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High frequency power amplifier, transmitter and mobile communication terminal using the power amplifier

  • US 8,229,373 B2
  • Filed: 05/09/2006
  • Issued: 07/24/2012
  • Est. Priority Date: 05/11/2005
  • Status: Active Grant
First Claim
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1. A high frequency power amplifier for use in a high frequency mobile communication terminal, comprising:

  • at least one amplification stage that amplifies an input signal from a gain variable amplifier, wherein the at least one amplification stage includes an output amplification stage which comprises a transistor and constitutes a final stage of the at least one amplification stage;

    an output matching circuit that is connected to an output side of the final stage of the at least one amplification stage;

    a first detection unit that detects a voltage amplitude at a node between the transistor of the final stage of the at least one amplification stage and the output matching circuit, and outputs the voltage amplitude as a first signal of gain control information of the gain variable amplifier; and

    a supply voltage detector unit that detects a supply voltage being supplied to the final stage of the at least one amplification stage and outputs the supply voltage as a second signal of the gain control information of the gain variable amplifier,wherein the gain variable amplifier is controlled based on the gain control information so as to limit a gain of the gain variable amplifier upon the voltage amplitude exceeding a predetermined threshold voltage.

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