September 2010

© 2009 Fairchild Semiconductor Corporation

www.fairchildsemi.com

FSL137H Rev. 1.0.3

FSL137H

Green Mode Fairchild Power Switch (FPS™)

Features

Built-in 5ms Soft-Start Function

Internal Avalanche Rugged 700V SenseFET

Low Audio Noise

High-Voltage Startup

Fixed PWM Frequency at 100KHz

Linearly Decreasing PWM Frequency to 18KHz

Peak-Current-Mode Control

Cycle-by-Cycle Current Limiting

Leading-Edge Blanking (LEB)

Synchronized Slope Compensation

Internal Open-loop Protection (OLP)

Constant Power Limit (Full AC Input Range)

Internal OTP Sensor with Hysteresis

Applications

General-purpose switch-mode power supplies and

flyback power converters, including:

SMPS for VCR, SVR, STB, DVD & VCD Player,

Printer, Facsimile, & Scanner

Adapter for Camcorder

Description

The highly integrated FSL137H consists of an

integrated current mode Pulse Width Modulator (PWM)

and an avalanche-rugged 700V SenseFET. It is

specifically designed for high-performance offline

Switch Mode Power Supplies (SMPS) with minimal

external components.

The integrated PWM controller features include a

proprietary green-mode function that provides off-time

modulation to linearly decrease the switching frequency

at light-load conditions to minimize standby power

consumption. To avoid acoustic noise problems, the

minimum PWM frequency is set above 18KHz. The

green-mode function enables the power supply to meet

international power conservation requirements. With the

internal high-voltage startup circuitry, the power loss

due to bleeding resistors is also eliminated. To further

reduce power consumption, the PWM controller is

manufactured using the BiCMOS process, which allows

an operating current of only 3.5mA.

The FSL137H built-in synchronized slope compensation

achieves

stable

peak-current-mode

control.

The

proprietary

external

line

compensation

ensures

constant output power limit over a wide AC input

The FSL137H provides many protection functions. In

addition to cycle-by-cycle current limiting, the internal

open-loop protection circuit ensures safety when an

open-loop or output short-circuit failure occurs. PWM

exceeds ~28V, the internal OVP circuit is triggered.

Compared to a discrete MOSFET and controller or RCC

switching converter solution, the FSL137H reduces total

component count, design size, and weight while

increasing efficiency, productivity, and system reliability.

These devices provide a basic platform well suited for

design of cost-effective flyback converters.

Ordering Information

Part Number

SenseFET

Operating Temperature

Range

Package

Packing

Method

FSL137HNY

3.0A 700V

-40°C to +105°C

8-Pin Dual In-Line Package (DIP)

Tube