An electronic emulation component for actively emulating a passive electronic component such as a capacitor or inductor having a desired value, comprises a pair of terminals for connection to an external circuit and across which the desired value is to appear, a power convertor, and a passive electronic component of the type to be emulated but having a value different from the value to be emulated and isolated from the pair of terminals by the convertor.

A circuit comprises a first amplifier coupled to a first and a second node; a differential capacitive load coupled to the first and the second node, the differential capacitive load coupled between drains of transistors in a cross coupled transistor circuit; a current mirror coupled to a source of each transistor; and a capacitor coupled between the sources of the transistors. A plurality of amplifiers can be coupled to the differential capacitive load, wherein each amplifier comprises a clock-less pre-amplifier of a comparator. The amplifiers may be abutted to one another such that an active transistor of a first differential stage in a first amplifier behaves as a dummy transistor for an adjacent differential stage in a second amplifier

A lumped element directional coupler having an asymmetrical structure. The lumped element directional coupler can be integrated while being compact by using lumped elements, instead of transmission lines, have broadband characteristics through the lumped elements being asymmetrically arranged, and further increase bandwidth by additionally providing a negative capacitor element or, more particularly, a negative capacitor element having loss.

A radio frequency integrated circuit includes an amplification circuit for outputting a radio frequency signal to an antenna, a balun including a first terminal, a second terminal, a third terminal, and a fourth terminal, and a variable capacitance circuit including a fifth terminal and a sixth terminal. The first terminal and the second terminal of the balun receive output signals of the amplification circuit. The third terminal and the fourth terminal of the balun are connected to the fifth terminal and the sixth terminal of the variable capacitance circuit, respectively, and the fifth terminal is connected to a radio frequency output terminal. The variable capacitance circuit includes a plurality of capacity cells that are connected in parallel between two output terminals.

A circuit for controlling a capacitor having a capacitance adjustable by biasing, including an amplifier for delivering a D.C. bias voltage, having a feedback slowed down by a resistive and capacitive cell.

A circuit comprises a first amplifier coupled to a first and a second node; a differential capacitive load coupled to the first and the second node, the differential capacitive load coupled between drains of transistors in a cross coupled transistor circuit; a current mirror coupled to a source of each transistor; and a capacitor coupled between the sources of the transistors. A plurality of amplifiers can be coupled to the differential capacitive load, wherein each amplifier comprises a clock-less pre-amplifier of a comparator. The amplifiers may be abutted to one another such that an active transistor of a first differential stage in a first amplifier behaves as a dummy transistor for an adjacent differential stage in a second amplifier.

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.

A matching circuit which can handle a plurality of frequencies is provided. The matching circuit includes a transistor and an inductor. The matching circuit uses capacitance formed between a gate and a source/drain (referred to as capacitance Cgsd below) of the transistor as a condenser. The capacitance Cgsd changes with the voltage of the gate with respect to the source (referred to as voltage Vgs below). The transistor included in the matching circuit is an OS transistor including a metal oxide in a channel formation region. The OS transistor features larger variation in capacitance Cgsd with respect to the voltage Vgs than the MOSFET that uses silicon, which enables the matching circuit to handle alternating-current signals in a wide frequency range.

A radio frequency (RF) power amplifier circuit includes an input and an output. A power amplifier transistor has a first terminal connected to the input, a second terminal connected to the output, and a third terminal defined by a degeneration inductance. A first capacitor is connected to the third terminal of the power amplifier transistor, along with a negative capacitance circuit connected in series with the first capacitor. The negative capacitance and the first capacitor define a series resonance at a predefined operating frequency band, which shunts the degeneration inductance of the third terminal.

A radio frequency (RF) power amplifier circuit includes an input and an output. A power amplifier transistor has a first terminal connected to the input, a second terminal connected to the output, and a third terminal defined by a degeneration inductance. A first capacitor is connected to the third terminal of the power amplifier transistor, along with a negative capacitance circuit connected in series with the first capacitor. The negative capacitance and the first capacitor define a series resonance at a predefined operating frequency band, which shunts the degeneration inductance of the third terminal.