Features
High-Voltage CMOS Process with Excellent ESD
protection
Very Low Startup Current (<20μA)
Current Mode Control
Non-audible-noise Green Mode Control
UVLO (Under Voltage Lockout)
LEB (Leading-Edge Blanking) on CS Pin
Programmable Switching Frequency
Internal Trembling (±4KHz)
Internal Slope Compensation
OVP (Over Voltage Protection) on Vcc Pin
OLP (Over Load Protection)
300mA Driving Capability

Applications
Switching AC/DC Adaptor and Battery Charger
Open Frame Switching Power Supply

General Description
The LD7531 is built-in with several functions, protection and
EMI-improved solution in a SOT-26/ DIP-8 package. It takes
less components counts or circuit space, especially 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.
And the LD7531 features more protections like OLP (Over
Load Protection) and OVP (Over Voltage Protection) to
prevent the circuit damage from the abnormal conditions.
Furthermore, the frequency trembling function is to reduce
the noise level and thus helps the power circuit designers to
easily deal with the EMI filter design by using minimum
component cost and developing time.