The present disclosure generally relates to techniques and apparatus for implementing an envelope-tracking power supply for a radio frequency (RF) power amplifier. One aspect includes an amplification system. The amplification system may include a first amplifier configured to generate an amplifier output voltage, a second amplifier having an output coupled to a supply node for the first amplifier, a voltage regulator having an output coupled to a supply node for the second amplifier, and control circuitry configured to control the voltage regulator to generate a supply voltage at the supply node for the second amplifier based on an indication associated with the amplifier output voltage. In some aspects, the control circuitry may be configured to control the voltage regulator through at least providing an updated control setting for the voltage regulator with a periodicity associated with a power control period.

A radio frequency module includes a mounting board, a power amplifier, a plurality of transmission filters, a first switch, an output matching circuit, a low-noise amplifier, and an external-connection terminal. The mounting board includes a first principal surface and a second principal surface on opposite sides of the mounting board. The first switch switches a connection between the power amplifier and the transmission filters. The output matching circuit is connected between the power amplifier and the first switch. The low-noise amplifier is disposed on the second principal surface of the mounting board. The external-connection terminal is disposed on the second principal surface of the mounting board. The power amplifier, the output matching circuit, the first switch, and the transmission filters are disposed on the mounting board in stated order in a direction that is orthogonal to a thickness direction of the mounting board.

Power amplifiers with adaptive bias for envelope tracking applications are provided herein. In certain embodiments, an envelope tracking system includes a power amplifier that amplifies a radio frequency (RF) signal and that receives power from a power amplifier supply voltage, and an envelope tracker that generates the power amplifier supply voltage based on an envelope of the RF signal. The power amplifier includes a field-effect transistor (FET) for amplifying the RF signal, and a current mirror including an input that receives a reference current and an output connected to the power amplifier supply voltage. An internal voltage of the current mirror is used to bias the gate of the FET to compensate the FET for changes in the power amplifier supply voltage arising from envelope tracking.

An electronic device includes a battery, a plurality of capacitors, a converter that receives power from the battery and charges each of the plurality of capacitors to different voltages based on the power, a plurality of switches that switch a first path and a second path of each of the plurality of capacitors, and a controller. The controller selects a first switch among the plurality of switches based on a received signal, and controls the first switch such that a path of a capacitor connected to the first switch is switched from the first path to the second path, and the first path is a path which electrically connects each of the plurality of capacitors to the converter, the second path is a path which electrically connects each of the plurality of capacitors and a power amplifier (PA).

A front-end module including a power amplifier, first and second couplers, an antenna switch, and a switch sub-assembly. The power amplifier has an input to receive a radio frequency signal and an output to provide an amplified radio frequency signal. The first coupler has an input port coupled to the output of the power amplifier, an output port coupled to an input of the antenna switch, a coupled port, and an isolated port. The second coupler has an input port coupled to an output of the antenna switch, an output port coupled to an antenna port, a coupled port, and an isolated port. The switch sub assembly connects one of the coupled port and the isolated port of the second coupler to an output of the switch assembly and the other one of the coupled port and the isolated port of the second coupler to a first termination impedance.

Certain aspects of the present disclosure provide a circuit for clock signal generation. The circuit generally includes a plurality of clock generation circuits configured to generate a plurality of clock signals from a clock signal, and a power supply circuit having an output coupled to power supply inputs of the plurality of clock generation circuits. The circuit may also include a capacitor array coupled to the output of the power supply circuit and include a plurality of capacitive elements, the capacitor array being configured to selectively couple each of the plurality of capacitive elements to the output of the power supply circuit based on a quantity of one or more active clock generation circuits of the plurality of clock generation circuits.

Apparatus and method for detecting and clamping power of a power amplifier are disclosed. In certain embodiments, a power amplifier system includes a power amplifier that amplifies a radio frequency input signal to generate a radio frequency output signal, a bias circuit that controls a bias of the power amplifier, a radio frequency coupler that generates a radio frequency coupled signal based on the radio frequency output signal, a clamp that selectively clamps the bias of the power amplifier, and a power detector that controls the clamp based on the radio frequency coupled signal.

An electronic device includes an antenna, a communication circuit, and a processor. The communication circuit includes a first amplifier configured to amplify a radio frequency signal; a first coupler configured to output a first amplifier output signal output from the first amplifier, to the antenna through a first port, and output at least a part of the first amplifier output signal to a first switch through a second port; and a second amplifier configured to amplify the second portion of the first amplifier output signal, output from the first switch. The processor is operably connected to the antenna and the communication circuit, wherein the processor is configured to, based on a magnitude of the first amplifier output signal, control the first switch and the second switch to use the first amplifier, or to use the first amplifier and the second amplifier.

A power amplifier circuit includes a first amplifier that amplifies an input signal and outputs an output signal; a second amplifier that, in accordance with a control signal, amplifies a signal corresponding to the input signal, generates a signal having an opposite phase to that of the output signal, and adds the signal to the output signal; and a control circuit that supplies the control signal to the second amplifier. The control circuit outputs the control signal so that during operation of the power amplifier circuit in a first power mode, a gain of the second amplifier is not less than zero and less than a predetermined level and during operation in a second power mode lower than the first power mode in output power level, a gain of the second amplifier is not less than the predetermined level and less than a gain of the first amplifier.

A multi-transmitting multi-receiving magnetic-resonance wireless charging system for a medium-power electronic apparatus includes a magnetic-resonance transmitting module and a magnetic-resonance receiving module. The magnetic-resonance transmitting module includes a transmitting-end Bluetooth-communication and control module and at least two magnetic-resonance transmitting channels. Each magnetic-resonance transmitting channel includes a direct current/direct current (DC/DC) regulator module, a radio-frequency power amplifier source, a matching network and a magnetic-resonance transmitting antenna which are connected sequentially. The magnetic-resonance receiving module includes a receiving-end Bluetooth-communication and control module, a power synthesis and protocol module and at least two magnetic-resonance receiving channels. Each magnetic-resonance receiving channel includes a magnetic-resonance receiving antenna, a receiving-antenna matching network, a rectifier and filter module, a primary regulator and filter module and a secondary regulator and filter module which are connected sequentially. The magnetic-resonance transmitting antenna is coupled with the magnetic-resonance receiving antenna in one-to-one correspondence.