The NCP1568D is a highly integrated PWM controller designed to implement an active clamp flyback topology. NCP1568D employs a proprietary variable frequency algorithm to enable zero voltage switching (ZVS) of Super−Junction or GaN FETs across line, load, and output conditions. The ZVS feature increases power density of a power converter by increasing the operating frequency while achieving high efficiency. The Active Clamp Flyback (ACF) operation simplifies EMI filter design to avoid interference with other sensitive circuits in the system. The NCP1568D features a HV startup circuit, a strong low side driver, and a 5 V logic level driver for the active clamp FET. The NCP1568D is suitable for a variety of applications including power brick, industrial, telecom, lighting, and other applications where power density and efficiency are important requirements.