High frequency power amplifier circuit
First Claim
1. A high frequency power amplifier circuit comprising:
- a power amplifying circuit which amplifies a high frequency signal in accordance with an output power control voltage; and
an output power detection circuit which detects a level of an output power of the power amplifying circuit,wherein in a state where said output power control voltage is lower than a predetermined level, said output power detection circuit generates output voltage on the basis of the output power control voltage, and in a state where the output power control voltage is higher than the predetermined level, said output power detection circuit generates the output voltage on the basis of the level of the output power of the power amplifying circuit detected by said output power detection circuit.
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Accused Products
Abstract
The present invention provides a high frequency power amplifier circuit capable of obtaining sufficient detection output even in a range where a request output power level is low and performing a desired output power control by a control loop with the detection output in a radio communication system which detects output power and performs feedback control. An output power detection circuit which detects the level of output power on the basis of an AC signal supplied from a final amplification stage of a high frequency power amplification circuit via a capacitive element has a circuit configuration such that in a state where the output power control voltage is lower than a certain level, current (Isu) according to the output power control voltage is generated and supplied to the output power detection circuit, and detection sensitivity of the output power detection circuit improves according to the current.
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Citations
12 Claims
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1. A high frequency power amplifier circuit comprising:
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a power amplifying circuit which amplifies a high frequency signal in accordance with an output power control voltage; and an output power detection circuit which detects a level of an output power of the power amplifying circuit, wherein in a state where said output power control voltage is lower than a predetermined level, said output power detection circuit generates output voltage on the basis of the output power control voltage, and in a state where the output power control voltage is higher than the predetermined level, said output power detection circuit generates the output voltage on the basis of the level of the output power of the power amplifying circuit detected by said output power detection circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A high frequency power amplifier circuit comprising:
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a power amplifying circuit which includes an amplification transistor for amplifying an input high frequency signal and amplifies a high frequency signal in accordance with output power control voltage; an output power detection circuit which detects a level of an output power of the power amplifying circuit; and a bias circuit which gives bias voltage according to said output power control voltage to a control terminal of said amplification transistor, wherein in a state where said output power control voltage is lower than a predetermined level, said output power detection circuit generates an output voltage on the basis of the bias voltage at the control terminal of said amplification transistor, and in a state where said output power control voltage is higher than the predetermined level, said output power detection circuit generates the output voltage on the basis of the level of the output power of the power amplifying circuit detected by said output power detection circuit. - View Dependent Claims (9, 10, 11, 12)
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Specification