CROSS-REFERENCE TO RELATED APPLICATION

The present application is based on and claims priority to Japanese Patent Application No. 2020-076285 filed on Apr. 22, 2020. The entire disclosure of the above-identified application, including the specification, drawings and claims is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to a radio frequency (RF) module and a communication device.

BACKGROUND

Mobile communication devices such as mobile phones include a power amplifier that amplifies a radio frequency transmission signal.

Japanese Unexamined Patent Application Publication No. 2010-118916 discloses a differential power amplifier that includes: a first transistor which receives an input of a non-inverted input signal; a second transistor which receives an input of an inverted input signal; and a transformer disposed on the output terminal side of the first transistor and the second transistor. The transformer includes magnetically-coupled two primary coils and one secondary coil. The two primary coils are connected to each other in parallel, and each magnetically coupled to the secondary coil, allowing the input impedance of the primary coils to be reduced without decreasing Q-factors. As a result, it is possible to improve power gain.

SUMMARY

Technical Problems

However, as recognized by the present inventor, when the differential power amplifier disclosed by Japanese Unexamined Patent Application Publication No. 2010-118916 is applied to a radio frequency front-end circuit that supports multi-band technologies, differential power amplifiers need to be provided for the respective communication bands, leading to an increase in the total number of power amplifiers arranged. Furthermore, the differential power amplifier includes a large number of circuit elements, and thus there arises a problem that the radio frequency module increases in size.

The present disclosure addresses the above-described problems, and is presented to provide a small-sized radio frequency module that includes a differential power amplifier and supports multi-band technologies, and a communication device including the radio frequency module.

Solutions

In order to provide such a radio frequency module and such a communication device as described above, a radio frequency module according to one aspect of the present disclosure includes a module board including a first principal surface and a second principal surface on opposite sides of the module board; a first power amplifier configured to amplify a transmission signal of a first frequency band; a second power amplifier configured to amplify a transmission signal of a second frequency band different from the first frequency band; a first output transformer including a first coil and a second coil; and a second output transformer including a third coil and a fourth coil. In this radio frequency module, the first power amplifier includes a first amplifying element and a second amplifying element, the second power amplifier includes a third amplifying element and a fourth amplifying element, one of ends of the first coil is connected to an output terminal of the first amplifying element, a remaining one of the ends of the first coil is connected to an output terminal of the second amplifying element, and one of ends of the second coil is connected to an output terminal of the first power amplifier, one of ends of the third coil is connected to an output terminal of the third amplifying element, a remaining one of the ends of the third coil is connected to an output terminal of the fourth amplifying element, and one of ends of the fourth coil is connected to an output terminal of the second power amplifier, the first power amplifier and the second power amplifier are disposed on the first principal surface, and the first output transformer and the second output transformer are disposed inside the module board or on the second principal surface.

Advantageous Effects

According to the present disclosure, a small-sized radio frequency module that includes a differential power amplifier and supports multi-band technologies, and a communication device including the radio frequency module are provided.

