A radio frequency (RF) power amplifier is provided. In one aspect, the RF power amplifier includes a driver stage amplifier circuit, first and second power amplifier output stage circuits that each include a first and second array of bipolar junction transistors (BJTs), respectively, an inter-stage impedance matching network connecting the driver stage circuit’s output to a respective first input of the first and second output stage circuits, and first and second bias circuits connecting the driver stage amplifier circuit’s output to a respective second input of the first and second power amplifier output stage circuits. The first bias circuit and the first output stage circuit can set a quiescent point of each BJT in the first array to a first value, while the second bias circuit and the second output stage circuit are configured to set a quiescent point of each BJT in the second array to a second value.

A noise detecting circuit including an amplifier circuit amplifying an input signal indicating a noise level of a circuit to be detected and output an amplified signal; a filtering circuit receiving and filtering the amplified signal and output a filtered signal; and a comparing circuit receiving and compare the filtered signal to a reference voltage and output an output signal; wherein the filtering circuit includes: an output terminal; and a first filter selectively coupled to the output terminal, including: a sub-output terminal; a switch selectively coupling the sub-output terminal to the output terminal; a resistor, wherein a terminal of the resistor is coupled to the amplifier circuit and another terminal of the resistor is coupled to the sub-output terminal; and a capacitor, wherein a terminal of the capacitor is coupled to the sub-output terminal and another terminal of the capacitor is coupled to a reference voltage source.

A radio-frequency circuit includes a power amplifying circuit configured to amplify a first radio-frequency signal having a first channel bandwidth and a second radio-frequency signal having a second channel bandwidth greater than the first channel bandwidth. The power amplifying circuit is configured to amplify the first radio-frequency signal in an amplifying mode according to an average power tracking method, and to amplify the second radio-frequency signal in an amplifying mode according to an envelope tracking method.

Systems and methods for magnitude and phase trimming are provided. In one aspect, a radio frequency (RF) trimmer circuit includes an input terminal configured to receive an RF signal, an output terminal configured to output the RF signal, a control input configured to receive a control signal, at least one impedance element, and at least one transistor configured to selectively connect the impedance element onto a path between the input and output terminals. The selectively connecting the impedance element controls at least one of a magnitude trim and a phase trim of the RF signal.

An asymmetrical power amplifier circuit is provided. The asymmetrical power amplifier circuit includes a carrier amplifier and a peak amplifier. The carrier amplifier is always active to amplify a radio frequency (RF) to a carrier output power, while the peak amplifier is only active to amplify the RF signal to a peak output power when a time-variant output power of the RF signal is higher than a predefined power threshold. The RF signal in the carrier output power is summed with the RF signal in the peak output power to thereby output the amplified RF signal in the time-variant output power. Unlike a conventional symmetrical power amplifier, the carrier output power and the peak output power are different at a peak of the time-variant output power. As such, the carrier amplifier and the peak amplifier can both operate with optimal efficiency based on a same modulated voltage.

Systems and methods for calibrating a wireless power transmitter is described. A wireless power transmitter can include a controller and an amplifier module. The amplifier module can include an amplifier configured to amplify a voltage converted from a current proportional to power consumed by a wireless power transmitter, and a circuit connected to the amplifier. The circuit can be configured to receive a control signal from the controller. The circuit can be further configured to perform time division multiplexing on an output of the amplifier according to the control signal. A time division multiplexed output of the amplifier can include calibration data of the amplifier. The amplifier can be configured to output the time division multiplexed output to the controller.

Gradient power amplifier (GPA) systems and methods are provided. A GPA system may include a plurality of paralleled GPAs; and at least one controller operably coupled to the plurality of paralleled GPAs. The at least one controller may be configured to perform operations including: obtaining a total current parameter of the plurality of paralleled GPAs; determining, based on the total current parameter and a target current parameter, a first difference value; and determining, based on the first difference value, a first control parameter of a first GPA of the plurality of paralleled GPAs, wherein the first control parameter is configured to control an output current of the first GPA.

Amplification circuitry is disclosed that couples neutralization transistors to amplification transistors to neutralize parasitic capacitance of the amplification transistors. Gates of a first amplification transistor and a first neutralization transistor are coupled together, and gates of a second amplification transistor and a second neutralization transistor are also coupled together. Drains of the first amplification transistor and the second neutralization transistor are coupled together, and drains of the second amplification transistor and the first neutralization transistor are also coupled together. Sources of neutralization transistors are coupled together at a node, such that a voltage swing of a first signal in the first neutralization transistor may be canceled by a voltage swing of a second signal in the second neutralization transistor. The node also couples to a resistor that prevents charge building in the neutralization transistors.

Low noise amplifiers (LNAs) are disclosed. In one aspect, an LNA may have distortion cancellation that is orthogonally implemented relative to noise cancellation such that changes to the distortion cancellation do not affect the noise cancellation. In further exemplary aspects, cancellation circuitry is added in parallel to a main or primary LNA path. The cancellation circuitry may include an initial impedance matching amplifier that effectuates noise cancellation and a second amplifier that effectuates distortion cancellation. Variations in the placement and composition of the second amplifier are provided. By providing a second path that allows for independent control of noise and distortion cancellation, overall performance of the LNA is improved.

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.