| 摘要 |
PROBLEM TO BE SOLVED: To provide an on-board power source which is miniaturized and capable of micropackaging and reduces the influence due to stray capacitor or the like. SOLUTION: The on-board power source is constituted by packaging electronic components on a circuit board for power provided with a surface copper foil layer formed on the surface of a substrate, a first internal copper foil layer thicker than the surface copper foil layer and formed on a first plane inside the substrate, a second internal copper foil layer formed on a second plane different from the first plane, and plural through-holes to these internal copper foil layers. The fist internal copper foil layer is composed of independent plural individual copper foil layers, and the second internal copper foil layer is continuously formed within the internal surface area of the substrate, so s to have an area larger than the first internal copper foil layer, to form a main circuit wiring of one side at the stable potential of this on-board power source. Additionally, electrode pads are formed on the surface of the substrate including the surfaces of the through-holes from the substrate surface to the respective first and second internal copper foil layers, and the first and second main electrodes of a first main circuit element in the electronic components are fixed to these electrode pads. |
