An apparatus is disclosed for implementing a Darlington circuit with a driver amplifier to provide power clamping. In example aspects, the apparatus includes an amplifier circuit having an input port and an output port. The amplifier circuit includes a driver amplifier, a power amplifier, and a Darlington circuit. The driver amplifier includes a driver amplifier output and a transistor, with the driver amplifier coupled between the input port and the output port. The power amplifier includes a power amplifier input, and the power amplifier is coupled between the driver amplifier output and the output port. The Darlington circuit is coupled to the driver amplifier via a node that is coupled between the input port and the power amplifier input.

An apparatus is disclosed for implementing a Darlington circuit with an interstage matching network or between two amplifier stages to provide power clamping. In example aspects, the apparatus includes an amplifier circuit having an input port and an output port. The amplifier circuit includes a driver amplifier, an interstage matching network, a power amplifier, and a Darlington circuit. The driver amplifier includes a driver amplifier output and is coupled between the input port and the output port. The power amplifier includes a power amplifier input and is coupled between the driver amplifier output and the output port. The interstage matching network is coupled between the driver amplifier output and the power amplifier input. The Darlington circuit is coupled to the interstage matching network via a node that is coupled between the driver amplifier output and the power amplifier input.

A load detection circuit includes a first detection part and a second detection part. The first detection part includes a first capacitor and a second capacitor, forms capacitive coupling with a signal transmission line connecting an output port of an RF amplifier and a load, and outputs a first signal. The second detection part includes a first inductor and a second inductor, forms inductive coupling with the signal transmission line, and outputs a second signal.

Temperature compensation circuits and methods for adjusting one or more circuit parameters of a power amplifier (PA) to maintain approximately constant Gain versus time during pulsed operation sufficient to substantially offset self-heating of the PA. Some embodiments compensate for PA Gain droop due to self-heating using a Sample and Hold (S&H) circuit. The S&H circuit samples and holds an initial temperature of the PA at commencement of a pulse. Thereafter, the S&H circuit generates a continuous measurement that corresponds to the temperature of the PA during the remainder of the pulse. A Gain Control signal is generated that is a function of the difference between the initial temperature and the operating temperature of the PA as the PA self-heats for the duration of the pulse. The Gain Control signal is applied to one or more adjustable or tunable circuits within a PA to offset the Gain droop of the PA.

Methods and apparatus for providing amplifier protection for a radio frequency (RF) front-end circuit. An example RF front-end circuit generally includes an amplifier with a gain, a first sensor configured to sense a first power (or voltage) of a first node coupled to an input of the amplifier, a second sensor configured to sense a second power (or voltage) of a second node coupled to an output of the amplifier, and logic coupled to the first and second sensors. The logic is generally configured to determine that the second power (or voltage) is outside a range based on the gain and the first power (or voltage) and to take an action to protect the amplifier based on the determination. By utilizing the techniques and apparatus described herein, protection can be provided to the amplifier(s) in an RF front-end circuit without significantly impacting the performance of the RF front-end circuit.

Wireless circuitry is provided that includes at least a first amplifier, a second amplifier, and a power splitting transformer coupled to the first and second amplifiers. The first amplifier can include first input transistors, and the second amplifier can include second input transistors. The power splitting transformer can include a primary coil, a first secondary coil having terminals coupled to gate terminals of the first input transistors and having a center tap configured to receive a first bias voltage, and a second secondary coil having terminals coupled to gate terminals of the second input transistors and having a center tap configured to receive a second bias voltage. The first and second amplifiers may output signals to a power combining transformer. The power combining transformer can have a first primary coil, a second primary coil, and a secondary coil all disposed within a single compact transformer footprint.

A direct current (DC)-DC converter, which includes a charge pump buck power supply and a buck power supply is disclosed. The charge pump buck power supply includes a charge pump buck converter, a first inductive element, and an energy storage element. The charge pump buck converter and the first inductive element are coupled in series between a DC power supply, such as a battery, and the energy storage element. The buck power supply includes a buck converter, a second inductive element, and the energy storage element. The buck converter and the second inductive element are coupled in series between the DC power supply and the energy storage element. As such, the charge pump buck power supply and the buck power supply share the energy storage element.

A receiver is provided to support a plurality of carrier aggregation modes. The receiver includes a low-noise amplifier (LNA) module including a plurality of LNAs, wherein the LNAs are arranged to receive input signals from a plurality of input ports, respectively, and each of the LNAs generates and outputs a plurality of noise-cancelled signals at a plurality of output terminals of the LNA module.

The present disclosure describes a method and system for linearizing an amplifier using transistor-level dynamic feedback. The method and system enables nonlinear amplifiers to exhibit linear performance using one or more of gain control elements and phase shifters in the feedback path. The disclosed method and system may also allow an amplifier to act as a pre-distorter or a frequency/gain programmable amplifier.

Disclosed herein are power amplification (PA) systems configured to amplify a signal, such as a radio-frequency signal. The PA system includes a plurality of power amplifiers that are configured to amplify a signal received at a signal input and to output the amplified signal at a signal output. The power amplifiers are configured to receive a supply voltage that is a combination of a battery voltage and an envelope tracking signal. The PA system includes a PA controller configured to control the power amplifiers based at least in part on the battery voltage or a power output of the power amplifiers. The PA controller can be configured to alter impedance matching components of the PA system to reconfigure a load line of the power amplifiers.