An RF power package includes a substrate having a metallized part and an insulating part, an RF power transistor die embedded in or attached to the substrate, the RF power transistor die having a die input terminal, a die output terminal, an input impedance and an output impedance, a package input terminal formed in the metallized part or attached to the insulating part of the substrate, a package output terminal formed in the metallized part or attached to the insulating part of the substrate, and a first plurality of planar tuning lines formed in the metallized part of the substrate and electrically connecting the die output terminal to the package output terminal. The first plurality of planar tuning lines is shaped so as to transform the output impedance at the die output terminal to a higher target level at the package output terminal.

Examples disclosed herein relate to a Doherty Power Amplifier (“DPA”) with integrated second harmonic injection. The DPA includes an amplifier circuit having a carrier amplifier and a peaking amplifier, and a combiner network coupled to the amplifier circuit, the combiner network having a plurality of transmission lines and a LC resonant circuit to inject a second harmonic from the carrier amplifier into the peaking amplifier.

According to one embodiment, an amplifier circuit includes N (N>=3) transistors, two first branches and N−2 second branches. The N (N>=3) transistors are connected in parallel. The two first branches each include the transistor and a first transmission line which is connected to an output terminal of the transistor. The N−2 second branches each include the transistor and a second transmission line which is connected to the output terminal of the transistor. For each of the first branches, a sum between an electrical length of a parasitic component of the transistor and the electrical length of the first transmission line are odd multiples of approximately 90 degrees. For each of the second branches, the sum between the electrical length of the parasitic component of the transistor and the electrical length of the second transmission line are multiples of approximately 180 degrees.

The disclosure provides an amplifying apparatus including a plurality of amplifying circuits and an adjusting circuit. The input terminals of the amplifying circuits are coupled to a first common node. The output terminals of the amplifying circuits are coupled to a second common node. The adjusting circuit adjusts an input signal to generate an adjusted signal to the first common node; the adjusting circuit adjusts the signal of the second common node; or the adjusting circuit adjusts the input signal to generate the adjusted signal to the first common node and adjusts the signal of the second common node. The first control signal and the second control signal respectively control the amplifying circuits and the adjusting circuit to determine the gain, the linear power, and the output current of the amplifying apparatus.

An amplifier circuit includes an amplifier, a balun comprising a primary side having a primary inductance and a secondary side having a secondary inductance, the primary side coupled to an output of the amplifier, the secondary side coupled to a first output path of the amplifier circuit and a second output path of the amplifier circuit, a shunt inductance coupled to the first output path; and a compensating inductance in the balun, the compensating inductance coupled between a first node and a second node, the first node coupling the compensating inductance to the first output path, the second node coupling the secondary inductance to the compensating inductance.

A digital power amplifier comprising at least two individually activatable amplifiers connected to an output network comprising a first hybrid coupler. An output of a first amplifier is connected to a first input of the first hybrid coupler and an output of a second amplifier is connected to a second input of the first hybrid coupler such that activating an amplifier of the at least two amplifiers causes the amplifier to load modulate another activated amplifier of at least two amplifiers.

An embodiment of a dual-path amplifier includes a power splitter connected to first and second power amplifiers respectively connected to first and second transmission lines connected to a power combiner having a phase-offset deficit at the second harmonic frequency 2f0, where the first and second transmission lines are designed to provide a complementary phase offset at 2f0 substantially equal to the phase-offset deficit such that the two amplified signals will be combined at the power converter with a total phase offset at 2f0 of about 180 degrees in order to reduce harmonic distortion in the amplified output signal, without substantially diminishing the output power at the fundamental frequency f0. In certain PCB-based implementations, the transmission lines include metal traces and lumped elements providing different impedance transformations that achieve the complementary phase offset, where the metal traces may have significantly different physical and electrical characteristics.

A power converter produces power at a greater voltage than provided by a power source, while drawing power from the power source, wherein the power converter has a variable input current limit or a variable input power limit. One or more audio amplifiers are configured into i) drawing power from the power source bypassing the power converter and ii) drawing power from the power converter, according to audio signal amplitude, during audio playback and in accordance with an audio signal being amplified. A load of each amplifier is determined for when the amplifier is drawing power from the power source bypassing the power converter. The variable input limit of the power converter is adjusted in accordance with the determined load, during the audio playback. Other aspects are also described and claimed.

A radio-frequency module includes: a transmission power amplifier that includes first and second amplification transistors that are cascade connected to each other; and a mounting substrate that has first and second main surface that face each other, the transmission power amplifier being mounted on the first main surface. The first amplification transistor is arranged in a final stage and has a first emitter terminal. The second amplification transistor is arranged in a stage preceding the first amplification transistor and has a second emitter terminal. The mounting substrate has first to fourth ground electrode layers in order of proximity to the first main surface. The first emitter terminal and the second emitter terminal are not electrically connected to each other via an electrode on the first main surface and are not electrically connected to each other via the first ground electrode layer.

A digital power amplifier comprising two or more individually activatable amplifiers. The outputs of the amplifiers are connected causing an activated amplifier of the two or more amplifiers to load modulate another activated amplifier of the two or more amplifiers.