Compact inductor employing redistrubuted magnetic flux

Abstract

The present invention is directed to a compact inductor having the required (predetermined) inductance and current rating, further designed to avoid substantial heat generation by avoiding saturation, winding(s) possessing a low DC resistance and copper loss, and minimizing the required volume or profile in order to conserve circuit board real-estate. The compact inductor design of the present invention includes both enclosed core as well as enclosed winding type of inductor designs.

What is claimed herein is: 
     
         1 . A compact balanced field enclosed winding inductor comprising:
 a first core;   a first winding having a first end and a second end, said first winding adapted to spiral inwardly from said first end and terminates at said second end at a point substantially central to said first winding to form a first spiral of a first shape in a first plane, wherein said first winding is embedded in said first core;   a second core; and   a second winding having a first end and a second end, said second winding adapted to spiral inwardly from said first end of said second winding and terminates at said second end of said second winding at a point substantially central to said second winding to form a second spiral of a second shape in a second plane, wherein said second winding is embedded in said second core and said second end of said second winding is electrically connected to said second end of said first winding.   
     
     
         2 . The compact balanced field enclosed winding inductor of  claim 1 , wherein said core comprises a magnetically permeable material. 
     
     
         3 . The compact balanced field enclosed winding inductor of  claim 1 , wherein said winding comprises a winding wire. 
     
     
         4 . The compact balanced field enclosed winding inductor of  claim 1 , wherein at least one of said first shape and second shape is selected from the group consisting of circular and rectangular. 
     
     
         5 . A compact balanced field enclosed core inductor comprising:
 a plurality of interdependent cores having similar shape in order to enable nesting, wherein an interdependent second core is nested within an interdependent first core having a slot-width between said interdependent first core and said interdependent second core to permit the passing of an interdependent winding.   
     
     
         6 . The compact balanced field enclosed core inductor of  claim 5 , further comprising at least one interdependent cored nested within said interdependent second core. 
     
     
         7 . The compact balanced field enclosed core inductor of  claim 5 , wherein said winding comprises a winding wire. 
     
     
         8 . The compact balanced field enclosed core inductor of  claim 5 , wherein at least one of said interdependent first core and said interdependent second core comprises a magnetically permeable material. 
     
     
         9 . The compact balanced field enclosed core inductor of  claim 5 , wherein at least one of said interdependent first core and said interdependent second core comprises a cross-sectional shape defined by a shape selected from the group consisting of a rectangle and circle. 
     
     
         10 . The compact balanced field enclosed core inductor of  claim 5 , wherein said interdependent winding comprises a cross-sectional shape is a defined by a shape selected from the group consisting of a rectangle and circle. 
     
     
         11 . A method of constructing a compact balanced field enclosed winding inductor having a desired inductance L o  and a desired resistance R o , at least a first winding window and a second winding window, said method comprising:
 (a) predetermining a uniformity factor α of the compact balanced field enclosed winding inductor to a minimal value sufficient to maintain the benefit of a balanced field;   (b) determining a plate thickness H p , outer radius of the first winding window R O1 , inner radius of the first winding window R I1 , and outer radius of the second winding window R O2  of the compact balanced field enclosed winding inductor simultaneously;   (c) determining the radii of the remaining winding windows of the at least two winding windows of the compact balanced field enclosed winding inductor recursively, wherein the radii determined are limited by manufacturing constraints;   (d) determining the number of turns n j  of each of the at least two winding windows of the compact balanced field enclosed winding inductor; and   (e) determining the inductance L and resistance R dc  of the compact balanced field enclosed winding inductor,   wherein if the inductance L is not greater or equal to the desired inductance L o  and the resistance is not less than or equal to a desired resistance R o , the uniformity factor α is increased and steps (b)-(e) are repeated.   
     
     
         12 . A method of constructing a compact balanced field enclosed core inductor having a desired inductance L o  and a desired resistance R o  and at least two interdependent cores, wherein a second interdependent core is nested within a first interdependent core, said method comprising:
 (a) predetermining the uniformity factor α of the compact balanced field enclosed core inductor to a minimal value sufficient to maintain the benefit of a balanced field;   (b) determining the outer radius R O  and the inner radius R I  of each of said at least two interdependent cores;   (c) determining the ampere-turns NI between the outer radius R O  of an outer core and the outer radius R O  of a core nested within the outer core of said at least two interdependent cores; and   (d) determining the stored energy E, inductance L and resistance R dc  of the enclosed core inductor,   wherein if the inductance L is not equal to a desired inductance L o  and the resistance R dc  is not equal to a desired resistance R o , the uniformity factor α is increased and steps (b)-(d) are repeated.