PWM Controller with Adjustable Skip Level and External Latch Input

The NCP1218 represents a new, pin to pin compatible, generation of the successful 7-pin current mode NCP12XX product series. The controller allows for excellent standby power consumption by use of its adjustable skip mode and integrated high voltage startup FET. Internal frequency jittering, ramp compensation, timer-based fault detection and a latch input make this controller an excellent candidate for converters where ruggedness and component cost are the key constraints. The Dynamic Self Supply (DSS) drastically simplifies the transformer design in avoiding the use of an auxiliary winding to supply the NCP1218. This feature is particularly useful in applications where the output voltage varies during operation (e.g. battery chargers). Due to its high voltage technology, the IC can be directly connected to the high voltage dc rail.