Abstract: In a transformer including a coil part having a first bobbin to which a coil is mounted, a second bobbin to be fitted to the first bobbin combined to each other, the coil part being sandwiched between magnetic cores from above and below, the first bobbin includes at least one lead drawing through holes on a periphery on the inner peripheral side of a coil mounting surface, and at least one of coil-drawn-leads of the coil is drawn through the lead drawing through hole. With this transformer, coming out of the coil-drawn-lead, displacement, and erroneous wiring are prevented, and hence the inserting capability of the coil is improved. Therefore, the workability is remarkably improved, and hence a product which is low in price can be provided.

Abstract: In a power conversion module device of the present invention, a transformer, a primary power element and a secondary power element are mounted on a printed wiring board in surface-to-surface contact therewith, and no control circuit is mounted thereon. In addition to reducing impedance and loss in the wiring, this constitution improves the voltage waveform of the primary power element. Thus, noise reduction can be achieved. Further, because heat can be transferred to the printed wiring board, heat generated from the transformer, the primary power element and the secondary power element can be reduced. The size of the transformer can also be reduced.

Abstract: In a transformer including a coil part having a first bobbin to which a coil is mounted, a second bobbin to be fitted to the first bobbin combined to each other, the coil part being sandwiched between magnetic cores from above and below, the first bobbin includes at least one lead drawing through holes on a periphery on the inner peripheral side of a coil mounting surface, and at least one of coil-drawn-leads of the coil is drawn through the lead drawing through hole. With this transformer, coming out of the coil-drawn-lead, displacement, and erroneous wiring are prevented, and hence the inserting capability of the coil is improved. Therefore, the workability is remarkably improved, and hence a product which is low in price can be provided.

Abstract: In a power conversion module device of the present invention, transformer (11), primary power element (14), and secondary power element (15) are mounted on printed wiring board (16) in surface-to-surface contact therewith, and no control circuit is mounted thereon. In addition to reduction in impedance and loss in the wiring, this constitution improves the voltage waveform of primary power element (14). Thus, noise reduction can be achieved. Further, because heat can be transferred to printed wiring board (16), heat generated from transformer (11), primary power element (14), and secondary power element (15) can be reduced. The size of the transformer can also be reduced.

Abstract: A multilayered coil is formed by inserting insulating paper 13 having either a pressure sensitive adhesive or an adhesive disposed on both faces thereof into at least one place between thin coil layers and then magnetic cores 15 are mounted to the multilayered coil from above and below. Thus, a thin transformer for a switching power supply is provided, in which variation in distance between coil 11 and coil 12, of which one is disposed over the other, variation in distance of coil 11 and coil 12 from magnetic core 15 and the like are suppressed.

Abstract: A multilayered coil is formed by inserting insulating paper 13 having either a pressure sensitive adhesive or an adhesive disposed on both faces thereof into at least one place between thin coil layers and, then, magnetic cores 15 are mounted to the multilayered coil from above and below.