According to some example embodiments, an apparatus includes a buck-boost converter, a first buck converter connected at an output terminal of the buck-boost converter, a second buck converter connected at the output terminal of the buck-boost converter, a first LA including a first supply voltage input connected to the output terminal of the buck-boost converter, and an output terminal connected to an output terminal of the first buck converter, where the first LA is configured to provide a first modulated supply voltage to a first PA of a first transmitter, and a second LA including a second supply voltage input connected to the output terminal of the buck-boost converter, and an output terminal connected to an output terminal of the second buck converter, where the second LA is configured to provide a second modulated supply voltage to a second PA of a second transmitter.

A system and method which includes receiving an input signal having an envelope and generating an envelope detection signal corresponding to the envelope. A bias current provided to an amplifier circuit is adjusted based upon the envelope detection signal, the amplifier circuit including an amplifier and a transformer. The transformer is configured to establish a magnetically coupled feedback loop from an output of the amplifier to an input of the amplifier. An output signal is provided, by the amplifier circuit, in response to the input signal.

Apparatus and methods for load modulated power amplifiers are provided. In certain embodiments, a load modulated power amplifier system includes a power amplifier that receives a radio frequency signal at an input and provides an amplified radio frequency signal at an output, and a controllable load impedance coupled to the output of the power amplifier. The controllable load impedance receives an envelope signal that changes in relation to an envelope of the radio frequency signal, and the envelope signal is operable to control an impedance of the controllable load impedance to modulate a load at the output of the power amplifier.

Apparatus and methods for envelope tracking systems with automatic mode selection are provided herein. In certain configurations, a power amplifier system includes a power amplifier configured to provide amplification to a radio frequency signal and to receive power from a power amplifier supply voltage, and an envelope tracker including a signal bandwidth detection circuit configured to generate a detected bandwidth signal based on processing an envelope signal corresponding to an envelope of the radio frequency signal. The envelope tracker further includes a switch bank configured to receive a plurality of regulated voltages, a filter configured to filter an output of the switch bank to generate the power amplifier supply voltage, and a mode control circuit configured to control a filtering characteristic of the filter based on the detected bandwidth signal.

Envelope tracking systems for power amplifiers are provided herein. In certain embodiments, an envelope tracker is provided for a power amplifier that amplifies an RF signal. The envelope tracker includes a multi-level switching circuit having an output that provides an output current that changes in relation to an envelope signal indicating an envelope of the RF signal when the envelope tracker is operating in an envelope tracking mode. The multi-level switching circuit includes a multi-level supply (MLS) modulator that receives multiple regulated voltages of different voltage levels, and an MLS control circuit that controls the selection of the MLS modulator over time based on the envelope signal. When transitioning the MLS modulator from selection of one regulated voltage level to another regulated voltage level, the MLS control circuit provides a soft transition to gradually switch the regulated voltage levels.

Apparatus and methods for power amplifier distortion networks are disclosed. In one aspect, there is provided a power amplifier system including a power amplifier configured to amplify a radio frequency input signal. The power amplifier including an input configured to receive the radio frequency input signal and an output configured to generate an amplified radio frequency signal. The power amplifier system further includes a distortion network electrically coupled to either the input or the output of the power amplifier. The distortion network including a plurality of channelized resistors. The channelized resistors connected in series to either an input or an output of the power amplifier.

Various embodiments disclose a method and a device including: an antenna, a switching regulator, communication chip including an amplifier and a linear regulator operably connected to the amplifier and the switching regulator, the communication chip configured to transmit a radio-frequency signal from the electronic device through the antenna, and control circuitry configured to control the communication chip such that the linear regulator provides the amplifier with a voltage corresponding to an envelope of an input signal input to the amplifier, the input signal corresponding to the radio-frequency signal.

A power management circuit supporting phase correction in an analog signal is disclosed. The power management circuit includes a power amplifier circuit configured to amplify an analog signal having a time-variant power envelope based on a modulated voltage. The power management circuit also includes an envelope tracking (ET) integrated circuit (ETIC) configured to generate the modulated voltage and a modulated phase correction voltage to thereby cause a phase change in the analog signal. In embodiments disclosed herein, a correlation between the time-variant power envelope, the modulated voltage, and the modulated phase correction voltage is explored to thereby allow the ETIC to generate the modulated voltage and the modulated phase correction voltage based on the time-variant power envelope. As a result, it is possible to enable good time and phase alignment between the modulated voltage and the time-variant power envelope to thereby improve efficiency and linearity of the power amplifier circuit.

A distributed power management circuit is disclosed. Herein, a phase correction in a radio frequency (RF) signal is performed by a power management integrated circuit (PMIC), a distributed PMC, and a power amplifier circuit. The power amplifier circuit includes a phase shifter circuit configured to phase-shift the RF signal based on a phase correction signal and a power amplifier configured to amplify the phase-shifted RF signal based on a modulated voltage. The distributed PMIC is configured to generate the phase correction signal and the modulated voltage based on a modulated target voltage. The PMIC is configured to generate the modulated target voltage based on a time-variant power envelope of the RF signal. As a result, the modulated voltage and the time-variant power envelope can be better aligned in time and/or phase at the power amplifier circuit to thereby improve efficiency and linearity of the power amplifier.

A power amplifier circuit supporting phase correction in a radio frequency (RF) signal is disclosed. The power amplifier circuit includes a power amplifier configured to amplify an RF signal based on a modulated voltage. The power amplifier circuit also includes a phase correction circuit configured to generate a phase correction signal based on the modulated voltage to thereby cause a phase change in the RF signal before the RF signal is amplified by the power amplifier. As a result, the modulated voltage and the time-variant power envelope can be better aligned in time and/or phase at the power amplifier circuit to thereby improve efficiency and linearity of the power amplifier circuit.