Data Sheet

© 2009 Fairchild Semiconductor Corporation www.fairchildsemi.com
FAN7621S • Rev. 1.0.1 2
FAN7621S — PFM Controller for Half-Bridge Resonant Converters
Application Circuit Diagram
Figure 1. Typical Application Circuit (LLC Resonant Half-Bridge Converter)
Block Diagram
Figure 2. Internal Block Diagram
LV
CC
R
T
AR
CS
SG PG
HV
CC
V
O
R
max
R
min
R
ss
C
ss
V
CC
V
IN
Cr
FAN7621S
HO
CTR
LO
6
1
12
3
HO
CS
AR
LV
CC
HVcc
CTR
R
T
PG
2
8
16
9
10
SG
14
LO
HUV+ /HUV-
S
R
Q
High Side
Gate Driver
Low Side
Gate Driver
2V
V
ref
Internal
Bias
Level
Shifter
Balan cin g
Delay
Divider
1V
I
RT
I
RT
2I
RT
V
OVP
V
CssH
/V
CssL
LV
CC
S
R
Q
-1
Delay
1.5µs
V
AOCP
Delay
50ns
TSD
LUV+ /LUV-
V
OCP
V
ref
V
ref
3V
Time
Delay
Time
Delay
350ns
350ns
LV
CC
good
LV
CC
good
Shutdown without delay
5k