LTC3900_1 Datasheet, PDF (14/20 Pages) Linear Technology – Synchronous Rectifier Driver for Forward Converters

LTC3900
typical applications
18V to 40V Input to 14V at 14A Output Converter in 1/4 Brick Footprint
220pF
BAS516
255R
V_FB
22k
BC857BF
0.1µF
13.3k
165k
V_IN
18V TO 40V
PZTA42
V_U1
22k
1.5mH
6.8µF
×4
PDZ10B
1 _• 2, 3
BAS516
6
4, 5
V_IN
7 _{• FG}
40R2-4421.003
PA1494.362
HAT2266
33µF
CG
150µF
PXE
V_OUT1
14V
14A
LTC4441
1
10
PGND OUT
2
9
BL DRV_CC
3
R_BL
8
V_IN
V_U1
4
7
SGND FB
5
6
IN _PGND EN
V_R
332k
2.2µF
255R
57.6k
33k
LT1952-1
1 _COMP
S_OUT ¹⁶
115k
2 _{FB = 1.23V}
3 _ROSC
V_IN ¹⁵
OUT ¹⁴
4 _SYNC
0.47µF _{5 MAXDC}
PGND ¹³
DELAY ^{12 158k}
6 _{VR = 2.5V}
7 _SD
OC ¹¹
I_SENSE ^{10 2K}
8 _GND
BLANK ⁹
82k
22k
158k
0.1µF
0.1µF
BAS516
S_OUT ^10k
GATE
V_U1
4.7µF
1µF
Si3459
11
HAT2266
×2
0.004R
680µH
0.22µF
1k
BCX55
BAS521
82k
10k
10k
CG
V_AUX
V_AUX
LTC3900
47k
1 _CS+
8
SYNC
2 _CS–
3
CG
7
TIMER
6
GND
470pF
4
V_CC
5
FG
FG
560R
1µF
220pF
GATE
•
PE-68386
PDZ7.5B
BAS516
220R
15nF
PS2801-1
270R
LT4430
V_AUX
1
V_CC
6
OPTO
V_FB
2
5
GND COMP
1.2k
2.2nF
3
OC
1µF
4
FB
3.65k
1.96k
82.5k
V_OUT1
33pF
3900 TA03a
V_IN
V_R
By Using Active Reset and 60V MOSFETs Converter is Achieving 94% to 95%
Efficiency with Only Four MOSFETs.
96
94
92
90
88
86
84
82
02
V_IN = 24V
V_OUT = 14V
4 6 8 10 12 14
I_OUT (A)
3900 TA03b
3900fb
14