Cooling apparatus for electronic chips

Apparatus for cooling an integrated circuit chip mounted on a circuit board, said apparatus comprising:

• a heat sink having a base mounted in heat transfer relation upon the top of the chip;
• said heat sink including spaced apart fins extending upwardly from said base, said fins defining air flow interstices generally extending in a given direction parallel to said base, said fins being parallel to one another and separated from one another by a given generally constant distance so that said interstices are of generally uniform width;
• an outermost pair of said fins defining lateral side surfaces of said heat sink;
• the tops of said fins lying in a generally flat plane defining an upper heat sink surface;
• a shroud covering the chip and said heat sink;
• means including at least one fastener for mechanically attaching said shroud in a fixed position directly to the circuit board;
• said shroud having a flat, planar top wall parallel with the circuit board and overlying said heat sink and an opposed pair of side walls extending in said given direction, said side walls flanking the chip and said heat sink, said side walls extending from said top wall to the surface of the circuit board, said shroud having opposed air inlet and air outlet ends;
• said shroud top wall being parallel to said upper heat sink surface and spaced from said upper heat sink surface by a distance substantially equal to said given distance and said shroud side walls being parallel to said heat sink lateral side surfaces and spaced from said heat sink lateral side surfaces by a distance substantially equal to said given distance;
• and
• a fan attached to one of said ends for moving air through said interstices, the other of said ends opposite to said fan being unobstructed defining an air flow opening at least equal in width and height to the width and height of said heat sink;
• and
• said fan extending above the surface of the circuit board a distance equal to or less than the distance between the surface of the board and said shroud top wall.