Packaging and thermal management in electronic apparatus

摘要

Power conversion apparatus includes a circuit board with power conversion circuitry and a package. The package includes an upper portion that encloses circuitry on a top surface of the circuit board and a lower portion that encloses circuitry on a bottom surface of the circuit board. The lower portion encloses a region on the circuit board that is smaller than the region enclosed by the upper portion and is arranged to define an overhang region on the bottom surface of the circuit board. The overhang region preferably extends along two or more sides of the periphery of the bottom surface. Interface contacts are provided on the bottom surface in the overhang region for making electrical connections to the circuit board. The power conversion apparatus may be mounted in an aperture in an external circuit board or may be mounted horizontally or vertically to the external board using an interconnect extender. Heat sinks located on the external circuit board or on the interconnect extender may be thermally coupled to the power converter. The package may be formed by encapsulating areas of the circuit board assembly either before or after the interface contacts are attached to the circuit board. A method for encapsulating two sides of a substrate includes providing a mold that fills a larger first cavity to create a sealing force on a smaller second cavity. The encapsulant flows through the first cavity into the second cavity. A thermal extender includes a surface for mounting a heat dissipating power converter and a surface for mating with an external circuit board. Interface conductors mate with contacts on the heat dissipating power converter and with conductive regions on the external circuit board. A heat sink is thermally coupled to remove heat generated by the power converter. The heat sink may be molded or include an extension of a thermally conductive layer extending from the converter mounting area. The thermal extender may include an aperture for accepting a lower portion of the heat dissipating power converter.