ACT4303

Active-Semi ACT4303 Rev 0, 05-Dec-11 30V/3A Sensorless CC/CV Step-Down DC/DC Converter FEATURES 32V Input Voltage Surge 30V Steady State Input Voltage Up to 3A Output Current Output Voltage up to 12V Patent Pending Active CC Sensorless Constant Current Control − Integrated Current Control Improves Efficiency, Lowers Cost, and Reduces Component Count Resistor Programmable Current Limit from 1.5A to 3A ±7.5% CC Accuracy − Compensation of Input /Output Voltage Change − Temperature Compensation − Independent of inductance and Inductor DCR 2% Feedback Voltage Accuracy Up to 94% Efficiency 225kHz Switching Frequency Eases EMI Design Advanced Feature Set − Integrated Soft Start − Thermal Shutdown − Secondary Cycle-by-Cycle Current Limit − Protection Against Shorted ISET Pin SOP-8EP Package APPLICATIONS USB Chargers LCD TV and Monitors Digital Video Recorders Set-Top Box Battery Chargers General-Purpose CC/CV Power Supplies GENERAL DESCRIPTION ACT4303 is a wide input voltage, high efficiency Active CC step-down DC/DC converter that operates in either CV (Constant Output Voltage) mode or CC (Constant Output Current) mode. ACT4303 provides up to 3A output current at 225kHz switching frequency. Active CC is a patent-pending control scheme to achieve highest accuracy sensorless constant current control. Active CC eliminates the expensive, high accuracy current sense resistor, making it ideal for battery charging applications and adaptors with accur...