One example includes a device that is comprised of a pre-power amplifier, a power amplifier, a signal path, and a dynamic bias circuit. The pre-power amplifier amplifies an input signal and outputs a first amplified signal. The power amplifier receives the first amplified signal and amplifies the first amplified signal based on a dynamic bias signal to produce a second amplified signal at an output thereof. The signal path is coupled between an output of the pre-power amplifier and an input of the power amplifier. The dynamic bias circuit monitors the first amplified signal, generates the dynamic bias signal, and outputs the dynamic bias into the signal path.

A transistor package for a power amplifier is provided. The transistor package includes a plurality of radio frequency, RF, paths that includes a first RF path and second RF path. Each RF path includes a transistor-carrying die and at least one impedance element. The transistor package includes a circuit portion electrically coupling a first impedance element in the first RF path to a second impedance element in the second RF path where the circuit portion includes at least one resistor.

A power amplifier circuit includes a first transistor having a first terminal to which a first signal inputs, a second transistor having a first terminal to which the first signal inputs, a first resistor having a first end to which a first bias current is supplied and a second end electrically connected to the first terminal of the first transistor, a second resistor having a first end to which a second bias current is supplied and a second end electrically connected to the first terminal of the second transistor, and a third resistor having a first end connected to the first end of the first resistor and a second end connected to the first end of the second resistor.

A radio frequency circuit includes: an amplifier circuit configured to amplify a first radio frequency signal using a first power supply voltage, and amplify a second radio frequency signal using a second power supply voltage. The first radio frequency signal is a signal in a first band for Long Term Evolution (LTE), the second radio frequency signal is a signal in a second band for 5th Generation New Radio (5G NR) or a wireless local area network (WLAN) signal, and in a state in which a first predetermined condition regarding the first radio frequency signal and the second radio frequency signal is satisfied, a value of the second power supply voltage is greater than a value of the first power supply voltage.

Disclosed is an amplifying circuit and method. In one embodiment, an amplifying circuit, includes: a common-gate (CG) amplifier, wherein the CG amplifier comprises a first transistor, wherein source terminal and body terminal of the first transistor is coupled together through a first resistor.

Disclosed are systems configured to deliver wireless charging power to electronic devices and methods for delivering wireless charging power. In some implementations, a system can include a programmable radio-frequency generator capable of generating a beam of electromagnetic pulsed radiation and plurality of solid-state amplifiers to amplify the beam of electromagnetic pulsed radiation. The amplified beam of electromagnetic pulsed radiation can be configured to wirelessly charge electronic devices at distances greater than about 100 meters.

A circuit to modulate the power supply to track input or output voltages provided to or output by a plurality of amplifiers to reduce power dissipation is provided. The circuit may include a peak detection circuit configured to receive a plurality of voltages respectively corresponding to the plurality of amplifiers, and to detect and output information regarding a maximum instantaneous voltage from the received plurality of voltages, and a summing circuit configured to output a sum of the information regarding the maximum instantaneous voltage and an amplifier headroom voltage. A reference voltage may be provided for the supply voltage responsive to the output sum. The circuit may also include a scaling circuit configured to scale the output sum, and the reference voltage may be a scaled reference voltage output by the scaling circuit.

Described are circuits and techniques to increase the efficiency of radio-frequency (rf) amplifiers including rf power amplifiers (PAs) through supply modulation (also referred to as drain modulation or collector modulation), in which supply voltages provided to rf amplifiers is adjusted dynamically (modulated) over time depending upon the rf signal being synthesized. For the largest efficiency improvements, a supply voltage can be adjusted among discrete voltage levels or continuously on a short time scale. The supply voltages (or voltage levels) provided to an rf amplifier may also be adapted to accommodate longer-term changes in desired rf envelope such as associated with adapting transmitter output strength to minimize errors in data transfer, for rf traffic variations.

Combiners for Doherty power amplifier systems are provided herein. In certain embodiments, a combiner structure includes a first balun combiner for combining an output of a first auxiliary amplifier and a second auxiliary amplifier, and a second balun combiner for combining the output of a main amplifier and an output of the first balun combiner. Each combiner can include a balun having a first conductor connected between a first input port and an output port, a second conductor connected between an isolated node and a second input port and magnetically coupled to the first conductor. An isolation capacitor is connected between the first input port and the isolated node, and an output capacitor is connected between the second input port and the output port. In certain implementations, the balun combiner further includes a termination capacitor between the isolated node and ground.

Doherty power amplifier systems with envelope controlled state are provided herein. In certain embodiments, a Doherty power amplifier system includes a main amplifier, a first auxiliary amplifier, and a second auxiliary amplifier that operate in combination with one another to amplify an RF signal. The Doherty power amplifier system further includes a bias circuit that biases the first and second auxiliary amplifiers based on an envelope of the RF signal to control a state of the Doherty power amplifier system. For example, in certain implementations, the first and second auxiliary amplifiers are selectively activated based on a power level indicating by the envelope.