Disclosed are CMOS-based devices for switching radio frequency (RF) signals and methods for biasing such devices. In certain RF devices such as mobile phones, providing different amplification modes can yield performance advantages. For example, a capability to transmit at low and high power modes typically results in an extended battery life, since the high power mode can be activated only when needed. Switching between such amplification modes can be facilitated by one or more switches formed in an integrated circuit and configured to route RF signal to different amplification paths. In certain embodiments, such RF switches can be formed as CMOS devices, and can be based on triple-well structures. In certain embodiments, an isolated well of such a triple-well structure can be provided with different bias voltages for on and off states of the switch to yield desired performance features during switching of amplification modes.

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.

Various embodiments of switched amplifiers are disclosed herein. In some embodiments, a switched amplifier may include a first amplifier; a second amplifier; an input matching network common to both the first and second amplifiers; and at least one switch to couple an input of the switched amplifier, via the input matching network, to one of the first amplifier or the second amplifier. In some embodiments, a switched amplifier may include a first amplifier; a second amplifier; an input matching network common to both the first and second amplifiers or an output matching network common to both the first and second amplifiers; and a bias generation circuit to selectively (1) provide a first bias current to the first amplifier or (2) provide a second bias current to the second amplifier, wherein the second bias current is less than the first bias current.

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.

Apparatus and methods for providing variable regulated voltages are disclosed. Variable voltage control elements can adjust a regulated voltage provided by a single voltage regulator, thereby providing a variable regulated voltage. The regulated voltage can be used in a variety of applications, for example, as a bias voltage for a power amplifier.

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.

Device and methods for improving consistency of operation and therefore yield of scalable periphery amplifiers is described. Amplifier size of the scalable periphery architecture can be adjusted to obtain part-to-part consistency of operating performance as per a defined/desired set of criteria. Amplifier segments of the scalable periphery architecture can be rotated to distribute wear. Further, extra amplifier segments can be implemented on amplifier dies to extend the overall lifetime of amplifiers.

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 bias circuits are disclosed herein. In certain implementations, a power amplifier bias circuit includes a current source configured to generate a reference current, a plurality of reference bipolar transistors, a selection circuit configured to select one or more selected reference bipolar transistors from the plurality of reference bipolar transistors, and a transimpedance amplifier. The one or more selected reference bipolar transistors have a current therethrough that changes in relation to a power amplifier stage bias voltage, and the transimpedance amplifier is configured to control the power amplifier stage bias voltage based on an error current corresponding to a difference between the reference current and the current through the one or more selected reference bipolar transistors.