An amplifier circuit is provided. The amplifier circuit outputs a pair of differential output signals through a first output terminal and a second output terminal. The amplifier circuit includes a first amplifier stage electrically connected to a first node and a second node for amplifying a pair of differential input signals; a second amplifier stage which is electrically connected to the first node and the second node and coupled to the first output terminal and the second output terminal; a first switch, coupled between the first output terminal and a first reference voltage; a second switch, coupled between the second output terminal and the first reference voltage; a third switch, coupled between the first node and the first reference voltage; a fourth switch coupled between the second node and the first reference voltage; and a fifth switch coupled between a second reference voltage and the first amplifier stage.

A power amplifier structure includes at least one power amplifier circuit. The power amplifier circuit includes a transistor of a first type connected in series with a transistor of a second type connected between the same voltage supply. In a non-limiting nonexclusive example, an n-type transistor is connected in series with a p-type transistor connected between Vdd. The power amplifier structure can include two amplifier circuits configured in a differential amplifier structure. The differential amplifier structure includes two amplifier circuits operably connected in parallel between the same voltage supply.

An amplifier includes an input circuit that amplifies a difference between a first input voltage and a second input voltage to generate a first current and a second current. A positive feedback circuit amplifies a difference between the first current and the second current to generate a third current and a fourth current and outputs a difference between the third current and the fourth current through an output node. A temperature compensation circuit adjusts an amplification factor of the positive feedback circuit in response to a change of temperature.

An electronic device may include wireless circuitry with a processor, a transceiver, an antenna, and a front-end module coupled between the transceiver and the antenna. The front-end module may include one or more power amplifiers for amplifying a signal for transmission through the antenna. A power amplifier may include a phase distortion compensation circuit. The phase distortion compensation circuit may include one or more n-type metal-oxide-semiconductor capacitors configured to receive a bias voltage. The bias voltage may be set to provide the proper amount of phase distortion compensation.

Methods, systems, and devices for delay adjustment circuits are described. Amplifiers (e.g., differential amplifiers) may act like variable capacitors (e.g., due to the Miller-effect) to control delays of signals between buffer (e.g., re-driver) stages. The gains of the amplifiers may be adjusted by adjusting the currents through the amplifiers, which may change the apparent capacitances seen by the signal line (due to the Miller-effect). The capacitance of each amplifier may be the intrinsic capacitance of input transistors that make up the amplifier, or may be a discrete capacitor. In some examples, two differential stages may be inserted on a four-phase clocking system (e.g., one on 0 and 180 phases, the other on 90 and 270 phases), and may be controlled differentially to control phase-to-phase delay.

An operational amplifier includes a single-stage amplifier and a current controller. The single-stage amplifier receives an input signal, and amplifies the input signal to generate an output signal, wherein the single-stage amplifier includes a voltage controlled current source circuit that operates in response to a bias voltage input. The current controller receives the input signal, and generates the bias voltage input according to the input signal. The bias voltage input includes a first bias voltage, a second bias voltage, a third bias voltage, and a fourth bias voltage. None of the first bias voltage, the second bias voltage, the third bias voltage, and the fourth bias voltage is directly set by the input signal of the single-stage amplifier.

A voltage-to-current converter circuit comprises an amplifier, a resistor, first and second feedback circuits, and an output circuit. The amplifier is configured to receive a differential input voltage signal. The resistor is coupled between first and second nodes of the amplifier. The first feedback circuit is coupled to a third node of the amplifier, provides feedback to the first and second nodes when the value of the input voltage signal is in a first range, and is turned off otherwise. The second feedback circuit is coupled to a fourth node of the amplifier, provides feedback to the first and second nodes when the value of the input voltage signal is in a second range different from the first range, and is turned off otherwise. The output circuit produces a differential current output signal having a value according to the value of the input voltage signal.

A fully differential power amplifier has an input matching network, a plurality of stacked transistors connected by a plurality of inter stack networks (ISNs), and an output matching network for amplification and conditioning of signal components. The differential amplifier uses a modified cascode FET topology with the FETs connected by gate decoupling capacitors to strongly attenuate common mode oscillations and eliminate the need for a source degeneration inductor or matching transformer. Inter stack networks provide signal conditioning and filtering between amplification stages to improve amplifier performance metrics such as long-term reliability, output power, and efficiency.

A regulator circuit according to one embodiment includes a first transistor, a filter, and a differential amplifier. The first transistor is provided between an input terminal on a power supply side and an output terminal on an output side. The differential amplifier includes an output node connected to the first transistor, and controls the first transistor on the basis of a result of comparison between a reference voltage and a feedback voltage according to an output voltage applied to the output terminal. The filter is connected to a control node that makes a differential pair with the output node, in the differential amplifier.

An image sensor may include an array of image sensor pixels. The array of image sensor pixels may be controlled by row driver circuitry. The row driver circuitry may include row drivers that receive power supply signals from transconductance amplifier circuitry. The transconductance amplifier circuitry may include multiple amplifiers with output ports shorted to one another. Each amplifier may include input transistors, cross-coupled transistors with a low threshold voltage, and additional transistors coupled in series with the cross-coupled transistors and having a moderate or high threshold voltage.