LT3762 60V Synchronous Boost LED Controller FEATURES DESCRIPTION n 3000:1 External PWM Dimming The LT 3762 is a synchronous DC/DC controller designed n 250:1 Internal PWM Dimming to operate as a constant-current source and constant- n voltage regulator. It features a programmable internal Wide V Operating Range: 2.5V to 38.5V IN n PWM dimming signal generator and a synchronous gate Synchronous Boost Output Voltage up to 60V n driver. The LT3762 is ideally suited for driving high cur- Spread-Spectrum Frequency Modulation for Lower EMI n rent LEDs with high efficiency and reduced power loss. PMOS Switch Driver for PWM and Output Disconnect n Rail-to-rail switch current sensing enables synchronous Constant Current (3.5%) Regulation boost topologies and nonsynchronous topologies such n Constant Voltage (2%) Regulation as SEPIC. A voltage feedback pin serves as the input for n Rail-to-Rail LED Current Sense: 0V to 60V several LED protection features and also allows the con- n Programmable V Undervoltage Lockout IN verter to operate as a constant-voltage source. n Analog Dimming via Two Control Pins n 100kHz to 1MHz Operation A frequency adjust pin allows the user to program the n Programmable Open LED Protection with OPENLED Flag frequency from 100kHz to 1MHz to optimize efficiency, n Short-Circuit Protection and SHORTLED Flag performance and external component size. Adding a n Drives LEDs in Boost, SEPIC, Buck Mode, or Buck- capacitor at SSFM pin activates the Spread-Spectrum Boost Mode Configurations Modulation feature to reduce EMI. The LT3762 also in- n 28 Lead TSSOP and QFN (4mm 5mm) Exposed cludes an integrated DC/DC converter to efficiently produce a regulated 7.5V supply for the N-channel MOSFET gate Pad Packages drivers. The PWM pin controls PWMTG to drive the P- channel MOSFET, allowing a high PWM dimming range APPLICATIONS (3000:1) and providing LED overcurrent protection and n Industrial and Automotive Lighting short-circuit protected boost capability. n Accurate Current-Limited Voltage Regulators All registered trademarks and trademarks are the property of their respective owners. Protected by U.S. Patents, including 7199560, 7321203, 7746300. Patents pending. TYPICAL APPLICATION 98% Efficient 60W Synchronous Boost LED Driver with 3V Minimum Input Voltage 22H 6m M2 V IN 3V TO 24V 4.7F 4.7F Efficiency vs Input Voltage M1 4 3 576k 1M 50V 50V V SNSP SNSN BG 100 IN EN/UVLO SW 98 0.1F 348k 36.5k BOOST CTRL1 96 TG VREF 66.5k LT3762 FB 94 150k ISP CTRL2 50m 92 INTERNAL PWM DUTY CYCLE 49.9k (0.4% TO 100%) ISN 90 VDIM = 0V TO 3V M3 PWMTG DIM 88 INTV PWM CC 47H 82nF AUXSW2 800Hz 100k 86 100k 0 4 8 12 16 20 24 28 AUXSW1 30V, 2A LED OPENLED 0.1F INPUT VOLTAGE (V) CURRENT DERATED 10V SHORTLED 3762 TA01b AUXBST FOR V < 8V IN V C 3.3nF SSFM RT GND SS INTV CC 5.6k 6.8nF 39.2k 0.1F 10F 200kHz 10V 3762 TA01a Rev 0 1 Document Feedback For more information www.analog.com EFFICIENCY (%)LT3762 ABSOLUTE MAXIMUM RATINGS (Note 1) AUXSW1, AUXSW2, TG, BG, PWMTG ISP, ISN .....................................................................80V BOOST, AUXBST, RT ....................................... (Note2) V , EN/UVLO, SNSP, SNSN, SW (Note 7) ................60V IN Operating Junction Temperature Range (Note 3, 4) CTRL1, CTRL2, OPENLED, SHORTLED ......................15V LT3762E/LT3762I ................................... 40C to 125C FB, PWM, INTV , DIM ...............................................8V CC LT3762H ................................................ 40C to 150C V , V , SS, SSFM .....................................................3V C REF Storage Temperature Range .................. 65C to 150C PIN CONFIGURATION TOP VIEW TOP VIEW 1 INTV EN/UVLO 28 CC 2 AUXSW2 OPENLED 27 3 AUXBST SHORTLED 26 28 27 26 25 24 23 4 AUXSW1 PWM 25 PWM 1 22 AUXSW1 5 V DIM 24 IN DIM 2 21 V IN 6 SNSP RT 23 RT 3 20 SNSP 7 SNSN SSFM 22 29 4 19 SSFM 29 SNSN GND 8 BG SS 21 GND SS 5 18 BG 9 BOOST V 20 6 17 REF V BOOST REF 10 SW CTRL1 19 7 16 CTRL1 SW 11 TG 8 15 CTRL2 18 CTRL2 TG 9 10 11 12 13 14 12 ISP V 17 C 13 ISN FB 16 14 PWMTG GND 15 UFD PACKAGE FE PACKAGE 28-LEAD (4mm 5mm) PLASTIC QFN 28-LEAD PLASTIC TSSOP = 43C/W, = 3.4C/W JA JC = 30C/W, = 10C/W JA JC EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION