Description

The UC1846/7 family of control ICs 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 pusn-pull converters, and the ability to parallel "power modules" while maintaining equal current sharing. Protection dircuitry 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 sup--pression, deadline adjust capability, and a $1% trimmed bandgap reference. The UC1846 features low outputs in the OFF state, while the UC1847 features high outputs in the OFF state.