LD7531A

LD7531A 7/6/2009 Green-Mode PWM Controller with Frequency Trembling and Integrated Protections REV: 00 General Description The LD7531A 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 LD7531A 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. Features z High-Voltage CMOS Process with Excellent ESD protection z Very Low Startup Current (<20μA) z Current Mode Control z Non-audible-noise Green Mode Control z UVLO (Under Voltage Lockout) z LEB (Leading-Edge Blanking) on CS Pin z Programmable Switching Frequency z Internal Trembling (±4KHz) z Internal Slope Compensation z OVP (Over Voltage Protection) on Vcc Pin z OLP (Over Load Protection) z 300mA Driving Capability Applications z Switching AC/DC Adaptor and Battery Charger z Open Frame Switching Power Supply Typical Application AC EMI input Filter VCC RT 100K Ohm COMP 32V 16.0V /10.0V ...