Various methods and circuital arrangements for biasing gates of stacked transistor amplifier that includes two series connected transistor stacks of different polarities are presented, where the amplifier is configured to operate according to different modes of operation. Such circuital arrangements operate in a closed loop with a feedback error voltage that is based on a sensed voltage at a common node of the two series connected transistor stacks. According to one aspect, gate biasing voltages to input transistors of each of the two series connected stacks are adjusted by respective current mirrors that are controlled based on the feedback error voltage. According to another aspect, other gate biasing voltages are generated by maintaining a fixed gate biasing voltage between any two consecutive gate basing voltages.

A radio frequency (RF) power amplifier includes an amplifying stage that includes an amplifying module, an input module and a feedback module. The amplifying module receives an RF to-be-amplified signal, and performs power amplification on the RF to-be-amplified signal to generate an RF output signal. The input module receives an RF input signal. The feedback module receives the RF output signal, cooperates with the input module to provide the RF to-be-amplified signal based on the RF input and output signals, and cooperates with the amplifying module to forma positive feedback loop that provides a loop gain which is less than one.

A radio frequency (RF) power amplifier includes an amplifying stage that includes an amplifying module, an input module and a feedback module. The amplifying module receives an RF to-be-amplified signal, and performs power amplification on the RF to-be-amplified signal to generate an RF output signal. The input module receives an RF input signal. The feedback module receives the RF output signal, cooperates with the input module to provide the RF to-be-amplified signal based on the RF input and output signals, and cooperates with the amplifying module to forma positive feedback loop that provides a loop gain which is less than one.

A power amplifier includes an outphasing amplifier. The outphasing amplifier includes a first amplifier and a second amplifier, and is configured to provide a first amplified RF signal and a second amplified RF signal that is phase shifted from the first amplified RF signal. The power amplifier further includes an output circuit that is configured to combine RF power of the first and second amplified RF signals at a summing node. The output circuit includes a first branch connected between the first amplifier and a summing node and a second branch connected between the second amplifier and the summing node. The first and second branches are each configured to match an output impedance of the first and second amplifiers and to phase shift the first and second amplified RF signals for an outphasing operation using common reactive components for the match of the output impedance and the outphasing operation.

A power amplifier includes an outphasing amplifier. The outphasing amplifier includes a first amplifier and a second amplifier, and is configured to provide a first amplified RF signal and a second amplified RF signal that is phase shifted from the first amplified RF signal. The power amplifier further includes an output circuit that is configured to combine RF power of the first and second amplified RF signals at a summing node. The output circuit includes a first branch connected between the first amplifier and a summing node and a second branch connected between the second amplifier and the summing node. The first and second branches are each configured to match an output impedance of the first and second amplifiers and to phase shift the first and second amplified RF signals for an outphasing operation using common reactive components for the match of the output impedance and the outphasing operation.

An amplifier according to an embodiment of the present disclosure includes a first transistor and a first matching circuit. The first matching circuit is connected between an input terminal and a control terminal of the first transistor. The first matching circuit includes a first inductor, a second inductor, and a first switch. The first inductor has an end connected to the control terminal. The second inductor has an end connected to the other end of the first inductor. The first switch is configured to selectively switch between electrical continuity between the input terminal and the other end of the first inductor and electrical continuity between the input terminal and the other end of the second inductor.

An amplifier according to an embodiment of the present disclosure includes a first transistor and a first matching circuit. The first matching circuit is connected between an input terminal and a control terminal of the first transistor. The first matching circuit includes a first inductor, a second inductor, and a first switch. The first inductor has an end connected to the control terminal. The second inductor has an end connected to the other end of the first inductor. The first switch is configured to selectively switch between electrical continuity between the input terminal and the other end of the first inductor and electrical continuity between the input terminal and the other end of the second inductor.

A trans-impedance amplifier (TIA) may include an input stage and an output driving stage. The input stage may include a pair of input PMOS transistors, a pair of input NMOS transistors, and a pair of differential voltage input nodes. The output driving stage may include a pair of output circuits, each may include a first pair of PMOS and NMOS transistors electrically connected in parallel, a second pair of PMOS and NMOS transistors electrically connected in series, a pair of capacitors electrically connected in series, a differential output node, a third PMOS transistor, and a fourth pair of NMOS transistors cross-coupled between the pair of output circuits of the output driving stage. The structure can lead to a reduced noise level and a reduced peak transient current level of the TIA.

A power amplifier includes a common source amplifier and a common gate amplifier circuit. The common source amplifier circuit has a terminal connected to a radio frequency (RF) input terminal and uses a source terminal commonly as an input terminal and an output terminal of the power amplifier. The common gate amplifier circuit has a terminal connected to the common source amplifier circuit and another terminal connected to an RF output terminal, and uses a gate terminal commonly as the input terminal and the output terminal of the power amplifier. The common gate amplifier circuit includes a Doherty amplifier including a main power amplifier and an auxiliary power amplifier that is connected to the main power amplifier in parallel.

A power amplifier includes a common source amplifier and a common gate amplifier circuit. The common source amplifier circuit has a terminal connected to a radio frequency (RF) input terminal and uses a source terminal commonly as an input terminal and an output terminal of the power amplifier. The common gate amplifier circuit has a terminal connected to the common source amplifier circuit and another terminal connected to an RF output terminal, and uses a gate terminal commonly as the input terminal and the output terminal of the power amplifier. The common gate amplifier circuit includes a Doherty amplifier including a main power amplifier and an auxiliary power amplifier that is connected to the main power amplifier in parallel.