An aspect of the disclosure relates to a method of reducing a third-order intermodulation component at a first terminal of a transistor, including: receiving an input radio frequency (RF) signal cycling with a first frequency at a control terminal of the transistor; generating a feedback RF signal cycling at a second frequency at a second terminal of the transistor, wherein the second frequency is substantially twice the first frequency; and generating a third-order intermodulation cancellation component at the first terminal including combining the input RF signal with the feedback RF signal, wherein the third-order intermodulation cancellation component has a magnitude and phase substantially equal to and opposite a magnitude and phase of the third-order intermodulation component at the first terminal of the transistor, respectively.

Provided are a low noise amplifier and a receiver. The low noise amplifier comprises at least one input port configured to receive an input signal including a carrier, first to third output ports connected to first to third load circuits, respectively, and configured to transmit an output signal, a first amplifier stage comprising a first type gain stage connected to the input port and first to third first type drive stages connected to the first to third output ports, respectively and second to third amplifier stages, each comprising a second type gain stage and a second type drive stage, wherein the low noise amplifier is configured to vary an impedance of an input transistor included in each of the first type gain stage and the second type gain stage, so that an input impedance is uniform even when operating in a plurality of operation modes.

A power amplifier circuit includes a first transistor that amplifies a first signal and outputs a second signal; a second transistor that amplifies the second signal and outputs a third signal; a bias circuit that supplies a bias current to a base of the second transistor; and a bias adjustment circuit that adjusts the bias current by subjecting the first signal to detection. The bias adjustment circuit controls the bias current such that a first current extracted from the bias circuit depends on a magnitude of the first signal.

A power amplifier circuit includes a first transistor that amplifies a first signal and outputs a second signal; a second transistor that amplifies the second signal and outputs a third signal; a bias circuit that supplies a bias current to a base of the second transistor; and a bias adjustment circuit that adjusts the bias current by subjecting the first signal to detection. The bias adjustment circuit controls the bias current such that a first current extracted from the bias circuit depends on a magnitude of the first signal.

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.

Disclosed is a technology related to a low noise amplifier applied between an RF receiver and an RF switch. A phase difference matching circuit having the same phase difference as a positive gain amplifier is added to an output terminal of an attenuator of a low noise amplifier having a variable gain switching structure. In addition, a variable impedance circuit connected to an output terminal of the positive gain amplifier and an output terminal of a phase difference matching unit to finely adjust the phase difference of each output terminal may be further included.

Disclosed is a technology related to a low noise amplifier applied between an RF receiver and an RF switch. A phase difference matching circuit having the same phase difference as a positive gain amplifier is added to an output terminal of an attenuator of a low noise amplifier having a variable gain switching structure. In addition, a variable impedance circuit connected to an output terminal of the positive gain amplifier and an output terminal of a phase difference matching unit to finely adjust the phase difference of each output terminal may be further included.

In one embodiment, a dual-mode power amplifier that can operate in different modes includes: a first pair of metal oxide semiconductor field effect transistors (MOSFETs) to receive and pass a constant envelope signal; a second pair of MOSFETs to receive and pass a variable envelope signal, where first terminals of the first pair of MOSFETs are coupled to first terminals of the second pair of MOSFETs, and second terminals of the first pair of MOSFETs are coupled to. second terminals of the second pair of MOSFETs; and a shared MOSFET stack coupled to the first pair of MOSFETs and the second pair of MOSFETs.

Methods and devices used in mobile receiver front end to support multiple paths and multiple frequency bands are described. The presented devices and methods provide benefits of scalability, frequency band agility, as well as size reduction by using one low noise amplifier per simultaneous outputs. Based on the disclosed teachings, variable gain amplification of multiband signals is also presented.

Various embodiments disclose a method and a device including: an antenna, a switching regulator, communication chip including an amplifier and a linear regulator operably connected to the amplifier and the switching regulator, the communication chip configured to transmit a radio-frequency signal from the electronic device through the antenna, and control circuitry configured to control the communication chip such that the linear regulator provides the amplifier with a voltage corresponding to an envelope of an input signal input to the amplifier, the input signal corresponding to the radio-frequency signal.