LD5537

09/07/2015

1

Leadtrend Technology Corporation

www.leadtrend.com.tw

LD5537-DS-01 September 2015

Green-Mode PWM Controller with Variable Frequency

and Brown IN/OUT Protections

REV. 01

General Description

The LD5537 is built with several functions, protection and

EMI-improved solution in a tiny package. It takes less

component counts or circuit space, especially in the ideal

for those total solutions of low cost.

The implemented functions include low startup current,

green-mode

power-saving

operation,

leading-edge

blanking of the current sensing and internal slope

compensation.

It also features more protections like

OPP (Over Power Protection), OCP (Over Current

Protection), OSCP (Output Short Circuit Protection) and

OVP (Over Voltage Protection) to prevent circuit damage

occurred under abnormal conditions.

Furthermore, the Frequency Swapping function is to

reduce the noise level and thus helps the power circuit

designers to easily deal with the EMI filter design by

spending minimum amount of component cost and

developing time.

Features

 High-Voltage CMOS Process with Excellent ESD

protection

 Very Low Startup Current (<12

A)

 Current Mode Control

 Green Mode Control

 UVLO (Under Voltage Lockout)

 Variable Frequency Technology around 130kHz

 LEB (Leading-Edge Blanking) on CS Pin

 Internal Frequency Swapping

 Internal Slope Compensation

 OVP (Over Voltage Protection) on VCC Pin

 BNO/BNI (Brown-Out/In) Function

 OPP (Over Power Protection)

 OCP (Over Current Protection)

 OSCP (Short circuit protection)

 300mA/-500mA Driving Capability

Applications

 Switching AC/DC Adaptor and Battery Charger

 Open Frame Switching Power Supply

Typical Application

EMI

Filter

BNO

OUT

CS/OVP

VCC

GND

COMP

LD5537

photocoupler

AC

input

DC

Output