LD7552B

1/2/2008

1

Leadtrend Technology Corporation

LD7552B-DS-01a January 2008

Green-Mode PWM Controller with Integrated Protections

Rev. 01a

General Description

The LD7552B are low cost, low startup current, current

mode PWM controllers with green-mode power- saving

operation.

The

integrated

functions

include

the

leading-edge blanking of the current sensing, internal slope

compensation. They provide the users a superior AC/DC

power

application

of

higher

efficiency,

low

external

component counts, and lower cost solution.

Furthermore, LD7552B feature more protections like OLP

(Over Load Protection) and OVP (Over Voltage Protection)

to eliminate the external protection circuits. It is designed for

the switching adaptor with 30W~60W output, offered in both

SOP-8 and DIP-8 package.

Features

High-Voltage CMOS Process with Excellent ESD

protection

Very Low Startup Current (<20

μA)

Current Mode Control

Non-audible-noise Green Mode Control

UVLO (Under Voltage Lockout)

LEB (Leading-Edge Blanking) on CS Pin

Programmable Switching Frequency

Internal Slope Compensation

OVP (Over Voltage Protection) on Vcc Pin

OLP (Over Load Protection)

500mA Driving Capability

Applications

Switching AC/DC Adaptor and Battery Charger

Open Frame Switching Power Supply

384X Replacement

Typical Application

OSC

16.0V

/10.0V

UVLO

Divider

32V

Control

Logic

EMI

Filter

RT

OUT

CS

VCC

GND

COMP

LD7552B

photocoupler

AC

input

TL431