Data Sheet

© 2006 Fairchild Semiconductor Corporation www.fairchildsemi.com
FSQ-Series • Rev. 1.1.3 3
FSCQ-Series — Green Mode Fairchild Power Switch (FPS™)
Internal Block Diagram
9V/15V
3 1
2
4
Auxiliary
Vref
Main Bias
S
Q
Q
R
OSC
Vcc
Vref
I
delay
I
FB
V
SD
TSD
Vovp
Sync
Vocp
S
Q
Q
R
R
2.5R
Vcc good
(Vcc = 9V)
Vcc Drain
V
FB
GND
AOCP
Gate
Driver
Vcc good
LEB
600ns
PWM
Soft Start
Internal
Bias
Normal
Operation
V
Burst
Vref
I
B
Vref
I
BFB
Burst Mode
Controller
Normal Operation
Burst Switching
5
Sync
Threshold
Quasi-Resonant
(QR) Switching
Controller
+
-
+
-
S
Q
Q
R
Power Off Reset (Vcc = 6V)
4.6V/2.6V : Normal QR
3.0V/1.8V : Extended QR
fs
Figure 2. Functional Block Diagram