POWER AMPLIFIER HAVING AN ADAPTIVE AMPLIFYING MECHANISM

摘要

By making use of two common-source amplifying units having a shared DC bias in conjunction with two current units or an extra amplifying unit, a power amplifier is capable of providing a high output power in a high power-gain operation and achieving a low power biasing consumption in a low power-gain operation. The two current units are utilized to provide auxiliary bias currents for diverting part of two bias currents corresponding to the shared DC bias for the two amplifying units so that the output power can be boosted in the high power-gain operation. Also, the extra amplifying unit can be coupled in series with the two amplifying units for improving the output power of the power amplifier in the high power-gain operation. The shared DC bias provides same bias current to the two amplifying units for achieving the low power biasing consumption in the low power-gain operation.