©2003 Fairchild Semiconductor Corporation
www.fairchildsemi.com
Rev.1.0.4
Features
• Quasi Resonant Converter Controller
• Int ernal Burst Mode Control ler for Stand- by Mode
• Pulse by Pulse Current Limiting
• Over Current Latch Protection
• Over Voltage Protection (Vsync : Min. 11V)
• Internal Thermal Shutdown Function
• Unde r Voltage Lo ck out
• Internal High Voltage Sense FET
• Auto- Re st art Mo de
Description
The Fairchild Power Swit ch(FPS) product family is speci ally
designed for an off-line SMPS with minimal external
components. The Fairchild Power Switch(FPS) consists of a
high voltage power SenseFET and a current mode PWM IC.
The integrated PWM controller includes the fixed oscillator,
the under voltage lock out, the leading edge blanking, the
optimized gate turn-on/turn-of f driver, the thermal shut down
protection, the over voltage protection, and the temperature
compensated precision current sources for loop compensation
and fault protection circuitry. Compared to a discrete
MOSFET and a controller or a RCC switching converter
solutions, a F airchild Power Switch(FPS ) can reduce the total
number of components, design size, and weight, so it will
improve ef ficiency, productivity, and system reliabilit y. It has
a basic platform well suited for cost-effective design in a
quasi-resonant converter as a C-TV power supply.
TO-220F-5L
1. Drain 2. GND 3. VCC
4. Feedback 5. Sync
Internal Block Diagram
-
+
Rsense
11V on
12V off
3
1
2
4
VREF
Internal
BIAS
SQ
R
LEB
450ns
SQB
R
Ro
n
Rof
f
Power
on
Reset
OVP
OLP
7.5V
-
+
12V
Sync
-
+
-
+
UVLO
15V/9V
5
Burst Mode
3.5V/1.25V
SYNC
SYNCSYNC
SYNC
-
+
R
2.5R
-
+
-
+
Offset
Thermal
Thermal Thermal
Thermal
Shut Down
Shut DownShut Down
Shut Down
S
Q
RPower on Reset
(VCC=6.5V)
Delay
80ns
1V
-
+
OCL
1V
FEEDBACK
FEEDBACKFEEDBACK
FEEDBACK
VCC
VCCVCC
VCC DRAIN
DRAINDRAIN
DRAIN
SOURCE
SOURCESOURCE
SOURCE
Normal Mode
4.6V/2.6V
OSC
-
+
-
+
Idelay
Ifb
VREF
32V 1%
+
-
Ron
Roff
KA5Q0740RT
Fairchil d Power Swi tch(FPS)