According to one embodiment, a differential power amplifier includes a pair of transistors, a transformer coupled to the drain terminals of the transistors, and an output transmission line. The differential power amplifier operates in a range of frequencies from a lower operating frequency to an upper operating frequency to provide a relatively linear gain between the lower operating frequency and the higher operating frequency. The drains of the transistors are coupled to the primary winding of the transformer. The output transmission line is coupled to the secondary winding of the transformer. The output transmission line further includes at least one inductor-capacitor (LC) circuit that is configured to match predetermined output impedance in view of the lower and upper operating frequencies of the differential power amplifier.

In one form, a signal generator system such as a power amplifier system includes an amplification stage, a lowpass filter, and a controller. The amplification stage includes a first amplifier having an input for receiving an input signal, a control input for receiving a first control signal, and an output. The lowpass filter has a first input coupled to the output of the first amplifier, and an output. The controller has a first input coupled to the output of the lowpass filter, and a first output coupled to the control input of the first amplifier, wherein the controller varies the first control signal to reduce a difference between the output of the lowpass filter and a first target voltage level.

According to an embodiment, an active inductor has a first conductivity type MOS transistor with a source that is connected to an electrical power source supply line and a drain that is connected to an output terminal. It has a capacitance between a gate of the first conductivity type MOS transistor and the electrical power source supply line. It has a diode element that is connected between a drain and a gate of the first conductivity type transistor. It has an electric current source that supplies a bias electric current in a forward direction to the diode element.

An integrated circuit includes a degeneration network configured to improve group delay across one or more variations, wherein the degeneration network includes a transimpedance amplifier with one or more degeneration inductors. The transimpedance amplifier further includes one or more transistors, and the one or more degeneration inductors are connected after at least one emitter of the one or more transistors.

A capacitor bank has a capacitance value that is discontinuous and has an extremely narrow variable range. Thus, in a case of obtaining a wide variable range of the capacitance value, a large number of capacitors are connected in parallel and used while being switched by switches. The present technology achieves at least one of: allowing the capacitance value of a variable capacitance circuit to be varied continuously by electrical control without increasing the parasitic capacitance; and decreasing the current consumption of an oscillator circuit using the variable capacitance circuit as compared to a conventional case. The variable capacitance circuit includes: a transconductance circuit that includes a MOS transistor; an inductor that is connected in parallel to the transconductance circuit; and a Gm control circuit that varies a transconductance of the MOS transistor.

An integrated circuit includes a degeneration network configured to improve group delay across one or more variations, wherein the degeneration network includes a transimpedance amplifier with one or more degeneration inductors. The transimpedance amplifier further includes one or more transistors, and the one or more degeneration inductors are connected after at least one emitter of the one or more transistors.

Systems, apparatuses, and methods for implementing a negative resistance circuit for bandwidth extension are disclosed. Within a feedback path of a differential signal path, capacitors are placed on the inputs and outputs of a fully differential amplifier connecting to the differential signal path. In one embodiment, a circuit includes a fully differential amplifier and four capacitors. A first capacitor is coupled between a first signal path and a non-inverting input terminal of the amplifier and a second capacitor is coupled between the first signal path and a non-inverting output terminal of the amplifier. A third capacitor is coupled between a second signal path and an inverting input terminal of the amplifier and a fourth capacitor is coupled between the second signal path and an inverting output terminal of the amplifier. The first and second signal paths carry a differential signal.

According to an embodiment, an active inductor has a first conductivity type MOS transistor with a source that is connected to an electrical power source supply line and a drain that is connected to an output terminal. It has a capacitance between a gate of the first conductivity type MOS transistor and the electrical power source supply line. It has a diode element that is connected between a drain and a gate of the first conductivity type transistor. It has an electric current source that supplies a bias electric current in a forward direction to the diode element.

A switching power stage for producing a load voltage at a load output of the switching power stage, wherein the load output comprises a first load terminal having a first load voltage and a second load terminal having a second load voltage such that the load voltage comprises a difference between the first and the second load voltages, that may include: a power converter comprising a power inductor and a plurality of switches, wherein the power converter is configured to drive a power converter output terminal; a linear amplifier configured to drive a linear amplifier output terminal; and a controller for controlling the plurality of switches and the linear amplifier in order to generate the load voltage as a function of an input signal to the controller such that energy delivered to the load output is supplied predominantly by the power converter.

A sensing system with an AC feedback to the non-signal and non-biased terminal of the transducer. An impedance element, such as two anti-parallel diodes, are provided at the amplifier input, and the amplifier gain is negative and has a size sufficient to ensure that the input on the one terminal does not exceed the forward voltage of the diode.