NCP1680 is a CrM PFC controller IC for driving bridgeless totem pole PFC topology. Bridgeless Totem Pole PFC is a power factor correction architecture consisting of a fast switching bridge arm driven at the PWM switching frequency and a second bridge arm operating at the AC line frequency. This topology eliminates the diode bridge that exists at the input of conventional PFC circuits, resulting in a significant increase in the efficiency of the power stage.