Power amplifying circuit
A power amplifying circuit includes a single-ended amplifier, a differential amplifier, a first balun transformer, a second balun transformer, and a first switching circuit. The single-ended amplifier operates in a first mode and a second mode different from the first mode. The differential amplifier operates in the second mode. The first balun transformer converts an unbalanced output signal from the single-ended amplifier into a differential signal and outputs the differential signal to the differential amplifier. The second balun transformer converts a balanced output signal from the differential amplifier into an unbalanced output signal. The first switching circuit outputs the unbalanced output signal from the single-ended amplifier in the first mode and outputs the unbalanced output signal from the second balun transformer in the second mode.
1. A power amplifying circuit comprising:
a single-ended amplifier configured to operate in a first mode and a second mode, the second mode being different from the first mode;
a differential amplifier configured to operate in the second mode;
a first balun transformer configured to convert an unbalanced output signal from the single-ended amplifier into a differential signal, and configured to output the differential signal to the differential amplifier;
a second balun transformer configured to convert a balanced output signal from the differential amplifier into an unbalanced output signal; and
a first switching circuit configured to selectively output the unbalanced output signal from the single-ended amplifier in the first mode, or the unbalanced output signal from the second balun transformer in the second mode.
2. The power amplifying circuit according to claim 1 , further comprising:
a first capacitor that is between the single-ended amplifier and a first end of an input-side winding of the first balun transformer; and
a second switching circuit configured to selectively connect a second end of the input-side winding of the first balun transformer to a reference potential in the second mode.
3. The power amplifying circuit according to claim 1 ,
wherein the single-ended amplifier is connected to a first end of an input-side winding of the first balun transformer, and
wherein a power supply voltage of the single-ended amplifier is supplied to a second end of the input-side winding of the first balun transformer.
4. The power amplifying circuit according to claim 2 , wherein the first switching circuit is configured to short-circuit an unbalanced-output path of the single-ended amplifier and an unbalanced-output path of the second balun transformer in the first mode.
5. The power amplifying circuit according to claim 3 , wherein the first switching circuit is configured to short-circuit an unbalanced-output path of the single-ended amplifier and an unbalanced-output path of the second balun transformer in the first mode.
6. The power amplifying circuit according to claim 4 , further comprising:
a second capacitor in the unbalanced-output path of the second balun transformer,
wherein a first end of the second capacitor is connected to a first end of an output-side winding of the second balun transformer, and a second end of the second capacitor is connected to a first end of the first switching circuit.
7. The power amplifying circuit according to claim 5 , further comprising:
a second capacitor in the unbalanced-output path of the second balun transformer,
wherein a first end of the second capacitor is connected to a first end of an output-side winding of the second balun transformer, and a second end of the second capacitor is connected to a first end of the first switching circuit.
8. The power amplifying circuit according to claim 1 , further comprising:
a third switching circuit configured to selectively connect an output of the first switching circuit to one of a plurality of output paths; and
a matching circuit that is between the first switching circuit and the third switching circuit.
9. The power amplifying circuit according to claim 8 , wherein the matching circuit is a variable matching circuit that is configured to adjust characteristics of the output signal from the first switching circuit.
10. A power amplifying circuit comprising:
a single-ended amplifier configured to operate in a first mode and a second mode, the second mode being different from the first mode;
a differential amplifier configured to operate in the second mode;
a first balun transformer configured to convert an unbalanced output signal from the single-ended amplifier into a differential signal, and configured to output the differential signal to the differential amplifier;
a second balun transformer configured to convert a balanced output signal from the differential amplifier into an unbalanced output signal; and
a first switching circuit configured to selectively output the unbalanced output signal from the single-ended amplifier in the first mode, and configured to output the unbalanced output signal from the second balun transformer in the second mode,
wherein the single-ended amplifier is connected to a first end of an input-side winding of the first balun transformer, and
wherein a power supply voltage of the single-ended amplifier is supplied to a second end of the input-side winding of the first balun transformer.