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