Murata Manufacturing Co., Ltd.

Hideyuki Satou

Satoshi Tanaka

Satoshi Goto

Yuri Honda

Hisanori Namie

Yoshiaki Sukemori

A power amplifier circuit includes a first path and a second path between an input terminal and an output terminal, a first amplifier located in the first path operative in a first mode, a second amplifier located in the second path operative in a second mode, a first matching circuit between the first amplifier and the output terminal in the first path, a first capacitor having a first end connected to the output terminal side of the first matching circuit, and a second end, a first inductor having a first end connected to the second end of the first capacitor and a second end grounded, and a short-circuit switch connected in parallel with the first inductor. The short-circuit switch short-circuits the first and second ends of the first inductor in the first mode and is placed in an open-circuit position in the second mode.

Power amplifier circuit

A power amplifying circuit includes a bias circuit that supplies a bias current or a bias voltage to a base of a first transistor, and at least one termination circuit that short-circuits a second-order harmonic of an amplified signal output from a collector of the first transistor to a ground voltage. An emitter of the first transistor is connected to ground. The bias circuit includes a second transistor. A collector of the second transistor is connected to the base of the first transistor. An emitter of the second transistor is connected to the emitter of the first transistor. A base of the second transistor is supplied with a predetermined voltage.

Power amplifying circuit

A power amplifying circuit includes an amplifier that amplifies a radio-frequency signal and a bypass capacitor section connected to a power supply terminal for supplying a power supply voltage to the amplifier. The bypass capacitor section includes a first capacitor, a second capacitor, and a first switch circuit. The first capacitor includes a first end connected to a power supply path, and a second end. The second capacitor includes a first end connected to the second end of the first capacitor and a second end connected to ground. The first switch circuit includes a first terminal connected to the second end of the first capacitor and the first end of the second capacitor, and a second terminal connected to the ground. The first switch circuit switches between connection and non-connection between the second end of the first capacitor and the ground.

A power amplifier circuit includes a first transistor having a base to which a radio frequency (RF) signal is supplied and a collector to which a variable power-supply voltage corresponding to a level of the RF signal is supplied, and being configured to amplify the RF signal; a bias circuit including a second transistor configured to supply a bias current to the base of the first transistor; and an adjustment circuit configured to cause the bias current to be supplied to the base of the first transistor to decrease with decrease in the variable power-supply voltage by causing a current to be supplied to a base of the second transistor to decrease.

A power amplifier circuit includes a first transistor having a base supplied with an RF signal and a collector supplied with a variable power supply voltage corresponding to a level of the RF signal, the first transistor being configured to amplify the RF signal, a bias circuit including a second transistor that supplies a bias current to the base of the first transistor, and a bias adjustment circuit that decreases a current to be supplied from an emitter of the second transistor as the variable power supply voltage decreases, thereby decreasing the bias current to be supplied to the base of the first transistor.

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Kyoto, Japan

Hideyuki Satou