The NCP1605 is a controller that exhibits near unity power factor while operating in fixed frequency, Discontinuous Conduction Mode or in Critical Conduction Mode.Housed in a SOIC16 package, the circuit incorporates all the features necessary for building robust and compact PFC stages, with a minimum of external components. In addition, it integrates the skip cycle capability to lower the standby losses to a minimum. The NCP1605A version lowers the UVLO ON threshold level to 10.5 V to allow operation with a lower Vcc.