The NCP1568 is a highly integrated Ac-Dc PWM controller designed to implement an active clamp flyback topology. NCP1568 employs a proprietary variable frequency algorithm to enables zero voltage switching (ZVS) of the MOSFETs across line & load conditions. The ZVS feature allows high frequency operation increasing power density of a power converter while achieving high efficiency. A HV startup circuit, a strong low side driver, and a 5V logic level driver for active clamp FET, including SJ FETs and GaN FETs, are integrated. The NCP1568 is suitable for a variety of applications including Ac-Dc adapters, industrial, telecom, lighting and other applications where power density is an important requirement.