Power transistor mounting

Claim 1

Power semiconductor device mounting apparatus comprising, a power transistor, bracket means of high thermal conductivity for supporting anD carrying heat from said power transistor and formed with an opening for accommodating leads from said power transistor, circuit board means for establishing electrical connection to said leads and having a foil side and secured to said bracket means by means for fastening said bracket means to said circuit board means including said power transistor, said power transistor and said circuit board means sandwiching a portion of said bracket means therebetween with said foil side away from said bracket means, said power transistor leads being soldered to said foil side, a heat sink, said bracket means formed with portions thereof for attachment to said heat sink in good thermal contact therewith, said heat sink being fastened to said bracket means in good mechanical and thermal contact therewith with said power transistor means between said bracket means and said heat sink means whereby said bracket means comprises means for fastening said circuit board means to said heat sink so that the assembly including said circuit board means and said bracket means may be removed, tested and serviced as a complete module, and thermostatic switch means in good thermal contact with said bracket means for interrupting power when the temperature of the bracket means exceeds a predetermined limit value even when said assembly is separated from said heat sink, said bracket means being formed with flanges in substantially the same plane spaced from the portion thereof formed with said opening for engagement with said heat sink and having a flange with a free end substantially in the plane of said opening with said thermostatic switching means attached to the latter flange.