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 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 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: There is provided a power amplifier circuit capable of adjusting the gain according to the power mode. A power amplifier circuit includes: a splitter outputting an input signal by splitting the input signal to a signal RF1 and a signal RF2; amplifiers connected to the splitter; and an amplifier provided in or on a signal path branching from between the splitter and an input of the amplifier, connected in parallel with the amplifier, and connected to a biasing terminal supplied with a third bias current or voltage.

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: A dust collector includes a main-body housing and a motor assembly disposed in the main-body housing. The motor assembly includes a blower fan, which is disposed in the interior of the main-body housing; and a suction motor, which rotates the blower fan. The motor assembly generates suction force at a suction port, which fluidly communicates with the interior of the main-body housing. At least one filter is disposed in a fluid communication path between the suction port and the blower fan. A filter cleaning apparatus is configured to clean the at least one filter. A cleaning-control part is configured to actuate the filter cleaning apparatus after a power tool, which is fluidly connected to the suction port, stops operating.

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 dust collector includes a main-body housing and a motor assembly disposed in the main-body housing. The motor assembly includes a blower fan, which is disposed in the interior of the main-body housing; and a suction motor, which rotates the blower fan. The motor assembly generates suction force at a suction port, which fluidly communicates with the interior of the main-body housing. At least first and second air-exhaust passageways are respectively in the up-down direction in the interior of the main-body housing and through which air exhausted from the motor assembly flows.

Abstract: A radio-frequency circuit includes an antenna connection terminal, switch circuits, a duplexer, a low-pass filter, and a high-pass filter. The switch circuit includes a port connected to the antenna connection terminal and ports. The switch circuit includes a single transmission port connected to the port, a simultaneous transmission port connected to ports. The duplexer is connected to the port. The low-pass filter is disposed on a signal path connecting the port and the simultaneous transmission port. The high-pass filter is connected to the port. No filter is disposed on a signal path connecting the port and the single transmission port.

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.

Abstract: A radio frequency circuit includes a carrier amplifier, a peak amplifier, a transformer, and an impedance converting circuit. One end of an input coil is connected to an output of the carrier amplifier, one end of an output coil is connected to an output terminal. The impedance converting circuit includes main and auxiliary lines. One end of the main line is connected to an output of the peak amplifier, and the other end of the main line is connected to the other end of the input coil. One end of the auxiliary line is connected to the one end of the main line, and the other end of the auxiliary line is connected to ground. A first direction from the one end to the other end of the main line, and a second direction from the other end to the one end of the auxiliary line (302) are the same.

Abstract: A radio frequency circuit includes carrier amplifiers and peak amplifiers, transformers, a signal output terminal connected to a first end of an output-side coil, an LC series circuit, and a capacitor. An input-side coil is connected, at its first end, to the carrier amplifier, and is connected, at its second end, to the carrier amplifier. An input-side coil is connected, at its first end, to the peak amplifier, and is connected, at its second end, to the peak amplifier. The LC series circuit is connected between the peak amplifier and the ground. The capacitor is connected to a second end of the output-side coil and a first end of an output-side coil. The output-side coil is connected, at its second end, to the ground.

Abstract: A high frequency circuit includes a switch that includes terminals; a switch that includes terminals; a filter that has a pass band including a first band; and a diplexer that includes terminals. The diplexer includes a filter that is connected between the terminals and has a pass band including a first frequency band group containing the first band and a filter that is connected between the terminals and has a pass band including a second frequency band group. The terminal is connected to an antenna terminal. The terminals are connected to one terminal of the filter. The terminal is connected to the terminal. The terminal is connected to the terminal.

Abstract: A power amplifying module includes a first input terminal, a second input terminal, a first power amplifier, a stage matching circuit, a bypass line, and a second power amplifier. The first input terminal receives a first input signal in a first operation mode. The second input terminal receives a second input signal in a second operation mode which is different from the first operation mode. The first power amplifier amplifies the first input signal and outputs a first amplified signal. The stage matching circuit is disposed downstream of the first power amplifier and receives the first amplified signal. The bypass line outputs the second input signal to the inside of the stage matching circuit not through the first power amplifier. The second power amplifier is disposed downstream of the stage matching circuit, and amplifies the first amplified signal or the second input signal and outputs a second amplified signal.

Abstract: A radio frequency module includes a transmit filter of Band A and Band B, a transmit amplifier, and a switch circuit and can perform CA using a transmit signal of Band A and a receive signal of Band B, a transmit band of Band B including a receive band of Band C. The switch circuit includes a switch switching connection between a common terminal and a first selection terminal, a switch switching connection between the common terminal and a second selection terminal, and a switch switching connection between the second selection terminal and a third selection terminal. The common terminal is connected to the transmit amplifier. The first selection terminal is connected to the transmit filter of Band A. The second selection terminal is connected to the transmit filter of Band B. The third selection terminal is connected to a receive path of Band C.

Abstract: Size reduction is enabled. A power amplifying circuit includes a splitter, a first amplifier, a second amplifier, and a third amplifier. The splitter splits an input signal into a first signal and a second signal. The first amplifier has a first input terminal and a first output terminal, amplifies the first signal, and outputs a first amplified signal. The second amplifier has a second input terminal and a second output terminal, amplifies the second signal, and outputs a second amplified signal. The third amplifier has a third input terminal and a third output terminal, amplifies the first signal, and outputs a third amplified signal. The first output terminal and the second output terminal are connected to each other, the third input terminal is connected to the first input terminal, and the third output terminal is connected to the second output terminal.

Abstract: A radio frequency module includes a transmit filter of Band A and Band B, a transmit amplifier, and a switch circuit and can perform CA using a transmit signal of Band A and a receive signal of Band B, a transmit band of Band B including a receive band of Band C. The switch circuit includes a switch switching connection between a common terminal and a first selection terminal, a switch switching connection between the common terminal and a second selection terminal, and a switch switching connection between the second selection terminal and a third selection terminal. The common terminal is connected to the transmit amplifier. The first selection terminal is connected to the transmit filter of Band A. The second selection terminal is connected to the transmit filter of Band B. The third selection terminal is connected to a receive path of Band C.

Abstract: A radio frequency (RF) module including a module substrate; a filter with a passband including communication band for TDD; a switch connected to the filter; a power amplifier that is arranged on a first surface of the module substrate and connected to the filter via the switch; a low-noise amplifier that is arranged on a second surface of the module substrate and connected to the filter via the switch; a filter with a passband including communication band; a low-noise amplifier that is arranged on the second surface and connected to the filter; and a conductive member arranged between the low-noise amplifiers on the second surface.

Abstract: A high-frequency circuit includes: a diplexer that is composed of a filter which has a pass band including a first frequency band group and a filter which has a pass band including a second frequency band group; a notch filter that is connected with the filter and whose stop band is a frequency band which is not included in a first communication band; a notch filter that is connected with the filter and whose stop band is a frequency band which is not included in a second communication band; and switches that are connected with the notch filters. A band pass filter whose pass band is the first communication band and a band pass filter whose pass band is the second communication band are not connected between the filter and the switches.