Tunable transformer

A transmit chain, comprising:

• a power amplifier (PA);
• and
• a matching network coupled to the PA and to RF circuitry, the matching network including:
• a first transformer coil associated with an input port that is coupled to the PA;
• a second transformer coil associated with an output port that is coupled to the RF circuitry,
• wherein the second transformer coil has a plurality of taps, with different tap pairs from among the plurality of taps being configured to be coupled to the RF circuitry to change a first set of tuning characteristics of the matching network;
• and
• a third transformer coil that is configured to be selectively coupled to the first transformer coil and the second transformer coil to change a second set of tuning characteristics of the matching network.

A wireless device, comprising:

• a transmit chain that includes a power amplifier (PA);
• and
• a matching network coupled to the PA and to a transmission line that is coupled to an antenna, the matching network including:
• a first transformer coil associated with an input port that is coupled to the PA;
• a second transformer coil associated with an output port that is coupled to the transmission line,
• wherein the second transformer coil has a plurality of taps, with different tap pairs from among the plurality of taps being configured to be coupled to the transmission line to change a first set of tuning characteristics of the matching network;
• and
• a third transformer coil that is configured to be selectively coupled to the first transformer coil and the second transformer coil to change a second set of tuning characteristics of the matching network.

A tunable transformer, comprising:

• a first transformer coil coupled to a first power amplifier;
• a second transformer coil inductively coupled to the first transformer coil, the second transformer coil having a plurality of taps, with different tap pairs within the plurality of taps being selectively coupled to radio frequency (RF) circuitry to yield different respective inductance values, the RF circuitry comprising a second power amplifier;
• and
• a third transformer coil coupled to a variable capacitance, the third transformer coil being selectively coupled to the first transformer coil and to the second transformer coil,
• wherein the first transformer coil and the second transformer coil form a matching network between the first power amplifier and the second first power amplifier, and
• wherein the first power amplifier and the second power amplifier form part of a multi-stage amplifier.

A tunable transformer, comprising:

• a first transformer coil coupled to a transmission line that is part of a receive chain;
• a second transformer coil that is (i) coupled to a load, and (ii) inductively coupled to the first transformer coil, the second transformer coil having a plurality of taps, with different tap pairs within the plurality of taps being selectively coupled to radio frequency (RF) circuitry to yield different respective inductance values, the RF circuitry comprising a low-noise amplifier (LNA);
• and
• a third transformer coil coupled to a variable capacitance, the third transformer coil being selectively coupled to the first transformer coil and to the second transformer coil,
• wherein the first transformer coil and the second transformer coil form a matching network between the transmission line and an input to the LNA.