FAN7621 Fairchild Semiconductor, FAN7621 Datasheet - Page 2

• Manufacturer Part Number: FAN7621
• Description: The FAN7621 is a pulse frequency modulation controller for high-efficiency half-bridge resonant converters
• Manufacturer: Fairchild Semiconductor

© 2009 Fairchild Semiconductor Corporation
FAN7621 • Rev. 1.0.3
Application Circuit Diagram
Block Diagram
V
CON
R
IN
T
8
6
V
LV
REF
LV
OLP
OVP
C
CC
23 V
5 V
I
CC
CTC
DL
I
0.4 / 0.6 V
OLP
+
-
Figure 1. Typical Application Circuit (LLC Resonant Half-Bridge Converter)
+
-
+
-
I
2I
2V
CTC
-
+
CTC
V
CC
LV
CC
3 V
1 V
good
R
sense
CON
RT
CS
+
-
+
-
Figure 2. Internal Block Diagram
Auto-restart
LVcc
Protection
SG
R
S
Counter (1/4)
R
S
F/F
HV
CTR
-Q
HO
LO
Q
-Q
CC
Q
PG
11.3 / 14.5V
Protection
2
Q
-Q
Latch
Cr
S
R
LV
12
350ns
350ns
Delay
Delay
Time
Time
CC
+
-
Lm
L
Delay
lk
1.5µs
LV
Internal
Shutdown without delay
Bias
50ns Delay
LV
CC
Np
CC
good
< 5V
Level-Shift
Balancing
TSD
Delay
-
+
V
REF
V
+
-
0.58 V
V
OCP
Ns
Ns
AOCP
HV
Gate Drive
Gate Drive
High-Side
Low-Side
0.9 V
CC
D1
D2
KA431
good
-1
CS
8.7 / 9.2V
9
+
-
C
F
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R
F
14
16
10
1
3
2
PG
SG
HV
HO
CTR
LO
V
CC
O