I am designing a bridgeless PFC baed on ADP1048 with input 85-264VAC. It should also be possible to run the converter with DC input.
Would that be possible ?
I understand that when running on DC only on of the boost phases would be used. Meaning that running on DC input would require that each phase must be designed for full output power
Yes, it is possible. However, it is recommended that the VAC pin see a voltage that is always greater than 1/10 the full scale range i.e. > 1.6/10= 0.16V. This means that the resistor divider on VAC pin be such that at the minimum input voltage the VAC pin sees more than 0.16V.