Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
1999-02-13
2001-02-27
Picard, Leo P. (Department: 2835)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C361S702000, C361S719000, C361S724000, C361S739000, C361S752000, C174S016300, C174S050510, C165S080300, C165S185000, C257S707000, C257S710000, C257S713000
Reexamination Certificate
active
06195257
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention is directed, in general, to mounting techniques for electronic components and, more specifically, to an apparatus and method of adapting a rectifier module to enhance cooling of the same.
BACKGROUND OF THE INVENTION
Rectifier modules are commonly available in a number of package styles, each suitable for a particular range of voltage and current. A rectifier module generally includes a rectifier bridge (in die form) encapsulated in a substantially flat, rectangular package having two parallel major surfaces and a number of minor surfaces normal to the major surfaces. The major and minor surfaces are designated as such to indicate that a surface area of the major surface is greater than a surface area of the minor surface. Bond wires couple the rectifier bridge die to rigid leads that protrude from the package.
Rectifier modules employable in low to medium power applications (e.g., up to 800 W) are typically embodied in a so-called “vertical” package wherein the leads protrude from a minor surface of the package and are arranged in a single row. The “vertical” package is designed to be mounted “vertically,” with its major surfaces substantially normal to a circuit board. While the “vertical” package occupies minimal board real-estate, some of the bond wires coupling bond pads on the rectifier bridge die to bond pads on the package (at the leads) may be relatively long. Long bond wires are subject to many disadvantages, such as, limited current carrying capacity or fatigue fractures. Further, the leads of the “vertical” package are usually spaced 0.1′ apart in accordance with conventional through-hole component mounting specifications. The 0.1′ spacing limits a maximum voltage difference that may exist across the leads before arcing occurs. The thickness of the leads is also constrained by the through-hole component mounting specifications, thereby limiting an amount of current that each lead may carry. The fixed lead spacing and lead thickness thus restrict both the voltage and current rating of the rectifier module.
Rectifier modules employable in high power applications (e.g., 800 to 3000 W) are typically embodied in a so-called “horizontal” package wherein the leads protrude from a major mounting surface of the package. The “horizontal” package is designed to be mounted “horizontally,” with its major surfaces substantially parallel to the circuit board. The “horizontal” package has the leads arranged in a grid pattern on the major surface, thereby allowing the leads to be spaced further apart. Further, lead spacing and lead thickness are not constrained to the through-hole component mounting specifications. The increased spacing between the leads thus allows the rectifier module to be operated at higher voltages (e.g., 800 V and above) without causing arcing between the leads. Additionally, the pin thickness may be increased to enable the rectifier module to operate at higher current levels.
While the “horizontal” package is capable of operating at higher power levels, significantly more board real-estate is required. Additionally, since a height of the “horizontal” package is less than a height of many components (e.g., capacitors, power switches), a large heat sink cannot be mounted directly onto the major cooling surface of the rectifier module when the “horizontal” package is mounted in its intended manner. Therefore, a spacer must be employed to extend the heat sink above the other components. Since the spacer should be thermally conductive to transfer heat from the rectifier module to the heat sink, the cost of the spacer can be prohibitive.
Accordingly, what is needed in the art is a module mount for mounting a rectifier module operable at high power levels that avoids the deficiencies of the prior art.
SUMMARY OF THE INVENTION
To address the above-discussed deficiencies of the prior art, the present invention provides a module mount for use in electrically and mechanically mounting an encapsulated power rectifier module, having a plurality of rigid leads protruding from a major mounting surface thereof, in an orientation in which the major mounting surface is substantially normal with respect to a substantially planar circuit board. In one embodiment, the module mount includes (1) a substantially planar substrate having a plurality of apertures located to register with the plurality of rigid leads and (2) a plurality of power conductors, associated with the plurality of apertures, that electrically couple the plurality of rigid leads to an edge interface on the substrate, the edge interface adapted to be coupled to the circuit board.
The present invention therefore introduces a module mount that, in one embodiment, allows the encapsulated power rectifier module to be mounted with its major mounting surface substantially normal to the circuit board. The encapsulated power rectifier module thus occupies less board real-estate than if it were mounted with its major mounting surface substantially parallel to the circuit board.
In one embodiment of the present invention, the encapsulated power rectifier module further has a major cooling surface opposite the major mounting surface. In another embodiment, the module mount further includes a heat sink, mechanically and thermally coupled to the encapsulated power rectifier module to enhance cooling thereof. In an embodiment to be illustrated and described, the heat sink is mechanically and thermally coupled to the major cooling surface of the encapsulated power rectifier module while the module mount is mechanically and electrically coupled to the major mounting surface.
In a related embodiment, the heat sink is further mechanically coupled to the circuit board. The heat sink may thus provide mechanical support to the encapsulated power rectifier module and module mount.
In another embodiment of the present invention, the heat sink is couplable to a second encapsulated power rectifier module. The two encapsulated power rectifier modules may thus cooperate to reduce power dissipation therein.
In yet another embodiment of the present invention, the module mount further includes a connector, coupled to the edge interface, that connects the substrate to a mating connector on the circuit board. In another embodiment, the edge interface has projecting members adapted to mate directly to corresponding apertures on the circuit board. Costs associated with the connector and mating connector may thus be avoided.
The foregoing has outlined, rather broadly, preferred and alternative features of the present invention so that those skilled in the art may better understand the detailed description of the invention that follows. Additional features of the invention will be described hereinafter that form the subject of the claims of the invention. Those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiment as a basis for designing or modifying other structures for carrying out the same purposes of the present invention. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the invention in its broadest form.
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Janicek George M.
Liu Rui
Scocca Anthony J.
Datskovsky Michael
Lucent Technologies - Inc.
Picard Leo P.
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