An exemplary embodiment of the present disclosure relates to a rail-to-rail class-AB buffer amplifier using compact adaptive biasing, and the rail-to-rail class-AB buffer amplifier using compact adaptive biasing includes an input stage generating a differential current pair based on a voltage difference between a first input signal and a second input signal, an amplification stage outputting a driving signal based on the differential current pair, an output stage connected to the amplification stage and outputting an output signal, an auxiliary current source switch which is on/off based on the driving signal of the amplification stage, and a current mirroring unit generating bias current and outputting the generated bias current to the input stage when the auxiliary current source switch is on.

The present disclosure relates to current control circuitry for controlling a current through a load. The current control circuitry comprises amplifier circuitry, reference voltage generator circuitry configured to supply a fixed reference voltage to a first input of the amplifier circuitry and an output stage comprising: a control terminal coupled to an output of the amplifier circuitry; a current input terminal configured to be coupled to the load; and a current output terminal. The current control circuitry further comprises a variable resistance coupled to the current output terminal of the output stage, and a feedback path between the current output terminal of the output stage and a second terminal of the amplifier circuitry for providing a feedback voltage to a second input of the amplifier circuitry.

The present document relates to differential amplifiers. A differential amplifier may comprise a current source, a first transistor, a second transistor, and a compensation circuit. A reference voltage may be applied to a first terminal of the first transistor, and a second terminal of the first transistor may be coupled to an output of the current source. A feedback voltage may be applied to a first terminal of the second transistor, and a second terminal of the second transistor may be coupled to the output of the current source. The compensation circuit may comprise a capacitive element coupled to the first terminal of the first transistor, and the compensation circuit may be configured to reduce a change of the reference voltage at the first terminal of the first transistor.

A switching converter includes a voltage conversion circuit providing an output voltage from an input voltage and a PWM voltage generated in response to first and second oscillating voltages. The input stage of a transconductor circuit provides an input reference current following a difference between a reference voltage and a voltage dependent on the output voltage and according to a transconductance, and an output stage for providing an output reference current from the input reference current. A phase shifter shifts an oscillating reference voltage according to the output reference current to obtain the first and second oscillating voltages. The transconductance is controlled in response to the input voltage resulting in a change of the input reference current. Compensation for that change is provided by subtracting a variable compensation current from the input reference current, where the variable compensation current is generated in response to the input voltage.

Examples of the disclosure include a current-conditioning apparatus comprising a current mirror circuit including an input transistor adapted to receive an input current from an injection node and including an output transistor adapted to replicate in response to the received input current an output current with a predefined current mirror ratio, and a differential amplifier adapted to provide a negative feedback loop between the injection node of the apparatus and a control terminal of the input transistor of the current mirror circuit.

A sample-and-hold amplifier can include: an operational amplifier; a sampling capacitor having a first terminal coupled to an inverting input terminal of the operational amplifier, and a second terminal coupled to a reference ground; and a switching circuit configured to switch feedback paths of the sample-and-hold amplifier in a first stage and a second stage, such that an offset voltage of the operational amplifier is at least partially eliminated.

An operational amplifier includes a differential input stage that amplifies a differential input signal to generate an intermediate signal; an amplification stage including an output transistor that is connected between an output terminal and a fixed voltage line, and is driven according to the intermediate signal; and an assist circuit, wherein the assist circuit includes: a first transistor connected in parallel with the output transistor; and a drive circuit that drives the first transistor according to a gate voltage of the output transistor.

Provided herein are amplifiers, such as buffers, with increased headroom. An amplifier stage includes a follower transistor and current source configured to receive a power supply voltage comprising an alternating current component and a direct current component. The alternating current component of the power supply voltage has substantially the same frequency and magnitude as the input signal received by the follower transistor. In radio frequency (RF) and intermediate frequency (IF) buffer applications, for example, the increased headroom can allow for linear buffering of an input signals with increased amplitude so that the output power one decibel (OP1dB) compression point can be increased.

Monitoring circuitry, comprising: a current monitoring unit operable to monitor a speaker current flowing through a speaker and generate a monitor signal indicative of that current; and a controller operable, based on a control signal, to control the current monitoring unit to control whether the monitor signal is generated and/or a property of the monitor signal.

An output buffer circuit includes an operational amplifier configured to generate an amplifier output voltage signal based on an input voltage signal and on a compensation current, a slew rate compensating circuit configured to generate the compensation current to increase a slew rate of the amplifier output voltage signal based on a difference between the input voltage signal and a feedback voltage signal, an output path circuit connected between the operational amplifier and an output pad, the output path circuit configured to transfer the amplifier output voltage signal to generate a pad output voltage signal through the output pad, and a feedback path circuit, the feedback path circuit connected between the slew rate compensating circuit and a feedback input node that is on the output path circuit, the feedback path circuit configured to generate the feedback voltage signal.