Differential power amplifier

A differential power amplifier comprising:

• a plurality of differential amplifiers, comprising a first differential amplifier and a second differential amplifier;
• a first balun transformer configured to convert a balanced output signal of the first differential amplifier into a first unbalanced signal;
• a second balun transformer configured to convert a balanced output signal of the second differential amplifier into a second unbalanced signal;
• and
• a switch circuit that is configured to:
• in a first mode, directly connect an unbalanced output terminal of the first balun transformer and an unbalanced output terminal of the second balun transformer, and
• in a second mode, connect the unbalanced output terminal of the first balun transformer and the unbalanced output terminal of the second balun transformer with a capacitor interposed in between,
• wherein in the first mode, both the first differential amplifier and the second differential amplifier are configured to perform an amplification operation, and
• wherein in the second mode, the first differential amplifier is configured to perform an amplification operation, and the second differential amplifier is configured to not perform an amplification operation.