A single servo control loop for amplifier gain control based on signal power change over time or system to system, having an amplifier configured to receive an input signal on an amplifier input and generate an amplified signal on an amplifier output. The differential signal generator processes the amplified signal to generate differential output signals. The single servo control loop processes the differential output signal to generates one or more gain control signals and one or more current sink control signals. A gain control system receives a gain control signal and, responsive thereto, controls a gain of one or more amplifiers. A current sink receives a current sink control signal and, responsive thereto, draws current away from the amplifier input. Changes in input power ranges generate changes in the integration level of the differential signal outputs which are detected by the control loop, and responsive thereto, the control loop dynamically adjusts the control signals.

An LNA having a plurality of paths, each of which can be controlled independently to achieve a gain mode. Each path includes at least an input FET and an output FET coupled in series. A gate of the output FET is controlled to set the gain of the LNA. Signals to be amplified are applied to the gate of the input FET. Additional stacked FETs are provided in series between the input FET and the output FET.

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.

An automatic gain control system and a control method, a power detector and a radio frequency receiver are provided, wherein the power detector includes: a detection circuit, having a first and second input terminals connected to respective first and second differential output terminals of the trans-impedance amplifier, and configured to sample a peak of a differential output signal of the trans-impedance amplifier along with a clock cycle and provide a differential detection signal at a first output node; a filter circuit converts energy of the differential detection signal obtained at the first output node into an output voltage, so that the power detector may be used to detect an output power of the trans-impedance amplifier and adjust, by a control logic unit, a gain or an output power of a low noise amplifier connected to a radio frequency signal.

Methods related to amplification of radio-frequency signals. In some embodiments, a method for amplifying a radio-frequency signal can include configuring a gain stage to be in a selected one of a plurality of gain settings, with at least some of the gain settings resulting in different phases for the radio-frequency signal. The method can further include adjusting the phase of the radio-frequency signal for the selected gain setting, such that the adjusted phase is part of desired phases adjusted from the different phases.

A programmable gain amplifier includes a programmable resistor ladder deployed across N.sub.max junction nodes and controlled by N.sub.max−1 resistor control signals, where N.sub.max is an integer greater than one; a common-gate cascode amplifier multiplexer comprising N.sub.max common-gate cascode amplifiers configured to receive N.sub.max internal voltages at the N.sub.max junction nodes and output N.sub.max output currents in accordance with N.sub.max amplifier control signals, respectively, to an output node that is loaded with a load; and an AC (alternate current) coupling capacitor configured to couple an input node to the first junction node.

Techniques for controlling one or more audio amplifiers in or associated with a device coupled on a local area network are disclosed. An example playback device includes a processor, an amplifier, a network interface, and a memory. The memory includes a software module that, when executed by the processor, causes the playback device to: operate in a first power mode in which the amplifier consumes a first amount of power; while operating in the first power mode, determine that a defined time has passed since receiving, via the network interface, a specified type of data packet; and based on determining that the defined time has passed since receiving the specified type of data packet, transition from operating in the first power mode to operate in a second power mode in which the amplifier consumes a second amount of power, wherein the first amount of power is greater than the second amount of power.

A high-frequency amplifier circuit has a source-grounded first transistor that amplifies a high-frequency input signal, a gate-grounded second transistor that further amplifies the amplified signal, a first inductor and a first reference voltage node, a second inductor connected between a first node and a second reference voltage node, a third transistor that is connected between the first node and a drain of the second transistor, is turned on at the time of selecting the first mode to transmit the amplified signal to the first node, and is turned off when selecting a second mode to disconnect the first node from the drain of the second transistor, a bypass path that bypasses the high-frequency input signal from an input node of the high-frequency input signal to the first node at the time of selecting the second mode, and a bypass switching circuit that is connected on the bypass path.

Described herein are variable gain amplifiers and multiplexers that embed programmable attenuators into switchable paths to provide variable gain for individual amplifier inputs. The variable gain for an individual input is provided using an amplification stage that is common for each input of the amplifier. A variable attenuation is provided for individual inputs through a combination of a band selection switch and an attenuation selection branch. Individual inputs can be configured to bypass the variable attenuation in a high gain mode.

Methods and devices for amplifying an input RF signal according to at least two gain-states is described. According to one aspect, a multi gain amplifier circuit including a low noise amplifier having a stack of transistors is used for amplification of the input RF signal. When switching from a low gain-state to a high gain-state, the drain-to-source voltage of the output transistor of the stack is increased to affect region of operation of the output transistor, and thereby reduce non-linearity at the output of the amplifier. When switching from the high gain-state to the low gain-state, the drain-to-source voltage of the input transistor of the stack is increased to affect region of operation of the input transistor, and thereby reduce non-linearity at the output of the amplifier.