FAN7621B Fairchild Semiconductor, FAN7621B Datasheet - Page 2

• Manufacturer Part Number: FAN7621B
• Description: The FAN7621B is a pulse frequency modulation controller for high-efficiency half-bridge resonant converters
• Manufacturer: Fairchild Semiconductor

© 2009 Fairchild Semiconductor Corporation
FAN7621B • Rev. 1.0.1
Application Circuit Diagram
Block Diagram
CON
V
R
IN
T
8
6
V
LV
REF
LV
OLP
OVP
CC
23 V
C
I
5 V
CTC
CC
DL
I
0.4 / 0.6 V
OLP
+
-
+
Figure 1. Typical Application Circuit (LLC Resonant Half-Bridge Converter)
-
+
-
I
2I
CTC
2V
-
+
CTC
V
CC
LV
CC
3 V
1 V
good
R
sense
CON
CS
RT
+
-
+
-
Figure 2. Internal Block Diagram
Auto-restart
protection
LV CC
SG
S
R
Coun ter (1/4)
S
R
HV
F/F
CTR
-Q
HO
LO
Q
CC
-Q
Q
PG
10.0 / 12.5 V
protection
2
Q
-Q
Latch
Cr
R
S
LV
12
350ns
350ns
Time
Delay
Time
Delay
CC
+
-
Lm
L
Delay
lk
1.5μs
LV
Internal
Shutdown without delay
Bias
50ns delay
CC
LV
Np
good
CC
< 5V
Level-Shift
Balancing
Delay
TSD
-
+
V
REF
V
+
-
0.58 V
OCP
V
AOCP
Ns
Ns
HV
Gate Drive
Gate Drive
High-Side
Low-Side
0.9 V
CC
D1
D2
KA431
good
-1
CS
8.7 / 9.2 V
9
+
-
C
F
www.fairchildsemi.com
R
F
14
16
10
1
3
2
PG
SG
HV
CTR
HO
LO
V
CC
O