| 摘要 |
An object of the present invention is to allow the miniaturization of a mobile communication equipment and the reduction of consumption power, and to improve the electrical characteristics of a final stage amplifier. An inputted RF signal is amplified to a specified transmission output by a final stage amplifier, the output power and a reflected wave generated by mismatching between an output impedance of the final stage amplifier and a load impedance connected to an output side of the final stage amplifier are detected by a directional coupler. Two switches are selectively switched in a time division manner, a DC voltage corresponding to the reflected wave is selected, a comparator compares a threshold voltage with the DC voltage, a switch is switched by an output of the comparator outputted in accordance with the comparison, and gate voltages are selectively applied to the final stage amplifier. |
