A circuit board system includes a printed circuit board (PCB) having a first side and a second side opposite the first side. A plurality of plated through holes (PTHs) are defined through the PCB from the first side to the second side. A respective pad is defined at each end of each PTH of the plurality of PTHs. The PCB includes circuit traces electrically interconnecting among the plurality of PTHs for forming PCB circuitry. A coverlay is adhered with an adhesive layer to the first side of the PCB for insulating voltages among the plurality of PTHs.

A power supply device includes a first circuit board, a second circuit, and a plurality of circuit board coupling members. Each of the circuit board coupling members includes a body portion, a first protruding portion, and a second protruding portion. The body portion determines positions of the first circuit board and the second circuit board. The first protruding portion positions the body portion relative to the first circuit board. The second protruding portion positions the body portion relative to the second circuit board. A plurality of first positioning holes in which the first protruding portions are fitted is formed in the first circuit board. A plurality of second positioning holes in which the second protruding portions are fitted is formed in the second circuit board.

Solder (12) joins together a second conductive pattern (4) of a flexible substrate (1) and a third conductive pattern (7) of a print substrate (6) and joins together a second GND pattern (5) of the flexible substrate (1) and a third GND pattern (8) of the print substrate (6). A through hole (11) passes through the flexible substrate (1) and connects the first and second GND patterns (3,5) together. In an extension direction in which the second conductive pattern (4) extends, an end portion of a solder joint portion between the second conductive pattern (4) and the third conductive pattern (7) is in a position corresponding to the through hole (11) and is shifted from an end portion of the through hole (11).

A circuit board for a power semiconductor module, having at least one top side and one bottom side, wherein at least one mounting area for a power semiconductor component is provided on the top side, wherein on the mounting area, at least one solder layer is provided for connecting at least one power semiconductor component to the mounting area, which layer is divided into regions that are separated from one another by intermediate spaces, and wherein multiple thermal vias are provided in the circuit board and extend from the top side to the bottom side of the circuit board in the region of or near the mounting area, wherein each upper opening of the thermal vias is directly surrounded by a respective region of the solder layer and each lower opening of the vias is covered by a layer of electrically insulating material.