Electronic circuit board assembly and method of closely stacking boards and cooling the same

• US 5,991,163 A
• Filed: 11/12/1998
• Issued: 11/23/1999
• Est. Priority Date: 11/12/1998
• Status: Expired due to Term

• Current Assignee: WSOU Investments, LLC (WSOU Holdings, LLC)
• Original Assignee: Nexabit Networks, Inc. (Nokia Corporation)
• Inventors: Rigby, Michael John, Bilodeau, Theodore W., Marconi, Peter
• Primary Examiner(s): Picard, Leo P.
• Assistant Examiner(s): Vigushin, John B.
• Application Number:
  US09/190,521
• Time in Patent Office: 376 Days
• Field of Search: 361/684, 361/686, 361/687, 361/692, 361/693, 361/695, 361/788, 361/796, 361/797, 361/800, 361/802, 361/816, 361/818, 361/831, 361/724, 361/727, 312/223.2, 439/61, 439/64, 439/377, 710/102, 211/26, 211/26.2, 211/41.17
• US Class Current: 361/788
• CPC Class Codes: G06F 1/184 Mounting of motherboards
• CPC Class Codes: G06F 1/185 Mounting of expansion boards
• CPC Class Codes: G06F 1/186 Securing of expansion boards in correspondence to slots provided at the computer enclosure
• CPC Class Codes: G06F 1/20 Cooling means
• CPC Class Codes: H05K 7/1429 for circuits carrying a CPU and adapted to receive expansion cards

Abstract

An electronic circuit board assembly and method that enable close stacking and cooling of closely positioned pluralities of similar electronic I/O or memory boards and requiring high speed communication between the boards, such as high speed switching amongst the I/O terminals of the boards or CPU processing, and having an upper and a lower set of similar spaced groups of closely spaced vertical boards; powering terminals aligned along the upper edges of the upper set of boards, and along the lower edges of the lower set of boards, and terminals for connection with a switching fabric disposed along the lower edges of the upper set of boards and the upper edges of the lower set of boards; power backing planes mounted to power and support the lateral edges of the respective sets of groups of boards and extending across the upper and lower sections of the frame; and a plurality of parallel closely spaced vertical switching fabric boards comprising switching fabric (or CPU processing boards) and centrally mounted in the central space of the frame between the groups of boards of the upper and lower sets of boards, and with a backing plane therefor extending intermediately of the frame between the upper and lower section backing plates and isolatively separate therefrom to provide a no-power quiescent zone for the switching fabric (or CPU) boards.

Claims

1. A method of assembling closely positioned pluralities of similar electronic circuit boards provided with powering terminals and requiring high speed communication between said circuit boards and adapted for substantially uniform cooling of the closely positioned boards, that comprises, parallely stacking an upper set of similar spaced groups of closely spaced boards in an upper section of a frame with an intermediate space provided between the groups, and with the powering terminals aligned near the upper edges of the boards, and terminals provided for high speed interfacing at the lower edges of the boards;

parallely stacking a lower set of similar spaced groups of closely spaced boards in a lower section of the frame with a similar intermediate space provided between the groups, and with the powering terminals of the boards aligned near the lower edges of the boards, and terminals provided for high speed interfacing aligned at the upper edges of the boards facing the high speed interfacing terminals of the lower edges of the boards of the upper groups of boards;

mounting a power backplane to support the set of groups of upper section boards and extending across the upper section of the frame, and mounting a similar power backplane to support the set of groups of the lower section boards and extending across the lower section of the frame; and

positioning a plurality of parallel closely spaced high speed logic boards substantially centrally of the frame and disposed in the spaces between the groups of boards of the upper and lower section sets of boards, and with a backplane therefor extending intermediately of the frame between the upper and lower section backplanes and isolatively separate therefrom to provide a no-power quiescent zone for the high speed logic board signals; and

substantially symmetrically connecting the lower edge interfacing terminals of the upper section boards and the upper edge interfacing terminals of the lower section boards to the high speed logic boards at their backplane.

2. The method of claim 1 wherein the circuit boards comprise one of I/O and memory boards, and the high speed logic boards comprise one of switching fabrics and CPUs.

3. The method of claim 1 wherein cooling air flow is passed in-line through the lower, the central and upper sections of the frame.

4. The method of claim 1 wherein all the boards are substantially vertically oriented and the backplanes are extended horizontally of the frame.

5. The method of claim 1 wherein the upper and lower sets of groups of boards each comprise a left-hand quadrant group and a right-hand quadrant group respectively aligned vertically, and the high speed logic group is mounted in a central space between the upper and lower frame sections between the left and right-hand quadrant groups of upper and lower board sets.

6. The method of claim 5 wherein the lower edges of the switching fabric boards are positioned to be somewhat in line respectively with, though between, the interfacing lower and upper terminal edges, respectively, of the upper and lower section boards.

7. An electronic circuit board assembly of closely positioned pluralities of similar electronic boards provided with powering terminals and requiring high speed communication between said circuit boards, having, in combination, mounting slots within a frame for parallely stacking an upper set of similar spaced groups of closely spaced boards in an upper section of the frame and with an intermediate space provided between the groups;

powering terminals aligned near the upper edges of the boards, and terminals for high speed interfacing disposed near the lower edges of the boards;

mounting slots for parallely stacking a lower set of similar spaced groups of closely spaced boards in a lower section of the frame with a similar intermediate space provided between the groups;

powering terminals aligned near the lower edges of the lower set of boards, and terminals for high speed interfacing near the upper edges of the boards, facing the high speed interfacing terminals of the lower edges of the boards of the upper groups of boards;

a power backplane mounted to power and support the set of groups of the upper section boards and extending across the upper section of the frame, and a similar power backplane mounted to power and support the set of groups of the lower section boards and extending across the lower section of the frame; and

a plurality of parallel closely spaced high speed logic boards centrally mounted in the frame and extending in the spaces between the groups of boards of the upper and lower section sets of boards, and with a backplane extending intermediately of the frame between the upper and lower section backplanes and isolatively separate therefrom to provide a no-power quiescent zone for the high speed logic board signals; and

substantially symmetrical connections from the lower edge interfacing terminals of the upper section boards and from the upper edge interfacing terminals of the lower section boards to the high speed logic boards at their backplane.

8. The electronic circuit board assembly as claimed in claim 7 wherein the circuit boards comprise one of I/O and memory boards, and the high-speed logic boards comprise one of switching fabrics and CPUs.

9. An electronic circuit board assembly as claimed in claim 7 wherein the mounting slots maintain all the boards substantially vertically oriented, and the backplanes extend horizontally of the frame.

10. The electronic circuit board assembly as claimed in claim 9 wherein means is provided for passing cooling air flow in-line through the lower, the intermediate and upper sections of the frame.

11. The electronic circuit board assembly as claimed in claim 7 wherein the upper and lower sets of groups of boards each comprise a left-hand quadrant group and a right-hand quadrant group respectively aligned vertically, and the high speed logic group is mounted in a central space between the upper and lower frame sections between the left and right-hand quadrant groups of the upper and lower board sets.

12. An electronic circuit board assembly as claimed in claim 11 wherein the lower edges of the high speed logic boards are positioned to be somewhat in line respectively with, though between, the interfacing lower and upper terminal edges, respectively, of the upper and lower section sets of boards.

13. A method of assembling closely positioned pluralities of similar electronic circuit I/O boards provided with powering terminals and requiring high speed switching amongst the I/O terminals of the boards and adapted for substantially uniform cooling of the closely positioned boards, that comprises, parallely stacking upper and lower quadrant sets of similar spaced groups of closely spaced boards in a frame with an intermediate central space provided between the groups, and with the powering terminals aligned near the upper edges of the upper set of boards and near the lower edges of the lower set of boards, and with terminals provided for interfacing connection with a high speed switching fabric near the lower edges of the upper set of boards and near the upper edges of the lower set of boards, facing one another;

mounting upper and lower power backplanes to power and support the respective sets of groups of boards and extending across the upper and lower quadrant sections of the frame, respectively; and

providing a plurality of parallel closely spaced switching logic boards comprising said switching fabric substantially centrally of the frame in said central space between the groups of boards of the upper and lower section sets of boards, and with a backplane provided therefor and extending intermediately of the frame between the upper and lower section backplanes and isolatively separate therefrom to provide a no-power quiescent zone for the switching fabric boards; and

substantially symmetrically connecting the lower edge interfacing terminals of the upper section set of boards and the upper edge interfacing terminals of the lower section set of boards to the switching fabric boards at the switching fabric backplane.

14. An electronic circuit board assembly of closely positioned pluralities of similar electronic I/O boards provided with powering terminals and requiring high speed switching amongst the I/O terminals of the boards, having, in combination, mounting slots within a frame for parallely stacking an upper and a lower quadrant set of similar spaced groups of closely spaced boards in an upper and a lower section of the frame, respectively, and with an intermediate space provided between the groups of each of the upper and lower quadrant sets of groups;

powering terminals aligned near the upper edges of the upper set of boards and near the lower edges of the lower set of boards, and terminals for interfacing with a switching fabric disposed along the lower edges of the upper set of boards and the upper edges of the lower set of boards;

power backplanes mounted to power and support the respective sets of groups of boards and extending across the upper and lower sections of the frame; and

a plurality of parallel closely spaced switching logic boards comprising said switching fabric and centrally mounted in said central space of the frame between the groups of boards of the upper and lower sets of boards, and with a backplane therefor extending intermediately of the frame between the upper and lower section backplanes and isolatively separate therefrom to provide a no-power quiescent zone for the switching fabric boards; and

substantially symmetrical connections from the lower edge interfacing terminals of the upper section boards and from the upper edge interfacing terminals of the lower set of boards to the switching fabric boards at their backplane.

15. The electronic circuit board assembly as claimed in claim 14 wherein means is provided for passing cooling air from an intake at the bottom of the frame upward through the frame along the boards mounted therein to an exhaust at the top of the frame, and a metallic egg-crate grill is mounted over each of the air intake and exhaust of the frame and the openings of which are dimensioned relative to the wavelength of the high frequency radiation generated by the high speed switching to serve as cut-off electromagnetic waveguide traps for the high frequency radiation.

16. The electronic circuit board assembly of claim 15 wherein the openings of the grill are substantially square or rectangular and of the order of 1/2-inch on a side and in depth, providing substantial trapping of high frequency radiation of the order of 12 GHz and below.

17. The electronic circuit board assembly as claimed in claim 14 wherein the mounting slots comprise U-shaped single-piece channels for receiving and mounting the upper and lower edges of the boards transversely of the frame towards the backplanes.

18. The electronic circuit board assembly as claimed in claim 17 wherein the U-shaped single piece channels are formed of a folded sheet of metal the upper portion of one side of which serves as one wall of the U-shaped channel, with the lower portion of said one side juxtaposed against the lower portion of the other side of the folded sheet and then bent transversely to form the bottom of the U and then upwardly parallel to the one side upper portion to serve as the opposite wall of the U-shaped channel.

19. The electronic circuit board assembly as claimed in claim 14 wherein the power backplanes and intermediate switching fabric backplane are mounted in a further frame to simulate the physical appearance of a single continuous backplane.

20. An assembly of closely positioned similar circuit boards such as I/O and memory boards containing high speed interconnect circuits and provided with powering terminals and requiring high speed communication between said circuit boards and centrally located high speed logic circuit boards, such as switch fabrics and CPUs, having, in combination with a circuit board card cage system divided into four equal-size outer quadrants surrounding a central column, similar pluralities of equal-size boards mounted within the four quadrants, with all the boards installed vertically within the upper two outer quadrants and the upper half of the central column installed upwards, and all the boards installed vertically in the lower two outer quadrants and the lower half of the central column installed upside down;

and power terminals provided along the tops of the upper boards and the bottom of the lower boards, and high speed logic-interfacing terminals provided along the bottom of the upper boards and the top of the lower boards, connecting to the high speed logic circuit boards, in turn mounted vertically at the center of the card cage so as to limit all high speed inter-board communication to within a central area.

21. The assembly of claim 20 wherein upper and lower backplanes are provided for mounting and distributing power to the upper and lower quadrant boards and containing no logic signals;

and an intermediate backplane is provided for the central high speed logic circuit boards carrying all logic signals and containing no power distribution voltages.

22. The assembly of claim 21 wherein the backplanes span the back of the card cage and are mounted to a frame that causes them to appear as one uniform backplane.

23. For use in an electronic circuit board assembly mounted within a frame and wherein high frequency radiation is generated as from high speed switching or CPU circuits disposed on the circuit boards, means for passing cooling air from an intake at the bottom of the frame upward through the frame along the circuit boards mounted therein and out an exhaust on the top of the frame, and a metallic egg-crate grill mounted over each of the air intake and exhaust of the frame and the openings of which are dimensioned relative to the wavelength of the high frequency radiation generated by the high speed switching to serve as cut-off electromagnetic waveguide traps for the high frequency radiation.

24. For use in an electronic circuit board assembly, U-shaped single-piece channels for receiving circuit boards, formed of a folded sheet of metal the upper portion of one side of which serves as one wall of the U shaped channel, with the lower portion of said one side juxtaposed against the lower portion of the other side of the folded sheet and then bent transversely to form the bottom of the U, and then upwardly parallel to the one side upper portion to serve as the opposite wall of the U-shaped channel.