Highly Integrated Dual-Mode Active Clamp PWM Controller

The NCP1566 is a highly integrated dual-mode active-clamp PWM controller targeting next-generation high-density, high-performance and small to medium power level isolated dc-dc converters for use in telecom and datacom industries. It can be configured in either voltage mode control with input voltage feed-forward or peak current mode control. Peak current mode control may be implemented with input voltage feedforward as well. Adjustable adaptive overlap time optimizes system efficiency based on input voltage and load conditions.This controller integrates all the necessary control and protection functions to implement an isolated active clamp forward or asymmetric half-bridge converter. It integrates a high-voltage startup bias regulator. The NCP1566 has a line undervoltage detector, cycle-by-cycle current limiting, line voltage dependent maximum duty ratio limit, over voltage protection, and programmable overtemperature protection using an external thermistor. It also includes a dual-function pin used for communicating the presence of a fault but also for shutting down the controller. A dedicated dual-function synchronization pin eases operations when associating bricks together.