A low distortion transconductance amplifier provides current to a grounded load using a virtual ground input stage, a pair of current mirrors, and a bias current source. The virtual ground input stage may include transistors arranged as a Darlington pair. The low distortion transconductance amplifier can function as a voltage-controlled AC current source that is operable at high frequencies.

A power amplifier circuit includes a first amplifier that amplifies an input signal and outputs a first amplified signal, a second amplifier that is disposed subsequent to the first amplifier and that amplifies the first amplified signal and outputs a second amplified signal, and a clamp circuit that is disposed between ground and a signal line extending between the first amplifier and the second amplifier and that suppresses an amplitude of the first amplified signal.

Apparatus and methods for radio frequency (RF) amplifiers are disclosed herein. In certain implementations, a packaged RF amplifier includes a first bipolar transistor including a base electrically connected to an RF input pin and a collector electrically connected to an RF output pin, and a second bipolar transistor including a base electrically connected to an emitter of the first bipolar transistor and a collector electrically connected to the RF output pin. The packaged RF amplifier further includes a first bias circuit electrically connected between the base of the first bipolar transistor and the RF output pin, a second bias circuit electrically connected between the base of the first bipolar transistor and a power low pin, an inductor implemented at least partly by a bond wire, and a third bias circuit electrically connected in series with the inductor between the base of the second bipolar transistor and the power low pin.

A circuit that includes a Darlington transistor pair having an input transistor and an output transistor configured to generate an output signal at an output node in response to an input signal received through an input node is disclosed. The circuit has a feedback coupling network coupled between the output node and the input node for feeding back to the input node a portion of an amplified version of the input signal that passes through the input transistor. The circuit further includes a bias feedback network that includes a bias transistor and a resistive network that consists of only resistive elements such that no inductors and no capacitors are provided within the bias feedback network.

A rapidly regulable high-voltage supply for the electrical focusing of an electron beam using a high-voltage final stage is provided. The high-voltage final stage includes a plurality of amplification elements that are interconnected in a series configuration with a first high-voltage connection, and a potential dividing chain including a series of potential dividing elements. The potential dividing chain is interconnected with the first high-voltage connection and has a signal interconnection with the plurality of amplification elements, so that when a voltage is applied across the potential dividing chain, a difference in voltages between a signal input to any amplification element of the plurality of amplification elements and a signal input to a next amplification element of the plurality of amplification elements has a same sign.

Apparatus and methods for radio frequency (RF) amplifiers are disclosed herein. In certain implementations, a packaged RF amplifier includes a first bipolar transistor including a base electrically connected to an RF input pin and a collector electrically connected to an RF output pin, and a second bipolar transistor including a base electrically connected to an emitter of the first bipolar transistor and a collector electrically connected to the RF output pin. The packaged RF amplifier further includes a first bias circuit electrically connected between the base of the first bipolar transistor and the RF output pin, a second bias circuit electrically connected between the base of the first bipolar transistor and a power low pin, an inductor implemented at least partly by a bond wire, and a third bias circuit electrically connected in series with the inductor between the base of the second bipolar transistor and the power low pin.

An apparatus is disclosed for implementing a Darlington circuit with a driver amplifier to provide power clamping. In example aspects, the apparatus includes an amplifier circuit having an input port and an output port. The amplifier circuit includes a driver amplifier, a power amplifier, and a Darlington circuit. The driver amplifier includes a driver amplifier output and a transistor, with the driver amplifier coupled between the input port and the output port. The power amplifier includes a power amplifier input, and the power amplifier is coupled between the driver amplifier output and the output port. The Darlington circuit is coupled to the driver amplifier via a node that is coupled between the input port and the power amplifier input.

Apparatus and methods for radio frequency (RF) amplifiers are disclosed herein. In certain implementations, a packaged RF amplifier includes a first bipolar transistor including a base electrically connected to an RF input pin and a collector electrically connected to an RF output pin, and a second bipolar transistor including a base electrically connected to an emitter of the first bipolar transistor and a collector electrically connected to the RF output pin. The packaged RF amplifier further includes a first bias circuit electrically connected between the base of the first bipolar transistor and the RF output pin, a second bias circuit electrically connected between the base of the first bipolar transistor and a power low pin, an inductor implemented at least partly by a bond wire, and a third bias circuit electrically connected in series with the inductor between the base of the second bipolar transistor and the power low pin.

The invention relates to a high-performance audio amplifier intended to control at least one loudspeaker, the amplifier comprising a pre-amplification stage that receives an input signal, a power amplification stage connected to the pre-amplification stage and a feedback that delivers to the pre-amplification stage an image of the output signal, the power amplification stage comprising two power supply circuits comprising a MOSFET transistor. The invention is characterized in that it comprises: a sub-circuit for assisting with charging, a sub-circuit for assisting with discharging said MOSFET transistor, and a voltage-shifting sub-circuit.

The invention relates to a high-performance audio amplifier intended to control at least one loudspeaker, the amplifier comprising a pre-amplification stage that receives an input signal, a power amplification stage connected to the pre-amplification stage and a feedback that delivers to the pre-amplification stage an image of the output signal, the power amplification stage comprising two power supply circuits comprising a MOSFET transistor. The invention is characterized in that it comprises: a sub-circuit for assisting with charging, a sub-circuit for assisting with discharging said MOSFET transistor, and a voltage-shifting sub-circuit.