Patent ID: 8684709

Claim:
A micro cooling fan, comprising: a housing, having a wall body defining an accommodation space, a first inner surface at a first side of the wall body, a first outer surface which is physically a part of a second side of the wall body, with the second side opposite to the first side with respect to the wall body, the first outer surface comprises four sides, and the first inner surface comprises an inner bottom surface and an inner annular wall surface surrounding the inner bottom surface; a fan wheel, having a plurality of fan blades and disposed in the accommodation space to which the first inner surface faces; and a main circuit board, comprising a first circuit board and a second circuit board, wherein a stator is disposed on the first circuit board, a driving circuit is disposed on the second circuit board, the stator is electrically connected to the driving circuit, the first circuit board is disposed on the inner bottom surface, the second circuit board comprises a first plate portion and a second plate portion perpendicular to the first plate portion, and the first plate portion of the second circuit board covers the entire width of one side of the first outer surface; wherein the housing further has an opening and a rib extending along the radial direction of the fan wheel, the first circuit board has a connecting board, the opening is a position for placing the connecting board such that the connecting board connects the first circuit board and the second circuit board, the connecting board is disposed on the rib, and the width of the connecting board is smaller than or equal to the width of the rib.