High efficiency on-chip 3d transformer structure

Abstract

An integrated circuit transformer structure includes at least two conductor groups stacked in parallel in different layers. A first spiral track is formed in the at least two conductor groups, the first spiral track includes first turns of a first radius within each of the at least two conductor groups, and second turns of a second radius within each of the at least two conductor groups, the first and second turns being electrically connected. A second spiral track is formed in the at least two conductor groups, the second spiral track including a plurality of adjacent turns of one or more radii within each of the at least two conductor groups and disposed in a same plane between the first and second turns in each of the at least two conductor groups.

What is claimed is: 
     
         1 . An integrated circuit transformer structure, comprising:
 at least two conductor groups, each conductor group forming a spiral, the spirals of the at least two conductor groups being stacked in parallel in different layers;   the spirals including:   turns of a first radius connected in series between the layers to form a first cylinder of turns within the at least two conductor groups;   turns of a second radius connected in series between the layers to form a second cylinder of turns within the at least two conductor groups; and   turns of a third radius connected in series between the layers to form a third cylinder of turns within the at least two conductor groups, wherein the first and the third cylinder are electrically connected to each other and electrically isolated from the second cylinder, the second cylinder including a plurality of adjacent turns of one or more radii in each of the at least two conductor groups and disposed in a same plane between turns of the first and third cylinders in each of the at least two conductor groups.   
     
     
         2 . The structure as recited in  claim 1 , wherein the at least two conductor groups each include one or more metal layers. 
     
     
         3 . The structure as recited in  claim 1 , wherein the plurality of adjacent turns of one or more radii includes one of two turns and four turns. 
     
     
         4 . The structure as recited in  claim 1 , wherein at least one of the first cylinder and the third cylinder includes a plurality of adjacent turns of one or more radii within each of the at least two conductor groups and disposed in a same plane and surrounding turns of the second cylinder. 
     
     
         5 . The structure as recited in  claim 1 , wherein one of the first and third cylinders and the second cylinder includes a primary transformer coil and the other of the first and third cylinders and the second cylinder includes a secondary transformer coil. 
     
     
         6 . The structure as recited in  claim 1 , wherein the first cylinder is electrically connected to the third cylinder through a connection that is electrically isolated from the second cylinder. 
     
     
         7 . The structure as recited in  claim 1 , wherein at least one of the spirals has a line winding about a central axis and spaces between the line winding, the line having a cross-sectional line dimension reduced at a rate as winding toward the center axis and the spaces being increased at a rate as winding toward the center axis. 
     
     
         8 . The structure as recited in  claim 1 , wherein the spirals of different layers have at least one of different line widths and different line spacings therebetween. 
     
     
         9 . The structure as recited in  claim 1 , wherein the spirals of different layers are offset relative one another. 
     
     
         10 . A transformer structure, comprising:
 at least two conductor groups, each conductor group forming a spiral, the spirals of the at least two conductor groups being stacked in parallel in different layers;   a first spiral track including first sets of turns of one or more radii in all the different layers, the first sets of turns of one or more radii being connected in series between the layers; and   a second spiral track including second sets of turns of one or more radii in all the different layers, connected in series between the layers such that second sets of turns are disposed between first sets of turns within each plane of the layers in an alternating pattern and all first sets of turns are electrically connected and all second sets of turns are electrically connected.