A bias circuit for a PA. A first transistor has its drain terminal and its gate terminal connected to a first circuit node and its source terminal connected to a first supply terminal, a first current source connected to the first circuit node, and a first resistor connected between the first and second circuit nodes. A second transistor receives a first component of a differential input signal to the PA at its gate terminal, has its drain terminal connected to the second circuit node and its source terminal connected to a second supply terminal, and a third transistor receives a second component of the differential input signal to the PA at its gate terminal, having its drain terminal connected to the second circuit node and its source terminal connected to a second supply terminal. The gates terminals of the second and third transistors are biased by a first voltage.

Systems, circuits and methods related to dynamic error vector magnitude (DEVM) corrections. In some embodiments, a power amplifier (PA) system can include a PA circuit having a plurality of amplification stages, and a bias system in communication with the PA circuit and configured to provide bias signals to the amplification stages. The PA system can further include a first correction circuit configured to generate a correction current that results in an adjusted bias signal for a selected amplification stage, with the adjusted bias signal being configured to compensate for an error vector magnitude (EVM) during a dynamic mode of operation. The PA system can further include a second correction circuit configured to change the correction current based on an operating condition associated with the PA circuit.

A power amplifier module includes an amplifier transistor and a bias circuit. A first power supply voltage based on a first operation mode or a second power supply voltage based on a second operation mode is supplied to the amplifier transistor. The amplifier transistor receives a first signal and outputs a second signal obtained by amplifying the first signal. The bias circuit supplies a bias current to the amplifier transistor. The bias circuit includes first and second resistors and first and second transistors. The first transistor is connected in series with the first resistor and is turned ON by a first bias control voltage which is supplied when the first operation mode is used. The second transistor is connected in series with the second resistor and is turned ON by a second bias control voltage which is supplied when the second operation mode is used.

Apparatus and methods for power amplifier biasing are disclosed herein. In certain implementations, a power amplifier system includes a power amplifier bias circuit and a power amplifier. The power amplifier bias circuit includes a reference current source that generates a reference current, a bipolar reference transistor, and a transimpedance amplifier that amplifies a difference between a collector current of the bipolar reference transistor and the reference current, and that provides a base bias voltage to a base of the bipolar reference transistor. The power amplifier generates a radio frequency output signal at an output based on amplifying a radio frequency input signal received at an input. The power amplifier includes a bipolar power amplifier transistor including a base biased by the base bias voltage such that the power amplifier has a substantially flat gain response versus time.

A power amplifier module that includes a power amplifier and a controller is presented herein. The power amplifier module may include a set of transistor stages and a plurality of bias circuits. At least one transistor stage from the set of transistor stages may be in electrical communication with a first bias circuit and a second bias circuit from the plurality of bias circuits. The first bias circuit can be configured to apply a first bias voltage to the at least one transistor stage and the second bias circuit can be configured to apply a second bias voltage to the at least one transistor stage. The controller may be configured to activate one of the first bias circuit and the second bias circuit.

An amplification circuit includes a first amplifier circuit and a second-stage amplifier. The second-stage amplifier is connected to the amplifier to form a multi-stage amplification circuit. The first amplifier circuit includes a first-stage amplifier and a bypass circuit. The bypass circuit includes a first transistor. A first end of the first transistor is coupled to the input end of the first amplifier circuit, a second end of the first transistor is coupled to the output end of the first amplifier circuit, and a third end of the first transistor is coupled to a supply voltage. The first end of the first transistor is further coupled to a first control terminal to receive a control signal for controlling a bias voltage of the first transistor, so as to make the amplification circuit work in different operation modes.

Apparatus and methods for power amplifier biasing are disclosed herein. In certain implementations, a power amplifier system includes a power amplifier bias circuit and a power amplifier. The power amplifier bias circuit includes a reference current source that generates a reference current, a bipolar reference transistor, and a transimpedance amplifier that amplifies a difference between a collector current of the bipolar reference transistor and the reference current, and that provides a base bias voltage to a base of the bipolar reference transistor. The power amplifier generates a radio frequency output signal at an output based on amplifying a radio frequency input signal received at an input. The power amplifier includes a bipolar power amplifier transistor including a base biased by the base bias voltage such that the power amplifier has a substantially flat gain response versus time.

Package assemblies for improving heat dissipation of high-power components in microwave circuits are described. A laminate that includes microwave circuitry may have cut-outs that allow high-power components to be mounted directly on a heat slug below the laminate. Electrical connections to circuitry on the laminate may be made with wire bonds. The packaging allows more flexible design and tuning of packaged microwave circuitry.

An amplifier circuit including an amplifying stage and a predistortion stage is disclosed. The amplifier circuit outputs an output signal X.sub.o. The predistortion stage is arranged for providing a predistortion signal X.sub.p to be added to an input signal X.sub.in of the amplifier circuit in order to compensate for non-linearites of said amplifying stage. According to the present invention, the amplifier circuit includes a working point unit arranged for determining a suitable working point WP.sub.suitable to be used for said amplifying stage based on said predistortion signal X.sub.p, and for adjusting an actual working point WP.sub.actual being used by said amplifying stage towards said suitable working point WP.sub.suitable.

Certain aspects of the present disclosure relate to methods and apparatus for power amplifier control. A power amplifier network includes a first path comprising a first power amplifier. The power amplifier network further includes a second path comprising a second power amplifier. The power amplifier network further includes a common input path to both the first path and the second path. The power amplifier network further includes a first power control network for controlling a first signal applied to the first power amplifier. The power amplifier network further includes a second power control network for controlling a second signal applied to the second power amplifier, wherein the first power control network is different from the second power control network.