Power amplifier circuit
AssigneeMurata Manufacturing Co., Ltd.
InventorHideyuki Satou
Life of this patent
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Abstract
A power amplifier circuit includes a first transistor having a base supplied with an RF signal and a collector supplied with a variable power supply voltage corresponding to a level of the RF signal, the first transistor being configured to amplify the RF signal, a bias circuit including a second transistor that supplies a bias current to the base of the first transistor, and a bias adjustment circuit that decreases a current to be supplied from an emitter of the second transistor as the variable power supply voltage decreases, thereby decreasing the bias current to be supplied to the base of the first transistor.
Claims8
A power amplifier circuit comprising:
- a first transistor having a base supplied with a radio frequency (RF) signal and a collector supplied with a variable power supply voltage, wherein the variable power supply voltage corresponds to a level of the RF signal, and the first transistor is configured to amplify the RF signal;
- a bias circuit including a second transistor configured to supply a first current from an emitter of the second transistor, the first current including a bias current portion supplied to the base of the first transistor and an adjusted current portion supplied to a bias adjustment circuit;
- and
- the bias adjustment circuit configured to decrease the adjusted current portion as the variable power supply voltage decreases, thereby decreasing the bias current portion supplied to the base of the first transistor.
A power amplifier circuit comprising:
- a first transistor having a base supplied with a radio frequency (RF) signal and a collector supplied with a variable power supply voltage, wherein the variable power supply voltage corresponds to a level of the RF signal, and the first transistor is configured to amplify the RF signal;
- a first bias circuit including a second transistor configured to supply a first bias current to the base of the first transistor from an emitter of the second transistor;
- and
- a second bias circuit comprising a third transistor configured to supply a second bias current to the base of the first transistor from an emitter of the third transistor, wherein a voltage corresponding to the variable power supply voltage is supplied to a base of the second transistor.
Dependencies are inferred from the claim text.