Power switching device having improved heat dissipation means

Claim 1

A power control assembly, comprising a solid state device including a heat generating portion, an electrically insulating thermally conductive substrate having a first side operatively connected in heat transfer relation to said heat generating solid state portion, a heat sink having an outer surface abutting a second substrate side spaced from said first side for dissipating heat from said solid state device, an electrically insulating housing having a first side including an outer wall surrounding an opening providing a recessed inner wall spaced from said outer wall with said substrate enclosing said opening and spaced from said inner wall to form a cavity about said solid state device, said inner wall including a terminal opening extending from said cavity to a second side of said housing, means for mechanically clamping said substrate to said heat sink, and electrical conductor means including a first conductive portion attached for electrical connection to said solid state device, said first conductive portion includes a thin bendable terminal strip portion extending from a conductive strip adhered to said first substrate side, said terminal strip portion including first and second parts with said first part substantially normally connected to said conductive strip and said second part substantially normally connected to said first part, and a second conductive portion extending through said terminal opening and including a conductive lead wire having a bare end soldered to said second part, said second conductive portion disposed within said terminal opening and maintained substantially normal to said substrate and providing external electrical access to said solid state device.

Claim 7

A method of attaching lead wires to a power control device whose major parts are a ceramic substrate on which electric circuit means are adhered and an insulating housing for said substrate, which device is preliminarily fabricated to the extent of having conductive film bands bonded to said substrate and a lead frame comprised of thin sheet metal strips bonded to selected bands and having electric circuit components connected to selected ones of the strips to form an electric circuit mounted to said substrate, said method including the steps of: providing said lead frame with thin strips that extend laterally from and substantially coplanar with the lead frame after preliminary fabrication, which strips have first and second parts, the first of which is nearest to the lead frame, bending said strip part on a line intermediate said first and second strip parts such that said second part is generally normal to said first part, soldering the end of a lead wire to each of said second parts and bending said first part on a line intermediate said first part and said lead frame to thereby dispose said first part generally normal to said lead frame and said lead wires generally normal to said second part, then inserting said substrate with lead wires attached into a recess in the bottom of said housing such that said lead wires extend through openings in said housing and the bottom of said substrate is exposed.

Claim 8

A method of attaching lead wires to a power control device whose major parts are a ceramic substrate on which electric circuit means are adhered and an insulating housing for said substrate, which device is preliminarily fabricated to the extent of having conductive film bands bonded to said substrate and a lead frame comprised of thin sheet metal strips bonded to selected bands and having electric circuit components connected to selected ones of the strips to form an electric circuit mounted to said substrate, said method including the steps of: providing said lead frame with thin strips that extend laterally from and substantially coplanar with the lead frame after preliminary fabrication, which strips have first and second parts, the first of which is nearest to the lead frame, bending said strip part on a line intermediate said first and second strip parts such that said second part is generally normal to said first part, soldering the end of a lead wire to each of said second parts and bending said first part on a line intermediate said first part and said lead frame to thereby dispose said first part generally normal to said lead frame and said lead wires generally normal to said second part, then inserting said substrate with lead wires attached into a recess in the bottom of said housing such that said lead wires extend through openings in said housing and the bottom of said substrate is exposed.