SC4812

Current Mode PWM Controller with Integrated Start-up Circuit and Op Amp POWER MANAGEMENT Description The SC4812 is a highly integrated current mode PWM controller designed for isolated or non-isolated dc-dc converters in telecommunication and data communication applications. It minimizes the amount of external discrete components needed and leads to substantial cost and space saving converter designs. SC4812 Features Wide input range 12V to 90V High-voltage start-up circuit Current mode control Transconductance error amplifier Leading-edge blanking Cycle by cycle current limit Programmable external soft-start Thermal shutdown SO-8 package. Fully WEEE and RoHS compliant ‹ ‹ ‹ ‹ ‹ ‹ ‹ The circuitry of the SC4812 includes an integrated high voltage start-up circuit suitable for telecom/industrial ‹ www.DataSheet4U.com voltage applications. It is disabled during regular opera- ‹ tion and improves efficiency. Current mode control with leading-edge blanking simplifies control loop design and internal ramp compensation circuit stabilizes the current loop when operating above 50% duty cycle. Internal error amplifier could be used for non-isolated applications. Applications ‹ ‹ ‹ ‹ ‹ IP phones, PoE Telecom isolated converters Off-line isolated power supplies Instrumentation power supplies Battery chargers Typical Application Circuit Vin T1 C2 C3 R2 1 U1 D1 C1 Vout R1 C4 VIN VCC 8 Q1 7 5 6 R5 2 3 C5 R3 R4 4 C6 FB SC4812 COMP SS/SHDN OUT CS GND Revision: February 6, 2...