Patent ID: 7821375

Claim:
A multiphase coupled inductor for a multiphase voltage converter, comprising: a magnetic core having a ladder structure comprising a first rail extending in a rail direction, a second rail extending approximately parallel to the first rail, a first connecting rung connecting said first rail to said second rail, and a second connecting rung connecting said first rail to said second rail; a first inductor extending under the first rail, over the first connecting rung, and under the second rail; and a second inductor extending under the first rail, over the second connecting rung, and under the second rail, wherein said first and second rails and said first and second rungs have top and bottom surfaces forming two respective substantially planar surfaces such that top surfaces of said first and second rails and top surfaces of said first and second rungs are substantially coplanar and bottom surfaces of said first and second rails and bottom surfaces of said first and second rungs are substantially coplanar and which are substantially parallel to a surface supporting portions of said first and second inductors, wherein the first connecting rung extends from the first rail to the second rail in a direction substantially nonperpendicular to said rail direction, and wherein the second connecting rung extends from the first rail to the second rail in a linear direction substantially nonperpendicular to said rail direction such that said first rail, said second rail, said first rung and said second rung define an interior region that can be filled with ferromagnetic material.