A variable gain low noise amplifier (LNA) and a method for controlling a gain of the variable gain LNA are provided. The variable gain LNA may include a first transistor, a first degeneration inductor, a second transistor and a second degeneration inductor, wherein the first degeneration inductor is coupled to a source terminal of the first transistor, and the second degeneration inductor is coupled to a source terminal of the second transistor. Gate terminals of the first transistor and the second transistor are configured to receive an input signal. The first transistor and the first degeneration inductor belong to a first branch of the variable gain LNA, and the second transistor and the second degeneration inductor belong to a second branch of the variable gain LNA. More particularly, a gain of the variable gain LNA is determined by controlling whether to turn off the second branch.

A front end module (FEM) integrated circuit (IC) architecture that uses the same LNA in each of several frequency bands extending over a wide frequency range. In some embodiments, switched impedance circuits distributed throughout the front end circuit allow selection of the frequency response and impedances that are optimized for particular performance parameters targeted for a desired device characteristic. Such switched impedance circuits tune the output and input impedance match and adjust the gain of the LNA for specific operating frequencies and gain targets. In addition, adjustments to the bias of the LNA can be used to optimize performance trade-offs between the total direct current (DC) power dissipated versus radio frequency (RF) performance. By selecting appropriate impedances throughout the circuit using switched impedance circuits, the LNA can be selectively tuned to operate optimally at a selected bias for operation within selected frequency bands.

Disclosed are a hybrid mode based audio processing method and an apparatus therefor. A hybrid mode based audio processing apparatus according to an exemplary embodiment of the present disclosure includes a signal converting unit which converts a digital signal of an input sound source into an analog signal; a mode controller which analyzes the input sound source, sets an amplification mode according to the analysis result, and generates an amplification control signal to control the amplification mode; an amplifying unit which amplifies the analog signal in the amplification mode set based on the amplification control signal; and an audio output unit which outputs an audio corresponding to the amplified analog signal.

A communication device includes a power amplifier that generates power signals according to one or more operating bands of communication data, with the amplitude being driven and generated in output stages of the power amplifier. The final stage can include an output passive network that suppresses suppress an amplitude modulation-to-phase modulation (AM-PM) distortion. During a back-off power mode a bias of a capacitive unit of the output power network component can be adjusted to minimize an overall capacitance variation. An output passive network can further generate a flat-phase response between dual resonances of operation.

A circuit arrangement is provided which includes an array of stages for photon counting current to voltage conversion. Each stage includes a tunable operational transconductance amplifier and a feedback network forming a feedback loop of the operational transconductance amplifier. Each stage is configured to provide an output signal as a function of an input signal that is provided to the amplifier input of the operational transconductance amplifier, wherein the input signal comprises one or more current pulses and the output signal comprises one or more voltage pulses. With the tunable operational transconductance amplifier the transconductance of a stage can be tuned so that differences in peaking time and gain are avoided. Furthermore, an imaging device and a method for operating a circuit arrangement are provided.

Methods and circuital arrangements for turning OFF branches of a multi-branch cascode amplifier are presented. First and second switching arrangements coupled to a branch allow turning OFF the branch while protecting transistors of the branch from a supply voltage that may be greater than a tolerable voltage of the transistors. The first switching arrangement includes a transistor-based switch that is in series connection with the transistors of the branch. The first switching arrangement drops the supply voltage during the OFF state of the branch and provides a conduction path for a current through the branch during the ON state of the branch. A resistor and a shunting switch are coupled to a gate of the transistor-based switch to reduce parasitic coupling effects of the transistor-based switch upon an RF signal coupled to the branch during the ON state and OFF state of the branch.

Circuits and methods for using in parallel amplification and signal combining are described herein. A circuit uses a digitally controlled multistage cascade combiner, a digital phase and drive signal amplifier controller and a digital combiner controller circuit with N parallel signals with constant amplitudes belonging to an alphabet with M discrete values and discrete phases feeding it. The signals resulting from N power amplifiers (PAs) have also constant amplitudes belonging to an alphabet with N discrete values and discrete phases prior to being fed to the multistage combiner. A digital combiner controller circuit generates digital control information to activate, or deactivate, the outputs of the PAs, where a set of digital control signals generated in digital combiner controller are used to control sets of switches, where the signals can be activated at the combiner's inputs, according to their power and phase values. The digital control information ensures that only in-phase signals are combined in the active combiner stage and any difference among the inputs of the combiners is always minimized. Both digital combiner controller and digital drive signal amplifier controller, share information about the signals not to be fed to the multistage combiner, so that PAs drive signals can also be powered off under these circumstances. In provide high efficiency amplification the signal amplifiers employed before the combining stage may be of switched or current source type.

A differential amplifier is provided. The differential amplifier includes a first load, a second load, a current source, a differential pair circuit, a first and a second switch circuit. The differential pair circuit includes a first transistor, a second transistor, a third transistor, and a fourth transistor. The first switch circuit controls the first and the second transistors, and the second switch circuit controls the third and the fourth transistors. Through the control and selection of the first and second switch circuits, a differential pair is selected in the differential pair circuit to receive and process a first input signal and a second input signal for signal.

A communication device includes a power amplifier that generates power signals according to one or more operating bands of communication data, with the amplitude being driven and generated in output stages of the power amplifier. The final stage can include an output passive network that suppresses suppress an amplitude modulation-to-phase modulation (AM-PM) distortion. During a back-off power mode a bias of a capacitive unit of the output power network component can be adjusted to minimize an overall capacitance variation. A output passive network can further generate a flat-phase response between dual resonances of operation.

A multi-band power amplifier module includes at least one transmission input terminal, at least one power amplifier circuit that receives a first transmission signal and a second transmission signal through the at least one transmission input terminal, a first filter circuit that allows the first transmission signal to pass therethrough, a second filter circuit that allows the second transmission signal to pass therethrough, at least one transmission output terminal through which the first and second transmission signals output from the first and second filter circuits are output, a transmission output switch that outputs each of the first and second transmission signals output from the at least one power amplifier circuit to the first filter circuit or the second filter circuit, and a first tuning circuit that adjusts impedance matching between the at least one power amplifier circuit and the at least one transmission output terminal.