Datasheet

LT3755/LT3755-1/LT3755-2
19
37551fd
V
IN
LT3755-2
L1
22µH
D1
GNDV
C
INTV
CC
SHDN/UVLO FB
V
REF
ISP
16.9k
INTV
CC
R1
1M
100k
C
IN
4.7µF
C
C
0.001µF
C
SS
0.01µF
V
IN
8V TO
40V
R2
187k
R
C
10k
R
T
28.7k
375kHz
C
VCC
4.7µF
SEE SUGGESTED LAYOUT, FIGURE 5
100k
NTC
RT1
CTRL
R
SENSE
0.015Ω
R
LED
0.1Ω
R3
1M
R4
23.7k
M1
M2
1A
C
OUT
4.7µF
50W
LED
STRING
37551 TA02a
OPENLED
PWM
SS
RT
ISN
GATE
SENSE
PWMOUT
L1: COILTRONICS DR127-220
M1: VISHAY SILICONIX SI7850DP
D1: DIODES INC. PDS5100
M2: VISHAY SILICONIX SI2308DS
RT1: MURATA NCP18WM1045
50W White LED Headlamp Driver
Efficiency vs Load
LOAD (A)
0.0
80
EFFICIENCY (%)
84
88
92
96
100
0.2
0.4 0.6 0.8
37551 TA02c
1.0
V
IN
= 12V
Waveforms for 50W LED Driver with
PWM Disconnect NFET
I
L1
2A/DIV
I
LED
500mA/DIV
50µs/DIV
V
OUT
= 50V
10V/DIV
PWM
0V TO 5V
37551 TA02b
V
IN
= 12V
TEMPERATURE (°C)
25
0
V
(ISP-ISN)
THRESHOLD (mV)
40
80
45 65 10585
120
20
60
100
125
37551 TA02d
V
(ISP-ISN)
Threshold vs Temperature
for NTC Resistor Divider
Typical applicaTions