Power amplifier

Abstract

A power amplifier, which includes a plurality of stages of amplification units each of which includes a common-emitter transistor, includes a first amplification unit including a first transistor configured to amplify an input radio-frequency signal, a second amplification unit including a second transistor configured to amplify an output of the first amplification unit, a voltage detection circuit including at least one impedance element and provided between the first transistor and the second transistor, and a protection circuit configured to reduce, based on an output of the voltage detection circuit, a base bias current applied to at least one of the first transistor and the second transistor.

Dependencies are inferred from the claim text.