A power amplifier device includes: a first power supply terminal for inputting a first power supply voltage; a first transistor for power amplification that (i) includes a first gate to which a bias voltage is applied, and (ii) is supplied with power from the first power supply terminal; a second power supply terminal for inputting a second power supply voltage lower than the first power supply voltage; a second transistor for monitoring that (i) includes a second gate to which the bias voltage is applied, (ii) is supplied with power from the first power supply terminal or the second power supply terminal, and (iii) imitates an operation of the first transistor; and a bias circuit that is supplied with power from the second power supply terminal and generates and adjusts the bias voltage according to a drain current or a source current of the second transistor.

An aspect includes an apparatus including a first amplifier; a first field effect transistor (FET) including a first source coupled to an output of the first amplifier, and a first drain for coupling to a first load; and a first gate drive circuit including an input coupled to the output of the first amplifier and an output coupled to a first gate of the first FET. Another aspect includes a method including amplifying a first audio signal using a first audio amplifier to generate a first voltage; generating a first gate voltage based on the first voltage; applying the first gate voltage to a first gate of a first field effect transistor (FET) coupled between the first audio amplifier and a first audio transducer; and applying the first voltage to a first source of the first FET.

An aspect includes an apparatus including a first amplifier; a first field effect transistor (FET) including a first source coupled to an output of the first amplifier, and a first drain for coupling to a first load; and a first gate drive circuit including an input coupled to the output of the first amplifier and an output coupled to a first gate of the first FET. Another aspect includes a method including amplifying a first audio signal using a first audio amplifier to generate a first voltage; generating a first gate voltage based on the first voltage; applying the first gate voltage to a first gate of a first field effect transistor (FET) coupled between the first audio amplifier and a first audio transducer; and applying the first voltage to a first source of the first FET.

An input signal is input to a main power amplifier and an auxiliary power amplifier. A combiner is connected to an output of the main power amplifier and an output of the auxiliary power amplifier. The combiner includes an impedance converter, first and second lumped elements. The impedance converter is connected to a combining point. The first lumped element is connected between the output of the main power amplifier and the combining point. The second lumped element is connected between the output of the auxiliary power amplifier and the combining point. A line length between the output of the main power amplifier and the combining point is the same as that between a line length between the output of the auxiliary power amplifier and the combining point.

An input signal is input to a main power amplifier and an auxiliary power amplifier. A combiner is connected to an output of the main power amplifier and an output of the auxiliary power amplifier. The combiner includes an impedance converter, first and second lumped elements. The impedance converter is connected to a combining point. The first lumped element is connected between the output of the main power amplifier and the combining point. The second lumped element is connected between the output of the auxiliary power amplifier and the combining point. A line length between the output of the main power amplifier and the combining point is the same as that between a line length between the output of the auxiliary power amplifier and the combining point.

According to an embodiment, An integrated circuit comprising a first cascode radio frequency (RF) power amplifier that includes a first common source transistor having a gate configured to receive a first RF signal, and a source connected to a neutral point; a first common gate transistor having a gate and a drain connected to a power source node, and a source connected to a drain of the first common source transistor; and a first resistor coupled between a bulk of the first common gate transistor and a first bulk bias node configured to provide a voltage that is greater than or equal to a voltage at the source of the first common gate transistor, wherein the first resistor is configured to obtain a floating point.

A signal to be amplified is applied to a gate terminal of an amplifier element that amplifies the signal and that is a transistor, the bias circuit includes: a switching element having a first terminal and a second terminal, the first terminal being electrically connected to the gate terminal; and a trap compensation element having a third terminal and a fourth terminal, the third terminal being connected to the second terminal. Further, the bias circuit includes a control circuit to apply a bias voltage to the gate terminal. Further, the bias circuit includes a voltage application circuit to apply a first voltage to the fourth terminal when the signal to be amplified is a transmission signal, and apply a second voltage to the fourth terminal when the signal to be amplified is a reception signal, the second voltage being a negative voltage.

A system for adjusting various parameters of an active electronic component based on sensed characteristics of the active electronic component and/or characteristics of the input or output power.

A system for adjusting various parameters of an active electronic component based on sensed characteristics of the active electronic component and/or characteristics of the input or output power.

Apparatus and methods for power amplifiers with positive envelope feedback are provided herein. In certain implementations, a power amplifier system includes a power amplification stage that amplifies a radio frequency signal, at least one envelope detector that generates one or more detection signals indicating an output signal envelope of the power amplification stage, and a wideband feedback circuit that provides positive envelope feedback to a bias of the power amplification stage based on the one or more detection signals. The power amplifier system further includes a supply modulator that controls a voltage level of a supply voltage of the power amplification stage based on the one or more detection signals such that the supply voltage is modulated with the output signal envelope through positive envelope feedback.