Murata Manufacturing Co., Ltd.

Kazuhiko Ishimoto

Fumio Harima

Fuminori Morisawa

Takashi Soga

Mikiko Fukasawa

There is provided a power amplifier circuit with improved operation speed of the protection function against overcurrent or overvoltage. The power amplifier circuit includes an amplifier configured to amplify a radio frequency signal and output the radio frequency signal, a bias current supply circuit configured to supply a bias current to the amplifier, a detection circuit configured to detect whether the current or voltage of the amplifier is equal to or greater than a predetermined threshold; and a draw circuit configured to, when the detection circuit detects that the current or voltage is equal to or greater than the predetermined threshold, draw at least a part of the bias current supplied to the amplifier.

Power amplifier circuit

A current output circuit includes an input circuit that outputs a second current in response to a first current when the first current is inputted, an output circuit that outputs a third current in response to the second current, and a control circuit that causes the output circuit to output a current when a control signal is inputted before the first current is inputted to the input circuit. The output circuit includes transistors of a first group and the input circuit includes transistors of a second group.

Current output circuit

A current control circuit controls a base current of a first transistor included in a bias circuit outputting a bias current to a power amplifier based on a base-collector voltage of the first transistor. The current control circuit includes a first circuit that outputs a signal associated with the base-collector voltage of the first transistor, and a second circuit that, based on the signal, provides electrical continuity between a base of the first transistor and a reference potential.

Current control circuit and power amplifier circuit

A power amplifier module includes a first amplification transistor that amplifies and outputs a radio frequency signal, a second amplification transistor that is connected in parallel to the first amplification transistor and that has a smaller size than the first amplification transistor, a bias circuit that supplies a bias voltage or a bias current to the first and second amplification transistors, a current detector circuit that detects a current flowing in the second amplification transistor, and a bias control circuit that controls the bias voltage or the bias current supplied from the bias circuit to the first and second amplification transistors depending on the detection result of the current detector circuit.

Growing community of inventors

Kyoto, Japan

Kazuhiko Ishimoto