Patent ID: 8405205

Claim:
A power semiconductor module, comprising: a plurality of sets of semiconductor switching elements; a molded resin casing with a box shape containing the plurality of sets of semiconductor switching elements; screw holders for receiving mounting screws, formed at bottom regions of four corners of the molded resin casing; first terminal blocks having main circuit terminals, and arranged on a central region of a top surface of the molded resin casing; second terminal blocks having control terminals arranged in a row at a side edge of the molded resin casing apart from the first terminal blocks and drawn out from the sets of the semiconductor switching elements; and insulating separation walls having a first rib erecting from a surface of the second terminal blocks for the control terminals and surrounding a middle control terminal among groups of the control terminals corresponding to the sets of semiconductor switching elements, and a second rib in a plate shape between the screw holder including the mounting screw therein on the molded resin casing and the control terminal at a high voltage side adjacent to the screw holder, wherein the first rib has three side walls in a U-shape with one open side at an outer edge side of the second terminal block.