A Doherty power amplifier includes a carrier amplifier, a peaking amplifier, and a peaking amplifier bias circuit coupled to the peaking amplifier and configured to provide a peaking amplifier bias signal to the peaking amplifier based on a saturation level of the carrier amplifier.

Apparatus and methods for phase compensation in power amplifiers are disclosed herein. In certain implementations, a method of phase compensation in a power amplifier includes amplifying a radio frequency signal using a power amplifier that includes an input stage and an output stage, powering a bipolar transistor of the output stage using a power amplifier supply voltage, changing a voltage level of the power amplifier supply voltage, the bipolar transistor having an input reactance that changes in response to the change in the voltage level of the power amplifier supply voltage, and compensating for a variation in a phase delay of the power amplifier arising from the change in the input reactance of the bipolar transistor using a compensation circuit that is electrically connected to an output of the input stage.

Apparatus and methods for phase compensation in power amplifiers are disclosed herein. In certain implementations, a method of phase compensation in a power amplifier includes amplifying a radio frequency signal using a power amplifier that includes an input stage and an output stage, powering a bipolar transistor of the output stage using a power amplifier supply voltage, changing a voltage level of the power amplifier supply voltage, the bipolar transistor having an input reactance that changes in response to the change in the voltage level of the power amplifier supply voltage, and compensating for a variation in a phase delay of the power amplifier arising from the change in the input reactance of the bipolar transistor using a compensation circuit that is electrically connected to an output of the input stage.

A power amplifier circuit comprising a transistor for receiving a signal to be amplified at an input and for outputting an amplified signal at an output; a modulated power supply connected to the transistor output; and a resistive element connected at the transistor output such that a low impedance is maintained at the transistor output across a range of operational frequencies.

A power amplifier circuit comprising a transistor for receiving a signal to be amplified at an input and for outputting an amplified signal at an output; a modulated power supply connected to the transistor output; and a resistive element connected at the transistor output such that a low impedance is maintained at the transistor output across a range of operational frequencies.

A quasi-differential amplifier with an input port and an output port. The amplifier has a phase shifter network with a first port connected to the input port, a second port, and a third port. A first amplifier has an input connected to the second port of the phase shifter network, and an output, and a second amplifier has an input connected to the third port of the phase shifter network, and an output. A balun circuit includes a first differential port connected to an output of the first amplifier, a second differential port connected to an output of the second amplifier, and a single-ended port. An output matching network is connected to the single-ended port of the balun circuit and to the output port.

A quasi-differential amplifier with an input port and an output port. The amplifier has a phase shifter network with a first port connected to the input port, a second port, and a third port. A first amplifier has an input connected to the second port of the phase shifter network, and an output, and a second amplifier has an input connected to the third port of the phase shifter network, and an output. A balun circuit includes a first differential port connected to an output of the first amplifier, a second differential port connected to an output of the second amplifier, and a single-ended port. An output matching network is connected to the single-ended port of the balun circuit and to the output port.

An integrated circuit that includes a die with an active radio frequency (RF) unit embedded thereon; a first port for receiving an output signal from the active RF unit; a harmonic filter that comprises a first harmonic filter inductor; and a first RF inductive load that is electrically coupled to the first port and is magnetically coupled to the first harmonic filter inductor.

The present disclosure relates to devices and methods for detecting and preventing occurrence of a saturation state in a power amplifier. A power amplifier module can include a power amplifier including a cascode transistor pair. The cascode transistor pair can include a first transistor and a second transistor. The power amplifier module can include a current comparator configured to compare a first base current of the first transistor and a second base current of the second transistor to obtain a comparison value. The power amplifier module can include a saturation controller configured to supply a reference signal to an impedance matching network based on the comparison value. The impedance matching network can be configured to modify a load impedance of a load line in electrical communication with the power amplifier based at least in part on the reference signal.

The present disclosure relates to devices and methods for detecting and preventing occurrence of a saturation state in a power amplifier. A power amplifier module can include a power amplifier including a cascode transistor pair. The cascode transistor pair can include a first transistor and a second transistor. The power amplifier module can include a current comparator configured to compare a first base current of the first transistor and a second base current of the second transistor to obtain a comparison value. The power amplifier module can include a saturation controller configured to supply a reference signal to an impedance matching network based on the comparison value. The impedance matching network can be configured to modify a load impedance of a load line in electrical communication with the power amplifier based at least in part on the reference signal.