A power combiner for an outphasing amplifier system comprises an output terminal, a first input terminal, a first inductor, and a first capacitor, wherein the first input terminal is connected to ground via the first inductor and the first input terminal is connected to the output terminal via the first capacitor. The power combiner further comprises a second input terminal, a second capacitor, and a second inductor, wherein the second input terminal is connected to ground via the second capacitor and the second input terminal is connected to the output terminal via the second inductor. The first capacitor can have a same capacitance as the second capacitor and the first inductor has a same inductance as the second inductor.

The present invention relates to an amplification device (10) of an input signal comprising: a first amplification stage (12), a second amplification stage (14), each amplification stage (12, 14) comprising: a switching circuit (22), the switching circuit (22) being able to generate, as output (22A, 22B), a switched signal having at least two states, and an inductive element (24) able to smooth the switched signal to obtain a smoothed signal (I1, I3), the smoothed signal (I1, I3) having a useful component and a stray component.

The amplification device (10) further comprises a compensation circuit (16), for each amplification stage (12, 14), able to generate a compensation signal (I2, I4) of the stray component of the smoothed signal (I1, I3) generated in the inductive element (24) of the corresponding amplification stage (12, 14).

Techniques for providing a modulation driver signal are disclosed. In an example, a modulation driver can include a first transistor configured to receive a first input signal having a first voltage swing, a second transistor coupled in series with the first transistor, and a third transistor configured to limit a third voltage swing across the second transistor. The second transistor can be configured to provide a representation of the first input signal as a first output signal of the modulator driver. The first output signal can have a second voltage swing greater than the first voltage swing.

Techniques for monitoring a distortion signal of a power amplifier circuit, where the output of a distortion monitoring circuit includes little or no fundamental signal and closely represents the actual distortion of the amplifier circuit of a wired communications system. The power amplifier circuit can generate a distortion feedback signal that does not affect the power amplifier's output power capability, e.g., no inherent loss in the fundamental output of the amplifier. That is, using a distortion monitor circuit, the power amplifier circuit can resolve a distortion feedback signal from the intended output signal of the output power amplifier circuit.

An integrated circuit includes a first high-pass filter having an input coupled to receive a first signal and an output coupled to a first input of a first differential pair of transistors. A second high-pass filter includes an input coupled to receive a second signal and an output coupled to a second input of the first differential pair of transistors. The second signal may be a complementary signal of the first signal. A second differential pair of transistors includes control electrodes coupled to a first voltage supply terminal. A boost circuit is coupled between the second differential pair of transistors and the first voltage supply terminal. A low-pass filter is coupled between the first differential pair of transistors and the second differential pair of transistors.

Amplifier configuration for load-line enhancement is described herein. In some implementations, an apparatus includes an amplifier. The amplifier includes at least one plus transistor stack, at least one minus transistor stack, and at least one inductor. The at least one plus transistor stack is coupled to a plus amplifier node and a plus input node. The at least one minus transistor stack is coupled to a minus amplifier node and a minus input node. The at least one inductor is coupled between the plus amplifier node and the minus amplifier node, with the at least one inductor including an inter-inductor node. The amplifier also includes a minus power switch coupled between the minus amplifier node and one or more supply voltages and an inductor power switch coupled between the inter-inductor node and at least one supply voltage.

Various methods and circuital arrangements for biasing one or more gates of stacked transistors of an amplifier are presented, where the amplifier can have a varying supply voltage that varies according to a control voltage. The control voltage can be related to a desired output power of the amplifier and/or to an envelope signal of an input signal to the amplifier. Particular biasing for selectively controlling the stacked transistors to operate in either a saturation region or a triode region is also presented. Benefits of such controlling, including increased linear response of an output power of the amplifier, are also discussed.

An amplifier for signal amplification, the amplifier comprising: a signal input arrangement; a signal output arrangement; a first transistor (Q.sub.1); a second transistor (Q.sub.2); and a third transistor (Q.sub.3), wherein: the first (Q.sub.1), second (Q.sub.2) and third (Q.sub.3) transistors are coupled to one another to form a transconductance cell, the transconductance cell is coupled to the signal input arrangement and the signal output arrangement, and the transconductance cell is operable to receive a first signal from the signal input arrangement, amplify the first signal and output an amplified first signal to the signal output arrangement. There is also disclosed a receiver incorporating the amplifier and methods of operating the amplifier.

Various envelope tracking amplifiers are presented that can be switched between an ET (envelope tracking) mode and a non-ET mode. Switches and/or tunable components are utilized in constructing the envelope tracking amplifiers that can be switched between the ET mode and the non-ET mode.

Systems and method for improving operation of a radio frequency system are provided. One embodiment includes a switching power amplifier that outputs an amplified analog electrical signal based on an input electrical signal and voltage of an envelope voltage supply rail. The switching power amplifier includes a first transistor with a gate that receives the input electrical signal, a source electrically coupled to the envelope voltage supply rail, and a drain electrically coupled to an output of the switching power amplifier; a second transistor with a gate that receives the input electrical signal, a source electrically coupled to ground, and a drain electrically coupled to the output; and a third transistor with a gate that receives the input electrical signal, a drain electrically coupled to the envelope voltage supply rail, and a source electrically coupled to an output of another switching power amplifier.