MULTILAYER CIRCUIT BOARD, AND MOTOR-DRIVING CIRCUIT BOARD

摘要

A multilayer circuit board in which wirings are arranged so that the inductance thereof is reduced is provided. A ground wiring 22 and a power source wiring 33 which are provided in a multilayer circuit board 100 are arranged so that most of the wirings are superposed vertically along a direction of a longer side of the circuit board, and since currents flow in an opposite direction to each other in the portions which are superposed, magnetic fields generated by the currents so flowing are canceled by each other. Similarly, a W-phase wiring 11, a V-phase wiring 21 and a W-phase wiring 31 are also arranged so that the wirings are partially superposed along their longer side direction vertically, and magnetic fields generated by currents flowing in the portions which are superposed vertically are canceled by one another. By this, the inductance of the wirings can be reduced by increasing a mutual inductance between these wirings.