| 摘要 |
An RF(Radio Frequency) power detection circuit of a communication apparatus and a mobile communication terminal having the circuit are provided to detect the current of an RF signal amplified by plural log amplifiers, through Schottky diodes arrayed in multiple stages, thereby maintaining I-V linearity of the Schottky diodes within a broadband dynamic range even though a signal level of the inputted RF signal is low. The first capacitor(20) removes DC(Direct Current) components from an RF power signal inputted through an RF input terminal(10). In a current detector(30), Schottky diodes(31-35) are connected in multiple stages to detect a current from an AC(Alternating Current) signal from which the DC components are removed. In a log amplifier unit(40), log amplifiers(41-44) for amplifying the inputted RF signal are connected in multiple stages, and the amplifier unit(40) is connected so that output of the respective log amplifiers(41-44) can be inputted to the respective Schottky diodes(31-35). An I-V converter(50) converts the outputted current of the detector(30) into a voltage according to an I-V characteristic of the Schottky diodes(31-35), and outputs the voltage to a DC output terminal(80). A controller(90) controls whether operation for each of the log amplifiers(41-44) is conducted, so that an output characteristic of the converter(50) can contain linearity.
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