The UCC28056 device drives PFC boost stages based on an innovative mixed mode method thatoperates in transition mode (TM) at full load and transitions seamlessly into discontinuousconduction mode (DCM) at reduced load, automatically reducing switching frequency. This deviceincorporates burst mode operation to further improve light load performance, enabling systems tomeet challenging energy standards while eliminating the need to switch off the PFC. UCC28056 candrive a PFC power stage up to 300 W, ensuring sinusoidal line input current with low distortion,close to unity power factor. When used with the LLC controller UCC256403/4, and dualsynchronous rectifier controller UCC24624 lessthan 80 mW system standby power can be achieved, enabling PFC always on architecture andeliminating the need for an auxiliary converter. This with FET Drain valley turn-on with simpleboost inductor allows fewest component count and reduced system cost.