Embodiments of the present application provide a power amplifier, a power amplification method, and a power amplification control apparatus and method. The power amplifier includes n Doherty power amplification units connected in parallel and an n-way outphasing combiner, where n2 and n is an integer. Each Doherty power amplification unit includes one input end and one output end. The n-way outphasing combiner includes n input ends and one output end. The output ends of the Doherty power amplification units are separately connected to the input ends of the n-way outphasing combiner.

An inverted three-stage Doherty amplifier is disclosed. The amplifier provides an input power divider, a carrier amplifier, two peak amplifiers, and an output combiner. The output combiner includes five quarter-wavelength (/4) lines, three of which correspond to the three amplifiers, one of which combines an output of the carrier amplifier with an output of the first peak amplifier, and the last of which combines the combined output of the carrier amplifier and the first peak amplifier with an output of the second peak amplifier. The five /4 lines have respective impedances to optionally adjust the output impedance of the respective amplifiers.

Ringing of a signal after passing through a low pass filter in an LINC type linear amplifier is remedied. A linear amplifying device includes the linear amplifier including the low pass filter for removing high-frequency components; and an origin avoiding circuit which receives an original input signal and is provided upstream of the linear amplifier. If the original input signal is sampled in the vicinity of an origin, the origin avoiding circuit modifies a sampled value so at to replace the sampled value with a fixed value, and supplies the modified input signal to the linear amplifier.

In one aspect the embodiments relate to amplifier circuitry comprising an outphasing region and envelope tracking region. The outphasing region includes a signal processing block capable of receiving an amplitude and phase modulated input signal that is to be amplified, and processing said signal to separate it into two signals (S1, S2) of constant amplitude and modulated phase, a first signal S1 for driving a first RF power amplifier RF PA1 and a second signal S2 for driving a second RF power amplifier RF PA2. The output signals from each of the RF PAs are then provided to a power combiner (PC) for obtaining an output amplified signal (RF output). The envelope tracking region (100b) includes a linear amplifier (Env Amp) capable of receiving an input representing an envelope of the input signal that to be amplified, a charge storage device C1 coupled to said amplifier for providing an amplified envelope signal for driving the RF PAs, said amplifier (8) and charge storage device C1 being arranged to receive a supply voltage V+. The amplifier circuitry is configured such that when the first signal S1 and the second signal S2 in the outphasing circuit 100a are in phase, an input voltage V1 based on the voltage of the received envelope signal is provided to the amplifier in the envelope tracking region to enable the charge storage device C1 to supply a voltage V2 above the supply voltage V+ such that the output voltage of the RF PAs driven by the amplifier (8) is increased by V2 above the supply voltage V+.

Described herein are power amplifier (PA) architectures that improve PA performance (e.g., efficiency, linearity, etc.) over an extended range of the operating power levels of the PA. These architectures can be implemented on a single chip to provide a single-chip standalone PA solution. This improvement comes with little additional complexity, little additional current consumption, and/or little additional chip area. The architectures utilize a dynamic biasing technique using positive envelope feedback based at least in part on an instantaneous envelope signal at an output of a power amplifier.

A first branch group circuit includes a first branch circuit receiving a first RF input signal and first control information; and a second branch circuit receiving the first input signal and second control information. Each of the first and second branch circuits includes a power amplifier. The second control information enables the second branch circuit to be switched on or off while the first branch circuit remains on. A second branch group circuit includes: a third branch circuit receiving a second RF input signal and third control information; and a fourth branch circuit receiving the second input signal and fourth control information. Each of the third and fourth branch circuits includes a power amplifier. The fourth control information enables the fourth branch circuit to be switched on or off while the third branch circuit remains on. A combiner combines output signals of the power amplifiers to produce an output signal.

An outphasing amplifier includes a first class-E power amplifier having an output coupled to a first conductor and an input receiving a first RF drive signal. A first reactive element is coupled between the first conductor and a second conductor. A second reactive element is coupled between the second conductor and a third conductor. A second class-E power amplifier includes an output coupled to a fourth conductor and an input coupled to a second RF drive signal, a third reactive element coupled between the second and fourth conductors. Outputs of the first and second power amplifiers are combined by the first, second and third reactive elements to produce an output current in a load. An efficiency enhancement circuit is coupled between the first and fourth conductors to improve power efficiency at back-off power levels. Power enhancement circuits are coupled to the first and fourth conductors, respectively.

The circuit includes a transformer having a first primary coil coupled to a first power amplifier (PA), a second primary coil coupled to a second PA, and a secondary coil. The secondary coil supplies a current to an antenna based on a first direction of a first phase of a first amplified constant-envelope signal in the first primary coil with respect to a second phase of a second amplified constant-envelope signal in the second primary coil. A first load impedance is associated with the first PA and a second load impedance is associated with the second PA. The first load impedance and the second load impedance receive currents from the first PA and second PA, respectively, based on a second direction of the first phase of the first amplified constant-envelope signal with respect to the second phase of the second amplified constant-envelope signal.

Spatially combining signals may include receiving a number of RF input signals at a number of RF input connectors. At least one of the RF input signals is a variable envelope signal. A variable envelope signal is converted into two or more outphased constant envelope signals. The two or more outphased constant envelope signals are amplified. The amplified outphased constant envelope signals are radiated. At a spatial combiner aperture, the radiated amplified outphased constant envelope signals are combined to create a combined signal. The combined signal is output onto an output RF connector.

An embodiment provides an amplifier system with multiple amplification paths connected to a combiner for combination of signals amplified in the amplification paths, each amplification path comprising an amplifier and a matching network provided between the amplifier and the combiner, wherein the individual amplifiers can interact through the combiner, causing an active load-pull effect. The matching networks of the paths comprise harmonic terminations configured to one or more of reduce an overlap between the voltage and current waveforms within the amplifier connected to the matching network and improve the linearity of one or more of the amplifiers.