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 V Transient Ride-Through Up to 60V mode architecture results in stable operation over a wide IN 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 V Undervoltage and Overvoltage IN 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. All registered trademarks and trademarks are the property of their respective owners. Protected n Automotive and Industrial Lighting by U.S. Patents, including 7199560, 7321203, 7746300. n RGB Lighting n Billboards and Large Displays TYPICAL APPLICATION Triple Boost LED Driver V IN 2.5V TO 40V 4.7F (60V TRANSIENT, 3 10H 10H 10H 41V INTERNAL OVLO PROTECTION) 4.7F 4.7F 4.7F ISP1 ISP2 ISP3 100V 100V 100V 3 3 3 250m 250m 250m ISN1 ISN2 ISN3 1A 1A 1A 50V 50V 50V 8m 8m 8m GATE1 SENSEP1 SENSEN1 TG1 GATE2 SENSEP2 SENSEN2 TG2 GATE3 SENSEP3 SENSEN3 TG3 ISN1-3 V ISP1-3 IN 1F 100k 23.2k LT3797 EN/UVLO FBH1-3 OVLO V CTRL1-3 PWM1-3 RT SYNC SS1-3 FLT1-3 SW1 SW2 BOOST INTV GND VC1-3 105k REF CC 47.5k 3.9k 1M 0.1F 47H 10F 310kHz V IN 0.1F 6.8nF 1M 140k 3797 TA01 Rev C 1 Document Feedback For more information www.analog.comLT3797 ABSOLUTE MAXIMUM RATINGS (Note 1) V , EN/UVLO ............................................................60V RT ............................................................................1.5V IN INTV , SYNC, OVLO, PWM1, PWM2, PWM3 ............8V SENSEP1, SENSEP2, SENSEP3, SENSEN1, CC ISN1 .......................................................ISP1-1.5V, 100V SENSEN2, SENSEN3, .............................................0.3V ISN2 .......................................................ISP2-1.5V, 100V SW1, SW2, BOOST, TG1, TG2, TG3, GATE1, ISN3 .......................................................ISP3-1.5V, 100V GATE2, GATE3 .................................................. (Note 2) FBH1 ...................................................... ISP1 6V, 100V Operating Ambient Temperature Range FBH2 ...................................................... ISP2 6V, 100V (Note 3) ...................................................... 40 to 125C FBH3 ...................................................... ISP3 6V, 100V Maximum Junction Temperature .......................... 125C VC1, VC2, VC3, V , SS1, SS2, SS3 ..........................3V Storage Temperature Range .................. 65C to 150C REF CTRL1, CTRL2, CTRL3, FLT1, FLT2, FLT3...................12V PIN CONFIGURATION TOP VIEW TOP VIEW 52 51 50 49 48 47 46 45 44 43 42 41 FLT1 1 40 VC3 FLT2 2 FLT3 3 38 FBH3 PWM1 ISP3 4 37 FLT1 1 36 VC3 FLT2 2 35 FBH3 PWM2 ISN3 5 36 FLT3 3 34 ISP3 PWM3 6 35 TG3 PWM1 4 33 ISN3 PWM2 5 32 TG3 V 7 REF 53 PWM3 6 49 31 NC GND CTRL1 8 33 TG2 V 7 GND 30 TG2 REF CTRL1 8 29 ISN2 CTRL2 9 32 ISN2 CTRL2 9 28 ISP2 CTRL3 31 ISP2 10 CTRL3 10 27 FBH2 RT 11 26 VC2 RT 11 30 FBH2 SYNC 12 25 SS2 SYNC 12 28 VC2 TG1 14 27 SS2 15 16 17 19 20 21 22 23 24 25 26 LXE PACKAGE 48-LEAD (7mm 7mm) PLASTIC LQFP UKG PACKAGE VARIATION: UKG52(47) = 19C/W JA 52-LEAD (7mm 8mm) PLASTIC QFN EXPOSED PAD (PIN 49) IS GND, MUST BE SOLDERED TO PCB = 28C/W JA EXPOSED PAD (PIN 53) IS GND, MUST BE SOLDERED TO PCB Rev C 2 For more information www.analog.com ISN1 OVLO ISP1 EN/UVLO FBH1 V IN SW1 VC1 BOOST SS1 SW2 SENSEN1 INTV CC SENSEP1 INTV CC GATE1 GATE3 GATE2 SENSEP3 SENSEP2 SENSEN3 SENSEN2 SS3 48 OVLO TG1 13 47 ENUVLO ISN1 14 46 V ISP1 15 IN 45 SW1 FBH1 16 44 BOOST VC1 17 43 SW2 SS1 18 42 INTV SENSEN1 19 CC 41 INTV SENSEP1 20 CC 40 GATE3 GATE1 21 39 SENSEP3 GATE2 22 38 SENSEN3 SENSEP2 23 37 SS3 SENSEN2 24