Power amplifier circuit and communication device

A power amplifier circuit comprising:

• a power supply terminal;
• an amplifier transistor that has a first control terminal, a first terminal connected to the power supply terminal, and a second terminal and that performs power amplification of a radio-frequency input signal input through the first control terminal to output a radio-frequency signal subjected to the power amplification from the first terminal;
• and
• a bias circuit that outputs bias current,
• wherein the bias circuit includes
• a first transistor that has a third terminal, a fourth terminal, and a second control terminal and that supplies the bias current from the fourth terminal to the first control terminal,
• a current terminal that is connected to the second control terminal and that receives constant current,
• a second transistor which has a fifth terminal, a sixth terminal, and a third control terminal and the fifth terminal and the third control terminal of which are connected to the power supply terminal,
• a third transistor which has a seventh terminal, an eighth terminal, and a fourth control terminal, the seventh terminal of which is connected to the second control terminal, and the fourth control terminal of which is connected to the sixth terminal, and
• a fourth transistor which has a ninth terminal, a tenth terminal, and a fifth control terminal, the ninth terminal of which is connected to the eighth terminal, and the tenth terminal of which is grounded.