In one embodiment, an IC package assembly for a switching regulator, can include: a power switch chip including a control electrode and a first electrode on an obverse side and a second electrode on a reverse side, where the second electrode is configured as a switching terminal of a switching regulator; a control chip including a driving electrode and a plurality of input and output electrodes on the obverse side; and a leadframe including an extension pin, a substrate, and a plurality of discrete pins, where the extension pin is formed integrally with the substrate, and where the reverse side of the power switch chip is arranged on the substrate of the leadframe by a conductive material to electrically connect the second electrode to the substrate.