Thermal management of printed circuit board components

Patent metadata

Field	Value
Publication number	US-10064311-B2
Application number	US-201515541127-A
Country	US
Kind code	B2
Filing date	Nov 11, 2015
Priority date	Dec 31, 2014
Publication date	Aug 28, 2018
Grant date	Aug 28, 2018

Abstract

A first thermal management approach involves an air flow through cooling mechanism with multiple airflow channels for dissipating heat generated in a PCA. The air flow direction through at least one of the channels is different from the air flow direction through at least another of the channels. Alternatively or additionally, the airflow inlet of at least one channel is off-axis with respect to the airflow outlet. A second thermal management approach involves the fabrication of a PCB with enhanced durability by mitigating via cracking or PTH fatigue. At least one PCB layer is composed of a base material formed from a 3D woven fiberglass fabric, and conductive material deposited onto the base material surface. A conductive PTH extends through the base material of multiple PCB layers, where the CTE of the base material along the z-axis direction substantially matches the CTE of the conductive material along the x-axis direction.

First claim

What is claimed is:

1. A printed circuit assembly (PCA) comprising:
at least one host-board, comprising electronic components mounted thereon;
a host-frame, said host-board mounted to said host-frame;
at least one mezzanine-board, comprising electronic components mounted thereon; and
at least one mezzanine-frame, said mezzanine-board and said host-board mounted to respective surfaces of said mezzanine-frame,
wherein each of said host-frame and said mezzanine-frame comprises a plurality of airflow channels extending through respective enclosed conduits defined through a volume cavity within said host-frame or said mezzanine-frame, each of said airflow channels comprising at least one inlet at a first edge surface of said host-frame or said mezzanine-frame, and at least one outlet at a second edge surface of said host-frame or said mezzanine-frame, each of said airflow channels configured to pass through cooling-air through a respective enclosed conduit, so as to dissipate heat generated by said host-board and said mezzanine-board while isolating the electronic components from said cooling-air,
wherein at least one of said airflow channels is selected from the list consisting of:
i) at least one of said airflow channels configured to direct air flow in a first direction, and at least another one of said airflow channels is configured to direct air flow in a second direction that is different from said first direction; and
ii) at least one of said airflow channels is configured with at least one inlet that is off-axis with respect to at least one outlet thereof.

2. The PCA of claim 1 , wherein for at least one of said airflow channels, said outlet at said second edge surface is orthogonal to said inlet at said first edge surface.

3. The PCA of claim 1 , comprising a first airflow channel comprising an inlet at said first edge surface and an outlet at said second edge surface, and further comprising a second airflow channel comprising an inlet at said second edge surface and an outlet at said first edge surface.

4. The PCA of claim 1 , further comprising a controller, configured to selectively adjust at least one channel property of at least one of said airflow channels, in accordance with at least one detected parameter of said host-board or said mezzanine-board.

5. The PCA of claim 4 , wherein said channel property is selected from the list consisting of:
an aperture diameter of the channel inlet or channel outlet;
the volume cavity of the airflow channel; and
at least one direction of air flow through said channel.

6. The PCA of claim 4 , wherein said detected parameter is selected from the list consisting of:
temperature level; and
current load.

7. The PCA of claim 4 , further comprising at least one sensor coupled with said controller, said sensor selected from the list consisting of:
a thermal sensor; and
a current sensor.

8. A method for cooling a PCA comprising: a host-frame; at least one host-board mounted to said host-frame; at least one mezzanine-board; and at least one mezzanine-frame, said mezzanine-board and said host-board mounted to respective surfaces of said mezzanine-frame, each of said host-board and said mezzanine-board comprising electronic components mounted thereon, the method comprising the procedures of:
providing a plurality of airflow channels extending through respective enclosed conduits defined through a volume cavity within each of said host-frame and said mezzanine-frame, each of said airflow channels comprising at least one inlet at a first edge surface of said host-frame or said mezzanine-frame, and at least one outlet at a second edge surface of said host-frame or said mezzanine-frame,
dissipating heat generated by said host-board and said mezzanine-board, by passing through cooling-air in each of said airflow channels through a respective enclosed conduit of said host-frame or said mezzanine-frame, while isolating the electronic components from said cooling-air,
wherein at least one of said airflow channels is selected from the list consisting of:
i) at least one of said airflow channels configured to direct air flow in a first direction, and at least another one of said airflow channels is configured to direct air flow in a second direction that is different from said first direction; and
ii) at least one of said airflow channels is configured with at least one inlet that is off-axis with respect to at least one outlet thereof.

9. The method of claim 8 , further comprising the procedure of selectively adjusting at least one channel property of at least one of said airflow channels, in accordance with at least one detected parameter of said host-board or said mezzanine-board.

Assignees

• Elbit Systems Ltd

Inventors

• Naigertsik Oleg
• Fischman Alex
• Engleman Ian
• Kettner Isaac Jak

Classifications

• H05K3/42

  Plated through-holes {or plated via connections} · CPC title

• H05K7/1422

  Printed circuit boards receptacles, e.g. stacked structures, electronic circuit modules or box like frames · CPC title

• H05K7/20163

  the components being isolated from air flow, e.g. hollow heat sinks, wind tunnels or funnels · CPC title

• H05K1/115

  Via connections; Lands around holes or via connections (H05K1/112 takes precedence) · CPC title

• H05K1/0366

  reinforced, e.g. by fibres, fabrics (H05K1/036 takes precedence) · CPC title