When the operation mode is set to FCCM, the controller operates in continuous conduction mode (CCM) during light-load conditions. During CCM, the switching frequency maintained to an almost constant level over the entire load range which is designed for applications requiring tight control of the switching frequency at the cost of lower efficiency.

When FCCM is selected, the TPS546C25 device operates at CCM during the whole soft-start period as well as the nominal operation.