©2001 Fairchild Semiconductor Corporation

www.fairchildsemi.com

Rev.1.0.2

Features

• Precision fixed operating frequency

• KA1L0880B(50KHz),KA1M0880B(67KHz)

• Pulse by pulse over current limiting

• Over load protection

• Over voltage protection (Min. 23V)

• Internal thermal shutdown function

• Under voltage lockout

• Internal high voltage sense FET

• Latch up mode

•Soft start

Description

The Fairchild Power Switch(FPS) product family is specially

designed for an off-line SMPS with minimal external

components. The Fairchild Power Switch(FPS) consist of high

voltage power SenseFET and current mode PWM controller IC.

PWM controller features integrated fixed oscillator, under

voltage lock out, leading edge blanking, optimized gate turn-on/

turn-off driver, thermal shut down protection, over voltage

protection, temperature compensated precision current sources

for loop compensation and fault protection circuit. compared to

solution, a Fairchild Power Switch(FPS) can reduce total

component count, design size, weight and at the same time

increase & efficiency, productivity, and system reliability. It has

a basic platform well suited for cost effective design in either a

flyback converter or a forward converter.

TO-3P-5L

1

Internal Block Diagram

32V

5

µA

5V

2.5R

1R

1mA

0.1V

+

−

OVER VOLTAGE S/D

+

−

7.5V

25V

Thermal S/D

S

R

Q

Power on reset

+

−

L.E.B

S

R

Q

OSC

5V

Vref

Internal

bias

Good

logic

SFET

#1 DRAIN

#2 GND

#4 FB

#5 Soft Start

9V

KA1L0880B/KA1M0880B

Fairchild Power Switch(FPS)