A circuit includes a first power transistor stage internally configured to function as a voltage-controlled current source, a second power transistor stage having an input impedance which varies as a function of input power and an interstage matching network coupling an output of the first power transistor stage to an input of the second power transistor stage. The interstage matching network is configured to provide impedance inversion between the input of the second power transistor stage and the output of the first power transistor stage. The impedance inversion provided by the interstage matching network transforms the first power transistor stage from functioning as a voltage-controlled current source to functioning as a voltage-controlled voltage source at the input of the second power transistor stage.

Provided are an output matching circuit and a power amplifier comprised thereof. The output matching circuit comprises an impedance transformation component and a first matching component connected to the input end of the impedance transformation component to establish matching. The first matching circuit comprises an impedance element and a controllable switch element whose on/off is controlled by an external control signal to form different impedances. The output matching circuit realizes the reconstruction of the output stage matching circuit and the switching of the output operating frequency band. It can be used for high frequency/medium frequency/low frequency, which reduces the cost, the number of components, and the design difficulty, and is easy to be integrated. It can be used for multi-band multiplexing power amplifiers. The wide-band amplifier is realized, the number of components and material cost are reduced, and the system integration degree of the power amplifier is increased.

A switched capacitor modulator (SCM) includes a RF power amplifier. The RF power amplifier receives a rectified voltage and a RF drive signal and modulates an input signal in accordance with the rectified voltage to generate a RF output signal to an output terminal. A reactance in parallel with the output terminal is configured to vary in response to a control signal to vary an equivalent reactance in parallel with the output terminal. A controller generates the control signal and a commanded phase. The commanded phase controls the RF drive signal. The reactance is at least one of a capacitance or an inductance, and the capacitance or the inductance varies in accordance with the control signal.

A device that includes a metal submount; a first transistor die arranged on said metal submount; a second transistor die arranged on said metal submount; a set of primary interconnects; and a set of secondary interconnects. Additionally, the set of primary interconnects and the set of secondary interconnects are configured to provide RF signal coupling between the first transistor die and the second transistor die by electromagnetic coupling.

An active bias circuit for a power amplifier and a mobile terminal are disclosed. The circuit includes a proportional to absolute temperature (PTAT) current source circuit, a reference voltage circuit, an isolation voltage stabilizing circuit, and a bias voltage circuit. An input end of the PTAT current source circuit is connected to a voltage source (Vbat), and an output end is connected to the reference voltage circuit. The reference voltage circuit generates a reference voltage that is in proportion to a current and a temperature. The isolation voltage stabilizing circuit isolates the reference voltage circuit from the bias voltage circuit, and supplies a stabilized voltage to the bias voltage circuit by using a negative feedback loop. The bias voltage circuit receives the voltage of the isolation voltage stabilizing circuit, and is also connected to the voltage source (Vbat).

A power amplification circuit that includes: a capacitor element in which a first metal layer, a first insulating layer, a second metal layer, a second insulating layer and a third metal layer are sequentially stacked, the capacitor element including a first capacitor in which the first metal layer serves as one electrode thereof and the second metal layer serves as another electrode thereof, and a second capacitor in which the second metal layer serves as one electrode thereof and the third metal layer serves as another electrode thereof; and a transistor that amplifies a radio-frequency signal. The radio-frequency signal is supplied to the one electrode of the first capacitor. The other electrode of the first capacitor and the one electrode of the second capacitor are connected to a base of the transistor, and the other electrode of the second capacitor is connected to the emitter of the transistor.

A hybrid RF transceiver circuit comprises a first matching network, a second matching network, a first power amplifier, a second power amplifier, and a low noise amplifier. The second matching network is coupled to the first matching network and an antenna. An output port of the first power amplifier is coupled to the first matching network and the second matching network. The output port of the second power amplifier is coupled to the first matching network. The input port of the low noise amplifier is coupled to the second power amplifier and the first matching network. The output port of the low noise amplifier is coupled to a receiver circuit.

A transceiving device includes: a signal port, arranged to relay an RF input signal during a first mode, and to relay an RF output signal during a second mode different from the first mode; a receiver, coupled to the signal port; a transmitter, coupled to the signal port; and a first adjustable capacitor, coupled to the signal port. The second adjustable capacitor is arranged to have a first capacitance during the first mode such that the RF input signal is received by the receiver, and the second adjustable capacitor is arranged to have a second capacitance during the second mode such that the RF output signal is transmitted to the signal port.

A power amplification module includes a first input terminal arranged to receive a first transmission signal in a first frequency band, a second input terminal arranged to receive a second transmission signal in a second frequency band higher than the first frequency band, a first amplification circuit that amplifies the first transmission signal, a second amplification circuit that amplifies the second transmission signal, a first filter circuit located between the first input terminal and the first amplification circuit, and a second filter circuit located between the second input terminal and the second amplification circuit. The first filter circuit is a low-pass filter that allows the first frequency band to pass therethrough and that attenuates a harmonic of the first transmission signal and the second transmission signal. The second filter circuit is a high-pass filter that allows the second frequency band to pass therethrough and that attenuates the first transmission signal.

Disclosed are devices and methods for improving power added efficiency and linearity of radio-frequency power amplifiers implemented in flip-chip configurations. In some embodiments, a harmonic termination circuit can be provided so as to be separate from an output matching network configured to provide impedance matching at a fundamental frequency. The harmonic termination circuit can be configured to terminate at a phase corresponding to a harmonic frequency of the power amplifier output. Such a configuration of separate fundamental matching network and harmonic termination circuit allows each to be tuned separately to thereby improve performance parameters such as power added efficiency and linearity.