A current sense loop includes an attenuator circuit, which has an embedded input chopper circuit, and an amplifier circuit, which has an output chopper circuit. The embedded input chopper has a first chopper input that is coupled to a first attenuator input, a first chopper output that is coupled to a first attenuator output, a second chopper input that is coupled to a second attenuator input, and a second chopper output that is coupled to a second attenuator output. An amplifier has a first input coupled to the first attenuator output and a second input coupled to the second attenuator output. An NFET has a gate coupled to the amplifier output, a source coupled to a ground plane, and a drain coupled to the second attenuator input.

A wireless access point is configured to regularly monitor the status of WLAN, WAN and ePDG data links to determine whether the current connections are sufficient to support VoWiFI services. When a device connects to the WLAN of the hub and attempts to switch from its VoLTE service to VoWiFi via the hub, the hub is configured to determine whether the current conditions can satisfy a VoWiFi connection. If the VoWiFi service can support the connection, the request is routed to the ePDG associated with the mobile device's subscriber LTE network. However, if the current conditions cannot satisfactorily support a VoWiFi connection such that incoming calls may be missed or the quality of active calls would not be clear, then the hub is configured to block the request so that the client device will time out and remain connected to VoLTE.

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.

Disclosed herein are methods for amplifying a signals. The methods include receiving signals at a plurality of input nodes. The methods also include configuring a gain stage to be in a selected one of a plurality of gain settings, at least some of the gain settings resulting in different impedances presented to the signal. The methods also include adjusting the resistance presented to the signal by the gain stage for the selected gain setting, the adjusted resistance being configured to provide a targeted constant value of the impedance at the input across the plurality of gain settings. The methods also include amplifying at least a portion of the received signals. Adjusting the resistance compensates for changes to the input impedance to improve return loss and mismatch over gain modes.

An amplifying device includes a first amplifier, a voltage-limiting circuit, a second amplifier, a first controller, and a second controller. The first amplifier is configured to amplify an input signal. The voltage-limiting circuit is configured to limit a voltage of an output signal from the first amplifier to within a limit range. The second amplifier is configured to amplify an output signal from the voltage-limiting circuit. The first controller is configured to control the limit range in accordance with a current supplied to a load from the second amplifier. The second controller is configured to decrease an amplification factor of the first amplifier in a state in which the voltage-limiting circuit limits the voltage of the output signal from the first amplifier.

According to an embodiment, a method includes amplifying a signal provided by a capacitive signal source to form an amplified signal, detecting a peak voltage of the amplified signal, and adjusting a controllable impedance coupled to an output of the capacitive signal source in response to detecting the peak voltage. The controllable impedance is adjusted to a value inversely proportional to the detected peak voltage.

An amplifier for a radio communications system in a shielded tunnel is disclosed. In one example, the amplifier comprises a processor configured to execute a plurality of modules comprising a gain control module and an attenuation control module. Methods and systems are further provided for controlling and monitoring amplifier characteristics.

A power amplifier circuit includes an amplifier unit disposed on a die of a semiconductor device. The amplifier unit includes an amplifier transistor. The power amplifier circuit further includes a detector transistor disposed on the die of the semiconductor device, a variable attenuator that compensates for a gain of the amplifier unit, a bias level setting holding unit that holds a bias level setting value, which is set based on at least a detection value of the detector transistor, and a bias generation unit that generates a bias value of the variable attenuator based on the bias level setting value.

A power amplifier module that includes a power amplifier having a plurality of amplifier gain stages, a memory device including a plurality of memory locations, and a controller to receive a control signal having at least one of a first state and a second state. The plurality of memory locations includes at least one first memory location to store a first set of configuration parameters for operation in a first mode, and at least one second memory location to store a second set of configuration parameters for operation in a second mode. The controller configures the power amplifier module in the first mode based on the first set of configuration parameters responsive to receiving the control signal having the first state and configures the power amplifier module in the second mode based on the second set of configuration parameters responsive to receiving the control signal having the second state.

Provided is an amplification circuit for amplifying an input signal. The amplification circuit includes an input stage including an input matching circuit that receives the input signal and an input attenuation circuit that attenuates a gain for the input signal outside an operating frequency band of the amplification circuit, a transistor that amplifies the input signal provided from the input stage, and an output stage including an output matching circuit that receives a signal amplified by the transistor and an output attenuation circuit that attenuates the gain for the input signal outside the operating frequency band of the amplification circuit, and the input attenuation circuit includes a first resistor and a second resistor that are connected to a ground voltage, a first passive element connected between the input matching circuit and the second resistor, and a second passive element connected between the first passive element and the first resistor.