Title: Automatic current reduction biasing technique for RF amplifier
Application Number: 200580011908 Application Date: 2005.04.05
Publication Number: 1961477 Publication Date: 2007.05.09
Approval Pub. Date: Granted Pub. Date:
International Classifi-cation: H03F3/24;H03G3/20
Applicant(s) Name: Sige Semiconductor Inc. Address:
Inventor(s) Name: Doherty Mark;Quaglietta Anthony;Yuen Gregory
Attorney & Agent: pengjia en
Abstract:
    A power amplifier (PA) circuit is disclosed that comprises a PA output stage having a first amplifying portion having a first gain portion and disposed in parallel with a second amplifying portion having a second gain portion, the PA output stage having an output stage gain, an input port for receiving of a RF input signal. A second RF power detector is provided for detecting a signal power of the RF input signal and for providing a second detected signal. An at least a biasing circuit is provided for biasing the first amplifying portion and the second amplifying portion in dependence upon the second detected signal for amplifying the RF input signal such that for the output stage gain the ratio between the first gain portion and the second gain portion varies in dependence upon the second detected signal.
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