High frequency power amplifier circuit and radio communication system
First Claim
1. A high frequency power amplifier circuit, comprising:
- an output power detection circuit for receiving a signal from a power amplifier circuit for amplifying a high frequency signal to thereby detect output power of the power amplifier circuit;
a differential amplifier circuit for comparing a detection signal delivered from the output power detection circuit with a signal designating an output level to thereby output a signal according to a potential difference therebetween; and
a bias control circuit for providing the power amplifier circuit with a bias based on an output of the differential amplifier circuit, wherein the output power detection circuit is configured such that the signal from the input terminal or the output terminal of an output transistor of the power amplifier circuit is impressed on the input terminal thereof, comprising;
a detection transistor connected to a resistor between the output terminal and a power source voltage terminal; and
an operational power source voltage fed to the power source voltage terminal is set so as to be less in variation than an operational power source voltage fed to a power source voltage terminal of the power amplifier circuit.
1 Assignment
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Accused Products
Abstract
There is provided a high frequency power amplifier circuit capable of enhancing detection accuracy of an output level, necessary for feedback control of the high frequency power amplifier circuit, and capable of executing output power control with higher precision, With the high frequency power amplifier circuit, the detection of the output level, necessary for feedback control of the high frequency power amplifier circuit is executed by use of a current detection method, and in an electronic device comprising a differential amplifier for comparing an output power detection signal with an output level designation signal and for generating a signal for controlling a gain of the high frequency power amplifier circuit according to a potential difference between the two signals, a power source voltage with variation less than that for the power source voltage of the high frequency power amplifier circuit is used as the operational power source voltage of the output power detection circuit. Further, there is provided a capacitor across which an AC component is taken out from the output side of a power amplification transistor in the final amplification stage of the high frequency power amplifier circuit to be thereby impressed to the interior of the output power detection circuit.
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Citations
11 Claims
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1. A high frequency power amplifier circuit, comprising:
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an output power detection circuit for receiving a signal from a power amplifier circuit for amplifying a high frequency signal to thereby detect output power of the power amplifier circuit;
a differential amplifier circuit for comparing a detection signal delivered from the output power detection circuit with a signal designating an output level to thereby output a signal according to a potential difference therebetween; and
a bias control circuit for providing the power amplifier circuit with a bias based on an output of the differential amplifier circuit, wherein the output power detection circuit is configured such that the signal from the input terminal or the output terminal of an output transistor of the power amplifier circuit is impressed on the input terminal thereof, comprising;
a detection transistor connected to a resistor between the output terminal and a power source voltage terminal; and
an operational power source voltage fed to the power source voltage terminal is set so as to be less in variation than an operational power source voltage fed to a power source voltage terminal of the power amplifier circuit. - View Dependent Claims (6, 8, 9, 10, 11)
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2. A high frequency power amplifier circuit, comprising:
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an output power detection circuit for receiving a signal from a power amplifier circuit for amplifying a high frequency signal to thereby detect output power of the power amplifier circuit;
a differential amplifier circuit for comparing a detection signal delivered from the output power detection circuit with a signal designating an output level to thereby output a signal according to a potential difference therebetween; and
a bias control circuit for providing the power amplifier circuit with a bias based on an output of the differential amplifier circuit, wherein the output power detection circuit is configured such that the signal from the input terminal of an output transistor of the power amplifier circuit is impressed on the input terminal thereof, comprising;
a detection transistor connected to a resistor between the output terminal of the output transistor and a power source voltage terminal, wherein the signal from the output terminal of the output transistor of the power amplifier circuit is impressed on one of the terminals of the resistor via a capacitor, and wherein an operational power source voltage fed to the power source voltage terminal is set so as to be less in variation than an operational power source voltage fed to a power source voltage terminal of the power amplifier circuit.
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3. A high frequency power amplifier circuit, comprising:
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an output power detection circuit for receiving a signal from a power amplifier circuit for amplifying a high frequency signal to thereby detect output power of the power amplifier circuit;
a differential amplifier circuit for comparing a detection signal delivered from the output power detection circuit with a signal designating an output level to thereby output a signal according to a potential difference therebetween; and
a bias control circuit for providing the power amplifier circuit with a bias based on an output of the differential amplifier circuit, wherein the output power detection circuit is configured such that the signal from the input terminal of an output transistor of the power amplifier circuit is impressed on the input terminal thereof, comprising;
a first detection transistor connected to one of the terminals of a resistor between the output terminal of the output transistor and a power source voltage terminal; and
a second detection transistor with the input terminal on which the signal from the output terminal of the output transistor of the power amplifier circuit is impressed, having the output terminal connected to the other of the terminals of the resistor, and wherein an operational power source voltage fed to the power source voltage terminal is set so as to be less in variation than an operational power source voltage fed to a power source voltage terminal of the power amplifier circuit. - View Dependent Claims (4)
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5. A high frequency power amplifier circuit, comprising:
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an output power detection circuit for receiving a signal from a power amplifier circuit for amplifying a high frequency signal to thereby detect output power of the power amplifier circuit;
a differential amplifier circuit for comparing a detection signal delivered from the output power detection circuit with a signal designating an output level to thereby output a signal according to a potential difference therebetween; and
a bias control circuit for providing the power amplifier circuit with a bias based on an output of the differential amplifier circuit, wherein the output power detection circuit is configured such that the respective signals from the input terminal and the output terminal of an output transistor of the power amplifier circuit are impressed on the input terminal thereof, comprising;
a first detection transistor connected to a first transistor, as a constituent of a current mirror circuit, between the output terminal of the output transistor and a power source voltage terminal;
a second detection transistor with the input terminal on which the signal from the output terminal of the output transistor of the power amplifier circuit is impressed, having the output terminal connected to the output terminal of a second transistor, as a constituent of the current mirror circuit; and
current-voltage conversion means for converting output current of the current mirror circuit into voltage, and an operational power source voltage fed to the power source voltage terminal being set so as to be less in variation than an operational power source voltage fed to a power source voltage terminal of the power amplifier circuit. - View Dependent Claims (7)
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Specification