Abstract: Electronic devices have peripheral drive centrifugal fans having smaller hubs and increased air flows to manage heat levels within the electronic device. A peripheral drive centrifugal fan includes a fan housing, an impeller including a plurality of blades, and a plurality of stacked inductor groups radially disposed about the impeller. Some of the blades have magnetically active portions. Each stacked inductor group includes first and second coils configured to impart a variable magnetic force to the magnetically active portion of a blade to drive the impeller along a rotational direction. The first and second coils can be selectively energizable independently from each other to provide greater control of the impeller.

Abstract: In an exemplary electronic device with a cooling fan, a fan assembly is attached to a keyboard assembly of the electronic device. The fan assembly includes an impeller at least partially inside a fan enclosure. The fan enclosure has, on a surface, an inlet opening and an external protrusion. The electronic device further includes a bottom case. The fan assembly is positioned between the keyboard assembly and the bottom case and oriented such that the inlet opening and the external protrusion face the bottom case. The external protrusion maintains a passage between the fan enclosure and the bottom case that allows air to enter the inlet opening and also resists interference between the rotating impeller and the stationary bottom case.

Abstract: In an exemplary electronic device with a cooling fan, a fan assembly is attached to a keyboard assembly of the electronic device. The fan assembly includes an impeller at least partially inside a fan enclosure. The fan enclosure has, on a surface, an inlet opening and an external protrusion. The electronic device further includes a bottom case. The fan assembly is positioned between the keyboard assembly and the bottom case and oriented such that the inlet opening and the external protrusion face the bottom case. The external protrusion maintains a passage between the fan enclosure and the bottom case that allows air to enter the inlet opening and also resists interference between the rotating impeller and the stationary bottom case.

Abstract: Electronic devices have peripheral drive centrifugal fans having smaller hubs and increased air flows to manage heat levels within the electronic device. A peripheral drive centrifugal fan includes a fan housing, an impeller including a plurality of blades, and a plurality of stacked inductor groups radially disposed about the impeller. Some of the blades have magnetically active portions. Each stacked inductor group includes first and second coils configured to impart a variable magnetic force to the magnetically active portion of a blade to drive the impeller along a rotational direction. The first and second coils can be selectively energizable independently from each other to provide greater control of the impeller.