The NCP1607 is an active power factor correction controller specifically designed for use as a pre-converter in ac/dc adapters, electronic ballasts, and other medium power off line converters (typically up to 300W). It utilizes Critical Conduction Mode (CRM) to ensure unity power factor across a wide range of input voltages and power levels. The NCP1607 minimizes the number of external components. The integration of comprehensive safety protection features makes it an excellent choice for designing robust PFC stages.