| 摘要 |
A circuit card module having increased cooling efficiency which comprises at least one printed wiring board (PWB), at least one component mounted on the PWB, a heatsink, an interchangeable frame, and a wedgelock for use with a chassis cold wall. One embodiment of the interchangeable frame comprises a protrusion so that it can be used with a convection-cooled chassis (fully compliant with IEEE 1101.2 Specifications). Another embodiment, for use with conduction-cooled chassis only (partially compliant with IEEE 1101.2 Specifications), is maximally efficient in removing heat as it does not include the protrusion. In the embodiment without the protrusion, the conduction contact area between the chassis cold wall and the frame is increased in width from approximately 0.25'' to approximately 0.35''. In either embodiment, the wedgelock is mounted to one surface of the frame such that when installed in a conduction-cooled chassis, the opposite frame surface is forced against the chassis cold wall. In addition, the wedgelock can be enlarged to increase the clamping force over the contact area. The increased wedgelock size approximately doubles the clamping force applied. The net effect of these improvements are a reduction in the thermal resistance per inch of wedgelock length. This, in turn, reduces the module to chassis interface temperature rise of an exemplary 40 W module from 8.3° C. to 4.15° C. The improved thermal resistances and decreased temperature rises boost the reliability of the circuit cards, particularly in the stringent environments experienced in military applications. |
