Power amplifier circuit
A power amplifier circuit includes: a power splitter; a first amplifier; a second amplifier; a first balun that splits a first amplified signal into a third amplified signal and a fourth amplified signal having a different phase from the third amplified signal; a third amplifier and a fourth amplifier that respectively amplify the third amplified signal and the fourth amplified signal; a second balun that splits a second amplified signal into a fifth amplified signal and a sixth amplified signal having a different phase from the fifth amplified signal; a fifth amplifier that amplifies the fifth amplified signal if a power level of the fifth amplified signal is equal to or higher than a predetermined power level; and a sixth amplifier that amplifies the sixth amplified signal if a power level of the sixth amplified signal is equal to or higher than a predetermined power level.
1 . A power amplifier circuit comprising:
a power splitter configured to split an input signal into a first signal and a second signal having a different phase from the first signal;
a first amplifier configured to amplify the first signal and to output a first amplified signal;
a second amplifier configured to amplify the second signal and to output a second amplified signal;
a first balun configured to split the first amplified signal into a third amplified signal and a fourth amplified signal having a different phase from the third amplified signal;
a third amplifier configured to amplify the third amplified signal;
a fourth amplifier configured to amplify the fourth amplified signal;
a second balun configured to split the second amplified signal into a fifth amplified signal and a sixth amplified signal having a different phase from the fifth amplified signal;
a fifth amplifier configured to amplify the fifth amplified signal when a power level of the fifth amplified signal is equal to or greater than a first predetermined power level; and
a sixth amplifier configured to amplify the sixth amplified signal when a power level of the sixth amplified signal is equal to or greater than a second predetermined power level.
2 . The power amplifier circuit according to claim 1 ,
wherein the power amplifier circuit is on a single semiconductor substrate, and
wherein the first balun or the second balun comprises a terminal configured to externally connect the semiconductor substrate.
3 . The power amplifier circuit according to claim 1 ,
wherein the power splitter does not comprise a terminal grounded through a resistor.
4 . The power amplifier circuit according to claim 1 ,
wherein the power splitter comprises a terminal grounded through a resistor.
5 . The power amplifier circuit according to claim 4 , wherein the power splitter comprises:
a first inductor having a first end to which the input signal is supplied and a second end that supplies the first signal;
a second inductor electromagnetically coupled to the first inductor and having a first end that is the terminal, and a second end that supplies the second signal;
a first capacitor having a first end connected to the first end of the first inductor, and a second end connected to the first end of the second inductor; and
a second capacitor having a first end connected to the second end of the first inductor, and a second end connected to the second end of the second inductor.
6 . The power amplifier circuit according to claim 1 ,
wherein the first balun is on a semiconductor substrate and comprises a third capacitor, and
wherein the first balun is connected to an output terminal of the first amplifier and comprises a terminal configured to externally connect the semiconductor substrate through the third capacitor.
7 . The power amplifier circuit according to claim 1 ,
wherein the second balun is on a semiconductor substrate and comprises a fourth capacitor, and
wherein the second balun is connected to an output terminal of the second amplifier and comprises a terminal configured to externally connect the semiconductor substrate through the fourth capacitor.
8 . The power amplifier circuit according to claim 1 , further comprising:
a power combiner configured to combine amplified signals respectively output from the third amplifier, the fourth amplifier, the fifth amplifier, and the sixth amplifier,
wherein a first part of the power combiner comprises a semiconductor substrate, and second part of the power combiner comprises a module substrate.
9 . The power amplifier circuit according to claim 8 ,
wherein a part of the power combiner comprises a lumped constant circuit element, and
wherein at least a part of the lumped constant circuit element is a surface mount device mounted on the module substrate.