Datasheet

LT3791
25
3791fa
Typical applicaTions
98% Efficient 50W (25V 2A) Buck-Boost LED Driver
R7
50Ω
C7
470nF
V
IN
4.7V TO 58V
INTV
CC
TG1
BG1
SNSP
SNSN
PGND
BST1
BST2
TEST2
BG2
SW2
TG2
RT
LT3791
SWI
R
IN
0.003Ω
SHORTLED
OPENLED
IVINN
IVINP
C3
1µF
V
IN
PWM
INTV
CC
IVINMON
SYNC
100Hz
300kHz
ISMON
CLKOUT
EN/UVLO
OVLO
M2
M1
M3
M4
R10
200k
V
REF
CTRL
TEST1
R8
86.6k
300kHz
V
C
SS SGND
PWMOUT
R2
121k
R9
200k
R1
332k
R3
1M
R4
54.9k
SYNC TWO
SIGNALS
R11
1M
R12
237k
C8
0.1µF
C
SS
10nF
C
C
22nF
3791 TA02a
C
IN
2.2µF
100V
×4
R
SENSE
0.004Ω
ISP
ISN
FB
R
LED
0.05Ω
25V LED
2A
C1
0.1µF
C2
0.1µF
D2D1
L1 10µH
C
VCC
4.7µF
C
OUT
4.7µF
50V
×4
R5
1M
R6
44.2k
M5
D1, D2: NXP BAT46WJ
L1: COOPER HC9-100-R 10µH
M1, M2: RENESAS RJK0651DPB 60V
DS
M3, M4: RENESAS RJK0451DPB 40V
DS
M5: VISHAY Si2318CDS 40V
DS
Efficiency vs V
IN
100Hz 1000:1 PWM Dimming
(V
IN
= 24V)
100Hz 250:1 PWM Dimming
(V
IN
= 24V)
INPUT VOLTAGE (V)
0
80
EFFICIENCY (%)
84
88
92
10
20
30 40
3791 TA02b
50
96
100
82
86
90
94
98
60
BUCK
BOOST
BUCK-BOOST
5µs/DIV
I
L1
5A/DIV
I
LED
2A/DIV
ISMON
1V/DIV
3791 TA02c
PWM
5V/DIV
5µs/DIV
I
L1
5A/DIV
I
LED
2A/DIV
ISMON
1V/DIV
3791 TA02d
PWM
5V/DIV