Datasheet

LT3956
18
3956f
90% Efficient, 20W SEPIC LED Driver
V
IN
LT3956
L1A
33µH
1:1
GNDV
C
INTV
CC
EN/UVLO SW
V
REF
ISP
100k
INTV
CC
1M
C1
4.7µF
50V
10nF
0.01µF
L1: COILTRONICS DRQ127-330
D1: VISHAY PDS5100
M1: ZETEX ZXM61N03F
V
IN
8V TO
50V
185k
250k
25k
C3
10µF
s2
35V
PGND
L1B
15k
28.7k
375kHz
C2
4.7µF
10V
CTRL
1M
0.25Ω
M1
1A
D1
C4
2.2µF (50V)
20W
LED
STRING
CURRENT
DERATED
FOR V
IN
< 13V
3956 TA05a
VMODE
PWM
SS
RT
ISN
FB
PWMOUT
56.2k
V
IN
(V)
0 10
80
EFFICIENCY (%)
84
88
92
96
100
30
40
3956 TA05b
20
50
Typical applicaTions
Efficiency vs V
IN
90W Buck Mode LED Driver, 80V
IN
/60V
OUT
V
IN
V
IN
LT3956
GNDV
C
INTV
CC
V
REF
INTV
CC
EN/UVLO
SW
ISP
100k
INTV
CC
1M
0.01µF
0.1µF
D1: VISHAY 10MQ100N
L1: WÜRTH ELEKTRONIK 744066330
M1: VISHAY SILICONIX Si7113DN
Q1: ZETEX FMMT593
Q2: ZETEX FMMT493
C1, C2: MURATA GRM42-2x7R225
V
IN
64V TO
80V
20k
28.7k
375kHz
4.7µF
0.1Ω
1.5A
16 WHITE
LEDs, 90W
3956 TA06a
VMODE
PWM
CTRL
SS
RT PGND
ISN
FB
PWMOUT
C1
2.2µF
s4
C2
2.2µF
s3
267k 200k
10k
Q1
M1
D1
L1
33µH
200k
470Ω
1k
Q2
24.3k
13k
V
IN
(V)
64
90
EFFICIENCY (%)
92
94
96
98
100
72
76
3956 TA05b
68
80
Efficiency vs V
IN