This application claims priority from Japanese Patent Application No. 2019-085021 filed on Apr. 26, 2019. The content of this application is incorporated herein by reference in its entirety.

BACKGROUND

The present disclosure relates to a high frequency circuit and a communication device including the high frequency circuit.

Japanese Unexamined Patent Application Publication No. 10-224157 discloses a high frequency amplifier circuit including a high frequency amplifier and an output matching circuit that adjusts the output impedance of the high frequency amplifier. By using the output matching circuit, it is possible to amplify high frequency signals in a particular frequency band with a low loss.

BRIEF SUMMARY

However, in the case of recent mobile communication devices supporting multiple modes/multiple bands, for example, when different communication modes are used, impedance matching may have to be established to achieve different optimum values of output load impedance of a high frequency amplifier with respect to two kinds of high frequency signals in adjacent or overlapping different frequency bands. In such a case, when the circuit constant of a passive element, such as an inductor or a capacitor constituting an output matching circuit is fixed, it is impossible to highly accurately establish impedance matching for both the two kinds of high frequency signals described above. As a result, the output matching circuit needs switching means, such as a switch in addition to the passive element described above, and thus, the size of a high frequency amplifier circuit is increased.

The present disclosure provides a small high frequency circuit and a small communication device that can highly accurately establish impedance matching with respect to two kinds of high frequency signals in adjacent or overlapping different frequency bands.

A high frequency circuit according to an aspect of the present disclosure includes a first terminal and a second terminal, a first amplifier that amplifies a high frequency signal inputted from the first terminal and outputs the high frequency signal toward the second terminal, and an output matching circuit that is positioned on a signal path connecting the first amplifier and the second terminal and that optimizes output load impedance of the first amplifier. The output matching circuit includes a first common matching circuit that is coupled to an output terminal of the first amplifier and that has a first passive element, a selective matching circuit that has a second passive element, and a first switching circuit that switches between a connected state and a disconnected state of the first common matching circuit and the selective matching circuit. The first amplifier and the first switching circuit are formed at a single semiconductor integrated circuit. The first passive element and the second passive element are formed outside the semiconductor integrated circuit.

The present disclosure can provide a small high frequency circuit and a small communication device that can highly accurately establish impedance matching with respect to two kinds of high frequency signals in adjacent or overlapping different frequency bands.

Other features, elements, characteristics and advantages of the present disclosure will become more apparent from the following detailed description of embodiments of the present disclosure with reference to the attached drawings.

