LT3795 110V LED Controller with Spread Spectrum Frequency Modulation FEATURES DESCRIPTION n 3000:1 True Color PWM Dimming The LT 3795 is a DC/DC controller designed to regulate a n Wide Input Voltage Range: 4.5V to 110V constant-current or constant-voltage and is ideal for driv- n Input and Output Current Reporting ing LEDs. It drives a low side external N-channel power n PMOS Switch Driver for PWM and Output Disconnect MOSFET from an internal regulated 7.7V supply. The fixed n Internal Spread Spectrum Frequency Modulation frequency and current mode architecture result in stable n 2% Constant Voltage Regulation operation over a wide range of supply and output voltages. n 3% Constant Current Regulation: 0V V 110V Spread spectrum frequency modulation (SSFM) can be OUT n Programmable Input Current limit activated for improved electromagnetic compatibility (EMC) n CTRL Inputs Linearly Adjust LED Current performance. The ground referred voltage FB pin serves as n Adjustable Frequency: 100kHz to 1MHz the input for several LED protection features, and also al- n Programmable Open LED Protection with OPENLED Flag lows the converter to operate as a constant-voltage source. n Short-Circuit Protection and SHORTLED Flag The maximum output current is set by an external resistor, n Programmable Undervoltage Lockout with Hysteresis and the output current amplifier has a rail-to-rail common n Soft-Start with Programmable Fault Restart Timer mode range. The LT3795 also includes a separate input n C/10 Detection for Battery Charging current sensing amplifier that is used to limit input current. n Available in 28-Lead TSSOP Package The TG pin inverts and level shifts the PWM signal to drive the gate of the external PMOS. The PWM input provides APPLICATIONS LED dimming ratios of up to 3000:1, and the CTRL inputs n provide additional analog dimming capability. High Power LED, High Voltage LED n Battery Chargers L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and True Color PWM is a trademark of Linear Technology Corporation. All other trademarks are the n Accurate Current Limited Voltage Regulators property of their respective owners. Protected by U.S. Patents, including 7199560, 7321203, 7746300. TYPICAL APPLICATION Short-Circuit Robust Boost LED Driver with Spread Spectrum Frequency Modulation Efficiency vs V IN V 22H IN 15m 100 8V TO 60V 2.2F 2.2F 110V (TRANSIENT) 499k 1M 3 4 63V OVLO 95 115k EN/UVLO V IVINP IVINN IN 90 GATE 13.3k OVLO SENSE 12.4k 85 CTRL1 15m CTRL2 80 GND V LT3795 REF PWM PWM FB 75 IVINCOMP ISP 10nF 620m 70 RAMP INTV CC 0 10 20 30 40 50 60 6.8nF ISN V (V) 100k 100k IN TG 3795 TA01b OPENLED OPENLED INTV INTV CC CC SHORTLED SHORTLED 4.7F V RT ISMON SS C 87V LED 400mA 31.6k 10k 0.1F 0.1F 250kHz 6.8nF 3795 TA01a 3795fc 1 For more information www.linear.com/LT3795 EFFICIENCY (%)LT3795 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1) TOP VIEW V .......................................................................... 110V IN EN/UVLO ................................................................. 110V ISP 1 28 IVINCOMP ISP, ISN ................................................................... 110V ISN 2 27 IVINP TG 3 26 IVINN TG, GATE...............................................................Note 2 GND 4 25 OVLO IVINP, IVINN ............................................................ 110V ISMON 5 24 EN/UVLO V - IVINN ................................................... 0.3V to 4V IN CTRL2 6 23 V IN INTV (Note 3) .....................................8.6V, V + 0.3V CC IN FB 7 22 GND 29 PWM, SHORTLED, OPENLED .....................................12V GND V 8 21 GND C FB, RAMP, OVLO .........................................................8V CTRL1 9 20 INTV CC CTRL1, CTRL2 ...........................................................15V V 10 19 GATE REF SENSE ......................................................................0.5V SS 11 18 SENSE ISMON, IVINCOMP .....................................................5V RT 12 17 GND V , V , SS ................................................................3V C REF RAMP 13 16 OPENLED RT ...............................................................................2V PWM 14 15 SHORTLED Operating Junction Temperature Range (Note 4) FE PACKAGE 28-LEAD PLASTIC TSSOP LT3795E/LT3795I .................................. 40 to 125C T = 150C, = 30C/W, = 10C/W JMAX JA JC LT3795H ................................................40 to 150C EXPOSED PAD (PIN 29) IS GND, MUST BE SOLDERED TO PCB Storage Temperature Range ......................65 to 150C