LT3757 LINER [Linear Technology], LT3757 Datasheet - Page 8

• Manufacturer Part Number: LT3757
• Description: Boost, Flyback, SEPIC and Inverting Controller
• Manufacturer: LINER [Linear Technology]

LT3757
block DiagraM

C
C1
C
FBX
C2
R
C
1
2
VC
FBX
–0.88V
1.72V
–0.8V
1.6V
–
+
–
+
FREQUENCY
FOLDBACK
2.5V
A11
A12
+
–
+
–
A1
A2
I
S3
G6
Figure 1. LT3757 Block Diagram Working as a SEPIC Converter
2.5V
3
2µA
I
SS
S1
1.25V
C
Q3
I
10µA
FREQ
FOLDBACK
SS
S2
Q2
–
+
A3
G4
UVLO
REGULATOR
5
VC
PWM
COMPARATOR
AND UVLO
1.25V
INTERNAL
SYNC
V
IN
–
+
A7
+
+
–
165˚C
G3
TSD
A10
G1
A4
R4
–
+
FREQ
PROG
SLOPE
RAMP
100kHz-1MHz
9
OSCILLATOR
GENERATOR
G5
1.22V
A8
A9
SHDN/UVLO
R3
RAMP
+
–
+
–
4
Q1
RT
17.5V
R
V
T
2.7V UP
2.6V DOWN
ISENSE
+
R
CURRENT
7.2V LDO
LIMIT
SR1
S
C
IN
O
DRIVER
A5
A6
–
+
+
–
G2
10
108mV
V
IN
INTV
SENSE
GATE
GND
3757 F01
CC
L1
11
8
7
6
C
VCC
C
M1
R
L2
DC
SENSE
•
D1
FBX
R2
R1
+
C
OUT2
C
OUT1
V
3757fb
OUT