A number of biasing circuits for amplifiers including voltage controlled amplifier is presented. Also a number of field effect transistor circuits include voltage controlled attenuators or voltage controlled processing circuits. Example circuits include modulators, lower distortion variable voltage controlled resistors, sine wave to triangle wave converters, and or servo controlled biasing circuits.

A circuit includes an operational amplifier and a resistor network coupled to an output of the operational amplifier. The resistor network includes a first set of resistors coupled between the output of the operational amplifier and a first node of the resistor network, wherein the resistors of the first set are electrically connected in series with each other, a second set of resistors coupled between the first node and a second node of the resistor network, wherein the resistors of the second set are electrically connected in series with each other and include a first number of resistors, a third set of resistors coupled between the second node and a third node of the resistor network, wherein the third node is coupled to a first voltage, and wherein the resistors of the third set are electrically connected in parallel with each other and include a second number of resistors, and a resistor coupled between the first node and the second node and arranged in parallel with the second set of resistors.

A variable gain amplifier circuit is disclosed. In one embodiment, an amplifier circuit includes first and second stages. Each stage includes one or more inverter pairs, with one inverter of each pair coupled to receive an inverting component of a differential signal and the other inverter of the pair coupled to receive a non-inverting component. The first stage receives a differential input signal and produces an intermediate differential signal. The second stage receives the intermediate differential signal and produces a differential output signal, the differential output signal being an amplified version of the differential input signal.

An electronic apparatus is provided. The electronic apparatus includes: a memory configured to store volume histories for a plurality of content sources; and a processor configured to, based on a content source for providing a content being changed from a first content source to a second content source, among the plurality of content sources, identify a volume level corresponding to the second content source based on a volume history of the first content source and a volume history of the second content source among the stored volume histories, and change a currently-set volume level to the identified volume level, and update the volume history of the second content source based on the changed volume level.

Apparatus and methods for vector modulator phase shifters are provided. In certain embodiments, a phase shifter includes a quadrature filter that filters a differential input signal to generate a differential in-phase (I) voltage and a differential quadrature-phase (Q) voltage, an in-phase variable gain amplifier (I-VGA) that amplifies the differential I voltage to generate a differential I current, a quadrature-phase variable gain amplifier (Q-VGA) that amplifies the differential Q voltage to generate a differential Q current, and a current mode combiner that combines the differential I voltage and the differential Q voltage to generate a differential output signal. A phase difference between the differential output signal and the differential input signal is controlled by gain settings of the I-VGA and the Q-VGA.

An output stage circuit of an operational amplifier, the operational amplifier, and a signal amplifying method applied to the operational amplifier are provided. The output stage circuit includes an inverting circuit and a compensation module. The inverting circuit is electrically connected to a gain stage circuit of the operational amplifier. The inverting circuit generates an output signal of the operational amplifier. The compensation module includes a first compensation circuit, including a first current providing path and a first suppression activation circuit. The first current providing path provides a first compensation current. The first suppression activation circuit conducts the first compensation current to the inverting circuit if a first compensation condition related to a first gain stage signal generated by the gain stage circuit is satisfied. Variation of the output signal is suppressed because of the first compensation current.

An amplification device including: a switch including an output that is suitable for being connected to a first or a second input; a first branch that is connected to the first input, which applies a first gain to generate a first amplified signal; a second branch that is connected to the second input, which applies a second gain to generate a second amplified signal; a controller for controlling the switching of the switch to apply the first or the second amplified signal to the output, depending on whether or not the value of a predetermined quantity of the first amplified signal falls within a predetermined range. The first gain and the second gain being non-zero real numbers of opposite sign.

A bi-directional active combiner and splitter using bi-directional variable gain amplifiers (BD_VGAs) is proposed. Advantages of the proposed bi-directional active combiner and splitter includes the following 1) compact sizefor each BD_VGA, cascode transistor pair is small and the same matching network is used by the cascode transistor pair for both directions; 2) high efficiencyno switching loss in signal path, only switched matching; 3) reduced passive trace loss and power consumptionsimplified signal interconnection; 4) active current combiningeliminates large size in the passive combiner; 5) high input-output isolationcascode and neutralization; 6) precise gain control and unequal combining or splittingchanging the gain of the BD_VGA; and 7) phase-invariant amplifier design.

A receiver signal path includes a programmable flat gain stage configured to provide an amplified differential pair of signals based on a first frequency response having a selectable flat gain and a differential input pair of signals received on an input differential pair of nodes. The receiver signal path includes a peaking gain stage configured to generate a second amplified differential pair of signals based on the amplified differential pair of signals according to a second frequency response including a first peak gain at or near a carrier frequency in a first pass band. The first peak gain occurs just prior to a first cutoff frequency of the peaking gain stage. The programmable flat gain stage and the peaking gain stage are configured as a variable peaking gain stage. The selectable flat gain is selectively programmed based on a predetermined power consumption of a receiver path.

A radio frequency switch is disclosed. The RF switch uses a combination of transistor technology and a topology to create an RF switch that has a high isolation and a high voltage breakdown at frequencies including those above a gigahertz.