Panasonic Corporation

Panasonic Intellectual Property Management Co., Ltd.

Masato Seki

Masahiro Maeda

Masatoshi Kamitani

Hiroshi Komori

Katsuhiko Kawashima

Shingo Enomoto

Kazuya Wakita

Masatosi Kamitani

A power amplifier includes an amplification transistor which performs power amplification, a bias circuit which outputs a bias voltage to a base of the amplification transistor, a control terminal to which a control voltage is applied for controlling switching between an operating state and a stopping state of the bias circuit, and a bias voltage adjustment circuit connected to the control terminal. The bias voltage adjustment circuit includes a variable capacitance element which is connected to the control terminal and whose capacitance value decreases as the control voltage increases, a discharge circuit which discharges electric charge accumulated in the variable capacitance element to the control terminal, and a control circuit which is connected to the bias circuit and controls the bias voltage. The bias voltage adjustment circuit outputs, to the bias circuit, a bias voltage adjustment signal which increases the bias voltage for a predetermined period after the control voltage is applied.

Power amplifier

A constant-voltage circuit includes: first and second field-effect transistors; a first node connected to the drains of the first and second field-effect transistors; a second node connected to the gates of the first and second field-effect transistors; a bipolar transistor whose collector is connected to the second node; a resistor connected to the source of the second field-effect transistor and the collector of the bipolar transistor; and a bias circuit that is connected to the source of the second field-effect transistor and supplies a bias voltage to the base of the bipolar transistor, wherein a power supply is connected to the first node and a constant voltage is outputted from the source of the first field-effect transistor.

Constant-voltage circuit

The radio frequency power amplifier is connected between an other end of the first switching element and an other end of the second switching element, supplies power to a second amplifier via the first switching element and a second matching circuit, and includes a first power supply line for supplying power to the third amplifier via a second switching element and a third matching circuit, and the other end of the first switching element is connected to an input node of the first matching circuit, the other end of the second switching element is connected to the input node of the first matching circuit via the first power supply line, and an impedance of an output side of the RF power amplifier as viewed from an output node of the third amplifier is higher than an impedance of the RF power amplifier as viewed from an output node of the second amplifier.

Radio frequency power amplifier

A radio frequency power amplifier includes an input terminal to which a radio frequency signal is applied; a first hetero-bipolar transistor (HBT), which amplifies the radio frequency signal; a second HBT, which amplifies the radio frequency signal; a matching circuit connected to an output node of the second HBT; a switch connected to an output node of the matching circuit; and an output matching circuit connected to an output node of the first HBT. The output node of the switch is connected to the output node of the first HBT via the output matching circuit, and an impedance looking into an output side of the radio frequency power amplifier from the output node of the switch is higher than an impedance looking into the output side of the radio frequency power amplifier from the output node of the first HBT.

Growing community of inventors

Osaka, Japan

Masato Seki