An apparatus includes a preamplifier stage to receive a power supply voltage and generate an output based upon an input. In particular, the preamplifier stage includes a biasing device coupled between the output and a ground node to bias a DC voltage level of the output independently of the power supply voltage. The preamplifier stage also includes a complementary circuit to receive the input and generate the output. The complementary circuit reuses a current through the preamplifier stage to provide an increased transconductance of the preamplifier stage for a given current level.

An amplifier circuit a differential input stage coupled to a first input and to a second input between which a differential input voltage is present. A converter stage is coupled to the input stage to convert the differential input voltage into a converted voltage. An output stage is coupled to the converter stage and generates, starting from the converted voltage, an output voltage on a single output of the amplifier circuit. A biasing stage is coupled to the input stage and to the output stage to supply a biasing current. A chopper module reduces a contribution of offset and noise associated with the output voltage. The chopper module is coupled to the input stage, converter stage, and to the biasing stage. The chopper module includes an input chopper stage, a converter chopper stage, and a biasing chopper stage that operate jointly under control of a chopper signal.

A two-stage operational amplifier is provided to comprise a bias voltage generator, a first stage operational amplifier and a second stage operational amplifier, wherein the first stage operational amplifier comprises a folded cascode amplifier circuit and a cross coupling load, the cross coupling load is coupled to a load differential pair in the folded cascode amplifier circuit, the cross coupling load comprises two transistors, the two transistors in the cross coupling load and two transistors in the load differential pair constitute two current mirror structures, which are cross coupled. In the solution, the cross coupling load is added to the load differential pair in the folded cascode amplifier circuit, to increase gain of the two-stage operational amplifier by using positive feedback and negative conductance gain enhancement technology; while parameters of MOSFETs in the folded cascode amplifier circuit are properly set to reduce noise of the two-stage operational amplifier.

An apparatus includes a preamplifier stage to receive a power supply voltage and generate an output based upon an input. In particular, the preamplifier stage includes a biasing device coupled between the output and a ground node to bias a DC voltage level of the output independently of the power supply voltage. The preamplifier stage also includes a complementary circuit to receive the input and generate the output. The complementary circuit reuses a current through the preamplifier stage to provide an increased transconductance of the preamplifier stage for a given current level.

An amplifier may include a first stage configured to receive an input signal at an amplifier input and generate an intermediate signal which is a function of the input signal, and a final output stage configured to generate an output signal which is a function of the intermediate signal at an amplifier output, and a signal feedback network coupled between the amplifier output and input. The final output stage may be switchable among a plurality of modes including at least a first mode in which the final output stage generates the output signal as a modulated output signal which is a function of the intermediate signal, and a second mode in which the final output stage generates the output signal as an unmodulated output signal which is a function of the intermediate signal. Control circuitry may reduce audio artifacts associated with switching between modes.

An operational amplifier based circuit has an operational amplifier, a feedback circuit, and a compensation circuit block. The feedback circuit is coupled between an output port and an input port of the operational amplifier. The compensation circuit block has circuits involved in stability compensation of the operational amplifier, wherein there is no stability compensation circuit driven at the output port of the operational amplifier.

A variable gain amplifier having stabilized frequency response for widened gain control range. A resistor-capacitor compensation network is provided between two differential current input ports and corresponding emitter nodes of cross-coupled four transistors in the variable gain amplifier to desensitize the gain control voltages to the system noise and provide compensation to the VGA frequency response when the differential gain control voltage varies the gain setting, yielding a substantially stabilized frequency response over a 3 dB bandwidth ranging from 1 GHz to 60 GHz with a widened gain control range up to 12 dB without increasing power consumption.

An amplifier circuit a differential input stage coupled to a first input and to a second input between which a differential input voltage is present. A converter stage is coupled to the input stage to convert the differential input voltage into a converted voltage. An output stage is coupled to the converter stage and generates, starting from the converted voltage, an output voltage on a single output of the amplifier circuit. A biasing stage is coupled to the input stage and to the output stage to supply a biasing current. A chopper module reduces a contribution of offset and noise associated with the output voltage. The chopper module is coupled to the input stage, converter stage, and to the biasing stage. The chopper module includes an input chopper stage, a converter chopper stage, and a biasing chopper stage that operate jointly under control of a chopper signal.

A power amplifier circuit includes N (N is an integer equal to or greater than 2) power amplifier circuit cores, which in operation, amplify power of an input signal, N inductors, which in operation, are connected to the N power amplifier circuit cores, and ring-oscillator-type transconductance (gm) generation circuitry, which in operation, generates transconductance (gm) for compensating power loss of the N inductors.

A power amplifier with supply switching is provided. The power amplifier detects a magnitude of an outgoing broadband communication signal and determines whether the magnitude exceeds a predetermined voltage threshold. The power amplifier applies a first gain to the outgoing broadband communication signal using a first voltage supply rail when it is determined that the magnitude exceeds the predetermined voltage threshold and a second gain using a second voltage supply rail that is smaller than the first voltage supply rail when it is determined that the magnitude does not exceed the predetermined voltage threshold. The power amplifier produces an output signal from the outgoing broadband communication signal with the applied first gain or the applied second gain, wherein a current of the outgoing broadband communication signal is switched between the first voltage supply rail and the second voltage supply rail in response to the magnitude being detected.