Abstract: A radio frequency circuit that includes a carrier amplifier, a transmission line transformer having a main line and a sub line, a signal output terminal, a voltage supply terminal and a capacitor, wherein the main line has one end connected to an output end of a peak amplifier, the main line has another end connected to the signal output terminal, the sub line has one end connected to the one end of the main line, the sub line has another end connected to the voltage supply terminal, and the peak amplifier has the output end connected to the voltage supply terminal with the capacitor interposed therebetween.

Abstract: A high frequency circuit includes power amplifiers, filters including a band A in their pass bands, filters including a band B in their pass bands, and a switch circuit that switches the connection between an antenna terminal and two terminals and switches the connection between another antenna terminal and two other terminals. The output end of one power amplifier is connected to the input ends of two of the filters, the output end of one filter is connected to one of the terminals, the output end of another filter is connected to another terminal, the output end of the other power amplifier is connected to the input ends of two others of the filters, the output end of one of the other filters is connected to one of the other terminals, and the output end of another of the other filters is connected to another of the other terminals.

Abstract: A high-frequency module is disclosed, comprising a carrier amplifier, peak amplifiers, a transformer, a phase-shifting line, and bias circuits, all integrated into a semiconductor IC. The input terminals of the semiconductor IC are connected to the input ends of both the carrier and peak amplifiers, while the output terminals are connected to their respective output ends. The transformer has one end connected to the output terminal, with the other end connected to the output terminal via the phase-shifting line. Additionally, the bias circuits are connected to the carrier amplifier and the peak amplifiers to regulate their operation.

Abstract: A Doherty amplification circuit includes a carrier amplifier, a peak amplifier, a phase shift circuit, a phase shift circuit connected to an output end of the peak amplifier, a transformer including an input terminal connected to an output end of the carrier amplifier, and output terminals, and a transformer including input terminals, which are respectively connected to the output terminals of the transformer, and an output terminal connected to an antenna connection terminal, in which the phase shift circuit is connected between the output terminal of the transformer and the input terminal of the transformer, and the peak amplifier and the phase shift circuit are connected between the output terminal of the transformer and the input terminal of the transformer.

Abstract: A high frequency circuit includes a signal input terminal and a signal output terminal; a first amplifier, a second amplifier, a third amplifier, and a fourth amplifier; and a first phase shift circuit. An input terminal of the fourth amplifier is connected to the signal input terminal, an output terminal of the fourth amplifier is connected to an input terminal of the first amplifier and an input terminal of the second amplifier, an output terminal of the second amplifier is connected to an input terminal of the third amplifier, an output terminal of the third amplifier is connected to one end of the first phase shift circuit, and the other end of the first phase shift circuit is connected to an output terminal of the first amplifier.

Abstract: A radio-frequency circuit includes a carrier amplifier configured to amplify radio-frequency signals in a band A, a carrier amplifier configured to amplify radio-frequency signals in a band B, peak amplifiers configured to amplify radio-frequency signals in the band A and radio-frequency signals in the band B, a transformer having an input-side coil and an output-side coil, and phase shift lines.

Abstract: A power amplifier circuit includes a carrier amplifier, a peak amplifier, an external output terminal, a combiner that includes an input terminal connected to an output terminal of the power amplifier, an input terminal connected to an output terminal of the power amplifier, and an output terminal connected to the external output terminal, a bias circuit that supplies a DC bias current to the carrier amplifier, a bias circuit that supplies a DC bias current to the peak amplifier, and a current limit circuit that is connected between the power amplifier and the bias circuit and that is configured to change a magnitude of the DC bias current according to a magnitude of a power supply voltage applied to the power amplifier circuit.

Abstract: A radio frequency circuit includes a carrier amplifier, a peaking amplifier, an input-side coil, an output-side coil, harmonic reduction circuits, and a phase shift line. One end of the input-side coil is connected to the carrier amplifier, and the other end thereof is connected to the peaking amplifier. In the harmonic reduction circuit, an inductor and a capacitor that are connected in series are disposed in series on a path connecting the carrier amplifier and the ground. The harmonic reduction circuit has an inductor and a capacitor that are connected in series and an inductor connected in parallel to the capacitor. The inductor and the capacitor are disposed in series on a path connecting the peaking amplifier and the ground.

Abstract: The power amplifier circuit includes an amplifier element, a transmission line transformer (TLT) circuit including a first, second and third line, and a switching circuit including a first, second, and third terminal. One end of the first line is coupled to an output terminal of the amplifier element, and the other end of the first line is coupled to one end of the second line. The other end of the second line is coupled to the terminal. One end of the third line is coupled between the one end of the first line and the output terminal of the amplifier element. The other end of the third line is coupled to the terminal. The switching circuit includes a first switch provided between the terminal and ground and a second switch provided between the terminal and ground.

Abstract: A radio frequency circuit including power amplifiers, a transformer having an input-side coil and an output-side coil, a bias circuit connected to the power amplifiers, an output terminal connected to one end of the output-side coil, an output terminal connected to another end of the output-side coil, a switch connected between the output terminal and a ground, a switch connected between the output terminal and a ground, a phase shift line having an input end connected to an output terminal of the power amplifier and an output end connected to one end of the input-side coil, and a phase shift line having an input end connected to an output terminal of the power amplifier and an output end connected to another end of the input-side coil.

Abstract: A power amplifier circuit that includes a carrier amplifier, peaking amplifiers, an input coil, an output coil, an input coil, an output coil, an output terminal to which one end of the output coil is connected, and ¼-wavelength transmission lines. The carrier amplifier is connected to one end of the input coil. The peaking amplifier is connected to one end of the ¼-wavelength transmission line. The peaking amplifier is connected to one end of the input coil. The peaking amplifier is connected to one end of the ¼-wavelength transmission line. The other end of the ¼-wavelength transmission line is connected to the other end of the input coil. The other end of the ¼-wavelength transmission line is connected to the other end of the input coil. One end of the output coil is connected to the other end of the output coil.

Abstract: A power amplifier circuit includes an external input terminal, an external output terminal, a power amplifier connected to the external input terminal, power amplifiers, a power supply terminal connected to the power amplifier, and a power supply terminal connected to the power amplifier. The power amplifiers are connected in parallel with each other between the power amplifier and the external output terminal. A first power supply voltage which is variable to multiple discrete first voltage levels is supplied to the power amplifier via the power supply terminal. A second power supply voltage which is variable to multiple discrete second voltage levels is supplied to the power amplifier via the power supply terminal. The multiple discrete second voltage levels are different from the multiple discrete first voltage levels.

Abstract: A radio frequency circuit includes power amplifiers, a transformer, a filter having a band A as a pass band, a filter having a band B as a pass band, a filter having a band C as a pass band, matching circuits connected to one end of an output side coil, and matching circuits connected to the other end of the output side coil. The matching circuit includes a capacitor disposed at a first path, a switch connected to the first path and a ground, a switch and an inductor connected in series, and the matching circuit includes a capacitor disposed at a second path, and a switch and an inductor connected in series, and the matching circuit includes a switch connected to a third path and the ground.

Abstract: A power amplifier circuit that includes an external input terminal and an external output terminal; a first power amplifier, a second power amplifier, a third power amplifier, and a fourth power amplifier; a transformer including an input-side coil and an output-side coil; and a first transmission line, the external input terminal being connected to an input terminal of the first and second power amplifiers, an output terminal of the first power amplifier is connected to an input terminal of the third and fourth power amplifiers, output terminals of the third and fourth power amplifiers being connected to a first and second end of the input-side coil respectively, the external output terminal being connected to a first end of the output-side coil, and an output terminal of the second power amplifier being connected to a second end of the output-side coil via the first transmission line.

Abstract: A power amplifier circuit includes a power amplifier and an external power terminal that receives a power supply voltage from a power supply circuit. The power amplifier includes two amplifying elements and, a limiter, and an RC circuit. The amplifying elements respectively include first and second input terminals, first and second output terminals, and first and second power terminals. The limiter restricts the power supply voltage to a predetermined range and outputs the restricted power supply voltage. The RC circuit is connected in parallel with the limiter. The first input terminal is connected to an external input terminal. The first output terminal is connected to the second input terminal. The second output terminal is connected to an external output terminal. The first power terminal is connected to the external power terminal via the limiter. The second power terminal is connected to the external power terminal.

Abstract: A power amplifier circuit includes external input and output terminals; a first power amplifier with first input and output terminals, the first input terminal being connected to the external input terminal, the first output terminal being connected to the external output terminal; a second power amplifier having second input and output terminals, the second input terminal being connected to the external input terminal, the second output terminal being connected to the external output terminal; a power supply terminal that receives a power supply voltage that is supplied to the first power amplifier and controllably supplied to the second power amplifier; and a switch having first and second terminals, the first terminal being connected to the power supply terminal, the second terminal being connected to the second power amplifier.

Abstract: A power amplifier circuit includes an amplifier transistor having a collector terminal, an emitter terminal, and a base terminal, bias circuits, and a current limiter circuit. The bias circuit includes a constant current amplifier transistor that supplies direct-current bias current from an emitter terminal to the base terminal. The current limiter circuit includes a current limiting transistor an emitter terminal of which is connected to the bias circuit, a resistive element connected between the current limiting transistor and a power supply terminal, and a resistive element connected between the current limiting transistor and the constant current amplifier transistor. The bias circuit includes a constant current amplifier transistor that supplies direct-current bias current i3 from an emitter terminal to the base terminal.

Abstract: An amplifier module includes an antenna that includes four power feed points, and four power amplifiers. Output ends of the four power amplifiers are connected to the four power feed points in a one-to-one relationship. The four power feed points are arranged rotationally symmetrically around a center of the antenna when a main surface of the antenna is viewed in plan.

Abstract: An amplifier circuit includes amplifiers, transformers, and a transmission line. A first end of an input-side coil is connected to an output terminal of the amplifier, a second end of the input-side coil is connected to an output terminal of the amplifier via the transmission line, a first end of an input-side coil is connected to an output terminal of the amplifier, a second end of the input-side coil is connected to the output terminal of the amplifier via the transmission line, a first end of an output-side coil is connected to an output terminal, a second end of the output-side coil is connected to a ground, a first end of an output-side coil is connected to an output terminal, and a second end of the output-side coil is connected to the ground.

Abstract: A radio-frequency module includes a module substrate, a carrier amplifier and a peak amplifier, a transformer, and a phase adjustment circuit. The carrier amplifier and the peak amplifier are included in a semiconductor IC. One end of an input-side coil is connected to an output terminal of the carrier amplifier. One end of the output-side coil is connected to a signal output terminal.