Patent ID: 7876159
Filing Date: 2011-01-25
Classification: H03F

Abstract:
1. A multi-frequency and multi-mode Doherty-type power amplifying circuit, comprising an input-signal processing unit, used to receive a radio frequency (RF) signal and to output a first signal and a second signal with equal or unequal powers; a first amplifier, having an input end coupled to the input-signal processing unit, and receiving the first signal to generate a first amplified signal, wherein the first amplifier further comprises a first transistor size adjusting unit that adjusts an equivalent transistor size according to a mode indication signal; second amplifier, having an input end coupled to the input-signal processing unit, and receiving the second signal to generate a second amplified signal, wherein the second amplifier further comprises a second transistor size adjusting unit that adjusts an equivalent transistor size according to the mode indication signal; and an output-signal processing unit, receiving the first and the second amplified signals, delaying a phase of the first amplified signal by 90 degrees and combining the phase-delayed first amplified signal and the second amplified signals, and then outputting an output signal.