An apparatus for controlling a power amplifier configured to amplify radio frequency (RF) signal includes a detector and a controller. The detector is configured to detect a power level of the RF signal with respect to a predetermined power threshold and to generate a corresponding detection signal. The controller is configured to provide a control voltage to an output transistor of the amplifier based on the detection signal. The control voltage has a low voltage value, which is substantially the same as a value of a supply voltage, when the detection signal indicates that the power level is below the power threshold, and the control voltage has a high voltage value when the detection signal indicates that the power level is above the power threshold. The controller generates the high voltage value by boosting the supply voltage.