Abstract: An amplifier provides a first amplifier circuit (16), a second amplifier circuit (17), a first hybrid-coupler circuit (18) and a termination (3). The hybrid-coupler circuit (18) provides an output terminal (13) and an insulation terminal (12). In this context, the termination (3) is connected to the insulation terminal (12) of the hybrid-coupler circuit (18). The termination (3) comprises a first capacitor (34) and/or an inductance (35), which is disposed directly at the insulation terminal (12) of the hybrid-coupler circuit (18).

Abstract: The augmented twin nonlinear two-box modeling and predistortion method for power amplifiers and transmitters provides power amplifier distortion modeling and predistortion linearization. A memoryless nonlinearity is combined with a memory polynomial function that includes cross-terms. The method can utilize an augmented forward twin-nonlinear two-box model, an augmented reverse twin-nonlinear two-box model, or alternatively, an augmented parallel twin-nonlinear two-box model. The present two-box models are validated in modeling and predistortion applications. Measurement results demonstrate the superiority of the present two-box models with respect to conventional state of the art models. The present two-box models lead to better accuracy with reduced complexity.

Abstract: A multistage amplifier may include a multistage amplifier circuit and a resistive voltage divider network. The multistage amplifier circuit may have multiple transconductance input stages, each of which may have differential inputs and an adjustable tail current input that controls the amount of the transconductance of the input stage. The resistive voltage divider network may control the closed loop gain of the multistage amplifier circuit and include multiple resistors that provide different voltage divider ratios at different points. Each point may be connected to one of the transconductance input stages. Adjustment of tail currents at the tail current inputs may control the degree to which each point affects the closed loop gain of the multistage amplifier.

Abstract: It is possible to increase linearity in a power amplification circuit. A power amplification circuit includes a first amplification element which amplifies and outputs an input signal with a gain according to the level of the input signal and the level of a bias voltage, a second amplification element which has the same gain characteristic as the first amplification element and amplifies and outputs the input signal, and a variable bias voltage generation circuit which generates a bias voltage decreasing with an increase in level of an output signal of the second amplification element.

Abstract: Methods and apparatus, including computer program products, are provided for hybrid DC-DC converters. In one aspect, there is provided a method. The method may include tracking, by an envelope detector, an envelope of a signal being amplified by an amplifier. The method may further include supplying, by a first direct-current to direct-current converter, power to the amplifier, the power supplied by the first direct-current to direct-current converter including one or more high-frequency components of the envelope tracked by the envelope detector. The method may further include supplying, by a second direct-current to direct-current converter, power to the amplifier, the power supplied by the second direct-current to direct-current converter including one or more low-frequency components of the envelope tracked by the envelope detector. Related systems, apparatuses, and computer program products are also disclosed.

Abstract: A circuit includes a first input terminal for receiving a first pulsed voltage and a second input terminal for receiving a second pulsed voltage. The circuit further includes a load and an LC filter. The LC filter includes a coupled inductor pair that includes a first winding and a second winding magnetically coupled to each other. The first winding is coupled between the first input terminal and the load, and the second winding is coupled between the second input terminal and the load. A frequency of a first current flowing through the first winding is increased by the second pulsed voltage applied to the second winding.

Abstract: An audio amplifier apparatus and method which has a preamp, active 2-way crossover, solid-state power amplifier, and tube power amplifier. Audio input from a musical instrument enters the preamp where pre-amplification, equalization, and other processes such as limiting or compression take place. Audio leaves the preamp and goes to a crossover, wherein frequencies below a crossover point are sent to a solid-state power amp via a first signal path, and wherein audio frequencies above the crossover point are sent to a tube power amp via a second signal path. Outputs from the solid-state power amp and tube power amp are sent to external or internal loudspeakers.

Abstract: A system comprises a power amplifier configured to amplify an input signal, a splitter configured to split the amplified input signal into a plurality of output signals, a plurality of filters configured to filter the plurality of output signals, respectively, to produce a plurality of filtered output signals, and a combiner configured to combine the filtered output signals to produce a combined output signal.

Abstract: A power amplifier is provided. The power amplifier comprises a plurality of power amplifier units and a bias unit. The power amplifier units are connected in parallel with each other to receive a differential input signal. The power amplifier units perform a power amplifying so as to output a differential output signal. The bias unit is coupled to the power amplifier units and supplies a plurality of bias signals to the power amplifier units respectively. At least two of the power amplifier units are enable to operate in different class regions in according with the corresponding bias signals.

Abstract: A system for combining power includes a plurality of branches and a secondary winding. The plurality of branches are configured to provide branch power. Each of the branches contribute to the branch power at non-peak power. The secondary winding is configured to combine the branch power from the plurality of branches into an output power.

Abstract: A direct current (DC)-DC converter, which includes a parallel amplifier, a radio frequency (RF) trap, and a switching supply, is disclosed. The switching supply includes switching circuitry and a first inductive element. The parallel amplifier has a feedback input and a parallel amplifier output. The switching circuitry has a switching circuitry output. The first inductive element is coupled between the switching circuitry output and the feedback input. The RF trap is coupled between the parallel amplifier output and a ground.

Abstract: A scalable periphery tunable matching power amplifier is presented. Varying power levels can be accommodated by selectively activating or deactivating unit cells of which the scalable periphery tunable matching power amplifier is comprised. Tunable matching allows individual unit cells to see a constant output impedance, reducing need for transforming a low impedance up to a system impedance and attendant power loss. The scalable periphery tunable matching power amplifier can also be tuned for different operating conditions such as different frequencies of operation or different modes.

Abstract: Embodiments of a radio frequency (RF) amplification device having an RF amplification circuit and an amplifier control circuit operably associated with the RF amplification circuit are disclosed. The RF amplification circuit is configured to amplify an RF signal in accordance with a transfer function. The amplifier control circuit includes a closed-loop linearization circuit and a calibration circuit. The closed-loop linearization circuit is configured to be activated so that the transfer function defines a closed-loop response and inactive so that the transfer function defines an open-loop response. For example, the closed-loop linearization circuit may become inactive at small-signal power levels. Accordingly, the amplifier control circuit also includes a calibration circuit configured to reduce a difference between the open-loop response and the closed-loop response of the transfer function.

Abstract: A high slew rate operational amplifier including an input terminal, an output terminal, and at least one slew-rate enhancing circuit is disclosed. Each slew-rate enhancing circuit includes a first stage enhancing unit and a second stage enhancing unit. The first stage enhancing unit is coupled between the input terminal and the output terminal. The first stage enhancing unit and the second stage enhancing unit are coupled. The slew-rate enhancing circuit has a threshold voltage and the threshold voltage is related to the size of the first stage enhancing unit. When the threshold voltage is driven, the slew-rate enhancing circuit will rapidly start the second stage enhancing unit to perform a slew rate compensation on the high slew rate operational amplifier.

Abstract: A differential cross-coupled common-source or common-emitter low-noise amplifier having capacitive degeneration is disclosed. Further, a radio receiver comprising such a low-noise amplifier is disclosed. Further, a method of controlling switched capacitive networks of an amplifier is disclosed. The method comprises controlling capacitances of the switched degeneration capacitor networks and/or the switched cross-coupling capacitor networks. Further, a computer program for implementing the method is disclosed.

Abstract: A circuit may include one or more transistors connected directly to an output, and an inductance network. The inductance network may connect to a source node of at least one of the transistors, to compensate capacitance of the output. Thus, the response time of the circuit may decrease, and a non-dominant frequency response pole frequency of the circuit may increase.

Abstract: A transconductance amplifier comprises a set of amplifier stages. The last stage of the amplifier is split with a certain ratio whereby one part is used to deliver output current and other part to deliver feedback current to the input.

Abstract: A circuit may include one or more transistors connected directly to an output, and a biasing network connected to at least one of a substrate, a well, and a back-gate of at least one of the transistors. The biasing network may bias the at least one of the substrate, the well, and the back-gate to a virtual floating bias, such that the virtual floating bias shifts in voltage level based upon an AC input signal of the circuit, to reduce the parasitic capacitance of the output node of the circuit.

Abstract: An amplifying device including: a first amplifier configured to generate a first output signal by amplifying an input signal, a second amplifier configured to generate a second output signal by amplifying the first output signal, and a processor configured to perform a first compensation by compensating a distortion for the second amplifier in accordance with the first output signal and the second output signal.

Abstract: An operational amplifier has two paths, a high frequency path and a low frequency path. In addition, it has three main sections of stages. A stage converts input voltage to an amplified output voltage, a stage converting an input voltage in to an output current and a final stage where the outputs of the two previous sections are supplied as inputs. Among them, the final stage acts as a voltage follower to a signal applied to its plus (+) input and as a transimpedance amplifier for a signal applied to its minus input (?). In this configuration, a path for low frequencies and a path for high frequencies are created in a single operational amplifier.