A power amplifier is provided. The power amplifier includes a power transistor configured to amplify and output an input radio frequency (RF) signal; a first transistor including a first terminal that provides a bias current to the power transistor; and a second transistor including a first terminal connected to a control terminal of the first transistor and a control terminal connected to the first terminal of the first transistor. Herein, the second transistor is configured to sink a first current from the control terminal of the first transistor when an output current of the power transistor exceeds a threshold value.