-disconnect P-channel MOSFETs, allowing high PWM Exposed Pad LQFP dimming range, and providing LED overcurrent protection
APPLICATIONS
and short-circuit protected boost capability. n Automotive and Industrial Lighting All registered trademarks and trademarks are the property of their respective owners. Protected by U.S. Patents, including 7199560, 7321203, 7746300. n RGB Lighting n Billboards and Large Displays
TYPICAL APPLICATION Triple Boost LED Driver
VIN 2.5V TO 40V 4.7µF (60V TRANSIENT, ×3 41V INTERNAL 10µH 10µH 10µH OVLO PROTECTION) 4.7µF 4.7µF 4.7µF ISP1 100V ISP2 100V ISP3 100V ×3 ×3 ×3 250mΩ 250mΩ 250mΩ ISN1 ISN2 ISN3 1A 1A 1A 50V 50V 50V 8mΩ 8mΩ 8mΩ GATE1 SENSEP1 SENSEN1 TG1 GATE2 SENSEP2 SENSEN2 TG2 GATE3 SENSEP3 SENSEN3 TG3 ISN1-3 VIN ISP1-3 1µF 100k 23.2k LT3797 EN/UVLO FBH1-3 105k OVLO VREF CTRL1-3 PWM1-3 RT SYNC SS1-3 FLT1-3 SW1 SW2 BOOST INTVCC GND VC1-3 47.5k 3.9k 1M V 310kHz 0.1µF 47µH 10µF IN 1M 0.1µF 6.8nF 140k 3797 TA01 Rev C Document Feedback For more information www.analog.com 1 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Revision History Typical Application Related Parts Features Applications Typical Application Description Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Applications Package Description Revision History Typical Application Related Parts