This part is a kind of semiconductor called NCP6151.

Function of this product has Dual Output 4 Phase +1/0 Phase Controller.

Manufacturers : ON Semiconductor

Image and pinout :

Some of the text within the PDF file :

NCP6151/NCP6151A Dual Output 4 Phase +1/0 Phase Controller with single SVID Interface for Desktop and Notebook CPU Applications http://onsemi.com The NCP6151/NCP6151A dual output four plus one phase buck solution is optimized for Intel VR12 compatible CPUs. The controller combines true differential voltage sensing, differential inductor DCR current sensing, input voltage feed-forward, and adaptive voltage positioning to provide accurately regulated power for both Desktop and Notebook applications. The control system is based on Dual-Edge pulse-width modulation (PWM) combined with DCR current sensing providing the fastest initial response to dynamic load events and reduced system cost. It also sheds to single phase during light load operation and can auto frequency scale in light load wh [ ... ]

NCP6151 PDF Datasheet Download