An integrated impedance-matching power combiner using a transformer with multiple primary windings

A compact impedance-matching power combiner comprises single-turn primary windings 213,214 for receiving the respective outputs of two or more CMOS differential amplifiers and a multi-turn secondary winding 215 coupled to a load such as an antenna. The circuits 420,421 may comprise series or parallel resonant LC circuits (figure 5) for reducing harmonics in the output. A tertiary winding (1002, figure 10) may be used for power sensing. The transformer may have a planar, stacked or multi-layer structure (figures 12-15).The transformer circuit has a reduced influence on other circuits in the IC.