COMBINED NETWORK DEVICE FOR POWER AMPLIFIER CAPABLE OF SWITCHING ROUTE

摘要

PROBLEM TO BE SOLVED: To provide a power amplifier equipped with two or more power output devices capable of achieving the high power efficiency even in operating stages in several levels. SOLUTION: A first power output device 102 is designed for the efficient amplification of a power signal in the highest output power level of a power amplifier 100. A second power output device 104 is designed for the efficient amplification of the power signal at an output power level at which the power amplifier 100 is allowed to operate most easily. Either the first or second output power device is enabled according to the output power level. The combined network is used for switching an output impedance as necessary for the proper operation of the output device in the enable state. Thus, the switching of the power devices is operated according to the output power level so that the power efficiency in the high level can be realized across the wide range operating state of the power amplifier 100.