Datasheet LT3755, LT3755-1, LT3755-2 (Analog Devices) - 21

LT3755/LT3755-1/LT3755-2
TYPICAL APPLICATIONS 50W White LED Headlamp Driver
L1 22µH D1 VIN 8V TO 40V CIN R1 R3 COUT V 4.7µF 1M IN 1M 4.7µF SHDN/UVLO FB R2 V R4 REF ISP 187k 23.7k 16.9k LT3755-2 RLED 1A CTRL 0.1Ω INTV ISN CC 100k NTC GATE M1 100k RT1 SENSE OPENLED RSENSE PWM 0.015Ω 50W LED SS STRING CSS RT PWMOUT 0.01µF VC GND INTVCC RT 28.7k RC C 375kHz VCC 10k 4.7µF CC 0.001µF M2 L1: COILTRONICS DR127-220 37551 TA02a M1: VISHAY SILICONIX SI7850DP SEE SUGGESTED LAYOUT, FIGURE 5 D1: DIODES INC. PDS5100 M2: VISHAY SILICONIX SI2308DS RT1: MURATA NCP18WM1045
Waveforms for 50W LED Driver with PWM Disconnect NFET
PWM VIN = 12V 0V TO 5V VOUT = 50V 10V/DIV IL1 2A/DIV ILED 500mA/DIV 37551 TA02b 50µs/DIV
V(ISP-ISN) Threshold vs Temperature Efficiency vs Load for NTC Resistor Divider
100 120 VIN = 12V 96 100 80 92 60 88 THRESHOLD (mV) EFFICIENCY (%) 40 84 V (ISP-ISN) 20 80 0 0.0 0.2 0.4 0.6 0.8 1.0 25 45 65 85 105 125 LOAD (A) TEMPERATURE (°C) 37551 TA02c 37551 TA02d Rev. E For more information www.analog.com 21 Document Outline 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