The ON Semiconductor series NCP1680 is a CRM PFC controller IC designed to drive the bridgeless totem-pole PFC topology. The bridgeless totem-pole PFC is a power factor correction architecture that consists of a fast switching leg driven at the PWM switching frequency and a second leg that operates at the AC line frequency. This topology eliminates the diode bridge present at the input of a conventional PFC circuit, allowing significant improvement in the power stage efficiency.

Totem Pole PFC Topology Eliminates Input Diode Bridge
Critical Conduction Mode (CRM) Operation
Discontinuous Conduction Mode (DCM) with Valley Turn On Under Light Load Condition
Frequency Fold back in DCM With 25 kHz Minimum Frequency
Skip Mode in Very Light Load Condition
Proprietary Current Sense Scheme
Digital Voltage Loop Compensation