A reconfigurable amplifier configured to decrease radio frequency (RF) signal distortion and increase dynamic range is disclosed. The reconfigurable amplifier includes an amplifier having an RF signal input, an RF signal output, and a bias signal input. A distortion detection network has a detector input coupled to the RF signal output and a detector output, wherein the distortion detector network is configured to generate a detection signal that is proportional to distortion at the RF signal output. A bias controller has a detection signal input coupled to the detector output and a bias output coupled to the bias signal input. The bias controller is configured to generate a bias signal that dynamically shifts level at the bias output to reduce the distortion at the RF signal output in response to the detection signal.

Examples provide methods and apparatus for controlling a DC bias current in an RF amplifier. In one example where the RF amplifier is implemented on an amplifier die, a reference voltage is produced across a reference resistor implemented on the amplifier die, the DC bias current is measured, and a current controller, which is implemented on a controller die that is separate from the amplifier die, operates a feedback loop using the reference voltage to control a level of the DC bias current.

A device includes an amplifier for amplifying and supplying a high frequency power supplied to a load, a parameter detector for detecting a parameter of a current, a voltage, or a power from the amplifier to the load, a current supply unit for supplying a driving current for the amplifier, and an output unit for outputting a command signal for changing an amplification degree of the amplifier based on the detected parameter such that the parameter becomes a target value. The device further includes a first abnormality detector for detecting an abnormality by monitoring the command signal, and/or a current detector for detecting the driving current, a current data storage unit storing an upper and a lower limit value of the driving current, and a second abnormality detector for detecting the abnormality based on at least one of the upper limit value or the lower limit value.

An apparatus for amplifying an audio source includes a speaker and a chip. The chip includes a processor configured to generate a signal and an amplifier element configured to amplify the signal into an amplified signal. The chip further includes a current monitor configured to monitor the current of the amplified signal prior to the amplified signal being output from the chip to the speaker and a voltage monitor configured to monitor the voltage of the amplified signal prior to the amplified signal being output from the chip to the speaker. The processor of the chip is configured to control a power of the amplified signal output from the chip to the speaker based at least on the current and the voltage.

An offset-cancellation circuit having a first amplification stage with a gain of the first amplification stage and configured to receive an offset voltage of a first amplifier. A storage element is configured to be coupled to and decoupled from the first amplification stage and configured to store a potential difference output by the first amplification stage. The potential difference is determined by the offset voltage of the first amplifier and the gain of the first amplification stage. A second amplification stage is coupled to the storage element and configured to receive the potential difference from the storage element when the storage element is decoupled from the first amplification stage and configured to deliver an offset-cancellation current. The offset-cancellation current is determined by the potential difference and a gain of the second amplification stage.

A power amplifier system having a carrier amplifier having a first supply node, a peaking amplifier having a second supply node, and envelope tracking (ET) circuitry is disclosed. The ET circuitry has a first tracking amplifier that generates a first voltage signal at the first supply node, a second tracking amplifier that generates a second voltage signal at the second supply node, and a transistor coupled between the first supply node and the second supply node. A control circuit has a first input coupled to an output of both or either of the first tracking amplifier and the second tracking amplifier and a control output terminal coupled to a control input terminal of the transistor, wherein the control circuit is configured to progressively turn on the transistor to pass current from the first supply node to the second supply node as the peaking amplifier progressively becomes active.

A capacitive trans-impedance amplifier comprising a voltage amplifier having an inverting input terminal for connection to an input current source. A feed-back capacitor is coupled between the inverting input terminal and the output terminal to accumulate charges received from the input current source and to generate a feed-back voltage accordingly. A calibration unit includes a calibration capacitor electrically coupled, via a calibration switch, to the inverting input terminal and electrically coupled to the feed-back capacitor. The calibration unit is operable to switch the calibration switch to a calibration state permitting a discharge of a quantity of charge from the calibration capacitor to the feed-back capacitor. The capacitive trans-impedance amplifier is arranged to determine a voltage generated across the feed-back capacitor while the calibration switch is in the calibration state and to determine a capacitance value (C=Q/V) for the feed-back capacitor according to the value of the generated voltage (V) and the quantity of charge (Q).

A method for compensating for power supply ripple that is present in a supply voltage that is generated by a switched-mode power supply, the method comprising: calculating an estimated power supply ripple that is expected to be generated by the power supply; generating a digital ripple compensation signal, based on the estimated power supply ripple; combining a digital baseband (BB) signal and the digital ripple compensation signal to generate a digital modified BB signal; converting the digital modified BB signal to an analog radio frequency (RF) signal; and amplifying the analog RF signal, based on the supply voltage, to generate a RF transmission signal.

A Class-D amplifier that includes a driver stage operable in a plurality of modes having different respective output impedances, a loop filter having an output, and a circuit configured to sense a current at a load of the Class-D amplifier, determine, based on the sensed current, an IR drop for a respective output impedance of the driver stage, and add the IR drop to the loop filter output to compensate for the respective output impedance of the driver stage to reduce distortion.

An operational amplifier includes a differential amplification circuit configured to receive and amplify an input voltage to generate an output voltage, and receive a feedback signal, and the feedback signal adjusts a common-mode voltage of the output voltage, a reference voltage generation circuit configured to detect status information of the operational amplifier, and generate a reference voltage based on the status information, where the status information includes a temperature or an operating voltage of the operational amplifier, and a common-mode feedback circuit configured to receive the output voltage and the reference voltage, and provide the feedback signal to the differential amplification circuit based on the output voltage and the reference voltage.