
LT3956
TYPICAL APPLICATIONS
Buck-Boost Mode LED Driver
Efficiency vs V IN
V IN
9V TO
45V
C1
4.7μF
1M
V IN
EN/UVLO
L1
68μH
SW
ISP
D1
1μF
100V
V IN
V OUT
4.7μF
35V
100
96
187k
INTV CC
100k
V REF
CTRL
VMODE
PWM
LT3956
ISN
FB
PGND
619k
10k
680m
24V
LED STRING
350mA
92
88
84
35.7k
300kHz
SS
RT
V C
3.4k
GND
PWMOUT
INTV CC
INTV CC
750
M1
80
0
10
20
V IN (V)
30
40
50
3956 TA03b
0.1μF
10nF
4.7μF
Q1
V IN
L1: COILCRAFT MSS1038-683
D1: ON SEMICONDUCTOR MBRS3100T3
M1: ZETEX ZXM6IP03F
Q1: ZETEX FMMT493
1k
3956 TA03a
L1A
33μH
D1
10μF
L1B
V IN
V IN
28V
≤ 1.2A
28V IN /0V to 28V SEPIC SuperCap Charger with Input Current Limit
C4
10μF
200m V OUT
0V TO 28V
1:1
C1
1μF ISP ISN
SW C3
10μF
EN/UVLO PGND
3.0
2.5
2.0
Input and Output Current
vs Output Voltage
LT3956
FB
536k
1.5
OUTPUT
2k
10k
PWMOUT
VMODE
INTV CC
PWM
V C RT
CTRL
V REF
SS
GND
25k
14k
1M
40.2k INTV CC
59k
Q1
1M
1.0
0.5
0
0
5
INPUT
10
15
V OUT (V)
20
25
30
3956 TA04b
C2
4.7μF
3956 TA04a
10nF
28.7k
375kHz
30.1k
L1: WüRTH ELEKTRONIK 744871330
D1: ON SEMI MBRS36OT
Q1: MMBTA42
C1, C3, C4: TAIYO-YUDEN GMK 3I6BJ106
3956f