Patent ID: 9319003
Filing Date: 2016-04-19
CPC Classification: H03F

Claim Text:
1. An amplifier, comprising: a first operational signal path, arranged to generate a first pre-output signal according to an input signal under a first operating mode of the amplifier; a second operational signal path, arranged to generate a second pre-output signal according to the input signal under a second operating mode of the amplifier; and an output stage, coupled to the first operational signal path and the second operational signal path, for outputting a first output signal according to the first pre-output signal under the first operating mode and outputting a second output signal according to the second pre-output signal under the second operating mode; wherein the first operational signal path and the second operational signal path are arranged to share at least one common circuit element for generating the first pre-output signal and the second pre-output signal under the first operating mode and the second operating mode, respectively; and when the amplifier operates under the first operating mode, the first operational signal path comprises: a common circuit stage comprising an operational amplifier, arranged to use the operational amplifier to amplify the input signal for generating a first signal; and a modulating circuit, arranged to perform a modulation upon the first signal for generating the first pre-output signal; and when the amplifier operates under the second operating mode, the second operational signal path comprises: the common circuit stage comprising the operational amplifier, arranged to use the operational amplifier to amplify the input signal for generating a second signal; and a middle circuit stage, arranged to receive the second signal for generating the second pre-output signal.