Patent ID: 7417861

Claim:
A weatherproof vehicular power converter comprising: a power circuit section provided with a switching element; a control circuit section for controlling said switching element; and a housing for accommodating said power circuit section and said control circuit section, said housing having a holeless cover, wherein: a first heat conducting layer intervenes in a space between a base plate, having a first heat exchange section for cooling only said power circuit section, and said power circuit section; a second heat conducting layer intervenes in a space between said cover, having a second heat exchange section for cooling only said control circuit section, and said control circuit section; said first heat exchange section and said second heat exchange section are disposed on one main surface side and on an opposite main surface side of an outer circumferential surface part of said housing, respectively; heat generation of said power circuit section is larger than heat generation of said control circuit section; thermal resistance of a first path which extends from said power circuit section to ambient air through said first heat exchange section is smaller than thermal resistance of a second path which extends from said control circuit section to the ambient air through said second heat exchange section, said first and second paths being in a non-interfering arrangement; a heat radiation area of said first heat exchange section is larger than a heat radiation area of said second heat exchange section; and said first and second heat exchanger sections are physically spaced apart and electrically isolated from said power and control circuit sections.