US Patent 7948349 Magnetic coupler

A magnetic coupler having higher response is provided. The magnetic coupler includes a thin film coil wound in a first layer; a first MR element being disposed in a second layer, and detecting an induced magnetic field generated by a signal current flowing through the thin film coil; and yokes being disposed close to the first MR element, and including a soft magnetic material. The first MR element is disposed in a position corresponding to a linear region of the thin film coil in a stacking direction. The yokes are disposed at both of an inner turn side and an outer turn side of the thin film coil in a manner of interposing the first MR element in the second layer. Thus, reduction in intensity of the induced magnetic field is suppressed, and intensity distribution of the induced magnetic field becomes flatter.