KA3846

www.fairchildsemi.com KA3846 SMPS Controller Features Automatic Feed Forward Compensation Programmable Pulse by Pulse Current Limiting Automatic Symmetry Correction in Push-Pull Configuration Enhanced Load Response Characteristics Parallel Operation Capability for Modulator Power Systems Differential Current Sense Amplifier with Common Mode Range Double Pulse Suppression 200mA Totem-Pole Outputs ±2% Band gap Reference Under-Voltage Lockout Soft-Start Capability Shutdown Terminal 500KHz Operation Description The KA3846 control IC provides all of the necessary features to implement fixed frequency, current mode control schemes while maintaining a minimum external parts count. The superior performance of this technique can be measured in improved line regulation, enhanced load response characteristics, and a simpler, easier-to-design control loop. Topological advantages include inherent pulse-by-pulse current limiting capability, automatic symmetry correction for push-pull converters, and the ability to parallel “power module,, while maintaining equal current sharing. Protection circuitry includes built-in-under-voltage lockout and programmable current limit in addition to soft-start capability. A shutdown function is also available which can initiate either a complete shutdown with automatic restart or latch the supply off. Other features include fully latched operation, double pulse suppression, deadtime adjust capability, and ±2% trimmed bandgap r...