Abstract: In some embodiments, a power amplification system can comprise a current source, an input switch configured to alternatively feed current from the current source to a high-power circuit path and a low-power circuit path, and a band switch including a switch arm for switching between a plurality of bands. Each of the high-power circuit path and the low-power circuit path can be connected to the switch arm.

Abstract: Apparatus and methods for power amplifier bias modulation for low bandwidth envelope tracking are provided herein. In certain embodiments, an envelope tracking system includes a power amplifier that amplifies an RF signal and a low bandwidth envelope tracker that generates a power amplifier supply voltage for the power amplifier based on an envelope of the RF signal. The envelope tracking system further includes a bias modulation circuit that modulates a bias signal of the power amplifier based on a voltage level of the power amplifier supply voltage.

Abstract: Systems and methods including variable power amplifier bias impedance are disclosed. In one aspect, there is provided a power amplifier system including a bias circuit configured to receive a bias voltage and generate a bias signal and a power amplifier stage configured to receive an input radio frequency (RF) signal and generate an output RF signal. The power amplifier system may also include a bias impedance component operatively coupled between the bias circuit and the power amplifier stage. The bias impedance is component configured to receive a control signal and adjust an impedance value of the bias impedance component in response to the control signal.

Abstract: 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.

Abstract: Circuits, devices and methods related to antenna tuner. In some embodiments, an antenna can be tuned by amplifying a signal for transmission by operating a transistor with a base current, and monitoring the base current. The method can further include adjusting an antenna tuner to thereby adjust an antenna load impedance presented to the amplified signal, with the adjustment being based on a variation of the monitored base current.

Abstract: Systems and methods including variable power amplifier bias impedance are disclosed. In one aspect, there is provided a power amplifier system including a bias circuit configured to receive a bias voltage and generate a bias signal and a power amplifier stage configured to receive an input radio frequency (RF) signal and generate an output RF signal. The power amplifier system may also include a bias impedance component operatively coupled between the bias circuit and the power amplifier stage. The bias impedance is component configured to receive a control signal and adjust an impedance value of the bias impedance component in response to the control signal.

Abstract: Apparatus and methods for quadrature combined Doherty amplifiers are provided herein. In certain embodiments, a separator is used to separate a radio frequency (RF) input signal into a plurality of input signal components that are amplified by a pair of Doherty amplifiers operating in quadrature. Additionally, a combiner is used to combine a plurality of output signal components generated by the pair of Doherty amplifiers, thereby generating an RF output signal exhibiting quadrature balancing.

Abstract: Apparatus and methods for quadrature combined Doherty amplifiers are provided herein. In certain embodiments, a separator is used to separate a radio frequency (RF) input signal into a plurality of input signal components that are amplified by a pair of Doherty amplifiers operating in quadrature. Additionally, a combiner is used to combine a plurality of output signal components generated by the pair of Doherty amplifiers, thereby generating an RF output signal exhibiting quadrature balancing.

Abstract: According to some implementations, a radio-frequency (RF) device includes a communication interface coupled to a serial bus. The RF device also includes a monitoring component coupled to the communication interface, the monitoring component configured to monitor the serial bus for first data transmitted to a first device coupled to the serial bus and configure the RF device based on the first data.

Abstract: 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.

Abstract: A power amplifier layout can include multiple cascoded devices each having a radio-frequency transistor coupled to a cascode transistor. An orientation of a radio-frequency transistor of a first cascoded device relative to a cascode transistor of the first cascoded device can be configured to be different than an orientation of a radio-frequency transistor of a second cascoded device relative to a cascode transistor of the second cascoded device.

Abstract: Antenna impedance prediction via power amplifier parameter. In some embodiments, a power amplification system can include a splitter circuit and a combiner circuit, and first and second Doherty power amplifiers implemented in a quadrature configuration between the splitter circuit and the combiner circuit, with each Doherty power amplifier including a carrier amplifier and a peaking amplifier. The power amplification system can further include a monitoring circuit configured to measure at least some of base currents associated with the carrier and peaking amplifiers of the first and second Doherty power amplifiers, and generate a signal capable of adjusting a load impedance presented to an output of the combiner circuit.

Abstract: In some embodiments, radio-frequency amplifiers can include a plurality of narrow band power amplifiers implemented. Each narrow band power amplifier can be configured to operate with a high voltage in an average power tracking mode and be capable of being coupled to an output filter associated with a respective individual frequency band. Each narrow band power amplifier can be sized smaller than a wide band power amplifier configured to operate with more than one of the frequency bands associated with the plurality of narrow band power amplifiers.

Abstract: Wideband power combiners and splitters are provided herein. In certain embodiments, a power combiner/splitter is implemented with a first coil connecting a first port and a second port, and a second coil connecting a third port and a fourth port. The first coil and the second coil are inductively coupled to one another. For example, the first coil and the second coil can be formed using adjacent conductive layers of a semiconductor chip, an integrated passive device, or a laminate. The power combiner/splitter further includes a fifth port tapping a center of the first coil and a sixth port tapping a center of the second coil. The fifth port and the sixth port serve to connect capacitors and/or other impedance to the center of the coils to thereby provide wideband operation.

Abstract: In some embodiments, an amplifier system can include an amplifier circuit having first and second amplifiers configured to amplify respective first and second portions of an input signal. Each of the first and second amplifiers can include a cascode stage with input and output transistors arranged in a cascode configuration. The amplifier system can further include an envelope tracking bias circuit coupled to the amplifier circuit and configured to provide a bias signal to the output transistor of the cascode stage of at least one of the first and second amplifiers. The amplifier system can further include a supply circuit configured to provide a non-envelope tracking supply voltage to the output transistor of the cascode stage of the at least one of the first and second amplifiers.

Abstract: Apparatus and methods for power amplifier bias modulation for low bandwidth envelope tracking are provided herein. In certain embodiments, an envelope tracking system includes a power amplifier that amplifies an RF signal and a low bandwidth envelope tracker that generates a power amplifier supply voltage for the power amplifier based on an envelope of the RF signal. The envelope tracking system further includes a bias modulation circuit that modulates a bias signal of the power amplifier based on a voltage level of the power amplifier supply voltage.

Abstract: Apparatus and methods for power amplifier bias modulation for multi-level supply envelope tracking are provided herein. In certain embodiments, an envelope tracking system includes a power amplifier that amplifies a radio frequency signal, a multi-level supply envelope tracker that generates a power amplifier supply voltage of the power amplifier based on an envelope signal indicating an envelope of the radio frequency signal, and a bias modulation circuit that modulates a bias of the power amplifier based on a voltage level of the power amplifier supply voltage.

Abstract: One aspect of this disclosure is a power amplifier system that includes a control interface, a power amplifier, a passive component on a same die as the power amplifier, and a bias circuit on a different die than the power amplifier. The control interface can operate as a serial interface or as a general purpose input/output interface. The power amplifier can be controllable based at least partly on an output signal from the control interface. The bias circuit can generate a bias signal based at least partly on an indication of the electrical property of the passive component. Other embodiments of the system are provided along with related methods and components thereof.

Abstract: A power amplification system with shared common base biasing is disclosed. A method for power amplification at a controller of a power amplification system comprising a plurality of cascode amplifier sections can include receiving a band select signal indicative of one or more frequency bands of a radio-frequency input signal to be amplified and transmitted. The method may further include biasing a common base stage of each of the plurality of cascode amplifier sections, and biasing a common emitter stage of a subset of the plurality of cascode amplifier sections.

Abstract: Apparatus and methods for saturation detection of power amplifiers are provided. In certain embodiments, a power amplifier system including a power amplifier and a saturation detector is provided. The power amplifier includes a gain transistor that amplifies an RF input signal to generate an RF output signal, and the saturation detector includes a detection transistor that is thermally coupled to the gain transistor. Additionally, the saturation detector monitors an input voltage to the gain transistor to generate a saturation detection signal indicating a saturation of the gain transistor.