LT3761A 60V LED Controller with IN Internal PWM Generator Fea T Descrip T n 3000:1 True Color PWM Dimming for LEDs The LT 3761A is a DC/DC controller designed to operate as n Wide V Range: 4.5V to 60V a constant-current source and constant-voltage regulator. IN n Rail-to-Rail Current Sense Range: 0V to 80V It features a programmable internal PWM dimming signal. n Programmable PWM Dimming Signal Generator The LT3761A is ideally suited for driving high current LEDs, n Constant Current (3%) and Constant-Voltage but also has features to make it suitable for charging bat- (2%) Regulation teries and supercapacitors. The fixed frequency, current n Analog Dimming mode architecture results in stable operation over a wide n Drives LEDs in Boost, SEPIC, Inverting, Buck Mode, range of supply and output voltages. A voltage feedback Buck-Boost Mode, or Flyback Configuration pin serves as the input for several LED protection features, n Output Short-Circuit Protected Boost and also makes it possible for the converter to operate n Open LED Protection and Reporting as a constant-voltage source. A frequency adjust pin n Adjustable Switching Frequency: 100kHz to 1MHz allows the user to program the frequency from 100kHz n Programmable V UVLO with Hysteresis to 1MHz to optimize efficiency, performance or external IN n C/10 Indication for Battery Chargers component size. n Low Shutdown Current: <1A The LT3761A senses output current at the high side or at n Thermally Enhanced 16-Lead MSOP Package the low side of the load. The PWM input can be configured to self-oscillate at fixed frequency with duty ratio program- a T mable from 4% to 96%. The LT3761A offers improved n accuracy of internal PWM dimming over LT3761. When High Voltage LED Strings >100V with Ground driven by an external signal, the PWM input provides LED Referred Current Sense n dimming ratios of up to 3000:1. The CTRL input provides Grounded Anode LEDs n additional analog dimming capability. Battery and SuperCap Chargers n L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and Accurate Current Limited Voltage Regulators True Color PWM is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents including 7199560, 7321203. Typical a T 94% Efficient Boost LED Driver for Automotive Headlamp with 25:1 Internal PWM Dimming PWM Dimming Waveforms at 10H V IN Various DIM Voltage Settings 8V TO 2.2F 60V 499k 2 V IN 1M 2.2F 0.25 1A GATE EN/UVLO 4 V = 7.7V V DIM REF SENSE 90.9k DC = 96% PWM 1M LT3761A 10m 16.9k V = 4V DIM CTRL DC = 50% GND PWM INTV CC 140k I LED V = 1.5V 1A/DIV DIM 100k FB DC = 10% PWM 60W ISP OPENLED LED V = 0.4V ISN DIM DIM DIM/SS STRING DC = 4.3% 140k PWM PWM PWMOUT V RT INTV 0.01F C CC 3761A TA01b 0.5ms/DIV 47nF 28.7k 5.1k INTV CC 300Hz 350kHz 4.7nF 1F 3761A TA01a 3761af For more information www.linear.com/LT3761A 1 ion pplica ions pplica ion uresLT3761A a Te m aximum r a T p in c F T (Note 1) TOP VIEW V , EN/UVLO ............................................................60V IN PWMOUT 1 16 GATE FB 2 15 SENSE ISP, ISN .....................................................................80V ISN 3 14 V IN ISP 4 17 13 INTV CC INTV ...................................................V + 0.3V, 9.6V CC IN V 5 12 EN/UVLO GND C CTRL 6 11 RT GATE, PWMOUT ................................................ (Note 2) V 7 10 DIM/SS REF CTRL, OPENLED ........................................................15V PWM 8 9 OPENLED MSE PACKAGE FB, PWM ..................................................................9.6V 16-LEAD PLASTIC MSOP V , V ......................................................................3V C REF = 43C/W, = 4C/W JA JC EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB RT, DIM/SS ..............................................................1.5V SENSE ......................................................................0.5V Operating Ambient Temperature Range (Notes 3, 4) LT3761AE .............................................. 40 to 125C LT3761AI ............................................... 40 to 125C Storage Temperature Range .................. 65C to 150C o r Der i n F T (