A mobile communication terminal including a power amplifier configured to amplify a power of a received signal and wirelessly transmit the amplified signal through an antenna, a high power detector configured to determine whether the amplified power of the signal exceeds a particular critical range, a detected voltage level converter configured to convert a voltage corresponding to the output power exceeding the critical range into a voltage having a particular voltage level, and a varied driving voltage output unit configured to vary the converted voltage and apply the varied voltage to the power amplifier.