Power amplifier circuit and power amplification method

A power amplification method comprising

• switching between a first mode and a second mode and performing the first mode or the second mode,
• the first mode being configured such that, using a transmission line transformer (TLT) circuit that includes a first line with one end coupled to an output terminal of the amplifier element, a second line with one end coupled to another end of the first line, and a third line with one end coupled between the one end of the first line and the output terminal of the amplifier element, while another end of the third line is coupled to ground, the amplifier element amplifies a radio-frequency signal, and the amplified radio-frequency signal is output from another end of the second line,
• the second mode being configured such that, while the other end of the second line is coupled to ground, the amplifier element amplifies a radio-frequency signal, and the amplified radio-frequency signal is output from the other end of the third line.